Hans,
Don't take it wrong. I have been in the business for many years and only
wanted to give you some tips. Feel free to ignore them.
-Mike
----- Original Message -----
From: "Hans Wedemeyer" <hans@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, May 18, 2003 11:52 AM
Subject: Re: [Homebrew_PCBs] How I make my PCBs
> Mike,
> H'mm as I have pretty good looking boards and can do 5 mil all day long
> !
>
> Here's an example http://hans-w.com/pcb_harwin_rivets.jpg
>
> I've only been using Round Bulbs of various types for about 27
> years......
> I like the short exposure time and never have noticed the effect you
> menitoned, my largest board size
> is about 6"X7" and it exposed uniformly.
>
> Just what is it about my boards that you think would make them any
> better ? Please explain !
>
> Hans Wedemeyer
>
>
> Mike Putnam wrote:
>
> > Hans,
> > I looked at the picture of your UV exposure setup. I just wanted to
> > comment
> > that I would never use the round bulb. Use the florescent tubes and
> > your
> > results will be better. I have found that the round bulb tends to give
> > more
> > exposure in the center than at the outer edges. Even more apparent
> > with
> > larger boards. This is the reason all exposure units sold on the
> > market use
> > the florescent tube. You can compensate somewhat by having the bulb
> > not so
> > close, but this just increases your exposure time. The other bad thing
> > about
> > the round bulb is the heat. This will actually get in the way of your
> > process, depending upon what type of photo etch you are using. I am
> > trying
> > to recall if it was a problem caused to the developer or if it was a
> > consistency problem in the exposure. Nevertheless, I found it to be a
> > problem several years back. If you modify your design to use the
> > florescent
> > bulbs, you will notice a marked difference in detail as well as less
> > exposure time needed.
> > -Mike
> >
> > ----- Original Message -----
> > From: "Hans Wedemeyer" <hans@...>
> > To: <Homebrew_PCBs@yahoogroups.com>
> > Sent: Sunday, May 18, 2003 7:41 AM
> > Subject: Re: [Homebrew_PCBs] How I make my PCBs
> >
> >
> > > Leon,
> > > good advice except for Easy-PC....
> > > I spent full price on that program and found I wasted my money.
> > > Here's what I think of Easy-PC
> > > http://hans-w.com/ezpcbugs.html
> > >
> > > I moved on to EAGLE and have been happy with it. It's STABLE does
> > not
> > > blow up cause me to lose work=time=money.
> > >
> > > A limited version of EAGLE is available for Free, it is limited to
> > two
> > > sided board and size check it out at
> > > http://www.cadsoftusa.com
> > > EAGLE has a VAST library of part and users add parts all the time.
> > > Compared EAGLE parts Library to to Easy-PC several 1000 to 1
> > >
> > > I put Easy-PC up for sale on eBay but none wanted it. In fact I put
> > my
> > > entire collection of Numberone product in the same auction
> > > Filter program, Easy-PC for DOS and for Windows and the digital
> > > simulator Pulsar. INo one reached my minimum Price of $200 ! It's
> > still
> > > here in a box onthe floor, I think I'll use the disks and CD's for
> > > target practice sometime...
> > >
> > > Here's one thing that is not (was not)( they may have fixed it by
> > now)
> > > possible to do with Easy-PC for Wndows, in a situation where top and
> >
> > > bottom layers have parallel tracks sections that overlap, and a
> > whole
> > > bunch of closely spaced via's or other pads, it is not possible to
> > put
> > > the cursor on the trace/pad that I want for move/edit. It just snaps
> > to
> > > the nearest and of course that is not handy at all ! I can turn snap
> > off
> > > but that is not what it's all about.
> > > EAGLE allows ANY pad/trace on any layer to be individually selected
> > even
> > > if they are overlapping.
> > >
> > > Pulsonix used to look like Easy-PC, I think they are the same
> > bunch...
> > > Although Pulsonix used to give the schematic editor away for free,
> > the
> > > PCB layout part is high $$$$ ! That's much like saying "this car is
> >
> > > free, but the special wheel cost $20,000 each "
> > >
> > > I'll get off my soap boix now...
> > >
> > > I make double side board all the time. I used to do it the way you
> > > mentioned, and even wrote a program for my CNC mill to compensate
> > for
> > > alignment problems.
> > > I found a better way by printing on transparencies and then aligning
> >
> > > them visually, then stapling them together. Then slide the board in
> > > between the transparencies and sandwich the whole lot between two
> > plates
> > > of glass, and place the sandwich between two lamps
> > > http://hans-w.com/setupforexposure.jpg
> > > and
> > > http://hans-w.com/twolampexposure.jpg
> > > Credit for this sandwich idea goes to
> > > http://www.electricstuff.co.uk/pcbs.html
> > >
> > > Alignment between top and bottom is good. Perhaps the greatest
> > problem
> > > I've run into is the HP LaserJet making different print sizes when I
> >
> > > mirror the one side.
> > > I used to worry about getting the printed side of the transparency
> > close
> > > to the PCB, after testing with 5 mil lines I decided there is NO
> > need to
> > > mirror. Using the exposure as I how in my photo it allows me to do 5
> > mil
> > > lines all day everyday.
