How to avoid PCBA wrong design

1. It’s too late. I suggest you get your EMS partners involved as soon as possible, preferably when the first draft of your PCB layout is available, and allow yourself enough time for prototype design and trial production. For all the checks you perform on paper or PC, there may be some “functions” that are only displayed when you produce the first batch of products. Before ordering all components for your first planned production build and submitting the design for CE certification, these components need to be refreshed.
2. Incorrect PCB Panel The ideal panel depends on the process that PCB and components will go through. If it is too big or too small, it may not be suitable for the production line. A special PCB (e.g. 0.8mm) may need to be in a smaller panel to avoid bending. Due to the lack of waste belts, it may be difficult to handle in production and testing. Breaking through in the wrong position may mean that the component is not rigid enough, or it is difficult to break through without damaging the component. Missing datum points may cause alignment problems. The best practice suggestion is to allow your EMS partners to cooperate with their PCB suppliers to optimize the panel design.
3. It’s too complicated. Unfortunately, if you install SMT on both sides of the component, the cost will be higher (usually double), so don’t do it unless you really need it. This also applies to via parts. Spending more time in the early stage of PCB design helps to shorten the assembly time and reduce the cost.
4. Error in component size or shape size It is worth checking carefully whether the components specified in the bill of materials (BOM) are actually suitable for the pads designed on PCB. Also consider whether the main body of the component is suitable; Usually, the components are placed too close or too close to the edge of PCB, which may cause them to be damaged during disconnection or processing.
5. Through-hole in solder pad When the space is tight, this is tempting, but in order to avoid solder disappearing from the hole when trying to connect components, the through-hole needs to be sealed.
6. There are too many component types and the number of components.
7. The size of mixed parts becomes more and more common with tiny components. People can easily use them, but if they are placed next to larger components that need more solder paste, the process will become a bit tricky and may require more expensive step templates. This is not a good idea.
8. Improper surface treatment of printed circuit boards. HASL conforming to ROHS standard is usually designated as standard surface treatment, but it is not applicable to fine pitch components. The shelf life of silver finishes is shorter than that of most products-maybe ENIG is enough? Consider whether the initially listed surface is the most suitable and how to change it to another surface, which can save time and cost in the assembly stage.
9. Unnecessary components When you go beyond the prototype design, do you really need these test points or programming heads? Obviously, deleting them will reduce the ongoing cost.
10. Components lacking resistance may easily share pads, or leave solder resist between pads on devices with small spacing. Try to consider where the solder flows and the cost of failure and rework in case of unnecessary short circuit.