Dry film resist application, exposing, and developing
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- เผยแพร่เมื่อ 26 ก.ย. 2024
- This video show how to apply, expose and develop dry film resist for printed circuit board fabrication. The associated text is at forum.allaboutc... in the completed project section under Photographic methods of making PCBs.
hello and thanks for your great video. I'm using dry film resist for flexible materials(double-sided flex substrate (Pyralux® AP 9111)) and on 110°C my resist will be damaged and I see some holes on it . when I decrease temperature to 80°C i don't see any holes but resist doesn't well pressed on my substrate and I can remove it completely with my hand. also because my substrate is very thin I use pet sheet to give it some thickness do you have any idea for this problem sir?
The UV led was bought through EBay. No part number. Parameters: 365 nm, 5 watts, UV LED.
+Mark Lockwood
Thank You. Power and wavelength it is crucial information. I'll find in catalogue similar diode. Greeting from Poland.
Write me down about Diode UV which You used. How is parameter this diode, or simply part number. Great thanks.
hello and thank you for your video. a question. are you using a yellow light? it seems to me that it is important, it does not need UV. Many tutorial or people use daylight, fixtures. Confirm you? Lionel (French)
Yes, I am using a yellow light. A yellow light will not expose the dry film resist. I hope this helps.
@@marklockwood7592 sorry I did not see your message. thank you. in a documentary about engraving, they used a yellow color. when in doubt I always use a yellow color with much less ultraviolet. I take particular care for the realization of the circuit.
Hey, great video, is there any advantage of using a point source for UV rather than, the more traditional array of UV tubes? as seen in most exposing units?
There are two advantages to using an LED point source. One, a point source casts a sharper line on the resist. This is important if your artwork is not in full contact with the resist. Second, the output of LEDs are much higher than tubes. A 5 or 10 watt LED can be placed 12 inches away and still give you short exposure times. Hope this helps.
Hi folks …
What is the reasoning behind the water bath to apply the film?
Is it essential?
Does it activate/increase the adhesive qualities of the film OR simply makes it easier to apply and position while submersed?
I have viewed a few instructional videos that simply (all be it carefully) apply the film directly onto the board without water immersion before insertion into a laminator.
Hi Roger. The reason for the water is to improve adhesion. The Riston general data sheet recommends "wet lamination" for fine line applications.
Thanks Mark for the reply ... Did you use Sodium Hydroxide (Caustic Soda) to strip the board? Was the mix ratio the same as the developer? (1/2 tablespoon (10grams) to 1 liter of HOT tap water)
Roger, I tried sodium hydroxide but I prefer acetone. It is quicker and cleans up easier. Both works.
I would like to know what kind of light bulb you use in handling the photoresist film. I know the exposure light is UV. I need to find a light source that has no UV rays so I can see what the heck I'm doing. I do like the idea of using water to apply the film. I make two-sided PCBs. Thanks!
....I did notice the light you used when you pealed off the top film. It looks like a yellow light. Is it?
...1 Liter = 4 cups
The light is commonly referred to as a yellow "bug Lamp" from the hardware store. I use both the incandescent version and the florescent.
What is the water for? Is it really necessary?
The water is used to soften the emulsion so it will adhere to the PCB. It is called out in the manufacturers application notes.
@@marklockwood7592 I just peel it off, then stick it to the pcb then put it through the laminator.
@@Berghiker OK, I have seen people do that. May I suggest that you download the application notes for the dry film you are using. They will tell what is acceptable. I know that I have never had an adhesion problem when using water.
@@marklockwood7592 I bought the photo resist film from Banggood.
@@Berghiker It appears to me that the Chinese copied the original DuPont "Riston" dry film. Here is a link: www.dupont.com/electronic-materials/dry-film-photoresists.html
I am guessing the "FX" film is the closest to what you have. In the end, go with what works.
I discovered an error in the video. The correct developer mix, sodium carbonate to water, is 1/2 tablespoon (10grams) to 1 liter of tap water.
Is your trans positive or negative for dry film method?
Dry film photo resist requires a negative photo image, as in, where light strikes, the photo resist will harden and prevent the copper from being etched.
How to export negative photo image from Eagle ver 7 freeware? Do you know
I am not familiar with Eagle. Perhaps you could find an Eagle forum and ask there.
I figured it out and now have negative capabilities. My HP prints dark so no litho
needed. Nice video & info.
Where do you get this film from ?
I have been getting it from EBay sellers.
Thank you.
What temperature do you use to laminate the film on to the copper clad ? Is it 230 degree C or F ?
230 deg F for my laminator. Use an IR thermometer to measure the temp of the board as it leaves the laminator. It should be between 110 and 130 deg F. Adjust laminator temp as needed to get this temp.
Thank you very much for the information. I also set my laminator temp as 110 °C (its 230 °F), but the problem is, when I use water layer in between copper and this film, sometimes after going through laminator, I find 1-2 backish spots. May be its due to high iron content in our tap water. I tried to use boiled water too, but without success. May be distilled water might help but havent tried that. I actually pass the filmed copper two three times in order to have better adhesion of this film to the board. And yes, I use two plain sheet of papers on both sides so that the roller of the laminator doesnt get direct contact with this film. My laminator is not that highest quality so a better protection. The main problem is getting this film without any wrinkles on it. I ordered 4 times from China, but the last one at least usable to some kind.