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help please about positive exposure printed board

help please about positive exposure printed board

Postby amro » 30 Jul 2007, 06:25

hi all
i need information or any kind of help
in my country no exposure printed board only Printed Circuit Boards - Standard Copper Clad and i can get chemicals Potassium Dichromate
my problem how to use chemicals Potassium Dichromate on the pcb to make
it exposure printed board
any information or link or book please
thanks in advance

Postby technophage » 06 Sep 2007, 12:13

hi amro first what country are u in.
try KPR kodak photo resist it is a liquid that u coat the cleaned copper clad with expose to sunlight or uv (400 watt mercury vapor lamp) anr develop in xylol or xylene an aromatic hydrocarbon solvent.
this process is negative.
There is however in the states companys that sell similar productds
both negative and positive with the matching developer. They also sell a reversing film also uv exposible, so u can turn a positive artwork into a negative film. It is very important to have a high qualiti neg or pos to make a usable pcb the film can also reverse ur neg into positive.
what are u going to use for an etchant ferric chloride or potassium chlorate. Ferric chloride is by far the easyest to use and cheapest.
u can also buy here already coated copper clad material in both exposure forms. If ur are up pto it u can also screen print the resist on to the copper clad, I use this method for production runs it is not as scary as it sounds. Depending on what country ur are in u should be able to screen printing supplys, every country screen prints.Making the stencil requires a positive film and is also uv exposable. If u want i can find the names of these people, they make kits for hobbyists i just remembered radio shack used to sell a pcb kit do u have radio shack (tandy electronics).I have made many thousands of circuit boards by many different methods in my time so one of these must work for u.
later technophage
Posts: 1
Joined: 06 Sep 2007, 11:53
Location: orange county usa

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