> > >
> > > Thanks for all the tips.
> > > Best Regards
> > > Hans Wedemeyer
> > >
> > >
> > > Leon Heller wrote:
> > >
> > > > I've been making my own PCBs at home for about 40 years, starting
> > by
> > > > painting the pattern onto single-sided PCB material using a fine
> > > > paintbrush and cellulose paint, with ferric chloride or ammonium
> > > > persulphate etchant. I used 0.1" graph paper for designing the
> > layout
> > > > then marked the holes with a centre punch through the paper onto
> > the
> > > > copper surface. I even made a couple of double-sided PCBs using
> > this
> > > > technique, by masking off one side, etching the other side,
> > drilling
> > > > it,
> > > > and using the drill holes as a guide when painting on the resist
> > on
> > > > the
> > > > second side. I then masked off the first side with tape to etch
> > the
> > > > second side.
> > > >
> > > > When low-cost CAD software became available (I used Easy-PC from
> > > > Number
> > > > One Systems for years) I progressed to printing 2:1 artwork on a
> > dot
> > > > matrix printer. I then got a local litho platemaking company to
> > > > produce
> > > > a 1:1 positive transparency that I used with a home-made UV
> > exposure
> > > > unit and resist-coated PCB material. When I got an ink jet printer
> > I
> > > > found that I could get reasonable results by printing 1:1 artwork
> > onto
> > > >
> > > > tracing paper.
> > > >
> > > > I now use an old LaserJet IIIp I picked up very cheaply to print
> > 1:1
> > > > onto LaserStar film and expose the PCBs in a home-made UV exposure
> >
> > > > unit.
> > > > I sometimes use tracing paper (nice and cheap), but find that I
> > get
> > > > better results from the LaserStar film. The CAD software I use is
> > > > Pulsonix, a professional package out of the same stable as
> > Easy-PC. I
> > > > regularly use 12/12 design rules, occasionally going down to 10
> > mils
> > > > if
> > > > I need to route tracks between IC pads. Rather than conventional
> > > > positive-resist FR4 PCB material, I usually use something called
> > > > FPC-16
> > > > which consists of a sandwich of compressed paper between thin
> > layers
> > > > of
> > > > fibreglass. It's cheaper than FR4 and much easier to cut and
> > drill.
> > > > It's
> > > > available from Mega Electronics, as is the LaserStar film.
> > > >
> > > > Etching is in ferric chloride. I place the etchant in a small
> > plastic
> > > > food container inside a larger container half-filled with hot
> > water
> > > > and
> > > > continuously agitate the etchant manually by rocking the
> > container.
> > > > Etching typically takes 5-10 minutes.
> > > >
> > > > I'm quite pleased with the results. I intend to experiment with
> > > > double-sided boards by making a UV exposure unit that can expose
> > both
> > > > sides of the PCB simultaneously. With a better printer and vacuum
> > on
> > > > the
> > > > UV exposure unit I think I could get 8 mil tracks quite reliably.
> > I've
> > > >
> > > > heard of other people managing it at home.
> > > >
> > > > Here is an example of one of my PCBs:
> > > >
> > > > http://www.geocities.com/leon_heller/pcb.html
> > > >
> > > > I often use the Pulsonix copper pour facility for this type of
> > board,
> > > > as
> > > > it makes the routing easier. Cross-hatching is better with a laser
> >
> > > > printer, as they don't tend to print large black areas very well.
> > > >
> > > > Links:
> > > >
> > > > Mega Electronics: http://www.megaelect.demon.co.uk/
> > > > Number One Systems: http://www.numberone.com/
> > > > Pulsonix: http://www.pulsonix.com/
> > > >
> > > > Leon
> > > > --
> > > > Leon Heller, G1HSM
> > > > leon_heller@...
> > > > http://www.geocities.com/leon_heller
> > > >
> > > > Yahoo! Groups Sponsor
> > > ADVERTISEMENT
> > > [Click Here!]
> > >
> > > >
> > > > Be sure to visit the group home and check for new Bookmarks and
> > files:
> > > >
> > > > http://groups.yahoo.com/group/Homebrew_PCBs
> > > >
> > > > To unsubscribe from this group, send an email to:
> > > > Homebrew_PCBs-unsubscribe@yahoogroups.com
> > > >
> > > >
> > > >
> > > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of
> > Service.
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > Be sure to visit the group home and check for new Bookmarks and
> > files:
> > > http://groups.yahoo.com/group/Homebrew_PCBs
> > >
> > > To unsubscribe from this group, send an email to:
> > > Homebrew_PCBs-unsubscribe@yahoogroups.com
> > >
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> > >
> >
> >
> >
> > Yahoo! Groups Sponsor
>
>
>
> >
> > Be sure to visit the group home and check for new Bookmarks and files:
> >
> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> > To unsubscribe from this group, send an email to:
> > Homebrew_PCBs-unsubscribe@yahoogroups.com
> >
> >
> >
> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
>
> [Non-text portions of this message have been removed]
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>