Saturday, 24 March 2012

how to print pcb without PC and printer at home







here,i want to show a simple method to print pcb at home even without a computer and a printer. Although this method is time consuming but very useful in absence of computer & printer. In this method, you will need following things :

  1. a copper clad sheet
  2. a general purpose pcb of same size
  3. a permanent marker
  4. a pair of hand gloves
  5. a hand drill or any alternative to make hole
  6. rubber bands and cello-tape
  7. kerosene or acetone to clean pcb
  8. ferric chloride for etching pcb(35 to 50 g in 1 liter distilled water)
  9. sponge or any piece of cloth
  10. sand paper
step1 gather all equipment mentioned above. Handel ferric chloride carefully. Some equipments are not shown in the photo.
step2 now, design a lay-out of your pcb with pen and paper. when you complete, carefully inspect all the traces and assure that you are not forgetting any kind of conection.make a lay-out as small as possible i.e. don’t make long connections. after making the complete lay-out design the same on general purpose pcb with the permanent marker.dont't worry you can use the same after washing it with acetone or kerosene.
step3 join the general purpose pcb & the copper clad with each other with the help of rubber bands and cello-tape.do this well because it is necessary that combination don't move from their positions.note that this method is only applicable for the components that fit on the general purpose pcb.
step4 now, drill the copper clad. Make holes in copper clad through the general purpose pcb .follow the design which you have made on pcb.this task require much accuracy & time. As you are drilling through the pcb the distance will be 0.1" between any two adjacent holes.
step5 here the photographs of completely drilled copper clad is shown.
step6 it's time for most complicated task. You have to design the same lay-out of pcb which you have made with the paper & pen. draw the lay-out on copper clad with marker pen. Some precautions which should be taken in order to make a perfect circuit:
* cheek that two non-touching holes also remain non-touching while drawing the lay-out.it is not necessary that you make a perfect round around the holes. But carefully see that rounds remain non-touching.
* make the traces as thick as possible.becausse it happen sometimes that the etching solution also etch the traces.
* if you can't make the traces directly ,you can use pensile and scale to draw the traces and then with marker.
step7 here the completely drawn circuit is shown.
step8 It’s time for chemistry. Ferric chloride is chemical which comes in solid form. Make liquid solution by adding 35g to 50g in 1 liter solution. Caution: Ferric chloride solution is toxic. It can cause skin burning or irritation. Use hand gloves during etching. Do not spill the ferric chloride on the skin. If this happens accidently, wash with water. Do not keep ferric chloride in places accessible to children. Don’t wear your favorite clothes while handling this chemical because it stains permanently your clothes. Place newspapers under the chemical container to protect the surface of your home .please do this in bathroom or any other place except in main room of your home. Do every thing at your own risk.
step9 now this step is not mandatory. But if you want to save unused clad from etching cover it with plastic.
step10 I had made this hanger to dip the pcb.it is very easy to make.
dip the pcb in ferric chloride
step11 the process of complete etching will take the time of 20 to 25 minutes or even more but don't be panic. Inspect the pcb periodically.
step12 when you become sure that pcb is completely etched, take out your pcb out of container and wash with water. Then clean your pcb with acetone or kerocine.it will remove the permanent marker from your pcb & only copper will stay.
step13 when your pcb is dried rub it with sand paper & your pcb becomes complete.
note: never place ferric chloride in steel or any other metal container always keep it in plastic container.