Is a slower outer perimeter speed still meaningful? In the past we had printers with poor mechanics and with primitive software algorithms, therefore we used to print inner perimeters faster than the outermost one. See for example (generic, found online):

However now we have pressure/linear advance which reduces extra oozing/extrusion in corners or areas with variable speed, and in Klipper we also have resonance compensation which takes care of imperfect mechanics allowing printers to be pushed to higher acceleration without visible artifacts (in my case from 2000 to 6000 mm/s^2), see (generic) photo:

However printing slower has a clear disadvantage: E steps calibration is speed dependent with more filament being pushed out at lower speed, see

Is there any reason left to print outer perimeters at a lower speed? Using one speed only except for specific areas (small perimeters, bridges, support) seems to make more sense to me to improve quality and reduce printing times.

Lowering speed on outer perimeter has always been mostly wrong, but possibly useful. Usually, it's a poor approximation for what you really want to do, which is lowering acceleration on the outer perimeter, to avoid surface quality and dimensional accuracy errors due to ringing and backlash. However, on bowden printers without compensation for pressure ("linear advance" in Marlin, aka "pressure advance" in some other firmware), slow acceleration and high speeds give really bad error in extrusion consistency, so you're better off just lowering the max speed too whenever you lower acceleration.
It's also possible that you may want to print at extremely high speeds for inner walls and infill - speeds so high that you get a lot of extrusion consistency problems. If so, it would make sense to retain a sensible max speed on the outer wall. This won't avoid the part strength problems from printing too fast, but if your models are just decorative, it might be worth it.
Generally, though, I'd recommend solving these problems right (using linear advance if your printer needs it, lowering outer perimeter acceleration to get rid of artifacts, printing at a speed your hotend can handle, etc.) and deem "slower outer perimeter" an idea whose time has passed.
Also, note that if you're using a bowden printer without linear advance, sticking to the same speed for all extrusion will largely paper over the problem. This is probably the source of your observation that it "improves print quality" for you.

Thanks to Input Shaper, you can print faster, sometimes to the point of reaching your speed limit on the max nozzle flow speed. At that point, if all speeds are hitting that threshold without any changes in quality, you could print every part at the same maximum speed.


Printer thermistors read completely wrong after changing firmware I recently installed Marlin 1.1.9.1 onto my Creality CR-10S. After doing so, the temperatures for both the bed and hotend now read -14 °C. I have changed the setting in the Marlin configurations.h to several different thermistors, and it either reads 0 or -14 °C.
I have now installed several different versions of Marlin and with each one I experience the same problem.
Is there some tuning setting that I am missing or has installing the firmware somehow fried something on my board?

Okay, to anyone who is looking at this post, I am an idiot. I have spent the last 4 or more hours sifting through youtube videos and forum posts to figure out this problem. I have reinstalled firmware modifications dozens of times. All of this, to just now discover that I never had the bed or hotend cables connected. That's right, I never even considered the fact that I had yet to plug in those cables after transporting my printer to a new location.
Don't be like me. Check the simplest solutions first.

If all cabling is correct, you have most likely chosen the wrong thermosensor type. You need to put the correct temperature table for your thermosensor into your Firmware. As explained here, you need to set the number at the end of these lines to match what you have installed. The "standard" CR-10 should use the Sensor type 1: 100k/4.7 k EPCOS.
* :{ '0': "Not used", '1':"100k / 4.7k - EPCOS", '2':"200k / 4.7k - ATC Semitec 204GT-2", '3':"Mendel-parts / 4.7k", '4':"10k !! do not use for a hotend. Bad resolution at high temp. !!", '5':"100K / 4.7k - ATC Semitec 104GT-2 (Used in ParCan & J-Head)", '501':"100K Zonestar (Tronxy X3A)", '6':"100k / 4.7k EPCOS - Not as accurate as Table 1", '7':"100k / 4.7k Honeywell 135-104LAG-J01", '8':"100k / 4.7k 0603 SMD Vishay NTCS0603E3104FXT", '9':"100k / 4.7k GE Sensing AL03006-58.2K-97-G1", '10':"100k / 4.7k RS 198-961", '11':"100k / 4.7k beta 3950 1%", '12':"100k / 4.7k 0603 SMD Vishay NTCS0603E3104FXT (calibrated for Makibox hot bed)", '13':"100k Hisens 3950  1% up to 300°C for hotend 'Simple ONE ' & hotend 'All In ONE'", '20':"PT100 (Ultimainboard V2.x)", '51':"100k / 1k - EPCOS", '52':"200k / 1k - ATC Semitec 204GT-2", '55':"100k / 1k - ATC Semitec 104GT-2 (Used in ParCan & J-Head)", '60':"100k Maker's Tool Works Kapton Bed Thermistor beta=3950", '66':"Dyze Design 4.7M High Temperature thermistor", '70':"the 100K thermistor found in the bq Hephestos 2", '71':"100k / 4.7k Honeywell 135-104LAF-J01", '147':"Pt100 / 4.7k", '1047':"Pt1000 / 4.7k", '110':"Pt100 / 1k (non-standard)", '1010':"Pt1000 / 1k (non standard)", '-4':"Thermocouple + AD8495", '-3':"Thermocouple + MAX31855 (only for sensor 0)", '-2':"Thermocouple + MAX6675 (only for sensor 0)", '-1':"Thermocouple + AD595",'998':"Dummy 1", '999':"Dummy 2" }
*/
#define TEMP_SENSOR_0 1
[...]
#define TEMP_SENSOR_BED 1


Cura 2.4 missing "split object into parts" I have an stl with multiple parts that I want to split up. Cura 15 had an option to "split object into parts" but I can't find that in cura 2.4. Did it get removed?

I don't think this feature was implemented at all with Cura v2.x.

As the developers say on the v2.1 release, "Cura has been completely reengineered".

Finding proper changelog documentation appears to be pretty hard because they have not posted any actual changelogs except the "user friendly viewable" changelogs which only list additions of new features but don't display what everything they changed between each version of their application.

Here is the most complete changelog I could find. I do not see any mention of this feature. https://ultimaker.com/en/products/cura-software/release-notes

Going through the Cura 2 manual or the Cura 2.1 FAQ, also does not mention this feature.
https://ultimaker.com/en/resources/20406-installation-cura-2-1

Furthermore, searching around for version 2 "split objects" lead to forum posts of people suggesting to use some other software to achieve this specific task. If you decide to go this route, I recommend Meshmixer from Autodesk to manipulate your models and then export to STL and import them to Cura either as a whole new position set up or separate model files where you can change them there as you need to (meshmixer allows for object repositioning around a defined build plate so you can just import the whole assembly into cura and then print).

It might also be worth to put in a feature request on the UM forums.

You can split STL files in Cura 2.4
Just open your STL file in Cura and right click it.
Select "Split object into parts"


I can not really connect successfully to my printer via USB I have a Tronxy P802M (very similar to the Anet A8, but using a Melzi2.0V5 board) that seems to work fine (I just finished building, and axes movement and the integrated display work) but when I try to connect to the printer from my Simplify3D on Windows 10, I get the following:

[...]
  Connected to machine!
SENT: T0
READ: ok 0
READ: wait
SENT: M105
READ: ok 0
READ: T:24.44 /0 B:23.33 /0 B@:0 @:0
  Connection failed.

My other printers all connect fine.

The Simplify3D support site mentions to disable the "wait for startup command" option in the firmware configuration for S3D.

This allows me to make a rudimentary connection to control the printer, however e.g. during the bed levelling wizard of S3D, the connection still breaks off.

It works reliably with Octoprint. I'll consider that good enough.

Try changing your port in the control menu. By default, mine is set to COM 1 and I have to change it to COM 3.


What causes this "stringing" and can my print recover from this? Here's what it looks like

This is the model
thingiverse linky

It looks like it couldn't print the edge, but this happened many many hours after printing the brim.

This did not happen with my 1st attempt at this print. The last print lost adhesion and I had to scrap it. This time, adhesion looks good so not sure why this happened.

Printing with Monoprice Select V2 with ABS, sliced with Cura. 100C bed / 250C extruder. 15mm/s initial layer speed. 60 mm/s print speed.

Update
It looks like the printer is starting to smooth it out like so. Still not sure if this will lead to an ok print or will fail because of this layer.
And it seems the stringing area does not have a brim underneath it. Did Cura just not calculate the brim size correctly?

Update2
Here's a few screenshots from Cura to show that the model is lying completely flat.

I let the print go on overnight and here's where I stopped it

It almost seems like the print shifted completely after printing the initial layer. Have you ever seen anything like this or is there anything in my Cura model that would make it do this?

No, your problem is not related to slicing, this is a hardware problem. Your complete print has shifted, this is called layer shift.

This could happen when the nozzle hits an obstruction while printing while the Y stepper continues. This could lead to skipping teeth on the belts, slipping of the pulley or missing steps. This results in printing over air as the print progresses. This manifests itself as stringing, but in fact is unsupported printing (in the air). In this case it is unrecoverable as the printer has lost the reference frame, it just continues to print with the new reference frame caused by the layer shift.

A Prusa MK3, or any printerboard using trinamic stepper drivers would be able to recover (if the belt and pulley are correctly attached, and steps are missed) as the skipping of steps is detected, in case of a Prusa  MK3 the machine will re-home when it detects skipped steps and continue printing. See also this answer for more details.

Possible solutions are increasing the belt tension, increase the stepper torque by increasing the current through the stepper drivers or re-tighten the pulley on the stepper of the Y belt.

There are many problems caused with this. It could be a faulty motors, an unlevel bed, a dirty nozzle, or even something as simple as using the wrong filament settings. It would be best to go through a checklist of things that might be wrong with your printer. It could also just be caused by the wear and tear of a  really old printer.


Can't connect Cura to my Anet A8 on OSX 10.11.6 I finished the mount of my Anet A8, tested everything and apparently it was ok. I installed the driver that came with it, CH341SER_MAC, turned on the printer, connect USB cable, but nothing happened.

In Cura, I tried to add a printer many times and this message always appears

  The printer isn't connected.

In OSX, I discover in System Information, an USB2.0-Serial, that I think can be the printer.  Is it a printer driver problem? Is it the Cura setting? I'm completely lost...

There are a lot of problems with the CH340 chipset drivers to be found on 3D SE and various forums on the internet. To use this cheap CH340 chip that is used by a number of Arduino compatible (clone) boards to provide USB connectivity (a USB bus converter chip that converts USB bus signals to serial interface) you need to install a correct working driver.

For Mac OS X you can try to download a working version for the OS system you are using. You can try to use this driver installer or this driver installer. Both reported to work with Mac OS.

Edit: If you are using OSX El Capitan, please read this. To  get the CH340 drivers to work you need to use the tool csrutil.

  Reboot and press CMD+R immediately after hearing the startup sound to boot to Recovery Mode
  Open Terminal
  Execute the following command: csrutil enable --without kext
  Reboot

More information is found here!

What Cura version do you have?
Cura only works with the Anet A8 via USB on versions 2.3 and lower according to this page. The page is from thingiverse(A 3d printing forum + print files page)


Why is Print Adhesion almost good, but still not right? It feels like my print is almost there, I spent a long time fine tuning the calibration with a fantastic set of G-code files from Chuck Hellebuyck.

I am using an Ender 3, on which I have modified the heatbed to carry a glass sheet, otherwise factory standard. The prints are done on the bare glass. When I printed a window some 14 feet (~4.5 meters) away was open to the cold New York winter. The cooling fan on the Ender 3 is mounted on the right side of the hotend and uses a simple declector, it can be seen in picture 2.

However, my print is not perfect yet. I'm using 1.75  mm PLA at a temperature of 200 °C for the 0.4 mm nozzle and a bed temperature of 60 °C. Out of the 4 corners, 3 printed perfectly, the back-left one did lift.

What do I need to do to fix the bed adhesion issue?

Based on the pictures, this looks like the bed wasn't clean enough, thus why it didn't adhere correctly in some spots. The lifted corner is the worst, but I can see a couple more spots where the PLA didn't stick well enough, though the brim prevented it to completely lift off the bed.

I would advise you to not print with the window open, even if it's only slightly ajar. Weather conditions and temperature will affect the quality of the print, even if it's only a small variation in temperature. I've had enough failed prints due to a shift in temperature to know that, even though PLA isn't affected as much than ABS by temperature changes through a print.

You might also try to increase the bed temperature a bit, up to 70°C or 80°C. I've looked at the recommended temperature for PLA with my UM3E and it says 80°C for the glass bed.

You should always make sure that the glass bed is clean: ie no dust on it and no grease. Yes, touching it with your fingers will leave a thin greasy residue in the form of fingerprints, and even one fingerprint can prevent good adhesion and result in the problem you had.

There are various products to clean glass beds, I've personally found out that the cheap yellow-colored window cleaner from Karcher works wonder. Do not use the standard blue colored window cleaner products: the blue one has a chemical in it that is made with the express intent to prevent anything to adhere to the glass, which is obviously not what we want. The yellow-colored cleaner doesn't have that chemical, and it cleans without depositing an anti-adhesion film on the glass.

If a thorough cleaning isn't sufficient, you can look into various adhesive products. While there is quite a lot of adhesive solutions marketed as being specifically for 3D printing, with insane prices most of the time, I've found that a simple UHU glue stick works wonders. I usually do not need glue when printing PLA, but I use it for Nylon, ABS and other filament that absolutely require it and it's a breeze to work with, and it cleans easily with soap and warm water.

I work with a glass surface on my machine and use a drop of superglue to attach the
corners after the first layer is complete. The biggest contributors to not sticking are :

Bed not level.
Temperature of filament not hot enough.
First layer print speed is too fast.
Heated Bed not hot enough to compensate for cold room. Try enclosing print area.
Head is snagging on print edges (no retraction when moving) and ripping print loose.
Print bed surface is not clean. Use acetone or ammonia for cleaning glass. Alcohol leaves an oily residue.

If you are printing on painters tape, make sure the bed is very clean when you put the tape
down. Then make sure you rub the tape down well so it doesn't pull off of the print bed
surface during printing. Then clean the tape surface to get the oil from your hands off of
the tape.

I use Glass Build Plate Wizard spray for delicate prints and a heated bed. It releases after the print plate cools down. That eliminates the need to chip the print loose. It releases itself after a few minutes.


Whats the difference between a basic rapid prototyping machine and a 3D printer? In general 3D printers are compact and smaller than RP machines. That's ok. But, what's the difference? 3D printers can be used as RP machine too.

All rapid prototyping means is automatically producing a physical part from a cad model. 3D printing is a way to achieve rapid prototyping. There are 2 main methods of rapid prototyping: additive, and subtractive.

A 3D printer is additive- you add materials to an object layer by layer.

Usually, when people talk about a subtractive machine, they are talking about a CNC mill (or lathe), which tend to be extremely large (most are over one ton). You start with all the material there, and you subtract the material that you don't want. This might be what you are thinking of.

A sintered metal printer is a version of a 3D printer that is rapid, but expensive. Seen 1 for 800,000$aud
Uses laser to melt metal particles like titanium.


Speeding up the heating of the heated bed Currently I am using a 12 volts, 20 amperes power supply (Model S-240-12)

The stepper motors and the extruder need 5 amp, and the heated bed build plate needs 11 amp.

Technically you only need to use a 12 Volts, 16 amperes power supply, but I understand that you use the one with 20 amp because pulse currents from extruders and stepper motors can be stressful to supplies loaded to the max, so for reliability and performance, it is better to use a supply rated for 25% more than you need

In the place where I buy the spare parts for my 3d printer they also sell 12 V power supplies capable of delivering 25 amp and 30 amp and they told me that if I use those ones you are going to be able to speed up the heating of the heated bed. Is that true? I understand that the heated bed is only going to take the 11 amp that it needs so is not going to make any difference to use power supplies capable of delivering more current

Changing the PSU with one with a higher amperage will not make the bed heat up any faster unless the PSU is underrated for the amperage required and the voltage is dropping as a result of the load. This can be checked by measuring the output voltage with a multimeter (when the PSU is loaded e.g. by a heating heat bed). In this case, the PSU has a marginal higher Amperage than the printer consumes (even has some room for the over-voltage; under the assumption that it is a good working PSU). Increasing the voltage will decrease the heat up time. There is a screw next to the 12 V connectors that can change the output voltage of the PSU. Usually, it is safe to increase the voltage up to 14 V, but that depends on your whole setup (and 14 V is applied to the whole setup, increasing the current for all parts, including your printer controller board, this board must be rated for the 14 V).  Please do check the stability of the voltage during load.
Although it can be done, it is not something I used. What is an extra minute on a print of several hours?
You can do the math: say the heat bed has a resistance of 1.2 Ω. We only need two formulas:

$U=R\times I$ - potential Difference U is Resistance R times Current I
$P=U\times I=I^2\times R=\frac {U^2} R$. The power P of an item the potential difference times the current through the item.

at 12 V that will draw 10 Amps (12 V / 1.2 Ω) resulting in a 120 Watt bed: $P= 12^2 \text V \times 10^2 \text A= {10^2 \text A}\times {1.2\ \Omega}=\frac{12^2 \text V} {1.2\ \Omega} $),
at 14 V that same bed will draw 11.7 Amps (14 V / 1.2 Ω) resulting in a 163.3 Watt bed.

Use at your own risk!
What you could do to decrease time to heat the bed without changing the PSU or the voltage is to insulate the bottom of the heat bed with heat bed cotton sheets or cork (placemats from IKEA ;) ), put a sheet of cork onto the heat bed before printing and start heating the bed through the LCD panel of the printer or any attached printer controller programs over USB prior to printing.

I hate to sound like the Toolman Tayler from that old TV show. "But, it comes down to More Power!"
Power is the ability to do work (move a mass certain distance) within certain amount of time.
Power =  mass x distance x Time.
It can also be expressed in electrical terms, as the ability to heat something within certain amount of time.
Power = Voltage x Current
Since most systems have a fixed voltage, it is still possible to increase power by increasing the current, since,
Voltage = Resistance x Current,
And Power = Voltage x Current,
So, Power =  (Resistance x Current) x Current.
So by switching a power supply with the same voltage, but higher current, it will provide additional power to the system. The larger current available would be able to flow through the heating elements, heating them up faster.
However the caveat will be the amount of heat dissipation in the system, the large surface of the bed, will carry away enough of the heat due to air convection, that it may not make much of a difference. Or perhaps the heating element may not handle the larger amount of current and burn out.
It would be worth testing it out, in my humble opinion. Hopefully without causing a fire somewhere. :-)


Which software do I need to start print something? I'm still new to 3D printing and I want to print something. I expect that I'll mess it up since I find nothing to adjust it but it is now laying around for 4 months and I'm sick of it.

So my question is where do I find Windows software to print something and of course where do I get a 3D model?

I own a Geeetech i3 Pro W.

First; find a model!
To print something you require a model (usually this is in STL format, look into websites called Thingiverse and MyMiniFactory for examples). Once you have a model file, you need to make it readable for the printer firmware.
If you can't find suitable model, then you need to design a model yourself (or ask someone to do it for you) or adjust an existing model to suit your needs. "Good (preferably free) Beginner Software for Part Creation?" is a good place to start.
Second; use slicer software
For a printer to be able to print the model, the model needs to be sliced into layers. These layers need to be printed at specific speeds, temperatures, etc. Search online and look at the filament packaging (usually the ideal temperatures are on the packaging) to find the ideal temperature for your filament. If you are not using the right temperatures, your print will most likely fail. Programs that are able to slice models are called slicers. The most popular free (and Windows compatible) slicers are Ultimaker Cura and Slic3r (or its Prusa distribution).
The slicer produces a printer readable file called a G-code file (file filled with printer instructions for e.g. movement and heating). This G-code file can be sent to the printer using specific printer software (e.g. OctoPrint, Repetier-Host, etc.) but more common or simple is to put the G-code file on an SD card and print the file using the print menu on the printer LCD.

