Intro: Super Easy & Cheap Flexible, Double Layer OR Multi Layer PCB
One of the basic component of an successful electronic project is PCB. If PCB is used for the project is designed with good quality, more the chances you have to get the project to success with minimum effort. Electronics project built using solder-less or solder-able boards are prone to errors and frustration.
There are many DIY projects around on the net explaining how to build PCBs but most of them are not of good quality, takes a lot of time to build and are restricted to single sided PCBs. Here in this instructable, I will provide you with the details of developing PCBs of Single, Double, Multi Layer AND Flexible PCBs which could be built easily at home and takes very less time to built same. The quality will be almost same as professional looking PCBs and will provide a solid base of your electronics project.
Step 1: Things You Will Require for Building PCBs
The basic idea is to use the Copper Clad boards which have base of "Fiber Sheets". The boards which have different material used for its base might not work but you can give try at your own risk. So below are the things that we need to build the PCBs...
- Copper Clad Board with Fiber sheet base
- Printed Circuit on Glossy Photo Paper
- Rubbing Alcohol
- Scratch Pen (visit my another project to see how to build it LINK)
- Masking Ink OR 5 minutes epoxy (and oil based color if you will be using epoxy)
Take a sharp knife and peel of all the fiber sheets attached to the copper clad as shown in the pictures. There could be multiple fiber sheets attached to the copper clad and you have to remove them all one by one with only last one attached to the copper clad.
The fibber sheets comes off very easily and you don't have to mess with it to take apart it. Insert knife at one edge of the fiber sheets, let it go 1-2 inch deep and pull the sheet with your fingers from the board. IT'S EASY!
Step 3: Cut and Clean the Copper Clad
Once you have the copper clad ready, cut the sheet to desired size.
- Flexible PCBs: If you want to make flexible PCB, just cut the copper clad to desired size. With my experiments so far you can't have double sided or multi layer flexible PCBs using this approach. May be you can just remove more fiber from the sheet using sand paper but be careful as it may make sheet thin and easily breakable. Or just use a single layer to make flexible PCBs
- Double Sided PCBs: Cut two piece of the sheets of same size and keep them apart for further processing (don't glue them at this stage)
- Multi Layer PCBs: Cut as much as the layers of same size you require from the copper clad and keep them apart as mentioned above
Step 4: Heatless Toner Transfer the Circuit to Copper Clad and Etch
This is an very interesting idea I got from this instructable. It uses the rubbing alcohol and acetone to transfer the toner from the glossy paper to PCB. Please follow the steps provided in the above link to transfer the circuit from paper to board.
Below are some points that you may want to follow to have an perfect image transferred...
- Make sure both copper clad and glossy paper are clean and have no oil / lubricant on it
- Just use fresh water and tissue paper to clean copper clad. Don't use any cleaner or some other chemical to clean it as it might leave oil on the copper clad
- Use good amount of Alcohol and Acetone mixture on the copper clad before placing the paper over. It should make whole paper wet once placed on top of copper clad
- Let it dry for atleast 30 minutes and don't peel it before the mentioned time
- Dip the board in water for couple of minutes before starting the paper peeling process
- Once you start seeing the printed circuit with having some paper on it, stop the peeling right there and let the board dry again for next couple of minutes
- Dip it in water again and peel of the remaining paper
- Take a wet tissue paper and remove any remaining paper within the traces by applying a gentle force on it. This step is necessary otherwise the copper will remain between the traces and you could have short circuit
- Once the copper clad is etched in the ferric chloride, check the traces against any source of light.
- Remove the unwanted copper you see between the traces using the scratch pen (or any other tool you have)
Step 5: Align the Copper Clad Sheets and Glue Them Together
Align the copper clad sheets together using an good source of light and apply 5 minute epoxy to glue them together. You may make few holes through all the sheets and use some wire to align them as shown in the pictures. Let it dry for couple of minutes and clean it using Acetone or any other cleaner. Use can sand the board also to remove extra glue stick to the board.
Step 6: Ink It, Drill Vias and Scratch Pads
Once your PCB is ready after you glue all the layers together, its time to mask it using Masking Ink or 5 minutes epoxy whatever you have. Usually masking is done using stencil where ink will be applied to all the traces except pads. If you know and have the stencil you can use same in this step or like me, apply the ink to whole board and later remove it using the scratch pen from the pads.
If you don't have the masking ink, you can use the two part epoxy in this step with oil color. Mix the color with the resin first and mix the hardener later on. You can mix a small part of acetone to thin it further if required.
Yes this step is time consuming if you don't have the stencil as you have to scratch all the pads one by one manually. Once done, drill the vias using any tool similar to handheld drilling machine.
Solder all the pads and solder vias using a thin wire between the layers.
Step 7: Your PCB Is Ready!
Your PCB is completed now and would be ready for the next level of adventure in your project. You can silk screen it if you know how to do it and have required tools with you.
Enjoy and provide suggestions / comments for same.