Your Thoughts About The RepRap and Similar Devices? - Page 1
Forum section: electronics / projects

author: thakidd
author_rank: Regular Contributor
timestamp: December 02, 2010, 07:58:11 am
content: Long story short: I live in a small apartment on the second floor and really do not have a way currently to etch prototype boards. To rule it out now, I am talking about experimentation before I talk to a PCB manufacturer. I do not need a list of them as I would like to run an @Home process first before ever sending off for them to make boards. I have been seriously looking at theRepRapand CNC milling to produce on-off test boards and also build prototype enclosures. I wondered if anyone who frequents EEVBlog has messed with/had experience with the RepRap or other similar devices like theMakerBot.What has been your experience?What machine(s) did you use?What are the positives and negatives in your mind?Is it worth the $600-$1000 investment for the RepRap?Can you or someone you know print RepRap parts in the US?Have you tried the etch resistant pin with RepRap or other kind of CNC?Is there a better way to go?Only other option I see is to build some kind of chemical venting system. Really do not want to mess with this route as the wife will be all over my ass.Please note: I am on a budget and would like to accomplish light milling and possibly 3D plastic printing on a max of $1500.All info and help is appreciated!

author: GeoffS
author_rank: Unknown
timestamp: December 02, 2010, 09:29:01 am
content: I can't comment on the RepRap. While it's an interesting device, I'm not sure how you would apply it to the making of PCBs.Milling on the other hand...I'm a member of several machining forums and PCB milling with CNC mills is a popular subject. There are people making complete PCBs while others use traditional methods but use the mill for hole drilling.A small CNC mill with suitable software would run close to $1500 unless you did the CNC conversion of the mill yourself.If you want, I can post a few URLs that may point you in the right direction - I'm just about to stop for dinner.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 02, 2010, 10:35:55 am
content: A cheap CNC mill is not going to make worthwhile PCBs.Traditional wet etching will give way better results much faster and much cheaper.

author: tyblu
author_rank: Frequent Contributor
timestamp: December 02, 2010, 11:13:01 am
content: May want to check and see if there is a local club with a RepRap.

author: saturation
author_rank: Super Contributor
timestamp: December 02, 2010, 12:32:29 pm
content: This is a very interesting device to make available to hobbyists/makers. I can see its roots in industry, but its certainly overkill for most electronics, excellent for robotics or mechatronics. Nevertheless, as prices drop, I'd get one!That said, a reality check on projects. Unless you intend to sell the device, the time you spend for board layout or even custom making your own PCB for manufacture for what maybe a single or a handful of prototypes needs to be considered, particularly if you dont' make more than handful of your design.An often heard phrase is, " I can't finish this", or, " I'll design one of these when I have time", because the thing we run out of and can't get back is time.That said, I rarely PCB after I learned the process, and depending on the parts type, either perf, vero, board or preferably dead bug construction. Ugly as it is, its the fastest way to everything from low to radio frequency designs with through-hole components. With parts counts already low given higher levels of IC intergration, you'll spend more time routing than getting the electronics done.Thus, project designs and construction can be done in minutes to hours, with most time spent testing and debugging. And once finished, the project is done in half a day or less.

author: joelby
author_rank: Frequent Contributor
timestamp: December 02, 2010, 12:37:41 pm
content: With an engraving tool, you can easily extend the technique to surface mount parts!

author: saturation
author_rank: Super Contributor
timestamp: December 02, 2010, 12:58:08 pm
content: Wow! Can you explain? That would $ave me a bunch. Sometimes digikey will only have SMT, at times cheaper than through hole, but some of those packages are hard to handle. Appreciate your help.Quote from: joelby on December 02, 2010, 12:37:41 pm

author: joelby
author_rank: Frequent Contributor
timestamp: December 02, 2010, 01:09:47 pm
content: It depends on the sort of packages you're after, but I've done it quite successfully with 0603 passives and four terminal SOT-143 parts. Basically, figure out where you want to place your parts and engrave out tracks to isolate pads as needed. A line carved by a standard engraving tool is perfect for isolating the two sides of an 0603 part.In this image is a band pass filter, low noise amplifier, and mixer.

