The Shop > Electronics & IC Programing

How do you do your PCBs?

<< < (2/9) > >>

philf:
Or, if you have a CNC router or mill, try machining them. No messy chemicals, no UV lamp, cheap copper clad board.



Phil.

jiihoo:
Hi Pekka,

I've used "Thermal transfer paper for PCB" (check ebay.co.uk with this search term, I don't want to link to any individual seller). Works on PCBs of "normal" complexity (i.e. try to avoid traces that are overly thin). All of mine have been fairly simple and the last were done a "few" years ago.

To make a simple double-sided board, iron the transfer on one side first and then drill a couple of locating holes to position the other side correctly. Fold the edges of the 2nd transfer paper to keep it positioned correctly. Try to make 4 extra "locating holes" on your PCB design if you can; if you used some of the normal holes for this then consider plugging them before etching as the edges of the holes you just drilled are not protected and will etch somewhat. Anyway don't make your boards 2-sided if you don't have to and when you do, try to keep the other side simpler to make the locating less critical.

My stack of 20 sheets of thermal transfer paper is from 2014 and none of them have been used  :( (but I am sure that I'll find a good use for them real soon now...).

You are welcome to a couple of sheets if you want to try them without waiting for long delivery from far away... Just PM me.

The Positiv 20 UV resist is usually good for a long time after the expiration date.


Jari

PekkaNF:
Thanks.

I have really been thinking of building a small CNC router just to do euro card size PCBs max. Just so hard to get started. I have seen some professional ones and hobby models or DIY types just feel so hopeless.

Direct toner method sounds nice, if it works. Specially if you can print also component outlines, markings and solder mask. I wonder if 3D printer could be used to dispence any of that stuff?

There were some nice stuff on lab when I was studying. Two sided was no problem: taped two repro films together on two sides (easy to index), then slip sensitized and oven dried PCB in between and tape tags on corners to immobilize the PCB and "pouch". But now I have only household stuff.

I'll have to take your offer JH, PM will follow....I have greatest faith on UV resist method, but I really like the direct toner transfer idea.

Pekka

Joules:
With a small cnc like my old Roland MDX3, you have the option of coating you PCB, then scratch the resist for normal etching.  It means even a small cnc machine can produce boards.  I made this tool to go in the 6mm collet of my little MDX3.

CrazyModder:

--- Quote from: PekkaNF on January 19, 2016, 04:04:57 AM ---You use photosensitive boards or do you spray on positive 20 or other UV-sensitive resist?

--- End quote ---

I use pre-made boards from Bungard.


--- Quote ---I have tried to buy some, much of them have gone old before I got them. Is there any other method to check, except to exposure, develop and etch and then try to figure out which step went wrong?

--- End quote ---

The story, as far as I can tell, is that they are forced to print a shelf date on the boards by regulations. In fact, they seem to hold for many years with no problems. Mine did, I'm sure; I have not tracked how old my boards are, but I have certainly used ones of 5 years or older with no noticeable difference.


--- Quote from: PekkaNF on January 19, 2016, 04:04:57 AM ---Has anybody tried toner transfer/laminator method?

--- End quote ---

I've tried it and found it as hit-and-miss as the other people here.

Really, the NaOH/FeCl3 method is not messy at all. If you are able to pour a liquid from one container into another without making big splashes everywhere, then you'll be fine. Sure, those are chemicals, but only mildly dangerous to humans. You won't get blind from fumes or destroy your lungs or something like that. You can store them indefinitely in plastic containers with no risk of them breaking (check the data sheet for which kind of plastic; I got my containers in a local apothecary when buying 2 liters of aqua dest there, for free ;) ). The dangers appear when you simply pour the used stuff in the toilet (especially the FeCl3 - I have heard that the utilities can track that and you'll get really punished, and the ground water will go to hell ;) ). You can use and re-use the FeCl3 a very long time though, it is very benign. The other danger is of course to clothes, and the FeCl3 will - duh - etch metal, so don't use it in the kitchen in the good stainless steel sink or the wife will put you in pain. :) All should be pretty obvious. Eye protection and simple gloves should be standard, no questions asked.

There *are* other chemicals that can be used for PCBs which *are* indeed very dangerous indeed. That's why I use NaOH/FeCl3. The FeCl3 step takes a long time (can be like 30-45 minutes) at room temperature, but that's fine with me.

All of those parts are easy to source and cheap (like 1-10€ cheap). The printer is kind of important though; I assume not every printer will give good results on transparents. A slight cloudiness does not hurt, but if there are holes in the print,  you will get holes in your copper. Mine cost < €100. And you can use it for standard printing as well, so I don't count it as investment at all.

Navigation

[0] Message Index

[#] Next page

[*] Previous page