I work in PCB assembly and my company just started requiring the CIS certification for senior technicians. I've been soldering and inspecting boards for 7 years so I know the hands-on side well, but the written exam format is new to me.
The IPC-A-610 standard is obviously central, but the exam scope includes workmanship standards I've never formally studied — just absorbed through practice. It's weird to now have to put that implicit knowledge into multiple-choice answers.
How much of the exam is about knowing the exact class distinctions (Class 1/2/3) vs. understanding the defect criteria themselves?
The defect criteria questions are very visual in the actual exam. They show you a solder joint or component and ask you to classify it. Seven years of hands-on experience is a huge advantage there — you'll recognize things faster than someone coming from a purely academic background.
Class distinctions matter a lot — maybe 30% of questions will hinge on knowing whether something is acceptable for Class 2 but not Class 3. Make sure you know the application context for each class, not just the names.
I passed CIS last year. The hardest part for me was the handling and ESD sections, not the solder standards. Don't underestimate that portion just because it seems basic.