If you're just starting out then Tinkercad (website) is a good place to start designing your own objects. Later you can get to grips with OpenScad for more complex shapes. Both are free.


XYZ calibration without PINDA probe I have been happily printing with my Original Prusa i3 MK2S for a few weeks now. I have been thinking about replacing the PINDA probe with a BLTouch tactile sensor.

If I do so, how will I be able to do the XYZ calibration? I believe that the tactile sensor would only be able to do Z calibration. If I need to redo the XYZ calibration in the future for some reason, is it possible to do manually? Or would I need to remount an extruder with a PINDA probe temporarily?

If you want to replace the PINDA probe (whatever reason for) then you can go with the BLTouch Sensor but only for certain operations.

It will be good for leveling the bed before printing because here, only the bed level is important and not the skew of the bed.

If it comes to calibration of the skew itself, the BLTouch Sensor will not be usable because the PINDA Probe detects the boundaries of the copper circles on the print bed. The BLTouch cannot detect these copper areas.

The PINDA Probe is a proximity sensor.

If you want to do a recalibration you have to mount the PINDA again.

Therefore, it is possible but not recommended.


E3D V6 nozzle vs MK8 nozzle, first layer adhesion Does anyone notice that when they upgrade from an MK8Makerbot(?) to a E3D V6 hotend that when using the same settings and bed-leveling/z-distance-setting procedures, that the filament is much more likely to be pulled up and bunch up around the nozzle while printing the first layer?

It occurs mostly when printing small details, such as 3 mm bolt holes, and not so much when laying down long lines.

Is this due to the shape of the nozzle, which on the V6 is much more flat when compared to the MK8 which is more sharp, or is it due to something else that can be easily fixed?

When filament curls up this generally means that there is some sort of obstruction or burned material in the nozzle causing uneven flow. You can use the Atomic Method from this answer.

Being a new nozzle, I would expect that this is not the case, so that it should just drop out of the nozzle and not curl up. It could be that the nozzle is not perfectly machined and a defect in the geometry is causing this. You could try to replace the nozzle with another nozzle. They are pretty cheap, you should buy a few extra.

As far as why the filament sticks easier to the E3D nozzle when it curls up, is that this nozzle has a (hexagonal) flange that sticks out, while the other nozzle does not have such a flange. If it curls up, it has a larger probability to hit the flange and stick to the outside of the nozzle than a nozzle that has no such flange.

Turns out this can be fixed by increasing the bed temp to 65-70 °C and of course increasing the extruder temp by 30 °C or so, which is standard for the all metal hotends (no idea why)


Can model used for 3D printing be later used for mold mass production? I am working on a project that requires an enclosure that I am thinking to prototype using a 3D printer (which is pretty easy and overall awesome).

My question is simply whether this same model can be used later on for mass production (i.e. mold injection)? What adjustment (if any) need to be done to model between prototype and mass.prod. stages? What areas in design to look out for that can make model viable for 3D printing non-viable for mass production?

I respectfully disagree with the hard no answer.  There are many casting methods, some of which are not compatible with 3D printed parts and at least one that definitely is.  See investment casting, aka lost wax casting.  (Ref 1)  Also search YouTube for "investment casting using 3D printing".  Formlabs, the company that makes the Form 2 and Form 3 3D printers, sells a 3d printable resin specifically for investment casting. (Ref 2).

There is a whole world of casting, so I will describe, as an example, a very simple process that will make a replica of your 3D printed part.  I will briefly address the steps necessary for making multiple copies at the end of my answer.  First you need to add a cylindrical extension to the shape that will create a sprue.  See the two models shown in the image below.  Next make a foil cup a little larger than your 3D printed part and place your part in the cup, suspended by the sprue.  Pour liquid plaster of Paris (POP) into the cup, covering the 3D printed part, with just the top of the sprue sticking out.  Once the POP has hardened, you can remove the 3D printed part by dissolving it in an organic solvent (acetone for acrylic) or by heating the part to several hundred degrees C so it will burn out (convert to gasses).  You will now have a block of POP with a void shaped like your 3D printed part plus a cylindrical hole to the outside that acts as a sprue.  Once you have heated the POP to drive out any remaining water, you're ready to cast.  Fill the void (via the sprue hole) with, for example, copper powder and heat it to well above its melting point.  Once everything has cooled, lightly tap the POP with a small hammer or equivalent, to remove it, leaving your final part plus the sprue.   You can remove any remaining POP with some warm baking soda and patience.  The final step is to cut or saw off the sprue shape.

Please understand that the process described above is just to give you a basic idea of the process.  There are many alternate or additional steps that may produce a better final product.  Also, the process described should work of the rook model shown on the left of the image below, but not the model on the right, which has a small hole through the middle.  There are ways to solve that issue, but as I said before, there is a whole world of this stuff.

Casting is a way to create parts out of materials that you otherwise could not 3D print directly (on a home budget).  For mass production, you would need to start with an inverse of the final shape.  For example, a cylindrical slug with a rook-shaped void.  Then you would use the investment casting process to create a mold out of a rigid material that you could use to, for example, create rubber copies of the original part that could, in turn, be used as the "wax" for copies in the final material.

I urge you to experiment, maybe following one of the tutorials on YouTube.  Good luck.

Ref 1 - Investment Casting
https://en.wikipedia.org/wiki/Investment_casting

Ref 2 - FormLabs 3D printable casting resin
https://support.formlabs.com/s/article/Using-Castable-Resin?language=en_US

That's a hard No.

Models used in industrial injection molding are very specific to the process sometimes even the machine. When they build those molds they have to include constructs like spurs and runners; things to get the molten plastic to where it needs to go. Further the wall thickness of an injection molded part can only be so thick, because the plastic will contract when cooled, which will distort the final part if it is too thick.


What could be causing my y axis to slip? Occasionally, while printing, my y axis will slip and the layer will, from that point forward, be shifted, ruining the print.

What might be the causes of an axis slipping? I have tried cooling the motor which seemed to have been getting warm, and the belts are not too tight.

This does not happen with every print, and seems to be an intermittent problem.

My printer is a MendelMax RepRap, and the y axis is my moving bed.

(source: all3dp.com)
Your printer is skipping steps in the y-direction. This can have several causes. Take a look into Shifted layer guide on RapRap.org which lists 29 possible problems that can cause this issue and how to fix them.
First items of the list:

Driver current is too low
Driver current is too high
Belt too Loose
Belt too Tight
Loose Set Screw/Grub Screw
Belt or Bearing is binding
Speeds are too high
Acceleration is too high
...

When I was dealing with this issue on my RepRap I had to increase current to the particular driver.

My Y axis runs on a channel and I believe there was some grit or metal flakes in the channel left over from manufacturing. The wheels in the channel got stuck on the debris and caused the belt to slip. It made a horrible grinding noise when this happened.

So I blew out the channel with pressurized air and tested all the wheels.

I'll update if necessary as I test my fix with longer (taller) prints.

Update

Actually, the print had messed up g-code. The gcode file was corrupted.


Delta Printer: Slighty incorrect print alignment on the build plate After building a Delta printer, I noticed that my whole prints are slightly tilted around the Z-axis in comparison to the slicer (e.g. Cura). There is no twist layer wise. This means, the prints themself look actually perfect.

I just don't know what could be the reason of the rotation. I do not believe it is a build issue of the printer, because I tried to keep the printer frame pretty stiff and symmetric.
Could it be, that the Auto-Calibrate Feature of Marlin can add such a rotation?

The picture below illustrates the problem. I expect the black alignment of the print and get the orange one. Note that the print is still a rectangle with ~90° corners.

I figured out that the reason is probably a slightly translated slider construction. Instead of using a proper centered slider as shown in red, I used a slider construction like illustrated in yellow. When all sliders are translated on each tower like this, the print should be tilted by the same amount. This seems to have no influence on the general shape of the object. However, for my next printer I will use a proper centered uni-body slider.

If I am reading this correctly, your prints are being either stretched or your prints are shifting / leaning on more complicated prints.

In this case, given that you are on a Delta printer, my answer is the same for all. I usually do Cartesian based 3d printing but the concept is the same for any drifting or leaning. You simply need to recalibrate your steps per MM for each motor, and tighten your belts. You will have the complication of the interaction of the 3 arms, that others will be able to answer better. But in the end, if each arm moves as it should, the belts are not slipping, and you do not have issues with moving too fast (jerking can cause the belt to shift, and a loose belt can cause whiplash / and other print artifacts). My bet is your steps per MM is off on one of the motors, or you could have an overheating issue (not likely).

There are many guides to help with Delta specific calibration.

I can provide a better answer with photos. See Stackoverflows guide on asking questions.

Edit with the diagram (not a photo), you issue might be caused by stepper over voltage and you will need to adjust your pololus. If you hear a repeating Thud noise, you have your voltage too high.


Can 3D printers print details in the 1/10 of the micrometer for metals? I'm starting to get familiar with 3D printers. I wish to know if printing details the size of 10-7 m (3.9*10-6 in) is possible these days with metals or any other material.

If anyone has information or articles as leads, I would really appreciate it.

You can get the 0.1 micron (100 nm) resolution with a 2-photon 3D printer, but only in a polymer resin.  Nanoscribe, in Germany, pioneered this technology, see Mechanical Microstructures.

Their commercial printer, the Photonic Professional GT, is about $350,000 US with software and accessories. There is some work being done to replicate the 3D printed polymer in metal using electroless plating or ALD (atomic layer deposition).  Other techniques are in development.

