Inspections, as they pertain to quality assurance in printed circuit board manufacture and assembly, are a double-edged sword for electronics providers. On the one hand, a thorough vetting of components and connections makes for a reliable, functional product with a long life cycle. Detailed inspections, however, obviously take time, which could lengthen PCBA lead times on prototypes or new goods.
But which is worse: Waiting a little longer for immaculate PCBA, or getting a faulty batch of circuit boards as quick as you can? Besides, IPC standards set a high bar for PCB manufacture and assembly, so why risk a redo?
Let's walk through the three major steps in the PCB inspection process and demonstrate their value, as well as ways PCB assemblers accelerate the process without detracting from its integrity:
1. Automated optical inspection
First things first: Is everything where it should be?
"AOI systems run down a preprogrammed checklist of critical components."
AOI can be performed both after the PCB manufacturing process and/or after assembly. AOI determines functionality visually using video capture technology. The system runs down a preprogrammed checklist of critical components, ensures their presence and performs a cursory examination of soldered elements - more on that later.
Because PCBA companies want their specialists to focus on more holistic, knowledge-driven management of their clients' goods, checking off components manually one by one takes a lot of time, too much menial effort and may even still result in the occasional error. Advanced computer technology does the work at a fraction of the speed and saves the big-picture problem solving for the experts.
2. Electrical verification
It's important to know how your PCBs will perform before you send them to market. After all, a single faulty board could impact the reputation of an entire product line, even cause serious injury to users.
EVs introduce a safe electrical current to surface-mount technology to confirm its functionality under standard operation. Like AOI, EV is performed quickly with automated technology to rapidly inspect SMT components without losing process efficiency.
3. X-ray inspection
Sometimes, you need to dig down deep to find what you're looking for. Inspecting PCBs for manufacturing or assembly flaws is no different.
Remember earlier when we mentioned soldering and how AOI could only give soldered joints a once-over? That's because PCBA professionals require high-resolution x-ray inspection to truly examine soldered connections since soldering paste holding components in place is sandwiched between the SMT and the PCB substrate. For PCBs with ball grid arrays, x-rays can notify PCBA experts of things like head-in-pillow defects according to AIM Metals & Alloys, a problem that could pass undetected through both AOI and EV. With a case of head-in-pillow, soldering paste and the soldering ball do not join properly. Though the fault may still be close enough to allow electricity to pass through, the problem could significantly reduce the life cycle of the electronic device.
X-ray inspection technology includes much more than a static x-ray image a doctor might take of a broken bone. VR Industries offers 3-D rendering technology capable of mapping out soldering balls to determine the potential for failure, as well as adherence to IPC standards.
Furthermore, like all other inspections listed here, x-ray inspections also include automation to move things along while still keeping quality high. Automated x-ray tech can even locate faults in wiring one thousandth of an inch thick. Imagine how long that might take to do manually.
For more information on any of the steps in the PCBA inspection process at VR Industries, check out our inspection services page or reach out to a representative today.