Printed circuit board or PCB manufacturing aims to deliver a functional circuit board for the best price and in the least amount of time. This requires coordinating different pieces of the manufacturing puzzle, from selecting parts to final QA while preventing several potential design flaws along the way. Yet, common PCB manufacturing defects surface from time to time. It’s essential to address those problems timely to ensure high-quality PCBs. Specifically, the following six areas can cause problems for assembly if not given due consideration.

Common PCB manufacturing defects

1. BOM problems

Bill of materials that consist of incorrect data could cause the wrong parts to get ordered and installed/mounted on the board. Also, BOMs can collect outdated details and specify parts that aren’t available for manufacturing. Before sending a circuit board for manufacturing, check its BOM for correct parts, part numbers that match their descriptions, and PCB footprints correctly associated with their parts.

2. Incorrect PCB footprints

As mentioned earlier, it’s imperative to review the BOM to ensure that the right footprint gets associated with the part. However, the review shouldn’t stop with the BOM. Make sure that the footprint is correctly built according to the manufacturer’s data-sheet and industry standards. This inspection must also include the footprint pads to verify that the part will sit properly and solder correctly to the board.

3. DFM errors

One of the most important criteria for designing a circuit board is design for manufacturability. Make sure that the components get placed with correct spacing to one other and the edge of the board or other board objects. Without proper spacing, the parts may not assemble using automated equipment. This, in turn, will add enough time and cost to the manufacturing process.

4. Soldering defects

All the components must be correctly arranged to prevent soldering defects. For wave soldering, each part must be rotated to enter the wave perpendicular to it. Also, don’t place taller components where they’ll precede shorter parts into the wave. This could create a shadow effect, thus reducing the strength of the solder joints on the pins. For parts that go through the solder re-flow oven, make sure that both pins of smaller two-pin discreet parts stay balanced thermally.

5. Lack of testability

PCBs are run through testing to verify the connectivity and strength of all their pins after soldering. So, testing should be built into the board during the design phase. A test point must be included for each net on the board. Plus, it should be located where the probes of a test fixture could access each one without hitting/touching other components. When the design gets ready for manufacturing, add a separate file to detail the location of each test point with the rest of the manufacturing data.

6. Inadequate human access

Re-work technicians can’t change parts, repair other assembly defects, or test the board if there isn’t enough space to work. The lack of space is one of the common PCB manufacturing defects that adds expense and time to PCB assembly because the technicians have to work around the obstacles. Plus, there’s the risk of damaging other components. Also, installing the circuit board into its system could get difficult and tedious if the connectors and human interfaces aren’t placed properly for easy access.

Ready for your own PCB building run? Consider this top PCB manufacturing AZ company to help you.