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  • Writer's picturehidet77

Inspection is a process.

“Build-In Quality at Production Process.”

When delving into this crucial topic, we often encounter the notion that “Inspection is the easier route.”

But let's pause for a moment. Inspection is indeed a process, and like any other process, it requires the management of many inputs. Those who claim that inspection is easy often overlook the importance of 'Process.’ When we strive to design a robust inspection process, we realize that the goal of building quality into the production process is not too far away.

Let’s look at some of the inputs.

[Inspection Standards]

Like any other production process, the inspection process requires standards. Unfortunately, I have been to many places where these standards were either missing or not meaningful. They often needed to be updated, corrected, or improved to be practical. They were designed for old products, different parameters, or aspects of the product that couldn’t be checked. Merely having a paper filled out doesn’t guarantee quality. This underscores the need for proper inspection standards and their relevance to quality production.


Once we have the proper inspection standards, we must train the people, just like any production process. I often encountered situations in which different shifts had different results. When we switched the inspectors, the results followed. Different inspectors inspected differently.

In such situations, there is always a discussion of “Who” is right or wrong. The preferred choice is always the one with stricter results. But we must be careful. So-called “tough” inspectors might reject products based on opinion, not by standard. Both might not be checking the critical points. The comparison should always happen against the standards, not who.

What is essential is not one-time training but continuous follow-ups of the inspection skills. Even with proper training, people could develop bad habits over time, or the criteria might move. So, periodically, we must test to see if the inspection is done according to the suitable standard.

[Tools and Machines]

Inspection uses many tools and machines, just like any production process. These tools and machines require preventative maintenance, which is often not provided. Some tools require even more sensitive care. For example, when you drop, you should calibrate most inspection tools. Such care is not provided, and abused tools are used. Tools and machines become what it is with maintenance. Without maintenance, they are mysterious objects.

One important aspect is to understand the frequency of maintenance needs. Is it based on time or volume? Depending on the frequency, we require different control mechanisms. We also need to be careful about the length of the frequency. If each tool and machine requires random maintenance frequency, it will become frequent interruptions. Then, it incentivizes the people to violate the maintenance rules. To avoid such conditions, list all the maintenance activities and discuss the option of doing all at the beginning of the shift.

[Defect handling]

The saddest moment in the inspection was that after identifying the defect, we mishandled it and returned it to the normal process. Like any other production process, 5S is necessary to avoid such mistakes, mixing, or contamination. Clear identification of the defect and where to keep it is required. The defect contains an enormous amount of hints towards the root cause. Keeping the 5S doesn’t mean throwing away the defect immediately when it is discovered. It needs to be identified so we can conduct the proper problem-solving. We need to keep the evidence without mixing it into the production flow.

One process that I always question is “re-testing.” In many places, we retest the product when it fails. But this doesn’t make sense. When the product failed, we made a hypothesis that the tester misjudged. Then, we retest using the same tester without any investigation. And when the result was favorable, we passed the product. However, the hypothesis that the machine’s testing capability has not yet been checked. Why are we passing based on suspected testing capability? The correct process for handling such a rejection is to call the team leader. Stop and investigate the tester, the product, and the methods. Never leave the inspector alone under the pressure of defects and output. Such pressure could lead to catastrophic decisions.

[Line Balance]

One of the trickiest things to consider in an inspection is balancing the workload. It is usually not fully loaded and has a long waiting time. And most will give up and leave it as is. Then, this position becomes like a sanctuary or a prestige position. They use the waiting time to do whatever they want, including misbehaviors that interrupt other processes.

Some challenged this sanctuary by outsourcing the inspection to a third party—possibly the worst decision. The inspector's cost might decrease, but the quality has become a foreign subject. A third party, which had high rotation and no proper training, provided ineffective services. If quality is important, I don’t understand why we can outsource inspection.

Then, how should we balance the workload? Should we do more inspections just because there is time? That’s silly, adding non-value-added work. Should the inspector cover different production lines/cells? That will create complex flows and takt changes.

As we challenge this “line balance” of inspection, we ask one question: “Isn’t it easier to rebalance with production processes?” We would have good inspection standards if we implemented a “good” inspection process. We know how to train. We have maintained machines and tools. We have suitable methods for handling rejects. If so, why not move to a production process at the same takt time? Once we have the in-process inspection, we will start thinking about combining the inspection and production processes. After all, the operator is already touching and looking at the inspection area.

The challenge of “Build-in Quality at the production process” is often compared to a broken inspection process. It is ineffective and does not necessarily deliver the results that it should. Yet, they don’t Kaizen. They believe the current inspection is the best. Unless they try to improve the current inspection process with tangible results, they won’t understand why TPS is thinking “Build-in Quality at production process.”

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