Dry Film PCB making

Korišćenje negativ fotopolimer filma za izradu štampanih ploča.
Vreme osvetljavanja mojim osvetljivačem sa UV LEDarama 30s.
Razvijanje u rastvoru kalcinisane sode, razmera: 1 kafena kašikica kalcinisane sode na 1 dl vode.
Nagrizanje pločice namerno nisam snimio, koristim HCl + H2O2.
Uklanjanje filma posle nagrizanja pločice u rastvoru HaOH veće koncentracije od one koja se koristi za razvijanje pločica oslojenih foto lakom.

[@keeper1855]

Thanks :)

[@michaelbrocato7535]

Hey Zasto its Cadcam man I want ot try and make a pcb just like this can you send me a list of materials you use and where you got them

[@ZoranScepanovic]

Hi Michael,
Choose a vendor for dry film:
www.aliexpress.com/af/photosensitive-dry-film.html?d=y&origin=n&SearchText=photosensitive+dry+film&catId=0&initiative_id=AS_20210111132630
As material for a PCB I prefer FR4.
It should be cleaned and de-greased. Cleaning could be done with 600 to 800 grit wet/dry sand paper and for de-greasing you can use acetone.
For template I use graphical film (I have friends who are running a business for producing films and CTP - Computer To Plate for offset printing) and the pattern must be NEGATIVE, i.e. all copper area thst should be left on PCB should be TRANSPARENT on film.
Template could be also printed on ink jet printer, you know, the spitting one :), but you will need at least two prints stacked on top of each other, as the single one does not block enough UV light.
Cut dry film to size, peel off protective foil from one side and adhere it to the PCB blank. I used "wet" method by spraying some DI water to pcb blank, but laminator can also be used.
When the film is adhered to board, place your template on it, put it under UV light source to expose it.
After exposing, peel off the top protective film and develop in sodium carbonate solution, 1 tea spoon of sodium carbonate in 100ml DI water.
When developed, use your preferred method for etching (HCl+H2O2 or FeCl3 or sodium persulfate).
After etching remove the dry film using acetone or sodium hydroxide solution.
Drill, cut to size :) ua-cam.com/video/jYrJSjSaITY/v-deo.html
Some useful videos:
ua-cam.com/video/1C3k6dyVN18/v-deo.html
ua-cam.com/video/xyBgbNPrWg8/v-deo.html
ua-cam.com/video/GEoQa_LG1S0/v-deo.html
BTW, this was my first board that I made using dry film, usually I use or pre-sensitized boards or spray the Positive 20 photo resist on blanks.

[@michaelbrocato7535]

Zasto can you explain the printing process on the clear film ?

[@ZoranScepanovic]

Use acetate overhead transparency sheets and print as dark as possible. Add alignment markers, at the diagonally opposite places, as per attached image, print two times and overlay both prints. print in REVERSE, i.e. text not readable, so that the ink is close to PCB.
cloud.mail.ru/public/bSzG/hbHYRV9zc

[@michaelbrocato7535]

@@ZoranScepanovic just to be sure I have to use laser jet printer right? And I am trying to make a double sided pcb . I will use your suggestion with the line up indicators but what can I do to line up on the bottom side of the board

[@ZoranScepanovic]

@@michaelbrocato7535 You do not have to use laser printer, what I had in mind is inkjet printer. You can notice near the alignment marker a small pad, it is used for drilling the hole through PCB and films/foils for aligning both sides.