author: Time
author_rank: Frequent Contributor
timestamp: December 02, 2010, 07:01:00 pm
content: self replicating machines!? PREPARE FOR THE ROBOT APOCALYPSE!

author: saturation
author_rank: Super Contributor
timestamp: December 02, 2010, 07:14:56 pm
content: Nice and easy. What is the greenish colored coating you painted on the leads and solder joints?Quote from: joelby on December 02, 2010, 01:09:47 pm

author: saturation
author_rank: Super Contributor
timestamp: December 02, 2010, 07:16:24 pm
content: it seems at first, but some assembly required and you still need to feed it raw materialsQuote from: Time on December 02, 2010, 07:01:00 pm

author: joelby
author_rank: Frequent Contributor
timestamp: December 02, 2010, 09:56:25 pm
content: Quote from: saturation on December 02, 2010, 07:14:56 pmI didn't! If you're talking about the tracks, that's just the colour of the PCB after the copper has been engraved away. If you're talking about something else, it's probably just the camera or lighting.

author: Jimmy
author_rank: Regular Contributor
timestamp: December 02, 2010, 10:47:49 pm
content: I am currently in the process of building a CNC 3 Axis machine simalar to the Robo CNChttp://www.robocnc.nl/?page_id=60I have got all the electronics and linear rails and need to start building the frame and stuff.If you just want to engrave pcb's for cheap then I have got the project for you. You only need 2 Axis machine and a manual height adjustment just rip apart 2 old scanners for parts and get a dremel with flex shaft. You could probably find most of the stuff in your mates places just ask for old crap scanners the older the better becase they will be better constructed.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 02, 2010, 10:58:09 pm
content: Couldn't you use an oil based black paint to mask the board, selectively cut away the paint with a laser, then etch the board conventionally? EDM is another possibility, although it would need the cutting order to be carefully planned.

author: scrat
author_rank: Frequent Contributor
timestamp: December 03, 2010, 01:24:55 am
content: After I took apart my printer for repairing, I had the idea of using one (after a little modification) to mask copper with ink, and then etching. It should do a precise work, since it is capable of working on non-absorbing surfaces too. I think someone other has already done something like this...For the CNC, maybe an old plotter would be a good solution, while recently made scanners/printers seem not to be robust enough.

author: GeoffS
author_rank: Unknown
timestamp: December 03, 2010, 02:03:48 am
content: Quote from: scrat on December 03, 2010, 01:24:55 amThere's athreadover at cnczone.com about modifying an inkjet printer to print directly to PCB. The article is a couple of years old but as far as I know, the device is still in operation.Warning: the thread has little electronics content

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 03, 2010, 03:42:59 pm
content: Quote from: Jimmy on December 02, 2010, 10:47:49 pmsame thought here. i'm planning to build my own CNC with just motors, encoders, mcu/arduino controlled/programmed by pc and hard real metals. but only when i really have a need for the device. i saw a printer is potentially be modified to become a 3axis cnc too! scrap out all the electronics, change with a whole new mcu board, only use back the rest (motors and sensors and the existing fine metals and gears. and err... swap the printer head with a drill or milling tools/bit.

author: Jimmy
author_rank: Regular Contributor
timestamp: December 03, 2010, 10:36:53 pm
content: shafriA stepper motor would be more accurate with less backlash. Why would you control it with an arduino its is just adding another layer of software in the system just drive it direct from parallel port. it is only a hand full of signals forward, back, lef,t right, up and down.

author: Zad
author_rank: Super Contributor
timestamp: December 03, 2010, 11:28:20 pm
content: I wrote a rant that Dave would have been proud of here, but I decided to cut to the chase:Why don't you want to use conventional etched PCB?

