Professional PCB making at home
We know that PCB has a great role in our circuits.
It not only keep parts arranged, but also makes the connections smartly navigated so that future parts change requires small effort. In readymade kits available in market, all kits comes with own PCB and this makes them look better too. But the circuits we make and develop in home, doesn’t have a specially designed PCB to suit the circuit, so we have to do them on veroboard, which also takes time in making and it requires much larger board size as we have to use manual jumpers everywhere.
So, what do we need?
Blank Copper Clad Board,
Ferric Chloride as etchant,
Rubber gloves and safety glasses for our safety from ferric chloride,
Scale for measurement,
Hack-saw Blade for cutting Copper Chad Board,
PCB Artwork Printed on magazine paper by laser printer,
Scotch Bite scrubber pad,
Ether, or spirit even nail polish remover
Soap, Water, plastic tray, cellotapes, miscellaneous…
First Step: Artwork preparation
Make own PCB layout in computer. You can use any PCB schematics drawing tool, or can use photoshop or other image creation software to make the layout. You need to follow some guide if doing in photoshop.
1. Make sure you draw lines with 13 pixels width
2. Make sure you put 45 pixels circle in each component’s pin point. Use 60px for thick pin components as TO-220 devices.
3. Make all corners smooth by creating a curvature.
Then print the artwork in flipped(yes, flipped) form to a magazine paper. Any glossy magazine paper can be used. Print this at 300 dpi (600 recommended) through a laser printer, or print it via inkjet printer and xerox it to a magazine paper. If your magazine page size allows multiple numbers of artwork to be printed, do that. In this example, I have printed four artworks in a magazine paper.
Second Step: Preparing Copper Clad Board
Cut a piece of Copper Clad Board which is 1cm large in length and breadth from actual borders of artwork. This ensures your PCB will have some spare space for bearing scratches, etc with the edges. Also after that you need to use sandpaper or sanddrill to give the edges a perfect surface (not essential). Then after preparing right sized Copper Clad Board, you need to scratch the copper surface a little hardly. This would remove all sticky dusts and other things from the surface, and will shine the copper indicating it’s ready for the next step.
Note: Use FR4 Copper Clad Boards
Third Step: Transferring layout to Copper Clad Board
Now it’s time to transfer the artwork to our Copper Clad Board. We’ll use normal heat toner transfer method for that. You need a Dry Iron for this.
Be careful while doing it because dry iron may burn you badly.
Now place the artwork upside down to our scratched Copper Clad Board. See through light if there is artwork got outside when placing. After correctly placing it, fix it by cellotapes in the backside,. This ensures your artwork will not move during heating.
Then heat the iron at ‘cotton’ preset, and rub it on the artwork very firmly. This will melt the toner printed on the paper and it will stick to the Copper Clad Board. Do rub it for 2-3 minutes and give attention to the corners and edges. After done, soak it in cold water, then in soap water to make the paper wet and tear it off. Remove the cellotapes and rub the paper with finger to remove it completely from the board. Iron-ed Copper clad board soaking in soap water
Please don’t use nails as it can cause the toner to be removed from the Copper Clad Board. It’s time to judge your work. If you haven’t did the right pressure or temperature while ironing, the artwork will contain some broken connections, even some missing points. For example see the below image.
In this case, you need to remove the broken artwork from the Copper Clad Board using ether, or spirit or nail polish remover, and scratch it again and do again the iron transfer process by increasing the heat and pressure a little and be sure to press it hard in corners and edges. This time, if you do it correctly, it will look like the below one.
Note: The toner covered area may contain micro fibers of papers, no need to worry. But if the toner covered area has small cracks, then use a waterproof marker pen to cover it. Micro Fibres of paper on tonerFourth Step: Etching the Copper
You can use any kind of etchant to etch the copper clad board. I use ferric chloride solution.Ferric Chloride etchant
Be careful while working with Ferric Chloride . It’s a very harmful chemical. If you have solid FeCl3, then dissolve it with 10x water in plastic dish and firmly stir it by a plastic teaspoon, or a stick. Be sure to put on safety glasses and rubber gloves, as ferric chloride can put irremovable stain on your clothes. While mixing with water, it creates much heat so, stir the water firmly and gently while adding Ferric Chloride. This Ferric Chloride evaporates HCL fumes, so you should do this step in outdoors. After the solution is ready, soak the Copper Clad Board in it and keep for some minutes. The etching speed will depend on temperature, density of FeCl3, etc many factors. 50-60degree Celsius temperature of solution is considered the best for etching. Take the board out of the dish and inspect it if unwanted copper has been completely dissolved or not. Partially etched PCBWhen you remove it from solution, rub and clean the surface by fingers(rubber gloves) to remove resistive Copper Chloride layer on it which slows the speed of etching. And after all unwanted copper are removed, then you take it out, and clean it with fresh water. And for the remaining ferric Chloride solution, if you are going to use it in a few days, then store it airtight in a plastic container. and if not then don’t throw it. You need to add washing powder or other soft base to it to make it neutral, and then throe it to the drain. And yes, throw the disposable rubber gloves too to trash.Completely etched Copper clad board
Fifth Step: Washing the PCB
Now clean the PCB with mix of soap water and spirit(ether) and the toner will be removed from the board. Use a scrubber for this purpose as the toner sticks very well to the copper. Removing toner from PCBAfter washing it properly, it will show shining copper layout on it. This step makes you happy as you can see the result of previous efforts. Cleaned PCB awaiting drillingSixth Step: Drilling component holes in the PCB
For drilling the holes, I use manual hand drill. But you can use power drills if you are experienced. Use 1/16? drill-bit for piercing components holes and 1/8? for PCB mounting screw holes. Be careful not to bend the drill, just drill straightly. And yes, put a block of light wood below PCB while drilling, this ensures your drill-bit’s head isn’t crashed with any hard surface below. PCB after Drilling
After drilling all necessary holes, rub both surface with sandpaper(120) to make the drilling hole’s both ends smoother, as it lifts up while drilling.
Seventh Step: Protecting the exposed copper from environment
Since there are exposed copper connections, these may get affected to weather and moisture. To prevent this, we need a special coating on them.I use air drying insulating varnish 1A-FD for that. You need to put a thin layer of this to the PCB surface by a cotton piece and let it dry in the air. Keep it front of table fan, so that it dries fast. This may take 10 minutes time. After applying Varnish coat.
Now, since some drops of the varnish got into the holes for components, you need to drill it again. This time you can also clean the holes by using a hard metal wire too. And remove this varnish from around holes (the soldering areas) by a sharp blade. After that, you will be amazed that you have finally built up your own homemade PCB.Complete PCB
Now it’s time to put components and solder them. Enjoy….
And yes, please leave a reply below if you found this useful or have some questions or doubts.
Comments on this article before 07-12-2011,
Well, it took 1 hour to make, and 5 hours to write down this summary.
Abhijith on May 30, 2011 – 8:27 pm
Elizabeth on July 19, 2011 – 5:44 pm
Logo Collection on November 22, 2011 – 4:22 pm
tahin hossain on November 22, 2011 – 5:00 pm