Re: gEDA-user: photo-imagable supplies (was: dremel drill press)
Hi, When I did double sided photoresist boards I used a frame made from aluminum. The frame was made from a rectangular piece of aluminum sheet that had the same thickness as the board that we were using. There was a large cutout in the middle of the sheet to allow the board to sit in there. Imagine what a matte for a picture frame looks like. The two masks were then taped one on each sides of the frame and were aligned by looking through them. One side was not taped all the way around so that you could lift it up and place the board in between them. Two sheets of glass were then placed one on each side, and held there with hose clamps. The resulting sandwich was then placed unde UV poster lamps to expose. First on one side, then the other. If we had more lamps we would probably have built a frame to expose both sides at once. With this setup I made quite a few ISA plug in cards for PC's. The only real problem I ran into was that occasionally the print shop that did my photomasks would use a different piece of glass to hold down my original, this different glass ended up making about a 2% difference in the output size. Unfortunately for me they did this randomly, and I would end up with top and bottom that did not align. After I got burned a couple of times, I added a vernier scale to the output plot, and showed them the error, and made them do it again until they got it right. The eventually figured it out, and after that they made real nice plots for me. -- Mike Jarabek FPGA/ASIC Designer, DSP Firmware Designer http://www.sentex.ca/~mjarabek -- -Original Message- From: John Griessen [EMAIL PROTECTED] Date: Mon, 16 Apr 2007 10:05:19 To:geda user mailing list geda-user@moria.seul.org Subject: gEDA-user: photo-imagable supplies (was: dremel drill press) DJ Delorie wrote: They seem to go where I want them. [jg]Great. I'll be trying some PCB carbide bits soon. The deviation of the bit itself is far less than the alignment accuracy of the two halves of the board. Off by 10 mil or so - this is my first try at double sided, I need to try a few techniques and see which is most accurate. I'm thinking of switching from toner transfer to photomask. Then, I can drill the board first and use the holes to line up the print. I've thought about that some, and also got a chance to do some film tests recently that were not acceptable -- it seems no easy photography supplier films are high enough contrast to get a good film for exposing photomask -- just dark grey instead of opaque black. Or black and grey if you expose it differently... So the supplies for making a pos from a neg or a reduction in size from a 2:1 print are hard to get. Agfa quit serving the US it seems -- I found one source that supplies super fine line chip/interconnect making film and didn't even bother to go through the hoops to get the price since they were dodging around the question so much. So, if you use toner on clear film and maybe stack two of them to get opacity, what's your source of photoimagable mask emulsions? I'd want some that are good with a red light instead of any total darkness processes. If you do photoimagable etch resist, you're all ready to go for soldermask also... and for masks to put on conductive inks too maybe... Conductive inks are now used in some lowest-cost-planet-wide circuit boards made in China so they have only one side etched, and the jumper layer is mostly ink on the same side, reducing holes to the minimum. You sometimes have to make conductive ink wide or use a copper wire jumper on the other side to get your desired conductance for a path, but leaving out drilling holes is best by me... John Griessen ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: photo-imagable supplies
Mike Jarabek wrote: Hi, When I did double sided photoresist boards I used a frame made from aluminum. [jg]Thanks Mike. Sounds like a good holder method. occasionally the print shop that did my photomasks would use a different piece of glass to hold down my original, After I got burned a couple of times, I added a vernier scale to the output plot, and showed them the error, and made them do it again until they got it right. The eventually figured it out, and after that they made real nice plots for me. This touches on the situation I've found now. Ordinary print shops don't do decent film repro work, and say they can't get the high contrast film, and I found only one expensive supplier so far. Microchrome Technology Products quoted $350 for 25 sheets film and $300 for cases of chemicals last October... An easy price for 50 micron line work, but not for us... anyone know a current supplier? John Griessen ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: CNC ROUTER PLANS
These look very interesting. If anyone build one, I would like to get their feedback. http://www.rockcliffmachine.com/cnchome.htm -- William Estrada [EMAIL PROTECTED] Mt-Umunhum-Wireless.net ( 64.124.13.3 ) ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: home-made dremel drill press
On Mon, 16 Apr 2007 15:50:27 -0400 Darryl Gibson [EMAIL PROTECTED] wrote: Is the site down? I can't seem to connect... I'm getting unable to connect errors too. Hmmm... I have the impression that DJ disappeared simultaneously! John ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Where's DJ? Was: Re: gEDA-user: home-made dremel drill press
On Tue, 17 Apr 2007, John Coppens wrote: On Mon, 16 Apr 2007 15:50:27 -0400 Darryl Gibson [EMAIL PROTECTED] wrote: Is the site down? I can't seem to connect... I'm getting unable to connect errors too. Hmmm... I have the impression that DJ disappeared simultaneously! I can't speak for DJ's situation since I haven't spoken or heard from him in a while. (And I wouldn't ordinarily hear from him anyway.) But I'll just remark that we've had some pretty bad weather up here in New England over the last few days. A big nor'easter decided to settle down and spend some time soaking New England with lots of rain, wind, and (in some areas) snow. Here in Boston I have seen a couple of trees blown down, tangling power lines. There was one on the street where I live. On the AM newsradio station there is lots of news about power outages occurring in New Hampshire where DJ lives. The wind and the heavy rain mean that lots of trees fall onto power lines, disrupting power for residential customers. Therefore, while I don't know what's up with DJ, I'll bet it's power related, and that he'll be back in a day or two, when the folks up in New Hampshire get the electricity net up and running again. Stuart (who thinks DJ is reading books by candlelight right now) ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: photo-imagable supplies
John Griessen wrote: Mike Jarabek wrote: Hi, When I did double sided photoresist boards I used a frame made from aluminum. [jg]Thanks Mike. Sounds like a good holder method. occasionally the print shop that did my photomasks would use a different piece of glass to hold down my original, After I got burned a couple of times, I added a vernier scale to the output plot, and showed them the error, and made them do it again until they got it right. The eventually figured it out, and after that they made real nice plots for me. This touches on the situation I've found now. Ordinary print shops don't do decent film repro work, and say they can't get the high contrast film, and I found only one expensive supplier so far. Microchrome Technology Products quoted $350 for 25 sheets film and $300 for cases of chemicals last October... An easy price for 50 micron line work, but not for us... anyone know a current supplier? John Griessen ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user I did find some film that appears to be ideal for this use: http://www.freestylephoto.biz/sc_main.php?cat_id=2000 It is also quite cheap (for sheet film). They have small containers of developer for this film (standard photo developer probably will not give sufficient contrast): http://www.freestylephoto.biz/sc_prod.php?cat_id=2003pid=1223 Or to make a gallon: http://www.freestylephoto.biz/sc_prod.php?cat_id=2003pid=1231 The only other thing you should need it fixer. I doubt stop bath would be needed. http://www.freestylephoto.biz/sc_prod.php?cat_id=303pid=591 I am planning on buying a box of the film and trying it out. I have an upcoming project where I will want to etch a few boards. Darrell Harmon ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