author: GeoffS
author_rank: Unknown
timestamp: December 04, 2010, 02:36:03 am
content: Quote from: Jimmy on December 03, 2010, 10:36:53 pmServo motors are usually more accurate and faster but overkill on a small mill. They do require encoders.Steppers are cheaper and if chosen correctly, are accurate.Backlash will come down to the choice of leadscrews or ballscrews. Ballscrews are best but dearer.I agree with the software comment. There are excellent software package for XP (Mach 3 - low cost) or Linux (EMC - free) that will provide the appropriate step/direction signals for the stepper/servo drivers.You'll need to run some sort of CAM process to generateG-Codefor the controller software from the Gerber files.Quite a few of these available for fairly low cost.I'm in the middle of CNCing a small mill using Mach 3. No plans to use it for PCBs but it should be up to the job.

author: thakidd
author_rank: Regular Contributor
timestamp: December 04, 2010, 06:50:11 am
content: Quote from: Zad on December 03, 2010, 11:28:20 pmIf this is directed at me, I would not want to risk it considering I only have a 4x3 ft front patio and a 6x9 ft back patio. Both with overhangs. I also have a 12x14 ft office that could be converted with a chemical hood but at what cost? I do have two windows facing east side and could make attic modifications if need be. I have a kid though so any kind of indoor chemical etching scares the shit out of me. Outdoor, not so much, since he is 3 months old, but I still have to dispose of whatever chemical I use.What do I do in later when he is walking?I realize no method is safe. I also realize chemical methods might be cheaper. I also realize that the dust from a mill can be toxic. I guess my philosophy though is to design one machine that can take care of all situations, hopefully be approximately 24" x 24" x whatever height, have multiple applications, and be safe.If I had enough space in a garage, I would have a CNC mill, 3d plastic printer, CNC etching pen, chemical etching area, etc. All separate. I just do not have that kind of room.What do you suggest taking no garage, limited outdoor/indoor setup and a baby involved into account?

author: Valhallasmith
author_rank: Contributor
timestamp: December 04, 2010, 07:10:02 am
content: Quote from: thakidd on December 04, 2010, 06:50:11 amPlenty of people manage to etch in tight quarters. Does your child drink the bleach and other chemicals in your home? Just keep them in a safe place where your kid can't get to them. You can etch out of a couple buckets if its that cramped for space there.

author: tyblu
author_rank: Frequent Contributor
timestamp: December 04, 2010, 08:02:16 am
content: I etch PCBs in my kitchen sink inside large freezer-type Zippo bags. Chemicals are kept in jam jars. The chemicals, gloves, and a sponge or two go inside of a plastic bag, then in another bag, and are then hung up in a closet.

author: Bored@Work
author_rank: Super Contributor
timestamp: December 04, 2010, 01:40:15 pm
content: Quote from: scrat on December 03, 2010, 01:24:55 amEveryone trying it with a laser printer failed, for a simple technical reason. The toner is hold on to the image drum by electrostatic, and the drum is supposed to then roll over the (non conductive) paper to press the toner on the paper. A copper surface, however, discharges the drum and the toner falls of in an uncontrolled way.Trust me :-), direct-to-coper printing on the cheap has been tried by thousands of people, they failed. If you want to make it happen cheap, you have to come up with something really new. If you can make it happen cheap you can become famous and rich.

author: scrat
author_rank: Frequent Contributor
timestamp: December 06, 2010, 01:03:47 pm
content: Quote from: BoredAtWork on December 04, 2010, 01:40:15 pmI was thinking of ink-jet, of course. However, I know it's not an easy thing to achieve.

author: Zad
author_rank: Super Contributor
timestamp: December 06, 2010, 07:46:23 pm
content: I think you have a massively disproportionate fear of how noxious etching chemicals are. Sure, if you use concentrated hydrochloric acid, that can cause nasty splashes, but things like sodium persulphate and ferric chloride are vastly less harmful than bleach and don't fume at all. Where do you think most of us do etching, some specialist chem lab we have built? I still use 8x10 photographic trays and store chemicals in bottles with locking tops. Hell, I was doing this at 11 years old without a major incident being called.

