The IPC said the USA made $24 billion worth of PCBs in October 2011. As we rely increasingly on electronics, we use more and more PCBs. So, PCB makers must label their products.
Putting a label on PCBs makes them real and helps sell them by making them recognizable in the market. There are many ways to label PCBs, like ink, stickers, stamps, and lasers.
Different producers use different ways to label PCBs based on their priorities for quality, cost, and time. We want to tell you that laser marking machines are the best way to mark PCBs because they are affordable, work well, and are easy to use, and the labels will last a long time. They are better than other labeling methods.
How to Make a Custom Laser Engraving Circuit Boards?
Tools & Materials
- 10W laser. It was utilized to draw the circuit onto a plain copper printed circuit board using a printer.
- Copper PCB. The entire surface of the circuit board is covered with copper on one or both sides. Copper can conduct electricity, but the phenolic material underneath cannot. By removing pieces of copper coating, people can create pathways between the elements and make the printed circuit board.
- Paintbrush. To cover the printed circuit board, a dense coating of paint will be needed, & a paintbrush will be helpful for this task.
- Ferric chloride. The material that you need to use comes in the form of salt, and you have to mix it with water before using it. This liquid can damage copper by taking it off its phenolic base. When you put on a mask, only the areas of the plate not covered by the show will be removed by the solution.
- Sandpaper. Lastly, it would help if we eliminated any leftover masks on the board. You can do this easily by using sandpaper.
PCB Assembly or Manufacturing Process
The process of making homemade printed circuit boards usually involves the following steps.
- Designing
In the first step, a drawing is made of the circuit board that will be created. You can either design the new circuit board or copy an open-source project. There are different computer-aided design (CAD) software options you can use, such as Fritzing, Proteus, KiCad, Eagle, and more.
- Masking
After designing the PCB, the design transferred onto the actual circuit boards. There are various ways to create the circuit, like using heat to transfer toner from paper, drawing it by hand with a special pen, or utilizing a 3D printer.
- Chemical etching of the PCB
After transferring the mask onto the board, the components of copper are eroded to remove them. By the end of the procedure, the circuit board must only have the pathways that create the circuit.
- End Finishing
After the corrosion process, The board will be prepared to be cleaned and drilled and have components soldered onto it. After that, you must check everything, turn it on, and be satisfied.
PCB Designing & Mask Creating Process
After creating a printed circuit board design utilizing the CAD software you prefer, you can save it as an SVG file to open in graphic designing software. Different coatings can be sent, such as the bottom view, top view, silk, mask, etc. You can also choose between normal/mirrored formats for each layer. To follow the process described, you need to apply a disguise to the printed circuit board.
The board part protected by the mask won’t rust and will stay on the final circuit board. The features of the committee that aren’t covered by the cover will be open to the iron chloride, which will rust and eliminate them from the board.
To create the PCB in this procedure, you must cover the entire board with a paint coating and use a laser engraver to remove specific sections.
To follow this method, you must invert the mask’s colors generated by most software (switch the black and white pixels). To do this, you can use two different software programs
- Inkscape: One software is utilized to change SVG into PNG, and it can also be used to turn the design into a black&white image if it was exported from the CAD software in color format.
- Gimp: Different software is used to change the mask’s color (turn white pixels to black pixels), and then the picture is added into the laser cutter software to be printed onto the plate’s surface.
Preparation of PCB
To start making the PCB, first, you need to apply a paint coating on the plate. A black water-based PVA paint is used, as a laser can quickly burn it. It is important to use dark paint as white paint reflects the laser and makes it less effective.
It is necessary to use water-based paint because it can be removed from the board easily after the copper board has been etched.
To begin the PCB production process, a paint coating is applied on the plate in a single, uniform layer. The entire surface should be covered without any holes/imperfections, which could cause damage to the tracks or create undesired points of contact. It is important to use dark water-based paint, which can be easily removed from the plate after the copper board has been etched.
It will help if you let the paint dry entirely before moving on to the next.
Engravings of Laser
After the paint has completely dried, the laser cutter can be used to remove the parts of the mask that are not needed.
As mentioned earlier, a 10-watt laser cutter was utilized in this tutorial.
If you use different equipment, you must try different combinations of such parameters to get the best outcomes. The laser does not have enough energy to make a hole in the copper plate, but it can remove paint and reveal the copper coating beneath it.
After using the laser engraver to remove the unwanted parts from the mask, it is essential to check if the circuit is printed on a board. This is because the laser can only deduct the paint, exposing the copper layer under it, and only the piece of the copper will rust. Remember that the dark parts will remain on the board after the corrosion.
The laser engraving process can take a long time, especially for larger boards. To speed up the process, it is recommended to only engrave the vital areas by using a tool in the CAD software that fills in the copper areas that do not need to be reduced. This will help to limit the quantity of paint that needs to be burned off by the laser. Otherwise, you will waste time removing the paint from unnecessary areas of the circuit board which are not part of the circuit. By reducing the quantity of copper removed by corrosion, the lifespan of the corrosive solution increases. This means that more prototypes can be made before the solution needs to be replaced.
Be careful not to print for too long, as the manufacturer suggests. It’s essential to take breaks of ten minutes as my printer recommends.
Etching of Chemicals
After printing the mask onto the plate with black lines to protect the areas that should stay and uncovering the copper that needs to be eliminated, you can use ferric chloride to corrode the copper. This process usually takes some minutes until all the unwanted copper is eroded. Check the plate occasionally to see if all the unwanted substances have been eliminated. It usually takes around 5 minutes to remove everything, but checking is essential. You can gently pour some water on the plate (without rubbing it) to see the result better. Also, it’s a good idea to shake the ferric chloride solution occasionally to make it work better.
Removing the Mask & End Finishing
After the rust is finished, you need to remove the leftover mask. You can use a brush & running water to do this. If you want a smoother finish, use sandpaper to eradicate the cover. Sandpaper is quicker and can make the surface look shiny and smooth.
When you’re finished, the circuit board should only have the copper pathways needed for the circuit. Drill the circuit board to make holes for the components, then sell everything together. Congratulations, you’ve made your first PCB utilizing a laser cutter( engraver ).