None of the direct metal 3D printing processes come close to your 0.1 micron resolution, although the field is rapidly evolving.  Only a couple of years ago, direct metal 3D printing was all based on powder bed fusion.  Now binder jet technology as been adapted to metals and, very recently, Xjet has developed a nanoparticle 3D printer. It prints "ink" composed of metal or ceramic nanoparticles suspended in a liquid.  The minimum layer thickness is 1 to 2 microns.  They have not released XY resolution data yet.

A good overall reference for the various 3D printing techniques (including Xjet, but not Nanoscribe) can be found at Explaining The Future - 3D Printing.

Today, only SLA/DLP will give features of that size (if even these technologies do), and I am unaware of anyone using these technologies to print with metals today.


ABS Filament safety concerns I have the XYZPrinting da-Vinci-1.0 with ABS filament. I am concerned about ventilation. If this is used inside, what safety precautions are necessary, which are recommended, and/or which are optional?

Yes... The issue with all 3d printing materials. Not just ABS, but worse with ABS is the fine air particulate and Ultra fine it creates during the 3d printing process. PLA is considered safer than ABS. But I fear people will use this as justification, it is like saying I only smoke one cig a day instead of two so I am safe and healthy. No it really should be taken seriously.

There are a number of scientific papers and articles proving that this is an issue. Specifically that 3d printers release ultra fine particles into the air. Which can damage the lungs over time. I would STRONGLY advise not using a 3d printer around children, or at least putting it in the garage where you will not contaminate your homes air supply.

I.E.

http://www.sciencedirect.com/science/article/pii/S1352231013005086
http://built-envi.com/portfolio/ultrafine-particle-emissions-from-3d-printers/
https://www.ncbi.nlm.nih.gov/pubmed/11139166
http://www.3ders.org/articles/20160201-new-study-shows-health-hazards-of-3d-printing-suggests-pla-could-be-your-safest-bet.html

Lot of these have some scary looking graphs. Note that I am being a bit sarcastic when I say "scary looking graphs" the take away is ABS has twice the Fine Partical emission as PLA. However should you be worried, is still up to debate. The idea is that FPE can maybe contribute to cancer or other illnesses. FPEs are thought to irritate the lungs.

These graphs are of the ultra fine particle emissions.

as you can see PLA is MUCH safer in this regard.

I cannot find the paper at the moment, but the recommendation is a full air cycle several times an hour. As someone that lives in a Cold state I personally just use PLA and am rolling the dice.

There is another SO where I cover my future plans for an air scrubber.

I will note that other materials such as Polycarbonate should just be plain avoided.

I also want to provide these links on WHY ultra fine particles are bad. In summary they really upset your lungs and are thought to cause lung cancer over time.

Wikipedia on Ultra fine particulates.
White paper on ultra fine particulates.

your fine at practical temperatures.
source: https://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene#Hazard_for_humans

recommended would probably be set your controller to not go above 380c if your really worried. but it's not needed.


When to use 1.75 mm vs 3 mm filament? Why do we have two standard filament sizes, 1.75 mm and 3 mm? Does it really make a difference when printing? Or is the 1.75 mm just for smaller printers?

In what situations should I be using 1.75 mm?

When should I be using 3 mm?

There's no appreciable difference. Just use the filament that fits your particular printer.

If you don't yet have a printer, then I'd get one that uses 1.75 mm filament:

1.75 mm is increasingly becoming the "standard", thus being easier to get. Some filaments are not available as 3 mm.
1.75 mm filament allows for finer control, because feeding in 1 mm of filament corresponds to less plastic extruded.
1.75 mm filament requires less force to extrude. Compressing 1.75 mm down to 0.3 mm takes less force than doing the same to 3 mm filament.

However, the advantages are fairly minor. I don't see any reason to replace a functioning 3 mm extruder with a 1.75 mm one (yet).

I agree with all the answers above but only would  like to add if you want to build a very large printer using 0.8 mm or 1.2 mm nozzle, i would advice to go 3 mm. 1.75 mm filament then just can't be fed in fast enough.


Will this MOSFET allow the heat bed to run at a different voltage than the control board I am currently running my Tronxy X5s with a MKS Gen L board. So far I have not ran the heat bed over 50 degrees C since I have only printed with PLA so far. I plan to try PETG and/or ABS in the near future and I have a spare power supply 12V/360W laying around.

When I first got my printer I purchased this external MOSFET board after reading about X5s "upgrades", but so far have not used it.

My plan is to now run the heat bed using a separate power supply than the one running my control board using the external MOSFET to switch it. Since this power supply will only be powering the bed, I would like to bump up the voltage, via trim-pot somewhere from 12V-15V, to gain some watts per square inch on my heat bed.

Will this MOSFET isolate the heat bed circuit from my control board to allow it be ran at a higher voltage? Is it safe to run the power supply/heat bed at a higher voltage than it is rated for a significant amount of time?

Short answer YES. You can run it from a different power supply at a higher voltage. Also it has a PC817 Optical isolator (for some reason) therefore the second power supply and your main board should not be electrically connected at all.

For reference,I done tracing this module as shown.

So you can use isolated power supply for load.
Also you can use up to 24V without any problem.
Edit:
This module still work with higher voltage up to 24V. But according to question. Using higher voltage supply more than rated is same as my question here.
For summary. Adding more voltage to resistive load results to higher current flow. Recheck your wire and connectors for current rate so you will know the limit of voltage you can go with.
One more thing, mosfet can fail like short circuit. At this situation the temperature of bed cannot be controlled.
At normal voltage rate even we left the bed connected to power supply the temperature will rising to about 100C if you add more voltage it will go higher than that can the heated bed will broken or burned or start to fires


Changing the home position on a Prusa i3 MK2 As part of a project with my university, I have developed a new extruder to attach to a Prusa i3 MK2. My problem is that both the nozzle and PINDA probe have moved 17mm forward and 0.5mm to the right. As a result when I try and calibrate the printer it moves to the home position and the PINDA probe is too far out over the heatbed so it doesn't detect the printing surface. What is the simplest method of moving the home position so that the printer can be properly calibrated?

UPDATE:
I am planning on removing the heatbed and placing spacers that will move the printing surface 17mm forward. This should then prevent the printer losing any printing area and hopefully prevents me having to edit any code. Can anyone see any problems with this I'm overlooking?

The simplest thing to do would be to move extruder 17mm closer to be the same as the original printer but my deadline is fast approaching and I haven't time for a redesign that large.

Consider the original installation with the orientation of the Pinda probe to the nozzle. Let's say for argument's sake that the Pinda probe is 3 mm to the right and directly in line with the nozzle on the y axis.
If you examine your new nozzle, I would expect that the relationship of the nozzle to the Pinda probe no longer matches the original spacing.
If possible, re-design the mount to place the Pinda probe in such a way as to match the original design.
Thanks for pointing out my oversight, Mac. If the relative position of the nozzle and pinda probe are as the original, the solution is then in changing the appropriate parameters in the firmware.
I found a reference for someone who had a bit smaller error in home position, but the concept is the same.
The link above points to information reading thus:

In Configuration_Prusa.h:
Code: Select all // Home position
define MANUAL_X_HOME_POS 0
define MANUAL_Y_HOME_POS -2.2
define MANUAL_Z_HOME_POS 0.15
// Travel limits after homing
define X_MAX_POS 250
define X_MIN_POS 0
define Y_MAX_POS 210
define Y_MIN_POS -2.2
define Z_MAX_POS 210
define Z_MIN_POS 0.15

it will be necessary to connect the printer via USB to a computer running an Arduino IDE and to load the Prusa specific files for that printer. Edit the noted location, save/write the configuration and test.
I would suggest small adjustments in only one or two parameters at a time, to avoid ambiguity in the cause/result sequence.

What is the simplest method of moving the home position...

I think the solution outline by @fred_dot_u is very elegant, so I would go with it.

  ...so that the printer can be properly calibrated?

I'm not sure that will be possible.

Because the physical lenght of the axis hasn't changed, by moving the nozzle/probe, you have actually reduced their reach in the opposite direction, so the probe may be unable to travel on top of the intended calibration points (the usable printing area has also shrunk, but that's less of a problem).

If that is the case, I can't think of an easy solution (bar not using the auto-calibration feature altogether).


Best material for compression? I'm designing a mount for a cylindrical speaker to attach to my bicycle. It will mount on the bottle cages. I've printed a few iterations with various infill settings (using PLA) and the weak point is always the bolts holding the entire mount to the bike. They can't handle the compression needed to secure it properly. I had thought about using an imbedded metal part to distribute the load, but it's not easily replicable and I want to make the design public and fairly accessible to others with the same speaker. I currently have PETG and ABS, would one of those perform better or should I order a specialty high strength polymer?

Infill has minimal effect on the strength of printed parts, so I would expect the part to break in the same spot regardless of what infill percentage you used.
PLA is especially poor in this exact application, and it undergoes significant creep/cold flow under mechanical compression over time, so even if achieved the necessary strength by changing settings (which you can), it would require that you periodically tighten the bolts more and more, as the PLA would slowly deform under the mounting pressure.

Perimeter width and number of perimeters are what primarily influence the strength of a printed object, infill has very little impact on strength in comparison, and unless you're using an exotic pattern like gyroid, what impact it does have is not even close to isotropic (will add strength in some directions while doing nothing in others).  But even then, infill only really has an effect when we are talking about forces that are spread evenly over the entire object, not concentrated strength of a specific spot of the part.  And that effect is always much weaker than what perimeter count or width will have.

Just bump up your perimeters to 4 or even more and that should make a huge difference.

And also, don't use PLA.  I think PETG is a much better choice in this situation.  It is more ductile only slightly less rigid than PLA, making it much more durable overall than PLA, and less prone to cracking under compressive forces.  PLA theoretically has higher tensile strength, but that often doesn't mean much.

I would not recommend ABS, it tends to have similar issues with brittleness and is one of the weaker materials one can 3D print.