author: DJPhil
author_rank: Frequent Contributor
timestamp: December 07, 2010, 12:06:04 am
content: Quote from: Zad on December 06, 2010, 07:46:23 pmI'll second this.I'm massively paranoid about dangerous chemicals. In my youth I was fascinated by explosives and had a few close calls and a few accidents, and the experiences made me very cautious.If you stick to ferric chloride you should be just fine. The big worry is spills and stains. The upside to ferric chloride is that you'll always know if you spill some as it's notorious for stains that are essentially impossible to remove. If you have a bathroom with a ventilation fan you can work in there, just get a piece of wood (preferably laminated in some way) to set over the top of your sink to work on. Close the door and keep the fan running. I usually cover my work surface with a layer of saran wrap (cling film) and a layer of wax paper. The paper blots up any spills, and the plastic wrap blocks it completely if you don't let it sit more than a few minutes. Even this is overkill really if you trust yourself not to make a mess. Keep some paper towels handy to blot up spills, and remember to tear a few from the roll before you start, as you may only have one hand free when you need them. It's worth picking up some (properly sized!) latex gloves to keep your hands clean. If you have someone in the house with a latex allergy like I do here you can use vinyl or nitrile gloves instead.Even this is the messy way to do things. You can use the 'in the zip lock bag' method if you like, but I prefer to use a sponge to work the edges as they seem slowest. You can store ferric chloride in the same manner and with the same caution you'd store bleach. My bottle is actually in my bedroom/lab. Invest in an etch tub and a rinse tub, and mark them clearly so they're never used for food. I use tupperware from the thrift store. When finished I wrap up the entire work surface with the saran wrap and toss it in the trash. The rinse tub is heavily diluted with water and poured down the drain, which is a calculated risk. The ferric chloride gets reused until it's no longer etching, then I take it to a local chemical disposal company. You'll see warnings about environmental damage from ferric chloride, and they're valid, but not really in the quantities you'll be dealing with. Always dilute it heavily if you send it down the drain because if it pools in your drain tap it'll start etching your pipes if they're metal. Most modern drain systems use PVC, and are much more resistant to this effect. Water treatment plants use ferric chloride to disinfect (actually I believe de-alginate) drinking water, and the system is designed to handle trace amounts. By minimizing your waste you'll minimize your environmental impact.I've also used the pool cleaner and H2O2 method, but it's much more inherently dangerous and a bit tricky to start. The real trick there is to get a good mixture going that you can regenerate with a bubbler of some sort. I only do this outside and wouldn't dream of attempting it indoors. The fumes are odorless and colorless, and you only realize you've inhaled a bunch of HCl vapor when your chest tightens up and congests. It's not a good feeling, and it takes a few days to pass (at least for this pack-a-day smoker). Storage of these chemicals is much more hazardous as well, as the vapor can slowly eat away at nearby metal. I keep them in airtight containers, and store them in a large cat litter tub in the laundry room over the winter as it can get cold enough here to freeze the mix (barely). I take the container outside once a week or so and open it up to ventilate so any remaining vapor is dispersed. If I had a small child in the house I'd be much more worried about this method.I hope that helps some.

author: David
author_rank: Frequent Contributor
timestamp: December 19, 2010, 09:01:23 pm
content: I have been pondering the idea of building a rep-rap for some time now...only cost really putting me off (£400-£450ish). I am particularly interested in the idea of using one as a solder paste dispenser/pick and place machine!

author: nessatse
author_rank: Regular Contributor
timestamp: December 23, 2010, 09:54:54 am
content: Quote from: BoredAtWork on December 04, 2010, 01:40:15 pmNot quite true. There have been very successful direct to pcb laser printer conversions. See the Yahoo group 'Homebrew_PCBs' for details (http://tech.groups.yahoo.com/group/Homebrew_PCBs/files/Direct%20Laser%20PCB%20Printing/). Very fine resolution has been obtained with this methodInkjet direct to pcb printing is also a fairly well established process.Both methods require a fair amount of mechanical modification, so be prepared to dedicate a printer to the task. As far as I am aware the method is also not too successful for double sided pcb's due to alignment issues.