Tips for the TronXY P802MA and in general

Ok just wanted to share a few tweaks I made to my TronXY P802MA that are economical, quick and may help others:

0) In the printer's controls, under "PRINT FROM SD CARD" in there are 2 files called "P802\_level\_test.gcode" and "P802\_auto\_level\_test.gcode". The first one is buggy in my experience and always causes a crash into the print bed. So use the second one.

1) You can fix warped x axis carriages for the lead screw attachment by printing 3mm washers with outside diameter of 4mm, inside 3mm and 0.2mm high.  I printed like 100 for less than a metre of PLA.  Took a whole minute to print lol.  Then I just packed the washers between the screws holding the lead screw guide/nut to the carriages.  You know when you have it right when the rod falls through the nut under gravity or a very small tap and if it is parallel to the guide rail. This adjustment process took about an hour because of the fiddly nature of it.  But it worked like a champ.  A razor blade and toothpick helps to align them.  Less material than printing a new carriage and faster.  I plan to epoxy this in place because that nut should be a permanent part of the carriage.  Here is the thingiverse link:

https://www.thingiverse.com/thing:2415415

2) I have ordered silicone PC washers for dampening sound, you need 8 for each motor (of which there are 5).  I am ignoring the extruder for now.  The inside diameter is 2.5mm but guess what, so is the shaft of an M3 screw (without thread) - the more you know.  This is way cheaper than buying vibration dampers.  I have no idea if they work as well though.  This has got to be better than building a LACK enclosure if you don't need air extraction or a controlled environment. The threads will settle into the washer sides.

http://www.ebay.co.uk/itm/Pack-of-32-Acousti-AP-1003W-C-Clear-Anti-Vibration-Silicone-Washers-/391731702501

Also, print 4 of these for each motor to make your washers last longer and work better:

https://www.thingiverse.com/thing:2423841

3) Properly tightening the threaded rod bolts using wrenches/spanners makes a massive difference to stability. I would guess about 20 Nm or 15 lbf of torque, but be careful not to crack the acrylic - sorry I didn't measure the torque. Make sure the frame is held square doing this. You can hold the z-x plane square using a woodworker's clamp for instance. Or just make sure it is square before tightening. The x-y plane I squared using a square/engineer's square/quick bevel measured at the y axis rails to front and rear panels and at the intersection of the two planes.

4) I printed some modular vertical frame braces to reduce wobble in the Z-X plane to less than 0.1mm relative movement at the top of the z axis. At this stability it is an angular error of 0.026 degrees and the deviation in mm is the z axis height x 0.000454. The multiplier comes from the tangent of the angular error. Thingiverse link:

https://www.thingiverse.com/thing:2415459

5) I have printed a case for the Melzi 2.0 board, which never seems to get too hot on mine.  It had mosfets and heatsinks built in.  If heat is a big problem when I try ABS then I have a giant heatsink from a pc that I can mount on the mosfets and add a fan.  Free upgrade heh.  Also a thermal fuse is cheap and could just be wired in line with the board power.

https://www.thingiverse.com/thing:2320498

6) I tried many thumbnuts etc to level the bed which all seem to strike the frame and ruin alignment.  So now I just keep them separate and use them as a tool to tighten an M3 nut instead of the wingnuts provided (which also hit the frame and ruin alignment).  Now there is no problem.

7) I use a binder clip to secure the ribbon cable to the display to keep it out of the way of the build volume.

8) I built a PSU lower case with a switch which comes in handy as a kill switch for instantly shutting down the machine.

https://www.thingiverse.com/thing:2415719

9) I check my filament spool for knots before a big print to save on failed prints due to filament breaking at the knot.  You can also wind the required length of filament on a spare spool to avoid this.

10) Print from SD card to avoid USB communication issues. I think there is an option in Slic3r to mount the SD card in a tab to the right of "Manual Control" in Repetier Host. Then you should be able to save it to the card and then print from the card. File names look funny though so keep it simple I suppose with no spaces or weird characters and short. 8 characters file name length and 3 characters for the extension for example "bracket.gco". It takes forever transferring the files over the USB cable due to the protocol. It took 20 minutes to transfer 5MB. Like you were using a voice modem HA! So either transfer the file using an sdcard reader on your computer or upgrade your printer with octopi. Some users say you need to reboot the printer after changing sdcards. I'd only do this for long prints personally.

