Statistical quality control (SQC) is the use of statistical tools and techniques to monitor and maintain product quality in industries such as food, pharmaceuticals and many manufacturing environments. Statistical quality control may be carried out as part of the production process, as a final quality control check or during random checks by quality control departments.
Statistical quality control techniques are vital for monitoring the inherent variations that are present in all manufacturing processes. These variations may be due to the raw materials, the uniformity of the product components, filling machines, techniques used, and the packaging process. Any, or a combination of these factors can influence the total final quantity of a product, and legislation requires manufacturers to ensure that their products contain at least the net quantity stated on the packaging. Equally, any over-fill is a financial loss to the manufacturer and is to be avoided.
Fill control, check weighing and weight variation are widely applied statistical quality control techniques that use the weight of the individual goods in the statistical analysis.
In the case of pharmaceutical products (tablets, pills and capsules etc.), the weight must not exceed the upper tolerance limit to prevent consumers from taking too high a dose of the active ingredient, which could have serious consequences. Equally, the weight cannot be too low otherwise the drug may not be effective. The weight variation statistical quality control test is used to confirm uniformity of the dosage unit and therefore also to support product safety, identity and quality.
In the production of food and beverages, checking the weight of packages provides fast confirmation that fill quantities meet legal requirements. Manufacturers must take any deviations seriously as they may be due to errors in the production process, including incorrect ingredient quantities which could have negative consequences.
To ensure consumer safety and compliance with regulations, statistical quality control using weight determination is of critical importance. An essential prerequisite for this is the use of accurate balances or scales and software that are adapted to the specific applications.