I was looking at two different PCBs recently; one assembled here at Screaming Circuits, and one, a PC graphics card assembled someplace else in the world. In both cases, a crooked component caught my eye. The graphics card, at least, would have done a passable job of meeting IPC-A-610 Class II, but in both cases, the offset was enough to inspire me to take a closer look and write this blog post.
On the graphics card, the particular component was an SMT inductor. I've been having some issues with the card and when I had it out of the PC, I saw that inductor. With further examination, I found a lot of other crooked components. My off-the-cuff conclusion was that the manufacturing workmanship was poor, therefore I shouldn't be surprised that the card was having issues, and perhaps I should look for a different brand for my next purchase. Again, everything would likely have met IPC Class II, but perception is close enough to reality and that manufacturer has probably lost a customer.
In the case here at Screaming Circuits, only the one component, an SMT SD card socket, was crooked. In addition to the signal pads, this socket has four large SMT pads, one on each corner, for mechanical connection to the PCB. One of those four pads on this PCB has a big hole in it. Not just a little 10 mil via in the pad, but a either a really, big via or a bolt hole. The unequal surface tension in the solder, caused by that pad being cut in half, caused the connector to twist a bit.
Yes, in a prototype world, we made it work, but it caught our attention here and if such a thing went into final manufacturing, it might very well catch a customer's attention and elicit the same response I had to the graphics card. It will work okay and would probably stay secure on the board (maybe), but it's not good practice and it looks wrong and wrong looks can cause customers to go elsewhere. Yes, function is key, but if form chases customers away, then function never gets a chance to matter.
We'll keep the robots in line
You keep the PCB in line