11) I printed brackets that clamp the threaded rods to a table surface or piece of wood.  I haven't needed these yet.

https://www.thingiverse.com/thing:1886045

12) I keep a log of print jobs on a spreadsheet to know how much filament I have left.  You can weigh the spool at the beginning and between jobs, but I find this much easier.  Beware that spool sellers that sell you 1kg sometimes include the weight of the spool so you only get 750g +/- 50g.  Your slicer should estimate filament usage.  It overestimates by around 5-8% in my experience with Slic3r, which is handy.

13) Print a skirt to make sure you get a clean extrusion.  You can adjust this in Slic3r, I print enough loops to extrude at least 0.5m onto the build plate. A brim helps with adhesion if you need it. Brims are important for tall prints at least for me.

14) I printed a Y axis tensioner.  It was easy and helped. Clean the holes then mount it in the frame before adding a nut or bolt to avoid breaking it.

https://www.thingiverse.com/thing:1280443

15) I printed an X axis tensioner but it reduced my axis travel.  So instead I used a removable belt clip 4mm wide and experimented with tension.  This worked without losing build volume.  But it will need a monthly check.

https://www.thingiverse.com/thing:2416069

16) I use glue stick on the aluminium bed for adhesion.  DO not use a razor blade to clean just warm water dissolves it very easily with a rag.  In less than a minute.  A blade helps remove prints and skirts. Letting the print bed cool also helps removing parts. Since I started using brims they usually pop off. Glue residue wipes off with water. I experimented with extruder and bed temperatures and the best settings vary for each roll of material, maybe it's the same per supplier/batch.

17) I am going to experiment with using glycerine/glycerol and water for an adhesion material because it is cheap and hopefully won't attract ants/bugs.  Has anyone tried this?

18) To further insulate sound I'm planning on putting rubber between the printer and the surface it's mounted on by cutting up an old timing/cam belt from my car! Free upgrade :D

19) it's probably worth mentioning that you could use a good quality old PC power supply if yours ever fails with enough wattage and of course appropriate wiring. There are some guides out there.

20) It's often mentioned that you can upgrade your electronics to Ramps 1.4 and the drivers and mosfets and kits are on ebay that are cheaper than a new Melzi board. This is just for anyone who doesn't know.

21) You can save a failed print sometimes by following this guide which I used myself:

http://www.instructables.com/id/continue-failed-3d-print/

The only thing I did differently was carefully adding some glue stick to the top of the part and preheating the bed.

22) Calibrate x and y axes and extruder also!! There are varying degrees of precision in doing this, and it can be corrected in start-up gcode in Repetier host. I'd google for a page that suits your comfort level because some people go after very careful precision and get very technical. I initially did it because I needed to use every square millimetre of my build plate.

23) If you are running out of filament mid-print you can carefully feed in more without stopping (same diameter) compensating for retraction using your hand in free air as a suspension system! It's an art but it worked for me to save a print. Be careful of course and don't touch anything hot. You don't have to press the extruder lever. Just wait for the free end to go 2 mm into the block, then hold the new end just above and lightly push in against the old free end and try to keep the two ends in contact. Straighten it first of course. Also keep in place until you are sure you are extruding the new filament. I waited 5-10 minutes to be sure.

24) The 62 commands in gcode and mcode (that I know of) that apply to Marlin firmware which is what the TronXY P802MA is based on (adapted from here https://softsolder.com/2013/03/14/g-code-and-m-code-grand-master-list/ where MF stands for Marlin Firmware - don't type the letters MF):

25) Correct the position of the bed after homing or G28 command. Assuming you're using Repetier Host and Slic3r, if you have large prints, you might notice that the bed is offset. If you print something 220mm x 220mm (including skirts and brims) it will try to print off the edge! This is because of the mounting positions of the x and y end stops I think. The printer itself doesn't have an option to correct this but it can be done in software.

In your start gcode under printer settings in Slic3r, you can use a custom version of this code to correct it. Use the parts that you don't already have. The order is important.