It terms of ordering a special high strength polymer.... unless printer and hotend is rated for in excess of 400°C, no such 'high strength polymer' exists, at least not that you can print.  PLA and PETG are close to the best you can get, with Polycarbonate inching out ahead but not by a huge amount (~20%).  Despite what filament companies would like you to believe, carbon fiber reduces the strength of PLA, ABS, PETG, PC, and probably nylon, and instead simply makes those polymers more rigid and increases dimensional stability.  The only filaments that would actually be made stronger with added fibers short enough for filament manufacturing processes are ones with glass fiber.  But you don't want to print those filaments, trust me.  They will dull the teeth on your hobbed gear(s), even if made from steel, and will just ruin all but ruby nozzles very very quickly.  And they still wear out ruby nozzles even then.

There are exotic polymers, but none of them print at less than ~350°C, and are generally exceedingly expensive.  All the polymers that can be used at normal printing temperatures are all fairly similar to each other in terms of tensile strength at least.

Try heating op your PLA while mounting it. The PLA wil temporarily weaken and will become a bit moldable. PETG is a bit more brittle than PLA is my experience so I'd say stick to PLA. Otherwise you might try Arnitel ECO. I can try to find an amazon purchase link for you if you want. Anyway, it is more rubber like and stays flexible, it will never crack but depending on your design it might become a bit more wobbly. If you share a picture of your design or an STL i might be able to help you a bit better.


Out-gassing of printed material when heated We know from this answer, 3d printed materials continue to outgas after printing and being cured. My question relates to this:

How much does heating the printed object after printing (or being cured) affect out-gassing?
Does the continued out-gassing degrade the stability/quality of the print?

This is not an answer to your question, but it relates to outgassing so I am sharing it here.

I have used the acetone vapor method of smoothing the surface of ABS prints.  It works really well, and the surface becomes much smoother and glassy.  I printed a large coffee mug (lets, for the moment, ignore food safety issues) and made it very smooth.

After a couple of weeks to allow the acetone to fully evaporate, I poured a nice, hot cup of tea.  Unfortunately, the acetone had not fully left the print, and the surface was immediately covered with dozens of bubbles as the acetone evaporated and pushed against the ABS.

This effect was only because of the acetone.  Another cup that had not been vapor smoothed worked perfectly and was unaffected by the hot water.

I have not seen similar outgassing from PLA, ABS, Nylon, or PETG.

If I may hazard an opinion about the substance of your question...

I don't think that outgassing is the biggest contributor to the aging of prints and their properties changing.  I suspect that (perhaps not in order) these are larger factors:

exposure to UV light.  UV light breaks polymer bonds and reduces
the strength of plastic.
absorption of water vapor, which can both expand the material which causes stress, and chemically break polymer bonds.
long-term crystallization of the material
fatigue from repeated sub-failure stress

NASA used to have resources that spoke to outgassing rates related to suitability for space applications.

The effect of temperature on outgas rates is a subject for Engineering.SE . As to continued outgassing - depends on the material in question.  To pick an extreme example, solid CO2 (dry ice) will outgas until it's gone.  But stuff that's got VOCs is expected to outgas; said volatiles leave by design and the remaining material stands on its own.


What is the melting temperature of a 3D printed part? Here is the context
I've got an old car for which I have a small plastic piece who is broken. As it's an old car and a very specific piece, I can't find it anymore. So I was thinking about 3D printing it.

My problem is this piece is on the carburetor, so close to the engine. This means, it can heat a lot, close to 90-100 °C.

My question
Do the pieces created with the common 3D printing techniques melt at 100 °C? If yes, what kind of other 3D printing technique can I use?

Here is the piece I want to recreate (sorry for the bad quality), the scale is in cm.

The number you're looking for is the glass transition temperature (the lowest temperature at which the material can flow or warp), not the melting point.  This depends on what material you're using; approximate temperatures for common printable materials are:

PLA: 60˚C
PETG, high-temperature PLA: 95 ˚C
ABS: 105˚C
Nylon: typically 70˚C or above ("Nylon" is a large family of similar polymers)
Polycarbonate: 145˚C

Any plastic under your hood is probably either nylon (for its durability, impact resistance, and chemical resistance) or ABS (for its strength and heat resistance).  These are both difficult materials to print: ABS emits toxic fumes while printing, and tends to warp if you're not using a heated enclosure, while nylon readily absorbs water from the air, causing the filament to bubble as it's printed.  Further, many printers can't handle the high temperatures needed to work with these materials.

If you're going to print this yourself, I recommend using PETG and inspecting the part after a few days of use to see if it's warping.  PETG is reasonably easy to print and comes close to your target heat resistance.

If you're going to get someone else to print it, I recommend using ABS.  It's probably what the original part was made of, and anyone willing to print ABS for you will have the heated enclosure and ventilation system to deal with printing it.

I'd avoid polycarbonate unless you know the original part was made of it.  Although PC is strong and heat resistant, it's also somewhat brittle and vulnerable to scratching.

High-temperature PLA is also brittle, and requires a heat-treating step that will change the dimensions of the part.  It will likely take several tries to get something that comes out the right size, and even then, you risk having the part break when your car hits a bump.

Nylon is probably your best bet.
It is resistant to some chemicals as well.
Figure on printing it at around 250 °C.
It might do the job.


Are large format prints more brittle? Recently on one of her videos a YouTuber stated that prints from large format printers are more brittle than if you were to print them in parts and glue them together. This seems to contradict the testimonials from the customers of a large format printer, who say that they get good prints from those printers (which print have a print area of a meter square).

Would a print form a larger format printer be more brittle than a print made of smaller pieces super glued together?

(with all other aspects being equal e.g. the nozzle, the temps, the material and the shape of the object).

The YouTube didn't cite any source information to back up her claim.

If you break up a large piece into multiple smaller pieces and properly glue them together, you basically add stiffeners (as a result of printing walls). This could lead to a more stiff model; this might have been confused by calling large prints more brittle opposed to constructed models.

If printing is conducted at similar conditions on large printers, there shouldn't be a reason why the model becomes more brittle unless the conditions aren't the same. But that would be true for printing at small printers too, e.g. if one print was printed in a draft.

I'd recommend getting the object to fit together by design, rather than glue - though I tend (if the item is never to be disassembled) use Zap-a-gap - that stuff sticks like crazy though you must not squeeze the parts together but let it naturally sit.


Looking for information on modifying Boots Industries 3D printers About two years ago I purchased a Boots Industries v.2.5 3D printer in a delta configuration. The wiki is still up at this location where you can see what the printer looked like.

The printer is prone to break and slip because the design uses thin wire to move the carriages up and down. I'd like to convert my printer over to using a belt like the one on this page, but the conversion kit is no longer available. I believe I can 3D print the carriages, but would anyone be able to point me toward the resources to convert my printer over to using a toothed belt?

Contact Brian or Lykle.  We all have Boots Industries printers and have heavily modified it to belt drive and magnetic effectors.  The print quality has improved drastically.  The old Boots support group has since moved on to Slack and we are in constant contact everyday.

https://biv25.slack.com/messages/@slackbot/

https://www.thingiverse.com/thing:1843195


Best method to make dissolvable supports? Sometimes supports are very difficult to remove (physically) when I print with ABS. The image below, from Thingiverse - MOF-5 unit cell, is after significant effort to remove the yellow ABS supports from a black ABS model.

I've learned about polyvinylalcohol (PVA) as a 3D-printing filament which is soluble in water. It seems like a great option for dual-extruder printers, where you can print the model with ABS or PLA and the supports with PVA, then throw the whole thing in water and let the supports dissolve.

I've considered other options since PVA is ~4x more expensive than ABS.

Doing a PLA print with ABS supports, followed by dissolution of ABS with acetone, is my best idea currently.

Has anyone found success with another option?

I've had great success printing with HIPS (high-impact polystyrene) as a support for both PLA and ABS. Most sites recommend it for use with ABS because the materials melt at similar temperatures and work best with heated beds, but I've had good luck using it as a support material with PLA on a bed at 60°C. It doesn't stick as well to PLA as it does to ABS, so supports tend to peel away very readily. The downside is that, if you need the support to anchor your print at all, it doesn’t really stick well enough to accomplish this task. For that, you must pair HIPS with ABS.

When you print with ABS or have complicated interwoven support structures, HIPS can be dissolved with D-limonene, a citrus based cleaner sold under various names like Citrisolv (others exist), or with dipentene (a mixture of L and D-limonene that doesn't smell as pleasant).

Regarding cost: I've found HIPS to be slightly more expensive than PLA/ABS, but only 1.5x the cost, not 4x like PVA. Additionally, it isn't hydroscopic in the same way as PVA so it lasts longer out of the package. Since you're using it as support, you also tend to use far less filament than you do for the main print (sparse support structures as opposed to solid print structures).

Water-soluble alternatives: There are a few proprietary blends of polymers sold by the big commercial printer manufacturers (3DSystems, Stratasys) that only work in their machines… these are generally soluble in basic solutions (water + sodium hydroxide or sodium carbonate). These are usually very expensive and you'd have to rewind the filament on a spool, as they come in cartridges made for specific printers. You'd also have to experiment with the right build conditions and solution blends to remove the material afterward. Airwolf has a support material called Hydrofill that purports to be soluble in plain water… I'm not sure how this is different from standard PVA, though I assume it is different. Hopefully more companies will work on developing water-soluble options to help us keep the 3D printing world full of renewable, less-environmentally-harmful options for filaments (both print and support).

Update:

Ultimaker now has a material called Ultimaker Breakaway. After using it for a few models, it works remarkably well, allowing me, for the first time, to print nice rounded surfaces on the bases of my prints. It really does just break away from the surface, much like HIPS but without the lack of adhesion problems between HIPS and PLA.

While I haven't used PVA yet, think of it this way, it may be 4x the cost but you use significantly less material for support structures even if you have a lot of support.


