Turning the acceptance sampling method to a quality improvement tool (Part 1)

Acceptance Sampling is a statistical measure used in quality control. A company cannot test every single piece of its product for damage to the product, or the number of products is too large. Acceptance sampling takes care of this by checking for errors on a typical sample product, instead of all products if inspected at the end of the line. This process allows a company to measure the quality of a shipment at a certain statistical level without having to test each unit of product.

Most manufacturers rely on end-of-line testing to show their customers that the company’s products meet quality requirements. Testing results are compared with the company’s own quality standards or set by customers, such as comparison with analytical index (COA). Based on the results, the controller will make a decision to accept or reject the shipment.

However, we all easily memorize principle 3 of the 14 management principles of Dr. W. Edwards Deming: “Organizations should end their reliance on end-of-line inspection results to confirm. product quality”, but this is not really easy. Ensuring the quality of the product when it is delivered to the customer is always a top priority, so most manufacturers cannot skip this step.

However, according to the overall approach, omitting the end-line quality control process does not mean completely surrendering to fate and hoping for standard products. In other words, the final product is the crystallization of the entire production process, not just the final step. In addition, data obtained through statistical process control (SPC) can become a useful support tool in this case.

Adopt an acceptable sampling method to minimize risk and optimize the process

In any case, a thorough inspection of the entire product is impractical, so acceptance of the end of the line cannot avoid errors. As a result, some organizations have begun to adopt an acceptance sampling procedure according to MIL-STD-1916 (A common method of DoD for making decisions on acceptance of product lots) or ANSI/ASQ Z1.4 or Z1.9. Regardless of the standard, the acceptance becomes much softer because the goal is some typical products, not the entire product.

Not only does it help the organization cut down on quality management costs, acceptance sampling also helps to prevent risks, reduce errors and prevent low-quality products from entering the manufacturing process. We will continue to explore this content later.

Productivity and Quality Office