What is the very best way to get a positive image for PCB making these days?
idbruce
Posts: 6,197
Hello Everyone
I am looking for the best way to get a positive PCB image. I already know about laser printing and transparencies, as well as using vellum. Years ago, you could create camera ready artwork and take it to a print shop to have a positive made, but I believe this method is now outdated, because the print shops don't offer that service anymore. Any suggestions?
Bruce
I am looking for the best way to get a positive PCB image. I already know about laser printing and transparencies, as well as using vellum. Years ago, you could create camera ready artwork and take it to a print shop to have a positive made, but I believe this method is now outdated, because the print shops don't offer that service anymore. Any suggestions?
Bruce
Comments
-Phil
You are half right: Actually using a Photo plotter (as in a Disk + Lamp + XY table) has not been done for a long time, but if you can find some print/imaging company that knows what Photoplotting is, and can import Gerber files onto their laser printer, then you are in luck.
Likely they have a laser imager at the better end of the scale.
Failing that, you may find a Silkscreen/print/imaging company that understands imaging Postscript onto film, but has no idea what a Gerber format is.
(Silkscreens still use the same photo-imaging they always have)
If you find one like that, (they are more common) just check the precision in the X and Y axes of their plots.
They may be used to lower levels of precision, and as long as the film distortions in their colour separation prints all track, usually their customers are happy.
A purist will print with the photo-emulsion on the film-side that will touch the photo-resist, but that can dictate a flip of one image.
On a low end printer, you may prefer the parallax issues, over image skew.
@devil in angel - You may want to refer to some of my other posts that are all inter-related to the subject of making PCBs. In my opinion, they all contain some worthwhile knowledge for those wanting to create PCBs.
http://forums.parallax.com/showthread.php?137850-DVD-Laser-Diode-And-Optical-Block-(Future-Laser-Photoplotter)
ATTN: PCBers SUBJECT: New website and exposure box design for your creative needs
http://forums.parallax.com/showthread.php?135950-ATTN-PCBers-SUBJECT-New-website-and-exposure-box-design-for-your-creative-needs
DIY PCB Fabrication For The Sake Of Science And Education
http://forums.parallax.com/showthread.php?138954-DIY-PCB-Fabrication-For-The-Sake-Of-Science-And-Education
Looking For Ideas - Temperature Control
http://forums.parallax.com/showthread.php?137511-Looking-For-Ideas-Temperature-Control
Alas my friend, you are half right also...
You are talking about the old method of photo plotting. They now use lasers to expose film. Perhaps you should also read the "DVD Laser Diode And Optical Block (Future Laser Photoplotter)" thread to gain a little more insight
The Canon ink did not effectively stick to the transparency matter and wasn't opague enough for exposure, while the HP ink is both sticky and opague. But please be aware that the HP doesn't fully dry and can be smugged by rough handling.
Resolution with SMD may indeed be an issue with the use of inkjet printers - the images are getting tougher to produce.
I'm not sure if the 5940 is still available. Current low-cost Deskjets such as the 3000 give 4800x1200 dpi colour, but only 600 dpi for B&W, which isn't much use.
As many of you know, it is very difficult to obtain a high quality mask by simply printing your circuitry onto a transparent film with a laser printer. However, in the past, I have read about and watched several videos of people producing high quality boards by doubling up their transparencies and gluing them together to make a more opaque mask. Last night, I made several photo masks using this method, and I must say that I am quite pleased with the outcome. They appear to be some fairly nice masks and should produce some nice boards.
Basically I printed each mask twice onto a premium laser transparency film using a LaserJet 6L 600 DPI laser printer. After cutting all the masks to size, I sprayed each mask with Acrylic Krylon Crystal Clear Satin to blend and darken the toner from the printer. After allowing the masks to dry, I then aligned duplicate masks together and applied a very fine layer of Elmers Glue-All to the edges.
They look good to me and I am a pretty picky person.
Just for giggles, give it a shot, but the key is to spray each mask with Clear Satin to blend and darken the toner. This will make the mask more opaque and it will help to protect the mask from smudging. The masks I made last night look pretty outstanding and very durable.
I threw out a Canon printer and bought yet another HP about a year ago.
I can't see any point in using a laser printer.
Take my word for it, buy yourself a can and give it a shot. I think you will be highly impressed with the quality and durability.
While making the masks last night, I chose 600 DPI because I figured that was what most people had access to, and this is an experiment for my exposure box.
Thanks!
600dpi is likely good enough resolution for both. I doubt if I could post a visual example of poor opacity as the image looks excellent on printed paper.
I do not believe that photos are capable of showing the desired quality. The main goal is for the artwork (circuitry) to be opaque as compared to translucent.
Opaque - Blocking the passage of radiant energy and especially light
Bruce
Perhaps a bit of overkill for the DIY
Jim
I would imagine there is probably a person or two out there looking for one of those, and I imagine they would be pretty rare. If they were mine, I would try selling them on eBay.
As far as wanting one, sure I want one
Bruce
Yes, it was kinda a funny. Gerber knew where it was going, so they bought two companies back in 1988-1989? One did direct to film and the other did direct to plate. The rest is history.
Jim
I'm looking for a yes/no answerable test. Your first statement doesn't get me there, and indicates there is no way to check if a solution is suitable.
But your next statement says there might be a method, and it might photograph-able.
(That's me, each requirement must have a yes/no test, or the requirement needs fixin')
Can you get (from your existing collection) an example of a good mask, and as you suggested hold it to the light and take a picture, and do the same with a bad mask?
I just want to see what good and bad look like, so I'll know it when I see it next.
If evaluation needs equipment that (sounds like it) cost more than my entire lab, I will probably drift off to another thread.
Evaluation takes no more that a Calibrated Loupe and a light table, (if I understand your question). When I was with Gerber, in field we would calibrate to .25-.5 mil. For a new machine, it would be calibrated to .1 mils before it shipped. Of course we used optical inspection equipment that was 50K at the time.
Jim
EDIT: of course I am referring to original artwork and not final PCB.
For one, I do not have a good digital camera, and secondly, the last thing you want to do, is directly point a camera at a light source. When taking photographs, the normal procedure is to apply light from the side, from behind, or from above a camera. Avoiding direct lighting into the lense is always a good idea if you want nice photographs.
The bottom line is this... You can produce a decent circuit board without a perfectly opaque mask, but it is much more difficult. The darker the lines the better.
Just to give you a general idea, locate a board layout, and print out two copies on standard paper. Walk over to the nearest window with sunlight, and first place one copy on the window and look at how the light passes through the black. Then place the second copy over the first and you will see that very little light passes through the black.
Like I said earlier, I have seen several videos of doubling the transparencies, which have produced some very nice looking boards. And I imagine that I will have similar results. When I get finished exposing and etching the boards that I create with my new masks, I will then have photographs taken of the resulting boards.
Bruce
If you are ever inclined to do so, you could always come by for another visit, and we will expose and etch a couple of boards just to give you a general and overall idea of the process. In fact, unless I achieve perfect results with the first attempts pertaining to the new masks, I will probably be experimenting with exposures for the next couple of days. During this time frame, it would be a good opportunity to learn what I have learned through trial and error.
Bruce