How does this multiple-curve-beam flexural pivot work? I found this in Handbook of Compliant Mechanisms (2013), page 162, or at the start of "Chapter 11, Elements of Mechanisms," subsection 11.1.2 Revolute
I don't understand how it's supposed to go from 1 to 2 when b rotates around c.
The description reads:

This element is a rotational flexural pivot constructed by three
curved beams to achieve a large range of motion. Theoretically, this
element will rotate without axial-drift motion, because of the
symmetric arrangement about the axis.
(1) Rigid body a is fixed. Rigid body b rotates about c-axis.
(2) Deformed configuration
(3) Photo of the device.

It's unclear which part of the beam is attached to what. I can understand how one curved beam could switch its curvature (in general, like they do in  bi-stable latches), but I don't see how they could both at the end of of the rotation end up curved in a way that's opposite to how they started.
How could c2/c3 go from the configuration in 1 to the configuration in 2 ?
Or could they be two different iterations of the same idea ? I can see how (1) or (2) would resist rotation of c around b, and snap it back to its original position.  The text claims (2) is the deformed configuration though. I can also see how (1) with just c1, c3, c5 would deform to (1) with c0, c2, c4 if (b) was turning anti clockwise.
Also, what would be an ideal material to print this kind of compliant mechanism ?

The picture looks as if there is a printed back surface to which the central part is attached.  This can not be the case, since otherwise the curved members would not be able to flex.  Everything inside the outer ring must be detached from the back shell.
Like all couplers, especially flexible couplers, there is a limit to the amount of torque the coupler can transmit.  Within the elastic limits of the material this looks like a good design, and a good match for 3D printing.  The forces are along the layers, not across the layers.
This looks like a good design for a rotary coupler.  I'm resisting calling it a "shaft" coupler since neither side is equipped with any connection to a shaft.  One could modify the design to have a larger central hub with a shaft hole (and set screw(s)).  As it is, there is an implied method to hold the outer ring, and a fairly explicit three-pin adapter to drop into the open slots in the arms which connect to the center.
I would use ABS rather than PLA, although it depends on the stiffness you require and ability to sustein abuse.  PLA is stiller than ABS, while ABS, within the elastic limits, is more compliant.  I am not confident that either of these plastics would stand up to thousands of millions of flexures.
I would prefer to print this of TPU or Nylon.  Both of these are tougher than ABS and PLA.  They withstand greater flex with fewer problems with micro cracks and degradation.  I have printed another shaft coupler of TPU, and it was both compliant and still.
It isn't possible to really nail down a material without knowing the application.
As to your question about one example being a transform of the other, I don't thing they are.  The A and B drawings are similar in function, but are not stressed and unstressed versions of the same part.  Either will work as a coupler.

I would try and print it in PLA because it is quite flexible.
ABS is harder in my experience and breaks more easily.
If you are able to print PET, you should also try that for the same reasons.
There might also be better materials I've never heard of, also please leave a comment if I'm wrong with anything.


What are the tradeoffs of a cantilever printer design? There are several cantilever-style printers around like some DIYs (2018), the TronXY-X1, the Monoprice Select Mini, Tiertime's Cetus line and the 2019 Prusa Minilinks for information, no affiliation.

While the specs of the printers are very different, what are the main benefits, tradeoffs and drawbacks that are inherent in the design compared to a more traditional Core-XY or Prusa/Portal design?

Cantilever printers constrain the X-axis carriage only on one side and have a free hanging side. This means, that the X-beam has to be rather sturdy and is limited in length, making them usually quite small machines.

Another tradeoff stemming from this source is, that they have to stiffen this one connection as much as possible. Any play on the connection leads to increasingly large errors the further the printhead is out from the Z-Axis and can lead to bad prints, banding and total failures of prints. This behavior, at least on the TronXY-X1, is sometimes called Z-Wobble and has brought up some aftermarket modifications. For example, this bracket constrains the movement of the X-cantilever.

While all axis would be affected by bad constraints, a cantilever suffers the most: The cantilever (if not well constrained) can deflect in both XY and XZ plane, pretty much opening a cone with the tip at the leadscrew nut. A one side-leadscrew portal design can only deflect in the XZ plane, opening an angle along with the center in the leadscrew nut. A double leadscrew design has, constrains both ends of the X-axis and prevents deflection but could suffer from bending the portal bar.

The main benefit of a cantilever design is that being of a rather simple design with few moving parts, understanding as well as repairing and modifying the motion control system is fairly easy. The ease of access and low component number also allows reducing manufacturing costs to some degree.

Another thing of note is, that these printers usually have a fairly small form factor, allowing them to be used in small workshops without taking up too much space. However, their build-volume to occupied-volume ratio usually is not as good as other designs - printers with a much larger build volume just get a much better ratio there.

The point of the cantilever design is for reduced cost. There are no other benefits beyond that.


Filament isn't going into the Bowden tube, instead it goes "into the room" The pictures explain my problem. I have already tried to reduce the retraction but that showed no effect. Thank you for your help.

The effect is a total stop of the print (no material is extruded).

Creality CR 10
Cura 3.4.1

I recently added this new feeder aluminium block because the 3D printed stock version was bad quality.

This is typically caused by resistance in the tube or hotend but in your case it appears to be mostly caused by a very poorly designed extruder.  The filament needs to be constrained closer to the drive gear.  You may be able to drill out the PTC connector to allow the PTFE tube to reach closer to the gears or print a spacer to fit in between but you need to support the filament in that gap.

You can try raising the hotend temperature as a band-aid until you can fix the problem, do not exceed 240 C if you have a PTFE lined hotend. Long retractions can also pull molten filament into the cold zone where it solidifies and make extrusion harder.

As an example, here is a picture of a Bondtech BMG extruder.  Note how the extruder constrains the filament path all the way from the drive gear to the hotend entrance.  While this example is extreme for normal PLA/PETG/ABS, it is required for flexible filament.  A 4mm gap (or closer) should be fine for PLA/PETG/ABS or other hard filaments.

You just have to cut the filament at a 45° angle. Then push down the extruder and push the filament in. Then heat up the nozzle. Next, hand feed the filament until the filament starts oozing out.


Should you use hairspray on a metal bed 3D printer? I've heard that using hairspray is useful for keeping the 3D objects from peeling off of the bed, but every example I have seen where someone uses hairspray, they use it on a glass bed.

Is it okay to use it on a metal bed as well?

I have been using a sort of a very strong hairspray called 3DLAC for about 2 years directly onto the aluminium heat bed of the Anet A8 printer I have.

Basically, all those sprays contain copolymer constituents, PVA (PolyVinyl Alcohol), Vinyl or Acetate.  These are also found in  certain glue sticks or wood glues. For me this spray works perfectly! On day one I assembled the printer, the paper tape tore and I was too anxious to wait for new tape to arrive. This worked so well that I have not changed it for that printer.

Cleaning is very easy as PVA or any of those constituents are solvable in water, so a moist cloth or paper towel over the plate is all to clean it. Furthermore, you do not require to spray before every print.

To answer your question if you should use a PVA based spray like hairspray directly onto the metal build plate is a matter of preference, but you definitely could use it as I have been doing it for about 2 years.

To address the comments:
I spray the heat bed platform whilst it is attached to the printer. I do pull it forward and gently spray the bed or just the location where the print is going to be build. Note that you do not need to do that for every print. I recently did notice very little spray on the X guide rods (maybe I have been careless once or twice), but that has not been a problem for my Chinesium iGus ripoff plastic bearings. It is very easy to clean with a damp cloth. It also works great on the glass bed of my Ultimaker 3E, but I usually (unless when I'm lazy ;) ) remove the slate of glass before printing. You could consider shielding the rods with a piece of paper, but it has not been necessary for 2 years.

Do you mean bare metal or metal with some film on top? You can apply hair spray to bare metal, but you will have troubles cleaning it off. Solvents do not evaporate hair spray, they only turn it into thick sticky goo you will need to clean off. I recommend that you try glue stick or even beer (seriously) before hair spray.
You should also know that any adhesive is required only when your printer has bed leveling issues. After I finally dealt with bed leveling, I print ABS, and even ABS/PC mix (nasty) without any adhesive, on a bare kapton film over a metal bed. I rub it with alcohol before printing.


Is there any way to shrink 3 mm filaments down to 2.85 mm? Some 3 mm filaments seem to actually be 3 mm - is there any way to shave off the excess and use it as 2.85 mm?

I would not recommend you to try and somehow re-size the filament, since even the smallest of irregularities and error in diameter occurring from such a process would ruin your prints with sporadic over and under extrusion. Rather, if you have the tools available, you could grind the filament into pellets, and use a filament extruder to make it anew with your desired diameter.

Alternatively, depending on your printer setup, you might very well extrude true 3.00 filament with your 2.85 mm filament printer. If you try to do that, make sure to:

Adjust filament diameter in your slicer
Check that your filament isn't getting squashed by the extruder wheel
Check that all mechanical parts actually can pass through your filament freely

I do not own a 2.85 mm printer myself, and therefore have not tried this procedure. There are, however, several people who seem to have done this successfully.

you could put a 3 mm extruder on you're printer. or (if you're r brave) put route filament in the oven for 10 minutes and unroll it than stretch it out. if you do this outside you can attach one ent to a stride licht or something an pul on the other end, if it is hot anoth it should hold its new position. but don't get it to hot or the filament will stick to itself, you can put talk powder on it to prevent this but be shore to watch it off before using your filament. i have never tried this and not komw is it will work. you can try it on i short pease of about 2 m first to test it oud. if it works, please tell me. i would love to know.


Why all the excitement about linear rails? Whenever a 3D printer that uses linear rails is announced (case in point: the cetus), the Internet (well... at least that corner of it dealing with 3D printing) gets abuzz with excitement.

I researched a bit the topic myself, and while I understand that linear rails can be produced to a fantastic degree of precision for super-heavy machinery, it escapes my comprehension why they are considered superior "by default", relative to the classic linear bearings on a shaft.

