How Does PCB Board Fabrication Ensure Durability?
PCB Board Fabrication Ensure Durability
The longevity and functionality of printed circuit boards, or PCBs, is largely determined by the quality of their construction. In the manufacturing process, a lot of attention is given to how well each layer, component and part of the board will hold up to various environments and conditions. For example, a military or defence application might require the board to withstand vibration, shock and exposure to a range of chemicals. PCBs are also subject to long hours of power usage. To ensure durability, the fabrication process takes many steps to guarantee that each layer will be able to perform as expected.
pcb board fabrication begins with a review of the design. This is known as a Design for Manufacturability (DFM) check and ensures that tolerances and specifications can be met during the fabrication process. The DFM check is also a good time to see if the board’s fabricator has all of the components required for the fabrication process.
Once the design is reviewed, it is scanned into a system called Gerber. This software translates the data and creates digital files that are used to produce the PCB’s inner layers. The next step is imaging the PCB’s inner layers on a plotter printer to create a film. Technicians then apply the film to the laminate material and line up each inner layer using registration holes. This will help to align the films when etching the copper onto the bare materials later.
How Does PCB Board Fabrication Ensure Durability?
After applying the film, technicians etch the copper onto the PCB’s inner layers. This is done with various methods, but the most common involves a solution of ferric chloride and water. This removes the areas of copper that don’t contain pathways, leaving behind the traces that carry electrical current from one end of the board to the other. This is a critical process for the integrity of the final product, as any errors will be very difficult to correct.
Afterward, the remaining copper is plated to create the conductive patterns on the board. This includes the traces, pads and holes for components. After plating, a machine runs an automated optical inspection to verify the absence of defects. This process looks for dents, pits, scratches and pinholes on printed traces and pads, as well as for mismatched diameters on plated holes.
The final step is drilling the registration holes on each inner layer pair. These are then drilled on the CNC machine to a precise location. A deburring process removes any elevated ends on the holes that are known as burrs. The hole walls are then electroplated with copper to form plated-through holes. This connects each of the conductive layers on the PCB.
The PCB can then undergo burn-in testing, which pushes the power through the board for up to 168 hours. This helps to ensure that the board will withstand the specified stresses and loads without failing early. This test is especially important for military and defence applications where a high degree of reliability is required.
