In most recent times, the terms DFM (Design for manufacture), DFA (Design for assembly) and, more widely, DFX (Design for Excellence) have appeared in many an electronics hobbyists and novice’s vocabulary. To clear up the confusion, we’re trying to make the term PCBA Design for Assembly (PCBA DFA) stick to highlight the distinction and importance of this step in a turnkey environment. PCB Design for manufacturing (PCB DFM) is steadily becoming a household name and often fab houses will say they offer free DFM review. But compared to a PCBA DFA – the level of verification and scope is miles apart.
Here we highlight the differences between the typical PCB DFM and PCBA DFA, and give reasons why you should be investing in good DFA practices and checks.
Strictly speaking, Design for Manufacture pertains to the stages that go into making the parts of a device – for electronic assembly, that would mean the individual components and the PCB. Therefore, it makes sense that Design for Assembly, pertains to the stage where all these parts are put together, i.e., populating the PCB. But in some circles, the assembly of a complete product, like a box-build with screws, casing and packaging is more like assembly. There is even DFMA term floating around to refer to both manufacture and assembly due to significant overlap. Such nuances can cause a bit of confusion when it comes to definitions and names.
For the big boys, strict and distinct methodologies exist for the traditional DFM and DFA disciplines that notably have specific focuses on yield and cost. But with the flourishing custom PCB industry, the world of manufacturing has become more and more accessible to more and more of us. And as a result, the terms DFM and DFA has evolved into something quite different.
In the most basic sense, you could say that DFM ensures that a product is manufacturable, i.e., That a printed circuit board can be manufactured (the alternative name ‘Design for manufacturability’ seems to lean towards this too). It, therefore, follows that DFA would ensure that something can be assembled. But notice that there is no specific focus on cost or yield with the ‘take my money and make it happen’ approach that has somewhat plagued the custom manufacturing industry.