3D printing is a lightweight application, and the motion of at least 2 axis does not happen against a solid surface (where you could bolt a linear rail every few cm) but suspended between the 2 ends of the axis.  Furthermore, the internals of the bearings used on linear rails are substantially identical to those used on a shaft.

The cetus site says under the heading "Quality Linear Rails":

  Self-lubricated | Maintenance Free | High Precision | Long Lifespan | Quiet

but this - in my experience - can be said of "Quality Linear Bearings on a Shaft" as well, and in some cases even bushing deliver to a high standard on 3D printers.

So, what am I missing?

The following is a compilation of the input from a number of sources.

Linear rails in general are mechanical components that - when designing equipment - offer great flexibility.

The profile of the rail can be designed in nearly infinite ways. This in turn allows for:

Different levels of stiffness in different directions (for example you may have stresses only on a given plane, or you may actually want the rail to slightly flex in one plane but not in another one).
Placing the surfaces for the rollers strategically, for example in a location that is unlikely to get contaminated, or where the maximum force will be applied.
Curved paths, so that the carriage can move along a line that is not straight.

Because the contact surface between the rollers and the bearings is flat, cylinders can be used instead of spheres.  This in turns diminishes the mechanical stresses, and the amount of play, increases longevity and allows for more bearing capacity, among others.

Linear rails can be anchored along their full length, rather that at their extremes, thus increasing the accuracy of their positioning, their stiffness and their bearing capacity.

Linear rails can be machined while pre-loaded, thus achieving maximum accuracy when in use, rather than when coming out of the factory.

The bearings on a linear rail only allow for one degree of movement.  There need to be two rods with linear bearings/bushes to achieve the same result.

All that said, when it comes to the specific application of consumer-grade FDM 3D printers, it seems that none of the above is very relevant, nor confers any real advantage to the printer in terms of quality of the final print:

the mechanical stresses involved in 3D printing are very small,
the movements all happen along straight lines,
most of the axis cannot be anchored to a large, rigid body,
...

On the other hand, the design with rods + linear bearings is cheap, effective, simpler and lightweight, all characteristics that are highly desirable in a 3D printer.

All in all, it seems that there is no good reason to prefer linear rails over rods in general.

Still, there may be specific designs that may benefit from their adoption. I postulate that the Cetus printer linked in the question may be such a design: the cantilever arrangement of its axis - for example - is well served by the fact that a single rail locks movement in all but one direction, and the orientation of the X rail offers maximum rigidity against the action of gravity.

Linear rails will always produce a high degree of accuracy and stability and more so than round rod with PTFE bushings and/or bearings.

One may argue the fact however even as a product developer and one who is involved with the mechanicals and development of machinery on a day to day basis comparing the two we see “significant” improvements using rails over rods and if properly utilized on a Z axis print bed you will have a bed free of leveling issues that can smoothly and accurately operate with one driver versus two.

I will further add that getting rods aligned perfectly is a difficult task for the average person and even a slight twist or angular position can affect final print quality. I’ve seen many linear rods that appear visually straight and when chucked into a lathe spindle with 0.0000 accuracy there will be 0.005 or more in runout. In fact I’ve yet to see one perfecting concentric motion that is longer than 6 inches. This tells me that they cannot plausibly be as accurate and that while they may function they will never function with a high degree of accuracy.

Do we need higher accuracy in 3D printer axis? Sure we can have quality control boards that compensate to some degree however the mechanics of the machine are utmost important before you choose the quality of board and software. Why install a \$300 motion control on a cheap linear rod printer if you’re not going to see the full benefits?

With technology further advancing into 64 bit and eventually 128 bit and higher degrees of precisional accuracy 3D printing is turning a page and will if not already be capable of micro resolutional accuracy and can only do so if all the components function properly together.

So sure, your rod guided printer works. However, it will never work as well as my linear rail guided printer with ballscrews and servos. You can have your layered fuzzy prints. I will keep my smooth finished injection molded looking parts that are made from materials a typical desktop cannot even print. So to argue it’s not needed is arguing that high quality isn’t accepted in a lower price point market.

One other addition here. Ask yourself how level and square is your printer? I’m not talking about using a carpenter's level for checking your machine they can be inaccurate up to a 1/4” per 10 feet. When you can dial your printers bed down to 0.00005 or less every direction and your structure is just as accurate than you know what a quality printer and print looks like.

I guarantee no printer priced \$300-\$1000 comes even close to that degree of accuracy. The average consumer is so drawn into the technology of a final print itself they overlook the precisional aspects involved and learn to settle for less. Then you wouldn’t expect your \$500 printer to compete with my \$10,000 printer either.

Bottom line you get what you pay for.


Connecting Anet A8 to PC issue I am still at calibration stage and need some info from the PCB. I connected the USB and ran Repetier. The PCB wants to talk at a higher baud rate than my serial port says it can do. I tried setting the serial port to its highest setting 125k and reduced the PCB baud in Repetier setting to 125k. No joy. PC port reverts to 9600 every time I check it. Thoughts?

PC running Windows 7 Home Premium 32bit.

Sorted. Repetier Server was hijacking my com port. Uninstalled it and Repetier host worked fine. As I have no desire to monitor or control prints remotely I have no use for the server software.

Hope that helps others.

My A8 just started doing this.

I shut down repetier server, and voila, all is good! Since I will go do OctoPi eventually, I just uninstalled RS.


3D prints keep suffering from warping I have a Prusa i3 made by Geeetech. My 3D prints keep suffering from warping when printing with PLA.

Whenever I print something with a base at about 10 cm x 10 cm, at least one corner of the print would warp up. I've read numerous articles about warping and tried all sorts of methods. My printer's bed is level, and heated to 60°C. My bed is made from clean glass. I've tried all sorts of adhesives. I tried blue tape, and used hair spray.

The only way for me to combat this is gluing the base to blue tape with 502 Glue. I used brim and the whole brim just warps up. I sometimes leave the model printing over night. For the first few hours it's perfectly flat. When I go back to it the next morning I'd find one corner warped up. This is very dysfunctional to my prints.

Is there a reliable way to stop this warping from happening?

For ABS it will warp unless you build a heat chamber.

That said the tricks to reduce warping come down to:

Material, i.e. PLA is less likely to warp;
Use a fan, it helps so much;
Make sure you have temps calibrated well - Too hot is more warp;
Use a raft. The Makerbot uses a raft and no heated bed;
Make sure the room is not drafty. Having it by the window will result in warping;
Adding a large brim also helps;
I find good ol' glue sticks work the best at keeping the print to the bed;
SMASH the first layer. This one is controversial. I personally do first layer at 130% and print speed of 30%. You get elephants foot sure, but it's on the bed real good.

Tom is right. It is very very hard to print that big of a piece without warping. That said I have done very large pieces on my Ultimaker, using a fan, glue stick, MatterHackers PRO PLA and no raft. But again that's on an Ultimaker.

Note you can build a heat chamber pretty easily. Specifically a passive heat chamber.

Source (at least in part):

SolidWorks 2015 Tutorial with Video Instruction, page 11-6, and;
12 ways to fight warping and curling, June 23, 2011 by MakerBlock

  Curling

  As printed plastic parts cool the different areas of the object can
  cool at different rates. 1  Depending upon the parts being printed,
  this effect can lead to warping and curling.  Although PLA has a much
  lower shrinkage factor than ABS, both can warp and curl, potentially
  ruining a print.  There are some very common ways to deal with this
  potential problem, the most notable being a heated build platform.
  However, sometimes that might not be enough.

  Use a heated build platform.  A heated build platform helps keep the lowest levels of a print warm as the higher layers are printed.
  This allows the overall print to cool more evenly.  A heated build
  platform, sometimes abbreviated as HBP, helps tremendously with just
  about any ABS print and large PLA prints.
  Print with a raft.  Rafts are a printing option in ReplicatorG and Skeinforge.  They’re basically a large flat lattice work of printed
  material underneath the lower-most layer of your printed object.
  They’ll also help reduce warping and curling by allowing your printed
  object to adhere better to your flat build surface.  Other variations
  on this are to print with a larger raft and/or a thicker raft
  comprised of more layers.
  Calibrate your starting Z height.  A good first layer makes all the difference.  If your starting Z axis height is too high, the extruded
  filament won’t be able to make a good bond with the platform.  If you
  think your Z axis starting height is too high, try lowering it by
  0.05mm increments until you find a good first layer.
  Get the right build surface.  Some people have experimented with different surfaces such as steel, titanium, glass, different kinds of
  plastic, different kinds of tape, and foam board.  However, I find
  both ABS and PLA seem to stick really well to hot or warm Kapton tape.
  Clean your build surface.  ABS and PLA stick better to a clean build surface.  Keep it clean of dust, pieces of old prints, and any
  other debris.
  Print slower.  Printing slower allows finer detail, better adhesion to the build surface and lower layers, and gives the printed part more
  time to cool evenly.
  Print cooler.  Printing at a lower temperature isn’t always an option.  Ideally, you should be printing at the lowest temperature
  required for extrusion and that allows good interlayer adhesion.
  However, trying lower temperatures isn’t for the faint of heart.
  Printing at a too low a temperature could cause harm to your extruder
  motor or extruder.
  Eliminate drafts or enclose your robot.  Forrest Higgs found that having his 3D printer too close to an open window caused very uneven
  heating across his build surface.  This in turn caused the side of his
  prints closest to the window to curl.  Since keeping the window closed
  wasn’t an option for him, he compensated for the window drafts by
  adding a heat lamp.  Cupcake and Thing-O-Matic owners might have an
  easier time of eliminating drafts by simply enclosing two or three of
  the sides of their robots.  It will also have a fortunate side effect
  of helping to control fumes.
  Design with mouse ears.  Zach Smith’s solution was to add little discs to corners of an object to help those corners stick to the
  platform.  These essentially serve as “mini-rafts” to give those
  corners more surface area and better adhesion without having to print
  an entire raft.
  Design with aprons to hold down corners.  Forrest Higgs suggested adding “aprons” around an object to be printed, while that object was
  being printed on a raft.  These low thick pieces of plastic help keep
  the raft flat and help prevent any curling or warping from affecting
  the desired printed object itself.
  Design with surrounding thermal walls.  While Forrest Higgs’ apron approach provides a mechanical advantage of essentially holding down
  corners with a chunk of plastic, Nophead has added thin surrounding
  walls to his designs to act as baffles to keep warm air around the
  printed object as it moves around.  He’s postulated that a very thin
  surrounding wall could have the same beneficial effect as printing
  inside an enclosed build chamber.  Interestingly, it seems that
  Nophead suggests that designing objects with more rounded corners
  might also help avoid curling and warping at those corners.
  Reduce infill.  When printing a model you can chose to print it hollow, completely solid, or some percentage between zero and 100.
  However, as Nophead points out even the plastic inside a model exerts
  a force on the entire printed object as it cools.  It stands to reason
  that the more plastic you have, the more those pieces of plastic will
  pull against themselves and the build surface as they cool.  By
  reducing infill there will a reduced amount of internal tension as the
  object cools.  Reducing these internal forces by printing with a lower
  infill ratio can help reduce curling and warping as well.


