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designing a PCB

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Hi uncle sam,
which part of designing the PCB are you talking about? The layout designing on the computer with a CAD program?

Or making the PCB with toner transfrer method, or UV exposure?

More information is needed...
 
Designing the layout of a PCB on the computer not a big deal.

If possible I want to know about both the process of designing the PCB( toner transfer n UV exposure).

But really like to know which one is the best method too.

thanks for any help
 
Well, UV method is probably the most accurate, you can get the smallest traces.

Basically, the toner transfer is when you print the circuit on a piece of photopaper, then iron it to the board so that the toner sticks to the board. The toner protects teh copper from the etchant, resulting in traces only where the etchant is.

The UV method (ive never done it) is where you print the circuit on a transparent sheet, and then place it over the board. then expose the board to UV light with the transparent sheet over it. The traces on the sheet protect parts of the board from the UV light. Then you stick the board in an etchant, and the places that got exposed to the UV light come off. The places that were protected don't.

I left out a lot of things that you have to do, but that is the main idea.
 
Just want to add that white fluorescent light could be used as an alternative to UV, just rquire longer exposure times.
 
you can use wax. Wax the side of the board you want to see copper on, and scrape off the wax from the copper that needs to be etched off or removed, then you are left with your design.
 
fsahmad, what is screen printing? I'm curious, is it any good? Ive been thinking about using UV exposure instead of toner transfer because the results are better. I'd like to check all my options first.
 
Screen printing is a veeeeeeeeeeerrrrrrrrrrryyyyyyyyyyy old printing technique still used for printing T-shirts..... in PCBs, if done right, gives u track width upto 17 mils.

U take (buy rather) a wooden frame with a silk screen on it. Then u apply a thin layer of photoresist enamel on it. Then u take a mirrored laser print of the pcb on a transparency or even butter paper would do. U put the image on the enamel covered screen & expose it to sunlight for a minute. Wash the screen & the part that was under the print clears out. U get a stencil of the PCB. Next u put the screen stencil on the copper plate, & apply a thin layer of etch resistant ink on it, the stencil blocks excess ink, passing only the design onto the board. Let & dry & etch it.

This process may seem quite tedious, but it just takes a bit longer in practice & once u get good at it, saves a lot on toner if u intend to mass produce the PCB since etch resistant ink is very cheap.
 
r u sure that we can get 17mils width track?

than that will be awesome, coz i have be using the pen with ethching resistant ink to get the pattern on the PCB, where i would only get large width track which is not absolutely good lookin.

but u said it can't be reuse again, did i hear u right
 
if you use toner transfer, you can get 10 mil track width. the transfer sheets are not reusable, but you can easily make many boards by just printing multiple copies of each PCB pattern...

I'm willing to bet it's cheaper than screen printing would be (especially if you make many different boards, and would have to get one screen pattern for each one), and it's certainly faster and more precise... and also easy!
 
uncle_sam said:
r u sure that we can get 17mils width track?

than that will be awesome, coz i have be using the pen with ethching resistant ink to get the pattern on the PCB, where i would only get large width track which is not absolutely good lookin.

but u said it can't be reuse again, did i hear u right

I beg ur pardon but I meant to say u CAN reuse the screen once made, until u clean it up. But I must warn u, indulge into it only if u can spare the time & toil, for it takes a loooooot of practice before u can get ur tracks down to 17 mils.
 
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