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Homemade PCB's. Share your methods

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LAN_403

Physics Junkie

Sat Jan 19 2013, 12:17AM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

Awesome stuff everyone! thanks for all the reply's.

@mikeselectricstuff your site is great I've read through your stuff and its helped me a lot. Thanks.

I just got done with developing a board using black lights, all i can say is that it worked GREAT. Heres some photos of my ghetto rigged setup

MG Chemicals and board, with the UV lights in the background

I stacked 4 blacklights, also used the two CFL's. The vice for holding the board. You can tell I expose both sides at the same time

I also put blacklights in the Ballast directly above the setup. I have sooo many of these lights from college dorm days

two transparencies taped together on glass plates

FeCl, H2O, Developer

Currently etching

The other side

This, I would say, is my first 'successful' process. I had no expectations when going into this with the blacklights. Next time I will trim the board down to correct size so I'm not wasting good pre-sensitized board

This also makes for an extra long etching time because of all that extra copper. Its still currently etching in the FeCl. I'll post finished product later. Thanks everyone!!

Conundrum

Sat Jan 19 2013, 08:50AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Hm, people have reported success using a blue laser (aka bluray burner diode) and a plotter.
Seems that an alternative approach is to use the "cooked ink" method ie yellow epson ink, then laser that to remove unwanted areas.

Re. 8 layer board. Yes you can, just make lots of dual layer boards but use the ultra thin laminate, and pre-test via densitometer using infrared light at 940nm to verify continuity.

I expect that DIY paper phenolic is also possible by getting cheap paper and then resin bonding it, vacuum sputtering on a thin copper layer then electroplating on the rest.
Such a board could also contain silver and other thermally conductive materials

Daedronus

Sat Jan 19 2013, 07:41PM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

This is one of my best done on the CNC.
That's 2 traces under a 1206 package resistor.

I don't use V bits, I find them too fragile for my taste, pyramid bits work just as fine (45 degrees I think).

I can completely disregard any PCB height variance, because I first probe the whole board, make a height map, and adjust the original g-code to take into account the actual pcb height.

2Spoons

Sun Jan 20 2013, 09:39PM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
Location:
Posts: 615

I mostly use toner transfer, with the Press'n'Peel blue "paper" - I get better results with this than with plain paper. Takes some effort to get the process worked out, but then its easy to rip a board out.
Also tried laser engraver with paint as the resist - some effort required to find a suitable paint that can be ablated off easily by the laser. Some success but hard to do double sided.

Etching : used to use persuphate, but went back to ferric chloride, as its faster, and unused solution can be stored.

Hazmatt_(The Underdog)

Mon Jan 21 2013, 05:14AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Why do you guys spend so much time and money on lights when 10 minutes outside in sun is free?

And yes, I have been making my own boars for 15 years now.

Physics Junkie

Mon Jan 21 2013, 05:48AM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

Hazmatt_(The Underdog) wrote ...

Why do you guys spend so much time and money on lights when 10 minutes outside in sun is free?

And yes, I have been making my own boars for 15 years now.

a) lights are less time
b) 15W 18" UV tubes I bought were 3 bucks and I only needed two for small board
c)depending on where you're at in the world and season, 10 minutes of good sunlight is not always readily available when a board is in need of exposing. Sometimes its more convenient to have a setup ready when you need. Although i suppose that as long as the UV rays are getting to the board through clouds and whatnot, direct sunlight might not be needed. Feel free to elaborate how you do it.

Carbon_Rod

Mon Jan 21 2013, 07:53AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

In general,
I only produce boards for evaluation, and usually prefer a professional plated hole version.

1.) Print PCB bottom-layer and mirrored top-layer image proofs (I place a few Markers outside board area for alignment later).

2.) Manually feed the transfer film into flatbed laser printer
Note: I recently found inkjet-photo paper is far superior than just about any process tested over the years. Although force feeding the slippery paper into the machine is a hassle, the results using this method are surprisingly excellent for $0.50 a board.

3.) Drill 4 staggered alignment holes using a printed paper-proof template to align films
4.) Use steel wool to remove PCB tarnish and deburr PCB on both sides
5.) Polish surfaces with disposable paper towels to remove dust and remaining tarnish etc.
6.) Use probe needle to align top transfer paper markers to PCB alignment holes, and use foil tape to secure PCB to film sheet.
7.) Cut bottom transfer film to size, align holes and markers.
8.) Secure bottom layer to board with foil tape, and check alignment markers with a light table.
9.) Use dry clothes Iron to preheat and adhere each side of the laminate pressing down.
10.) Cool laminated PCB and film by pressing in the back page of large book for an hour
11.) Place in warm water to remove paper backing
12.) Use warm water and brush to carefully scrub off inkjet coating from PCB
13.) Etch in FeCl with battery&sponge electrolysis method
(Faster etch times, dilute solution lasts longer, and doesn't noticeably undercut.)
14.) Rinse, drill, and clean off toner with steel wool before soldering

I was rather surprised the cheaper inkjet-photo-paper transfer method reliably yields double sided PCBs with 0.01"/0.254mm traces. However, this simple method is what I use to test assembly before ordering fabricated batches.

Best of luck,
Rod

Daedronus

Mon Jan 21 2013, 10:43AM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

Cutting a large PCB on my CNC (for a led UV exposure unit):

From center to corners there was almost 1mm difference in height, all corrected with a height map generated by first probing the board.

The spindle is also DIY, powered by a RC brushless motor.

Physics Junkie

Tue Jan 22 2013, 04:38AM

Registered Member #7267 Joined: Tue Oct 16 2012, 12:16AM
Location: Detroit, Michigan
Posts: 407

What is everyones thoughts regarding 're-usability' of ferric chloride? assuming that it is not spent. What I mean is for example, I just etched a board, so can I use that same ferric chloride for another board? It is concentrated with no water added. And if so how many times do you think I can re use it until I should make a new batch?

For the developer, I read NOT to ever re-use it, just to use fresh each time.

2Spoons

Tue Jan 22 2013, 04:46AM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
Location:
Posts: 615

reuse until it is dark green, or too slow to etch.

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