Wednesday, September 24, 2014
DIY How to Make PCB at Home
It is possible to make PCBs at home with lines as thin as 0.1 mm. And the method is neither difficult nor costly. A hundred pieces of 15cm x 10cm PCBs may cost only Rs 300. The step by step method is:
1. Draw the PCB pattern with black ink (preferably ‘Rotring’) on a white sheet of paper. This step is saved if the pattern is already available (say, from a magazine).
2. Ask a commercial photographer in your town to make a same-size negative of the drawing. A 15cm x 10cm negative may cost around Rs 10.
3. Cut the copper clad laminate in the required size, file its edges till they are smooth, and clean the board with Vim powder, spirit or alcohol. Take it to a dark room (improvised by drawing curtains) and coat it with some photo- resist chemical by pouring some of the chemical over it. (A small night lamp or a red or yellow coloured light may be used in the dark room for working.) Close the photo—resist bottle tightly within 30 seconds so that it is not spoilt by excessive exposure to air. The coated board would dry up within 5 to 10 minutes, after which the negative film may be placed on the board, ensuring that the films enameled side is in contact with the board.
4. Take two plain glass sheets of 6mm thickness with each side of about 30 cms, having holes drilled in all four corners of each sheet. Place the set of negative and copper-clad board in between, with the negative on top. Press the two glass sheets together with the help of four pairs of butterfly nuts and screws fitted in the corner holes, and tighten them carefully (so that you dont crack the glass plates). Cover all these with a thick black colored cloth and take them out in bright sunlight.
5. Remove the cloth for 2-3 minutes if the sunlight is very bright, as at noon, or for 3-4 minutes if its not so bright outside. Again cover them with cloth and bring them back to the dark room. Alternatively, at night, the coated board in glass frame can be exposed to a 200W bulb kept within 7.5 cms for an hour.
6. Pour some photo—resist developer in an enameled or glass bowl tray and immerse the exposed board in it for 60 to 90 seconds. Thereafter, put the board in a water bucket and let the chemicals get washed away thoroughly for a few minutes. The etched PCB pattern will now begin to show on the board.
7. To see the pattern clearly and check it. cover the entire board with a small amount of photo resist dye. Wash the board gently to remove unwanted dye and dry it. Check whether pattern lines are intact or broken. If broken, mend them neatly with resist ink, enamel paint or nail polish. Remove _shorts, if any, carefully with a knife. Place the board on a gas stove or in an oven and bake it for 3 to 5 minutes till A it becomes sufficiently warm but not very hot.
8. Put some ferric chloride in a large glass bowl and pour some hot water on it. After the ferric chloride has dissolved, immerse the board in it. Add a small amount of hydrochloric acid, if you wish to speed up etching. Stirr the solution during etching. Take the PCB out after 20 to 30 minutes and put it in a bucket of water. Wash it thoroughly in water and then wipe out all the chemicals from the board using thinner. Drill the holes at required points and the board is ready for use. Varnish may be used as a protective material for the PCB. Some use a green coloured lacquer to resist solder flow and moisture.
Manufacture The chemicals used being sensitive to light. should be stored in a cool and dry palce away from light. The chemicals and material required for PCB fabrication are avail- able easily in most towns. They are also available in kit form for hobbyists. . As the chemicals for PCBs have odd smell and can be injurious to health, all precautions should be taken in their use. Ventilation, in particular, should be good. Children should not be allowed near the chemicals and smoking should be strictly prohibited in the vicinity. As re-use of the chemicals is not recommended, it is better to make all the pieces you may require of a PCB at one go, instead of remaking them a few days later.
1. Draw the PCB pattern with black ink (preferably ‘Rotring’) on a white sheet of paper. This step is saved if the pattern is already available (say, from a magazine).
2. Ask a commercial photographer in your town to make a same-size negative of the drawing. A 15cm x 10cm negative may cost around Rs 10.
3. Cut the copper clad laminate in the required size, file its edges till they are smooth, and clean the board with Vim powder, spirit or alcohol. Take it to a dark room (improvised by drawing curtains) and coat it with some photo- resist chemical by pouring some of the chemical over it. (A small night lamp or a red or yellow coloured light may be used in the dark room for working.) Close the photo—resist bottle tightly within 30 seconds so that it is not spoilt by excessive exposure to air. The coated board would dry up within 5 to 10 minutes, after which the negative film may be placed on the board, ensuring that the films enameled side is in contact with the board.
4. Take two plain glass sheets of 6mm thickness with each side of about 30 cms, having holes drilled in all four corners of each sheet. Place the set of negative and copper-clad board in between, with the negative on top. Press the two glass sheets together with the help of four pairs of butterfly nuts and screws fitted in the corner holes, and tighten them carefully (so that you dont crack the glass plates). Cover all these with a thick black colored cloth and take them out in bright sunlight.
5. Remove the cloth for 2-3 minutes if the sunlight is very bright, as at noon, or for 3-4 minutes if its not so bright outside. Again cover them with cloth and bring them back to the dark room. Alternatively, at night, the coated board in glass frame can be exposed to a 200W bulb kept within 7.5 cms for an hour.
6. Pour some photo—resist developer in an enameled or glass bowl tray and immerse the exposed board in it for 60 to 90 seconds. Thereafter, put the board in a water bucket and let the chemicals get washed away thoroughly for a few minutes. The etched PCB pattern will now begin to show on the board.
7. To see the pattern clearly and check it. cover the entire board with a small amount of photo resist dye. Wash the board gently to remove unwanted dye and dry it. Check whether pattern lines are intact or broken. If broken, mend them neatly with resist ink, enamel paint or nail polish. Remove _shorts, if any, carefully with a knife. Place the board on a gas stove or in an oven and bake it for 3 to 5 minutes till A it becomes sufficiently warm but not very hot.
8. Put some ferric chloride in a large glass bowl and pour some hot water on it. After the ferric chloride has dissolved, immerse the board in it. Add a small amount of hydrochloric acid, if you wish to speed up etching. Stirr the solution during etching. Take the PCB out after 20 to 30 minutes and put it in a bucket of water. Wash it thoroughly in water and then wipe out all the chemicals from the board using thinner. Drill the holes at required points and the board is ready for use. Varnish may be used as a protective material for the PCB. Some use a green coloured lacquer to resist solder flow and moisture.
Manufacture The chemicals used being sensitive to light. should be stored in a cool and dry palce away from light. The chemicals and material required for PCB fabrication are avail- able easily in most towns. They are also available in kit form for hobbyists. . As the chemicals for PCBs have odd smell and can be injurious to health, all precautions should be taken in their use. Ventilation, in particular, should be good. Children should not be allowed near the chemicals and smoking should be strictly prohibited in the vicinity. As re-use of the chemicals is not recommended, it is better to make all the pieces you may require of a PCB at one go, instead of remaking them a few days later.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment