Quality assurance and quality control (QA/QC) are a continual part of any manufacturing process. No matter how many times your factory has executed the same procedure, you must regularly perform quality checks to maintain the same quality level of your process. Quality control on a manufacturing line often involves regularly testing samples of whatever is being produced. Most important, the samples must come from the production line.

By definition, no substitute sample is valid; otherwise, it’s not a “sample.” A quality control process might involve testing raw materials to verify material properties, testing manufacturing steps to ensure they are done correctly, and inspecting the finished product to ensure conformity.

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