Printed circuit boards are a vital component in today’s machine-dominated society. Aside from serving as a base for modern devices, it also functions as a bridge for electrical signals to pass through connected devices. A great PCB design allows a smooth exchange between electrical components. The manufacturing process is just as necessary to optimize its usage and potential.
Here are some PCB fabrication techniques to remember for high-quality raw board output:
This is where the fun begins – imaging is how a PCB blueprint is transmitted on the physical board. Etching the design into the board is a critical aspect because this decides whether the pattern fits and matches the circuit traces.
Once the PCB layout is established, the board is coated with a material that hardens using UV light. The spare parts of the unnecessary board are removed after the photoresist process.
In the present, the imaging process is usually done via the traditional method of ultraviolet light or a photo tool. However, some big companies employ the latest trend: direct laser imaging. This modern approach enables you to skip the UV hardening process and directly etch the pattern on the board using laser tech.
This is the step of cutting off the excess metal from the printed circuit boards to expose the needed circuit patterns and create a smoother finish. Etching is commonly done by utilizing industrial solvents such as ferric chloride, alkaline ammonia, ammonium persulfate, and cupric chloride.
Another alternative to this chemical approach is by utilizing plasma and laser. The laser etching approach uses a computer-controlled laser to carve the excess copper, which will serve only as baggage to the circuit boards. Plasma etching is a dry process of using the plasma of a gas mixture to cut off the unneeded parts.
This particular technique provides extra layers of protection to the PCB. Since the usual board is made mainly of copper, the lamination step ensures that the metal will not conduct unwanted currents. There are different types of lamination, depending on the product and PCB usage:
Multilayer PCB – the PCB is coated with several layers and cured using high heat.
Teflon Laminates – used in PCB needed for high-speed signal exchanges, such as radio signals.
Sequential Lamination – this method usually applies to multi-layered PCBs and creates a middle layer between each subset.
Machining – Machining is a PCB technique that takes place more than once in the fabrication process to increase efficiency. They are primarily utilized in these steps:
Through-holes and vias – this involves stacking PCBs together and drilling holes through each stack, saving time and energy.
Panelization – the process of testing multiple boards at once to save on time. This is done by using a drill to create route channels and paths.
Materials used, PCB thickness, and method of drilling is taken into account to maximize the manufacturing process.
This step entails applying a metal finish to your PCB while making sure that the holes and circuits paths are working as planned. While the most commonly used plating is copper, plating techniques include:
Electrolytic plating – Uses electrolysis to plate the surfaces of the PCB after being submerged in a liquid metal finish. This ensures that no anomaly or irregular shape is created, unlike when using electrolysis.
Electroless Plating – Catalysts are used instead of an electric current to apply a metal finish.
Dry Plating – Plasma in gas form is utilized for this method while being subjected to a vacuum. Metal particles are removed and reused in designated places.
Being informed and well-educated about the PCB fabrication techniques can ensure that you know how to identify high-quality boards created with functionality in mind. PCB fabrication may be a task for the contract manufacturer, but knowing the particulars will help you choose the suitable materials and circuit layout needed. In addition, getting to know the basics about line width, spacing, and whole quantity can help you identify how to price the board properly.
Aside from saving repair costs in the long run, the fabrication process is essential because this is the stage where the PCBs are tested for their effectiveness and yield rate. This fabrication step ensures that the PCB design is modeled to cater to manufacturability, functionality, and efficiency.