From china, with love: bad PCBs

Over the time I’ve collected some of the more obvious PCB defects that I could detect and have time to take snapshots of. When you’re in the rush assembly and dealing with solder paste,  managing the pick and place, and keeping track of the reflow oven, stopping the flow for taking photos is the last thing you remember. But I do have a few and I included some here for your delight, a complete set and future photos are posted here.

Now before I scare you into thinking my products are sloppy and based on a poor quality chain, let me say 2 things:

  • I switched PCB suppliers this year, all of these photos are from my old supplier, more about that story below.
  • PCB defects can lead to some very elusive errors. Which is why I do a fair amount of testing on all my products to ensure they work. This has always been and always will be the norm. All electronic boards that have integrated circuits are tested for functionality. For instance all Moteinos get loaded with a sample sketch to ensure they can send/receive (that also ensures uploads work), etc.

The defects I saw vary a lot but the most consistent ones were the following, from most to least prevalent:

  • Bad silkscreen or soldermask: blurry, wiped/smeared, fingerprinted, embossed, thinned out, missing. Especially bad when it’s soldermask since the copper is exposed, it looks like someone just spit all over the silk/mask films. When the films used to produce the silkscreen markings and soldermask overlay are dirty like that the effect is reproduced on all panels in the batch, not a happy day:
  • Individual PCBs (not panelized) almost always had incomplete routing, sometimes erroneous routing. I could give hundreds of examples here but I only took a few photos:
  • Shorts, you hate them most but when you find them it’s like Christmas again because you never knew they were there. I’ll throw in a free FTDIAdapter in a future order from the first person who can spot the short in the 4th photo (and leaves a comment below or contacts me to claim it CLAIMED):
  • Scratched or damaged panels (post-manufature). These photos are from a single order, all panels had edges damaged and I had to throw edge rows away:
  • Inconsistent vscoring. When the vscoring on panels is shallow, it’s hard to snap the panel apart, and it leaves FR4 burrs all around, requiring manual sanding of affected boards, what a pain and time burner. This photo shows the completely missing Vscoring of an order (that I badly needed to fulfill a backlog) lead me to fire my old provider. The panel has to go in the pick and place and having no vscoring after assembly means I can’t snap the tabs away, cutting FR4 is messy and time consuming to fix nicely, doing that for 42 times on a panel gives you a long break from otherwise more useful things to do, to reflect about a lot of time wasters like fixing the mess of your careless provider. Anyway here are the 100% useless panels:

With me using panelized designs for the vast majority of everything I put in the pick and place, when there’s a problem with a panel, all panels in the order usually have the same problem (because the same film exposes all panels). The work around is to make the pick and place skip the bad boards, but it’s not fun to lemon pick and then throw quarter panels away.

Poor quality is part of the reason I switched sourcing PCBs from hackvana PCBs this year. You may notice a significant improvement in silkscreen quality and a nicer darker crispier soldermask on my PCB products since then. Such a provider that keeps you on edge with a consistently inconsistent service, poor quality, personal drama, broken promises, failure to address any issues, insulting or accusatory attitude when confronted with a problem, doesn’t deserve your blood-sweat-and-tears and especially hard earned dollars. Move on to someone else who wants your business and is willing to appreciate it.

5 thoughts on “From china, with love: bad PCBs

  1. Thanks for the post. As a newbie maker, this was a great tutorial in shorts for pcb. Didn’t know what to look for in that fourth picture until I examined the first three pictures and then found it pretty quickly. Thanks for the posts (brought here by your laser cutter post) and keep on up the great work on the moteino!

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