PCB Board Fabrication
The PCB board fabrication process involves a series of steps. These steps include: 1. Design – creating the schematics and layout of the circuit board. 2. Prototyping – producing low volume initial boards for testing. 3. Production Preparation – getting the data and components ready for the actual PCB manufacturing process. 4. Fabrication – making the actual board through processes like etching and drilling. 5. Assembly – populating the boards with components either manually or using automation. 6. Testing – validating the functionality of the circuit board. 7. Delivery – shipping the finished boards to the customer.
One of the key steps in the PCB board fabrication process is ensuring that the circuit board follows the original blueprints provided by the designer. This ensures that the final product will work as expected and minimizes the risk of expensive mistakes later on. If the board cannot follow the original blueprints, it may not be able to perform its intended function, which is why it’s important for designers and contract manufacturers to communicate closely. This ensures that all parties understand what is required for the fabrication process and that each step is performed correctly.
During the pcb board fabrication process, each layer of the laminate is covered in photo-reactive chemicals that are then exposed to UV light. This hardens the areas of the laminate that need to be etched. Afterward, the non-etched copper on each laminate is exposed to ferric chloride to etch away any copper that does not belong in the finished circuit board.
Key Steps in PCB Board Fabrication
Once the conductive patterns are established on the internal layers, the outer layer of the PCB is coated in photoresist and imaged. Then the PCB is placed into a copper plating bath, which deposits copper onto the surface of the panel in precise locations. Then the remaining copper is plated with tin, which acts as an etch barrier for the conductive patterns and drilled holes on each side of the PCB.
Next, the panels must be cleaned and inspected for defects. The drilled holes from earlier are used to align the inner and outer layers of the PCB. Each panel is then inspected with a tool known as a flying probe, which searches both sides of the board for signs of shorting. The inspection is done with reference to the original CAD files supplied by the designer, which helps to reduce the number of errors that can occur during the etching and drilling stages.
After the tin plating is completed, the PCB is cleaned again. It is then ready for the silkscreen printing stage, which transfers a detailed circuit and component placement diagram to the PCB’s solder mask layer. The process begins with designing the PCB layout using specialized software like Altium Designer, Eagle, or KiCAD. The design includes the schematic of the circuit, component placement, and routing of copper traces that form the electrical connections. Once the design is finalized, it is converted into a format known as Gerber files. These files serve as a blueprint for the manufacturing process, containing detailed information about each layer of the PCB, including copper layers, solder mask, and silkscreen.
Once the information is silkscreened, the panels are placed into a press and heated to a temperature that varies according to the fabricator’s calibrations. This process fuses the layers of the PCB together. Then the layers are cured under UV light.
