Test Quality During PCB Board Fabrication
When it comes to PCB board fabrication, quality is key. The process involves many steps and inspections to ensure that the finished product complies with design requirements. This is especially important if you plan to use your PCB in an environment that requires high reliability and performance, such as aerospace or automotive. Here are some of the main tests and inspections that you’ll likely want to perform to ensure that your PCB satisfies these demands.
One of the most basic and effective tests is manual visual inspection (MVI). During MVI, a worker examines the PCB under magnification to make sure it has met all specifications. During this stage, technicians look for common defaults, such as incorrect dimensions, shorts and voids. They also check for other defects, such as uneven thickness and a lack of copper plating, that can impact the board’s functionality.
The next test is the etching of the copper layer, which can be done either manually or through an automated system. The pattern of the artwork is etched into the copper layer using a photoresist material that protects the preferred parts of the design from dissolving in the etching solution. Then, the excess copper is washed away and the bare copper layers are cleaned. Finally, the registration holes are punched into the bare copper using a machine. This step is crucial to ensuring that the inner and outer layers of the pcb board fabrication line up correctly and connect with each other through the plated copper.
How Do You Test Quality During PCB Board Fabrication?
Once the bare copper is ready, it’s plated with a thin copper coating to support conductivity. This layer must pass a number of tests to ensure that it supports your device’s functionality and performance, such as detailed analysis of the copper’s tensile strength and elongation and testing for its solderability (to ensure that components will adhere to the bare copper surface).
In addition to these essential mechanical tests, a PCB also needs to pass electrical tests, such as continuity and a hi-pot test, which is where the board is brought up to a high potential to check for shorts and opens between different copper layers. The latter is particularly important for high-speed circuits where signal transmission and integrity are critical.
Whether you’re designing for prototyping or for production, the key to ensuring good PCB fabrication is making a clear set of test and inspection requirements for your manufacturer. This will help them to identify and solve any issues before they become a problem for your project.
Depending on the class of a PCB, IPC standards set specific tolerances for pad, hole and trace dimensions that must be met during manufacturing. A manufacturer that does not meet these specifications will be at risk for production problems, such as shortened component lifespans or even premature failure. If you’re unsure of the testing and inspection requirements that are necessary for your PCB, contact a PCB engineering firm like EMSG to discuss them with a team of experts.