wave solder residue (don't let this happen!)
Manufacturers of PCBAs are everywhere, and though their assembly lines look similar at a distance, no two setups are created equal. I’ve visited factories all over the world with a huge variety of size, complexity, cleanliness, and quality. I’ve helped launch appliances, medical equipment, consumer products, and automotive components. I’ve managed product lines that were 10 years past their expiration date and built on tools no one has even heard of anymore.
And I can tell you that if you want to have your product come out of the factory right, you can’t simply trust that your manufacturer understands your design or assume that you know how they’re going to build it. In addition, designing products that can handle sourcing shortages and long lead-times is crucial for maintaining continuity in your customer delivery.
Design for manufacturability strategies can include a lot of things, but here are some big ones that when done poorly can negatively impact quality, cost, and availability:
• Board planning: placing heavy components on both sides of the board forces complex reflow strategies including gluing down parts. Component commonization can reduce the setup time of a production run and increase your buying power. Through hole components often require entirely different assembly lines, some of which you may want to avoid. Before starting to run your traces, make sure your component locations make sense with your manufacturer.
• Board testing: determining the best testing approach rarely means only one type of test. AOI, flying probes, ICT, bed of nails, function testing, and software-based self-test routines can all be used to great effect, but each comes with its own set of tradeoffs and cost. Test too much and you spend more than you need, test too little and you may deliver a bad product.
• Assembly and rework: the rework station is an often-overlooked area of a plant but it can be a source of major headaches. Warranty returns and field failures are often the result of units improperly handled in these areas. This is because rework areas often have fewer quality controls than the main assembly line where machines do most of the work in pre-programmed steps. In addition, the assembly station where PCBAs are stuffed into housings is often a major bottleneck in the manufacturing process and carries a disproportionate cost in the overall delivered product.
• Sourcing: how many of your parts are multi-source? How many are single sourced? Sole-sourced? How much of your time do you want to spend writing ECNs after your product launches? Avoiding component types with a troubling past of sourcing issues can be a game changer, but implementing this as a strategy is easier said than done, and often your CM can be a huge resource – if you know how to direct them.
Custom Bed-Of-Nails functional tester