Working for manufacturer engineering couple years. Sharing the manufacturing experience, skill, DFx, design, and information. Be care of this blog is personal share and content may not be 100% correctly.
In most electronics assembly organizations, there is a function called IQC (Incoming Quality Control). The primary purpose of IQC is to screen incoming materials to ensure they meet drawing specifications, preventing defective parts from directly entering the production line. This helps avoid defective output and even potential line shutdowns.
A good analogy is airport customs. When passengers enter a country, customs officers perform random inspections to prevent prohibited items from getting through. While they can’t catch everything, they act as a deterrent and intercept at least some problematic cases at the gate.
Back in an electronics assembly factory, IQC sampling is mainly aimed at catching batch-level defects. In reality, the sample size is often very small—sometimes only 1–2 pieces per lot. If you strictly follow AQL Acceptable Quality Level) standards, you would likely need more manpower.
From Workingbear’s perspective, setting up IQC serves several important purposes:
1. Clarifying Responsibility for Defective Parts
When defects show up on the production line, it’s often difficult to determine the root cause.
Did the issue come from the supplier?
Or was it introduced during our own process?
If the defect is only discovered after assembly, some suppliers may argue that the part was already altered or damaged during our process, making it harder to hold them accountable.
By performing incoming inspection upfront, it becomes much easier to separate supplier issues from internal process issues. This also helps build mutual trust between us and the supplier.
2. Understanding Incoming Quality Trends in Advance
In some cases, this may even lead to supplier audits when necessary.
3. A Dedicated Owner for Component Quality
In many companies, IQC is the owner of incoming material quality.
Beyond inspection, IQC also acts as the communication channel when defects are found during production. Issues are typically routed through IQC before being fed back to suppliers.
Having a dedicated function helps:
Streamline communication
Reduce confusion on the production floor
Prevent material shortages caused by quality disputes
Of course, IQC usually works together with process, test, and quality engineers to confirm that the issue is truly component-related before escalating it to the supplier.
When Companies Try to Eliminate IQC
Workingbear has also seen factories that believe IQC is a waste of resources—especially those strongly focused on lean manufacturing.
Their argument is:
👉 Inspection doesn’t add value to output 👉 Suppliers should be fully responsible for part quality
In principle, that’s not entirely wrong.
These companies often still keep a minimal IQC function to check critical items specified by engineers. They also rely heavily on SQE (Supplier Quality Engineering) to communicate with suppliers (and sometimes to push accountability).
However, here’s the problem I’ve observed:
When issues occur on the production line, some of these factories immediately blame the supplier—without proper analysis.
They assume:
👉 “The supplier is responsible for part quality.”
But they overlook an important fact:
👉 The issue might actually come from their own process.
This can lead to unnecessary line stoppages and conflicts. In some cases, I’ve even had to step in as a mediator between factories and suppliers.
When relationships break down, suppliers may refuse to ship parts altogether—which creates bigger problems than the original defect.
When Weakening IQC Might Be Acceptable
For factories that focus purely on PCB assembly—or for products with very stable processes—reducing IQC may not be a big issue.
Why?
Most electronic components already have solid quality control systems
Electrical defects are usually measurable
Pass/fail conditions are often clear-cut
But Be Careful with Final Assembly
Workingbear does not recommend weakening IQC for final product assembly operations. Why?
Also, assembly issues are not always caused by suppliers. They can come from:
Design tolerance stack-up
Poor fixture or tooling design
Operator handling errors
If an assembly factory cannot clearly distinguish whether the issue comes from the part or the process, conflicts with suppliers are almost inevitable.
Feel free to share your thoughts—Workingbear would love to hear different perspectives!
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