johndesigner
Newbie level 1
prototyping circuit boards hobby
I've been making printed circuit boards for prototyping for over 20 years. I print on opaque film with a laserprinter and use 2 sheets to obtain sufficient density. Then I use transparant strong air bubble foil (used for protecting fragile objects during transport) to make sure the film is pressed firmly to the circuit board. The bubble foil is placed between the GLASS plate and the FILM, this to avoid focus problems (thin or missing routes). I use UV exposure with 2 X 40W tubes running on an electronic ballast from OSRAM. Then I develop the circuit board in a warm solution of Natrium Hydroxide. With the rigt temperature and dosage the photo layer comes off in about 20 seconds. After etching I expose the circuitboard again to UV but now without film. Then I develop the circuit board again and the photo coating comes off perfectly without other chemicals. To protect the circuit board from corrosion I use a kind of soldering paste (also used for soldering copper tubing, in Holland where I live it comes in small round boxes. I apply a thin layer on the entire circuit board. Then I put a small amount of solder on my soldering iron and apply it to the copper traces (tip temperature around 300oC), keep adding small amounts of solder to the tip as needed. It flows out perfectly in a very thin layer. Afterwards I clean it with terpentine to remove the paste. Then I wash it with liquid soap and rub the surface with a cloth. A high gloss tin plating is the result. The last phase is drilling the holes (Tip when making a double sided circuit board only print holes on ONE side, this makes drilling easier). For trough metallizations I apply copper leads and bend them on towards each side of the board and cut them to approx. 1mm length, then solder them to the traces. I hope you can use some of these tips.
Moved here
I've been making printed circuit boards for prototyping for over 20 years. I print on opaque film with a laserprinter and use 2 sheets to obtain sufficient density. Then I use transparant strong air bubble foil (used for protecting fragile objects during transport) to make sure the film is pressed firmly to the circuit board. The bubble foil is placed between the GLASS plate and the FILM, this to avoid focus problems (thin or missing routes). I use UV exposure with 2 X 40W tubes running on an electronic ballast from OSRAM. Then I develop the circuit board in a warm solution of Natrium Hydroxide. With the rigt temperature and dosage the photo layer comes off in about 20 seconds. After etching I expose the circuitboard again to UV but now without film. Then I develop the circuit board again and the photo coating comes off perfectly without other chemicals. To protect the circuit board from corrosion I use a kind of soldering paste (also used for soldering copper tubing, in Holland where I live it comes in small round boxes. I apply a thin layer on the entire circuit board. Then I put a small amount of solder on my soldering iron and apply it to the copper traces (tip temperature around 300oC), keep adding small amounts of solder to the tip as needed. It flows out perfectly in a very thin layer. Afterwards I clean it with terpentine to remove the paste. Then I wash it with liquid soap and rub the surface with a cloth. A high gloss tin plating is the result. The last phase is drilling the holes (Tip when making a double sided circuit board only print holes on ONE side, this makes drilling easier). For trough metallizations I apply copper leads and bend them on towards each side of the board and cut them to approx. 1mm length, then solder them to the traces. I hope you can use some of these tips.
Moved here