> G28 ; home all axes to stops
>
>

> G1 X-1.9 ; home X to 0 with the offset of the bed/extruder/stop NOTE CHANGE NUMBERS
>
>

> G1 Y-5.0 ; home Y to 0 with the offset of the bed/extruder/stop NOTE CHANGE NUMBERS
>
>

> G92 X0.0 Y0.0 Z1.10 ; corrected bed position after homing all axes NOTE CHANGE NUMBERS
>
>

> G29 ; auto level
>
>

> G1 Z5.0 ; lift nozzle
>
>

> G1 X-5.0 ; added so easier to clean nozzle
>
>

> G4 S10 ; nozzle cleaning delay in seconds CHANGE NUMBER
>
>

Where it says NOTE CHANGE NUMBERS, do the following with Repetier Host connected:

a) level your machine as normal so the z offset is correct and set as per the bed levelling instructions file that came with the printer.

b) home the printer

c) read the info screen, it should say the x and y and z positions

d) using Repetier Host (which should already be connected to the printer) go to the manual control tab. Type G1 X0.0, hit enter, then G1 Y0.0 hit enter and wait for it to stop moving.

e) perform step c) and make sure it says X 0.0 Y 0.0 and Z will be what you set it to in part a). If it doesn't something has gone wrong

f) take a ruler or calipers and measure the position of the extruder tip from the edge of the build platform in the x and y directions. In my case the x position was +1.9mm (extruder within build platform xy area); y was +7.5mm and z was 1.10mm. Note: I could only correct y by 5mm because of the position of the end stop - trying to correct 7.5mm will cause a collision - so double check yours. Thus to make the corrections the codes for x and y above have a negative sign in front of them. At this point you edit the start code with the numbers you now have and follow steps b), d) and e) again. The G92 command tells your printer that it now has the correct position as you have told it. You might add an M500 command to save this after G92 but I haven't tried that. I have a nozzle cleaning delay during which I can clean the nozzle with a wire brush of 10 seconds.

26) After silencing the motors with silicone acoustic washers and PLA bushes to press the washers properly, I've been trying to silence the remaining noise. This was mainly coming from the Y axis pulley.

While inspecting the bearing it appears the wrong washers have been used. There are four washers in the assembly. The big ones are not the problem. The two small ones are supposed to grip the inner bearing ring, while the rest of the bearing rotates.

The issue is the small washers have an outside diameter of 10mm and the inner bearing has a larger diameter of 7mm. So the bearing is not working as a bearing, the outer bearing will be rubbing against the small washers and making a lot of noise!

This part replaces the small washer with the correct dimensions. It includes a sleeve for the play between the 5mm screw thread width and the 5.6mm inside diameter of the bearing. A little light filing with a nail file might be required. Also assemble the washers and bushes and bearing without the tensioner body and the action of tightening the nut will force the bush in and compress it in place.

You will need two but it is best to print one and then let the bed cool and then remove it. Then print the second one. Your slicer might show some small gaps in the walls, a few don't matter.

If you don't let the bed cool properly the part will deform. You can re-form it by placing it on a heated bed.

https://www.thingiverse.com/thing:2424509

Enjoy the silence!!

27) I made this rear motor mount for the Y axis motor with two sound dampening washers. I printed this laying flat. Now I get the sound reduction without having banding caused by removing the stock mount.

You will need two silicone acoustic washers for silencing PCs. 2.5mm inside diameter and 2mm thickness. The nubs are for the washers to be located on.

https://www.thingiverse.com/thing:2428376

28) To add to my series of printer improvements, I wanted to make sure I could keep my z offset well-calibrated.

The stock bracket and auto leveling sensor on the P802MA has
adjustment slots for mounting the sensor bracket and on the sensor
itself. These three pairs of slots make it easy for the sensor to move
out of place in my experience.

These slots are useful for adjustment, but once you have a
well-adjusted machine you can just measure the position of the sensor
and the bracket and make it immovable.

These parts fill the empty space in those slots to accomplish this.

You will need two of each part. I included the scad files.

If you have slight difficulty fitting the parts you might scale the
parts down to 90-95% or do very light sanding. I like a perfect fit, so
 I printed at 100% scale.

You will need to recalibrate your offsets after doing this.

https://www.thingiverse.com/thing:2445926

AAZeroThree4