How to make a PCB

Today, I will cover in detail and show the process of making a printed circuit board at home. In addition to a soldering iron and a pair of side cutters, you will need a laser printer, an iron, a micro drill, and a few other tools for this job.

I test my designs on traced PCBs and do not use universal prototyping boards. It’s more convenient for me personally, and here’s why.

On the one hand, tracing a PCB takes time. On the other hand, it is also required to carefully arrange components and connections on a universal board. Additionally, you will need to cut traces on a stripboard or, on the contrary, make the traces you need on a breadboard if it is a matrix of pre-drilled holes with separate copper pads.

A board designed in CAD can then be copied in any number, either by making it yourself or by ordering from a factory, all new and shiny, already with a solder mask and silkscreen printing.

Finally, repairing and modifying a circuit on a printed board can be easier than on a universal one. Especially if long pins of the components on a universal board are used as tracks.

So, I drew the scheme in Schematic Editor, part of the KiCad 7.0 software package. This will be a microphone preamp; I will describe it more thoroughly in the upcoming posts. Moreover, this essay is on making the actual board, not its schematics.

Next, one needs to run the footprint assignment tool and specify the footprint for each and every component.

Then, we need to export the netlist.

On the Edge. Cuts layer draw a rectangle that specifies the dimensions of our future PCB.

Now, we need to lock that rectangle so that it does not stand out too much and prevent it from being changed while we continue to draw our board layout.

One should ensure the Locked Items checkbox is unchecked on the Selection Filter.

Next, open PCB Editor and import the netlist.

Click Load and Test Netlist, and then Update PCB.

Then, you can place the components and draw the tracks.

We can view a 3D model of the future board at any time.

Once all the components are in place and the traces and polygons are drawn, one can print an image of the copper layer. You should turn off the toner save mode on your laser printer.

You can use glossy photo paper (designed for inkjet printing), any pages from glossy ad brochures or magazines, or special heat transfer paper for laser printers from electronics enthusiasts' stores. It is often colored yellow.

My board is single-sided, with all the components on the front side and all the copper on the backside. Therefore, we select the B.Cu and Edge.Cut layers for printing. The print scale should be 1:1.

If printing the front copper layer of F.Cu, we need to check the "Print Mirrored" checkbox.

Next, you must cut out a board of the required size from foil fiberglass. Some of us have access to professional cutters or use tin snips.

Others can utilize a rotary power tool with a cutting wheel or even an angle grinder. This is not the best option since fiberglass dust contains microscopic glass particles that irritate the skin and are very harmful if inhaled.

Due to its material, fiberglass PCB quickly dulls any tool except a diamond one. You can see the PCB with a hacksaw, but it will end up its teeth very quickly.

I use an adjustable tile hole cutter for cutting fiberglass. It contains two carbide cutters that can scratch a deep groove in the board and then simply break it along this groove.

These cutters are specifically designed for working on rigid materials, so CEM will not soon dull them. With this technique of cutting the PCB by scraping the track, we minimize the amount of glass dust and do not scatter it in the air.

Next, you need to carefully clean the surface of the copper foil. You can use the finest sandpaper, mild abrasive powder, or steel wool for dish cleaning. I use just a hard eraser. The point of cleaning is not only to remove dirt, oils, and oxides but also to cause micro-scratches for the toner to stick to.

Immediately after, the board must be thoroughly washed to remove any small foreign particles, then fried and degreased with acetone, lighter fluid, ethyl, or isopropyl alcohol.

So, we have a clean, dry fiberglass blank and a piece of glossy paper with traces printed on it. Textolite and paper are the same size. I fold them together and wrap them in a layer of office paper, newspaper, or, better yet, rolling paper.

Thin paper is needed so the glossy paper does not move relative to the PCB. Now, we place the wrapped board blank on a heat-resistant flat surface that we don't mind getting dirty. I use a stack of a few cardboard packaging sheets.

We take the iron, turn it on, and set the temperature as high as it goes. We place it on the blank board and iron it for three to four minutes so the blank has time to warm up nicely.

There is no need to press too hard, but the pressure should be firm. The skill comes with experience. To hold the hot workpiece while ironing, you can use a chopstick.

Remove the iron from the board and turn it off. Remove the wrapping paper from the board after it has cooled off, and place the PCB and the glossy paper in a warm water bath.

Next, slowly and carefully tear off the paper piece by piece from the fiberglass. The tracks and pads on the copper foil should be imprinted.

If some part of the board's design comes off, it can be restored with a permanent marker after the board is completely dry. If a significant piece of the polygon has fallen off, you can just tape it.

Next, I glue strips of tape on the non-foil side of the board to make small hanging rings to hold the board while etching. Throwing a chopstick through these rings is convenient to keep the board hanging. For etching to occur evenly, the board must be swiveled from side to side to mix the solution.

I use a ferric chloride solution for etching, which can be used multiple times. You can store it in a plastic or glass container with a non-metallic lid. This poisonous solution will corrode almost any metal, including stainless steel, so it should be stored, marked, and used cautiously.

To prepare an etching solution, you must take water at room temperature, pour it into a non-metallic container, and add ferric chloride little by little, stirring until the ferric chloride stops dissolving.

The solution will heat up during the dissolution process, not as much as when slaking lime, but noticeably. There is no need to filter the prepared solution or remove the sediment from the bottom of the container.

The optimal temperature for etching the board is 105–130°F (40–55°C). You can heat the solution past that, but then it may wash away permanent marker drawings.

I use plastic food containers for etching and a microwave to heat up the solution. I place the plastic container with the lid loosely closed inside a second bigger one with a lid on and turn on the microwave for one minute. This way, I can be sure that ferric chloride will not damage the microwave.

Once the excess copper on the board has completely dissolved, the board should be immediately washed with plenty of water using a toothbrush. If you do this over a metal sink, be sure not to leave a drop of etching solution anywhere; it can eat right through the sink.

Using acetone, we erased the toner from the washed and dried board and began drilling holes with a microdrill.

Trying the board in the case.

Then, you can begin soldering the components immediately. Still, the best results are obtained if you tin the entire copper foil. I use solder paste for this; just remember that it is toxic, and after working with it, you must wash your hands and wipe the table's surface clean.

Apply solder paste using a spatula in as thin a layer as possible, as if applying thermal paste to a processor. Next, heat the copper foil with a soldering iron.

Now, wipe or rinse the board with the same degreaser liquid you've used before transferring the toner, and you can place and solder the components.

This video shows a timelapse of all the DIY PCB steps.