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I don't have Ultraviolet source to expose PCB. I want to make PCB using UV expose method. I think normal home use CFLwill produce UV? How long time should i have to expose in this UV source? Guide me!!
The PCB used must be photosensitive. A bare PCB will not work.
You can buy pre-sensitized blank PCB's from most electronic suppliers. The most common variety of pre-sensitized board has a "positive" resist, which means that the areas shaded from light are NOT removed during photodevelopment ("development"). Thus, the developed board will show a pattern of the circuit you want. The positive-resist developer is usually an aqueous base, such as sodium carbonate or sodium hydroxide in water.
One can also buy a photosensitive film that you laminate to a bare board prior to exposure to light and development. Such films are usually "negative" resists. That is, the shaded areas ARE removed in development. DuPont makes a series of such films and they are available in small amounts on eBay. Your image must be a negative of the final PCB. The developers are proprietary and usually contain a particular organic solvent (check the MSDS's for more information). You must also consider the absorption spectrum of the resist and any photosensitizer included in it.
Since you are a beginner with little experience in UV or photochemistry, I strongly recommend that you buy a pre-sensitized, positive-resist board and use the commercial developer that is available with it.
John
I used toner transfer method before to make PCB. Now I want to make PCB from UV expose for better qualiy. Photosensitive PCB is nore expensive in market, so I want to expose in general PCB.Please read my replies again and take that advice.
1) NO, regular paint won't work. Some experimenters do use regular paint and ablate it with a CNC laser, which you are not doing. I don't think you have or are likely to get that equipment very soon.
2) Yes, you can buy the photoresist as a liquid and try to coat you own plates. You will get lousy results and not save any money.
3) As mentioned in post #6, you can buy photosensitive film and laminate it to the board. If you go that route, you will probably need to deal with a negative resist and special developers.
Are you trying to make a PCB for an electronic project, or are you trying to study all the different ways to make a PCB. If it is the latter, there are other ways we have not yet discussed.
John
Please read my replies again and take that advice.
1) NO, regular paint won't work. Some experimenters do use regular paint and ablate it with a CNC laser, which you are not doing. I don't think you have or are likely to get that equipment very soon.
2) Yes, you can buy the photoresist as a liquid and try to coat you own plates. You will get lousy results and not save any money.
3) As mentioned in post #6, you can buy photosensitive film and laminate it to the board. If you go that route, you will probably need to deal with a negative resist and special developers.
Are you trying to make a PCB for an electronic project, or are you trying to study all the different ways to make a PCB. If it is the latter, there are other ways we have not yet discussed.
John
MG Chemicals may still sell the liquid. I am not sure. I am not aware of a specific brand name. I would not consider even trying to do it. It is difficult to get a uniform coating. Spinning is probably the easiest -- check out YouTube for some examples. Again, I would not recommend making your own positive photosensitized boards. We do not know your location, so shipping of the liquid may present an additional problem.-What is the name of photoresist liquid in market?
That will depend on the resist that you get. I use Injectorall. My exposure with three, 15W BL bulbs runs about 12 minutes. From what I have read from people who use the MG boards, their exposure time would be less. With the same wattage of CFL, it will be longer than that. See the curves I posted.- Almost how much time it takes to expose in general CFL (15 or 20 watt) bulb?
You will get poor resolution. In fact, if it is over-exposed enough, the whole image may wash off. That is why I recommended using some sort of character and trial run to judge the exposure time needed.- What happens if I expose more than necessary?
Positiv 20 is actually 15 minutes at 70 degrees CUsing liquid photoresist you end up with a pretty messy work place and NO result at all. Liquid photo resists requires 24 hours of baking at 70°C and a slow cooling period in absolute darkness.
The same applies to Positive20 a sprayable photo resist made by Kontakt Chemie, Denmark.
Positiv 20 is actually 15 minutes at 70 degrees C
Datasheet here : https://www.electro-tech-online.com/custompdfs/2012/09/87-0705t.pdf