From: Jim Meissner (jpmeissner_at_mindspring.com)
Date: 2002-01-09 11:14:43
Dear Andreas:
I am also very interested in learning your double sided PC board technique.
I make my own single sided boards using a Kepro UV light box. I etch with ferric chloride with an air bubble stirrer in a heated bath. I use the positive resist pre-sensitized boards. Much of my artwork was done with tapeand donut negatives, some with rub on transfers. I have experimented witha simple PC program and printed to transparencies with my 300 DPI Laser printer. I have to tape two of the transparencies together to make it dark enough. I also have an Epson color 660 printer. That is what I have.
I think what I need is a program to do the artwork. What are you using andhow can I get that.
Also how do you do the schematics, and how can I get that program.
What brand, part number transparencies are you using? Laser or Ink jet? Which do you recommend?
Please tell me about the etching solution also.
Thanks.
Juergen P. (Jim) Meissner
Check out my Website at www.MeissnerResearch.com
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----- Original Message -----
From: sleeper75se
To: buildcheapeeg_at_yahoogroups.com
Sent: Wednesday, January 09, 2002 4:55 AM
Subject: [buildcheapeeg] 2-sided PCB manufacturing
--- In buildcheapeeg_at_yahoogroups.com, "Joerg Hansmann" <info_at_jhansmann.de> wrote:
> Can you explain, what materials and procedures you use
> for the UV-light transfer and etching ?
> What minimal copper/clearance can you produce reliably ?
Hi Joerg,
ok, here's how I do it:
Materials:
* A *good* 600dpi laser printer. I think a good inkjet printer can
work too.
Normally, I'm using 15-20mil traces with 10-15mil clearances. There's
usually text on the board, made up of 5mil wide traces. It gets
blurred and is barely readable, but it is sufficient to prevent me
from connecting the power supply the wrong way and so on.
* UV-lighting fixture using 3-4 fluorescent tubes. I donīt remember
what wattage they are... Tubes gives more even light than a simple
lamp, I think. The fixture is home-made by the way - nothing fancy.
* Double-sided FR4 laminate already coated with photo resist. Trying
to do your own coating is a complete waste of time, money and
sanity. :-)
*Sewing needle or other very thin, sharp object.
*A 0.6mm drill. You can of course use larger sizes, but it will be
harder to find wire that match that.
*A piece of wire. 0.6mm lead wire from a resistor works best with
0.6mm holes.
--- 1 ---
Place a couple of pads in your CAD program outside the board edges. I
usually put 5 pads in the shape of plus signs outside two opposite
corners, so that they get as far away from each other as possible.
These will be used as drill guides, so you will only actually use two
pads. The extra pads will give you several retries if you make a
mistake.
If the laminate size equals the board size - just select a few pads
inside the board, but still in opposite corners.
--- 2 ---
Print the layout (masks) on normal paper so that when you place it on
the laminate, the printed side is down.
--- 3 ---
Use the needle to make holes in the top layer mask at the center of
the pads designated as drill guides.
--- 4 ---
Place the BOTTOM layer mask where you want it to be on the laminate,
with the printed side UP so that you can see the layout. Later, this
side of the board will be the TOP side. Don't remove the protective
foil on the laminate yet.
Fixate the mask with small pieces of tape, then drill holes through
the drill guide pads in the paper. If you miss - don't worry, pick a
new pad, but be more careful next time.
--- 5 ---
Remove the bottom layer mask and the foil on both sides.
Cut short pieces of wire and push them halfway through the holes. The
wire should be thick enough so that it can stay in place by itself.
--- 6 ---
Place the masks on the laminate. You can only do this one way - match
the holes in the paper with the wires.
Fixate the masks by bending the wires and then tape down the corners.
If there is no room, make room by cutting off the corners of the
masks. (Prepare for this when designing the layout)
---- 7 ---
Remove the wires. Now it is ready for the UV-light.
Illuminate both sides (make sure the lights are warmed up before you
start). Wheigh down the laminate with a piece of sheet glass (UV-
transparent!).The time varies with different lights and fixtures. For
me, 15-17 minutes works best.
Then develop and etch as normal. I'm using an etching solution with
Hcl and H2O2. With this solution, a board is etched in less than 3
minutes. I don't have the exact concentrations here, but I can get
back to you about that if you want me to.
/Andreas
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This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:36 BST