Introduction: Making PCBs at Home (Toner Transfer Method)
There are lot of times when we, as a maker, face obstacles such as circuit complexity, wiring problems and untidy projects while using prototyping boards. Since any good project must be neat and tidy if it's meant for demonstration purposes. So to get rid of the above stated issues, we start looking for alternatives. Clearly, we have an idea that PCBs are the way to go but still, for some of us, there are equipment restrictions and we feel that its not possible. But believe me, it is!
This instructable focuses on guiding the reader to make his/her own PCB using the remedial Toner Transfer method. There are a lot of instructables and websites out there covering how to make PCBs at home affordably, and I too have followed them, but still there are some skills and hacks that one develops with time and experience and this instructable covers how I make my PCBs.
I don't like posting content which's already there on the internet, but this time I had to, because most of my projects revolve around custom PCBs and I didn't want to keep writing the PCB manufacturing process in them over and over again in all my instructables. I also wanted to detail the process a little more and so here we are.
That's all I have to say about this instructable. So, without further ado, let's begin this!
Step 1: Gather Around Some Stuff
The stuff which you are going to require for making a PCB are mostly hardware and building tools. They're neither too cheap nor too expensive and are easy to come by.
- Copper Clad Board
While buying this, keep in mind to buy a grease-free board, that is there should be almost no green spots on the board.
- Ferric Chloride Etching Solution
This is the etching solution which will be used for converting copper into a non-conductive compound.
- Drilling Machine
It is up to you whether you use a full-on drilling machine rather than a hand-held mini one. I use a handheld drilling machine myself. Here's how to make one yourself.
- A Permanent Marker
- Zero Grade Sanding Paper
- The Printed Layout
The printout of the circuit which you're going to make. Note that the paper on which this layout has to be printed must be glossy, the kind of paper in magazines which has smooth texture. Also make sure it's printed using a laser printer.
- A Clothes Iron
That's all for the requirements. Proceed to the next step.
Step 2: Preparing the Copper Clad Board
The copper clad board which you have is prone to passivity.
Passivity is the process of formation of oxide layers to prevent corrosion.
In any copper clad board, there's copper which is a passive metal, and therefore by the above definition, it, by itself, forms a layer of Copper Oxide whenever it comes in contact with the atmosphere to prevent corrosion. Since copper oxide is quite conductive, it will cause a problem in our PCB. Therefore our first job is the removal of this layer.
Removing the Copper Oxide layer:
Pick up the zero grade sandpaper and start sanding the copper board until you are able to see a metallic lustre.
You can clearly distinguish between the sanded and un-sanded boards in the above posted picture.
Cutting the Board:
Now that we've removed the copper oxide layer, let's cut the copper board according to the printed layout. Try to have extra keepout regions near the borders to allow cutting errors.
To cut the board, I use my handy scissors and sometimes my thermocol knife. If you have a circular saw, then use it because it is the best way to cut copper boards.
Step 3: Transferring the Toner
In this step, we'll be transferring the laser tonerfrom the printed layout to the copper clad board.
To transfer the toner:
- Pick up your clothes iron.
- Set it to max temperature and turn off the steam.
- Pick up your copper board and layout and place the layout on the board such that the toner on the printed layout must be in contact with the copper side of the board.
- Heat the entire set-up through the back side of the paper for 2 minutes using the clothes iron with great amount of pressure. Keep moving around the iron in a circular manner around the board to ensure consistent transferring.
- Once you feel all the toner has been transferred onto the board, stop the ironing.
- Drop the hot board in a water bath instantly.
- After a few minutes, pick it up and gently rub off all the paper so that you have only toner traces on the board as shown in the above picture.
Now the toner has been successfully transferred. If you notice some incomplete traces, no need to panic. You can easily complete them using your permanent marker.
However if a lot of toner hasn't been transferred successfully, repeat the process by sanding the toner and re-transferring it. It took me two attempts to do this. The failed attempt picture has been included above.
Step 4: Etching the Board
Right now our board has been carved onto with a layout. It's much like a piece of code left to be executed. Therefore to make it much closer to a finished PCB we'll have to etch it using an etching solution. I'll be using Ferric Chloride since it's easily available to me.
We'll be etching our board to keep only the useful amount of copper as conductive traces. The main concept of etching is basically converting surrounding regions of copper into a precipitate, in my case it's copper chloride,
and removing it along with the etching solution after the reaction's complete.
The useful traces part is kept from reacting by concealing it with toner. That's all that's happening over here.
To etch the board:
- Pour some ferric chloride solution into a non-metallic container.
Ferric Chloride is highly corrosive in nature therefore I'd like everyone to avoid using metallic containers because it reacts with the containers. Using plastic containers is a good choice. Also prevent any contact of your skin with this etchant. Instead, prefer wearing gloves throughout the process.
- Drop your copper board in it and leave it for some time.
In my case, the whole etching process took about 45 minutes.
- Keep watching your board in intervals of 15 minutes and pick it out when you feel it has been etched completely.
The way I test if a copper board has been completely etched or not is by looking whether it looks partly translucent or not. However the PCB that I had this time was wonderful. On etching, it turned yellow.
Now that your PCB has been successfully etched, let's remove the residual amount of toner to gain our printed circuit board.
Step 5: Removing the Residual Toner
Now our PCB is almost finished. All that's left to do is to remove the residual toner to expose the copper traces. So let's just get on it.
To remove the residual toner:
- Sand the whole PCB using a zero grade sandpaper.
- Using acetone-dipped cotton bale, clean the whole board thoroughly.
I have observed that using acetone for toner removal is better if you're wanting your PCB to be neat and clean. But it doesn't mean that the sanding method doesn't stand a chance, because it's not like that sanding is untidy. It just leaves a few scratches.
Step 6: Drilling
The PCB is done, the copper traces are there but where to insert the components? To be able to insert our components, we'll have to begin drilling holes for them.
Use any kind of drill you like for this purpose.
The only tip that I'd like to give to beginners is that while using drilling machines, first place the drill bit perpendicularly over the to-be-drilled spot and then power it up temporarily whilst exerting a small amount of pressure. This prevents the drill bit tip from straying off and produces good drilled holes.
Step 7: Tinning the Traces
In some cases, the traces of the PCB are narrow. This is the case for most SMD PCBs. In such cases, there's a risk of the wire breaking off the board due to excess while long soldering. To prevent this, what I, and many others do, is to apply solder on the traces, this process is known as tinning.
Thanks to sergeweb1 for pointing out that this process' main aim is to prevent corrosion of copper traces, that is the reduction of conductive copper due to formation of Copper Oxide caused by exposure to the atmosphere.
Not only does it strengthen the traces, but also it eases the soldering of components. Therefore it's a win-win.
To do this, simply apply some amount of solder on the soldering iron tip and gently slide it across the traces.
Applying flux on the traces before doing this produces better results.
Once you're done with the soldering, your PCB will look like the one posted above, cool.
Step 8: Congratulations!
Congratulations on making a PCB at home yourself and on learning how to do it. Now you're open to a whole new world of electronics where you can easily conquer complicated circuits with PCBs which seemed impossible using prototyping boards.
After completing the PCB, just insert and solder the components by referring to the schematic of the project you're making.
I've attached pictures of my PCB after all the components were soldered in to give you an idea of how a finished PCB looks like.
That's it for this instructable. If you have any doubt, feel free to comment. Don't forget to follow me if you liked this instructable. Also, post pictures of how your PCBs turned out!
Thanks to Ashish Choudhary for lending his camera.