Danger in 3D printing over a lithium ion battery So I bought a Lulzbot Mini a couple months ago and finally downloaded Ultimaker's version of Cura... Boy... have I been missing out...

One feature Ultimaker Cura implemented that I've been looking for is a "pause at z-height" feature ("post-processing tool"). I'm building prototypes of an electronics device, and creating two pieces that snap together looks a lot worse than printing a single piece. If I could pause my print, insert my electronics, and continue printing, my device would look a lot more professional (even if it took longer to make).

My one concern is the lithium ion battery. Right now I'm printing in TPU. With a heated bed of 40 degrees Celsius, and a heated extruder at 240 degrees Celsius, there seems to be a significant risk that the lithium ion battery reaches a temperature above 60 degrees Celsius (damaging the cell, causing a potential explosion). Granted, I am not sure what "60 degrees Celsius" actually means. It could mean only one part of the packaging needs to reach this temperature, or it could mean the entire LiPo's internal temperature would need to reach this. In either case, the numbers don't look good.

On the other hand, the heated bed surely doesn't need to remain heated beyond the first few layers? Additionally, I can create a "roof" for the LiIon battery that I can slip it under, providing some insulative TPU before the rest of the device. I think the print would happen safely like this, but obviously, an explosion would be really really bad. Like it would probably burn my house down, and I would be asleep when it happened.

Does anyone have any experience doing this?
Is there a way to turn off the heated bed mid-print? I guess I can insert a g-code line during the pause? Will this affect the remainder of the print you think?
Am I being paranoid? Can the extruder actually pass heat through a 1–2 mm of insulation and cause an explosion?
Anyone know how heat travels from the initial, liquid print material through the rest of the structure?

Any more advice or things I should consider before pursuing this?

A more specific pause type might be helpful, if anyone knows of any.

I would have to see your design to comment more but why not just change your model with the lid or top that can be either fused on later or attached in some other fashion?

It is possible to turn off the heated bed after a certain layer. It looks like there is a discussion here with the G-code: Can Cura Turn Off a Heated Bed Partway Into a Print?

I would personally avoid exposing the battery to the heat generated by the hotend or the build plate. Printers alone can burn your house down. Why combine it with the awesome power of a lithium ion battery?

Discharge the battery entirely, then there is no danger of ignition if the membrane breaks. The battery cells are usually protected by Kapton tape (LiPo) or maybe even metal (LiIon). Both will withstand the temperature of 240°C. The downside is that the cells are damaged after a deep discharge. You should discard the battery afterwards.

What I would expect when you do that:

A deeply discharged battery will bloat up because the solvents will gas out. This will also happen if you heat up the battery enough (>>60 degree). The gases themselves can be ignited again but are captured in our air sealed Kapton envelope :) Igniting these gases will be comparable to a short flash with a spray can.

The temperature is not enough to damage the envelope. The solvents will be also not very dangerous in that temperature range. In case of mechanical breakdown of the membrane nothing will happen anymore.

From Solvents and Additives:


Are there any "best" or at least "common" practices to handle allowances in OpenSCAD code? I'm designing a few mechanisms with OpenSCAD, and one of the parameters that need adjustment between printers/filaments is allowances between pieces that need to be assembled together (for example, if I want a "5 mm diameter pin" to fasten two pieces together, how much larger than 5 mm will the holes / how much smaller than 5 mm will the pin need to be).

Currently I approach the problem by setting a global variable allowance and manually using it in the code, something like:

module pin(radius) {
    cylinder(r = radius + allowance)
}

module hole(radius) {
    cylinder(r = radius - allowance)
}

I have no real world experience with design though, so I wonder if there are common or coding best practices to account for allowances when designing parts like for example:

specific modules to be used,
conventional names for variables
specific techniques to be used (scaling? vectors?)
conventions (like only use tolerances on the fastener, not the fastened object)
...?

To clarify: I'm not looking on advice on how to plan the dimensions of my designs.  Rather, I am looking for advice on how to organise the OpenSCAD code generating them.

It helps to understand the different aspects of dimensions, so you can use the terminology correctly.  This will help you define your variables in OpenSCAD with correct names.  (Tolerance is the wrong term to use.)  And once you have correct names, you'll understand how to specify the dimensions in OpenSCAD.

Tolerance is the amount of random deviation or variation permitted for a given dimension.
Allowance is a planned difference between a nominal or reference value and an exact value.
Clearance is the intentional space between two parts.
Interference is the intentional overlap between two parts.

Two other terms

Accuracy is the maximum dimensional variation between parts.  A machine cannot produce parts with a tighter tolerance than its accuracy.
Precision is the size of the steps your machine is capable of. It is often confused with accuracy.

In your case you need to define the allowance in order to create the clearance you desire.

To design your 5 mm pin and 5 mm hole, you need to understand your machine's accuracy.  The printer could print the pin larger than 5 mm or smaller than 5 mm.  Or it could print the hole larger than 5 mm or smaller than 5 mm.  You'll need to print some pins and holes and measure the differences between what you defined and what you printed.  The difference between the largest and smallest measurements you take is your machine's accuracy.  And be sure to check the accuracy in your X, Y, and Z dimensions; your printer might have a difference between them that would impact the roundness of the parts.

Let's say that your printer's measured accuracy is ± 0.2 mm.

Then, we move to clearance.  What is the minimum gap between parts you are looking for, and what is the maximum you can accept?

Let's say you want a clearance of at least 0.2 mm between the pin and hole, but no more than 1.0 mm.  Since your accuracy is ± 0.2 mm, your pin will be 5.0 ± 0.2 mm, so the hole must therefore be 5.6 mm ± 0.2 mm.  The minimum tolerance condition would be an minimum sized hole (5.4 mm) and a maximum sized pin (5.2 mm); the maximum tolerance would be a maximum sized hole (5.8 mm) and a minimum sized pin (4.8 mm).

Note that a clearance of 1.0 mm might be too sloppy for your application.  You might think to tighten the tolerances to 0.05 mm in order to reduce the clearance.  But if your printer can't produce a part that meets your specified tolerances, you would need to find a different way to manufacture or finish the parts.

Well, the tolerances will depend on material to be used for fabrication of the required part and also where the part will go and fit. Remember the all parts need some clearance to fit properly.

Few years ago (10 years) I was working as Quality Engineer and some Design Engineers were complaining about a Dupont pin was not fitting on the PCB so they told me that I need to force the PCB manufacturing to increase the holes to the higher tolerance. Which I had to ask him firstly the pin size and told me 0.70 mm and hole size 0.80 and maximum 0.90
 - hmmm and maximum size of the pin? I asked, and they told me proudly 0.78mm so the part will fit perfectly.
 - Oh, so one square pin of 0.78mm will fit on one hole of 0.9mm, but what about the diagonal dimension? if the pin on the higher dimension is close to 1.2mm.

Imagine what happened later, engineering changes and modifying other designs due improper tolerances. pro-engineer software was unable to calculate what the designers needed.

Material has shrinkage, warpage, and other conditions that is needed to know like malleability and hardness and some of this data is on the specification material or the part specification.


How to automate printing of multiple parts continuously? I would like to print multiple parts continuously (non-interactively), so
I can leave the printer alone for a longer time. So after finish, parts could be moved somehow out from the printing area, so the next can start.

Are there any methods of achieving that with standard desktop printers without having to use multiple printers?

The only thing I can think of off hand is an old mod for the early MakerBot machines. It first was released for the Thing-O'-Matic I believe, but is compatible with Replicator 1 machines (and its knock-offs). Here's the Thingiverse page, but look up Automatic Build Plate.

Essentially, you can use the Replicator G slicing program and there is a setting for "ABP" or Automatic Build Plate. This will basically tell the ABP to run its routine after the controller receives the response that the printing program is done and roll the finished part off the edge of the build plate, then start the same program over again.

Drawbacks:

I don't think it's easily compatible with newer machines/slicers. But, it's open source
Pretty sure you have to use Replicator G, which is outdated now and may make your machine sound like it's going to fall apart (I know from experience)

Going off of @Pete's answer about solenoids. It reminded me that someone integrated a solenoid "ejector" (aka Boxing Glove) for their machine.

Update (06/08/2016):

Forgot to mention that if you choose to create your own "Boxing Glove" or conveyor belt, some software such as Octo-Pi and Repetier-Host allow plugins. So, you could interface with your hardware via customized code and integrate the functionality directly into the slicing application for the full closed loop operation.

I Don't really think that it is possible without hardware modifications, or maybe some small parts that will fit in the bed of the printer all on the same time