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Out-of-Specifications Deviations of products from pre-determined specifications. This means when a product is unable to meet the predetermined limit for that particular product. There are several possibilities that could account for this deviation.
These possible reasons for out-of-specification can be divided into two categories. The first is an analytical defect where a product has no defect but its analysis has a problem, and the other is a manufacturing defect in the product where the analysis is correct but the product actually has a problem. Possible reasons for out-of-specification results are as follows.
1. Test analysis error in QC lab: Error in QC lab is human or analyst error. This is the most likely cause of OOS and should be investigated first when investigating OOS. There are many areas where mistakes can be made. An error may occur during product analysis, sample or standard handling. There may be errors in the weight of the sample and its dilution. Errors are possible in chromatography and titration or even in calculations.
2. Malfunction of lab equipment: Because of this problem analysis is also not aware of the occurrence of this error. Sometimes equipment or instruments are not calibrated on due dates and it shows wrong results due to which the product result deviates from the limits. However, in some other cases it is due to a defect in the equipment or instruments used in the analysis.
3. Defects in manufacturing equipment: This causes actual defects in the product being produced. An out of specification is observed when there is a problem with the production equipment and a defective product is produced. Equipment defects may include defects in timers or any other part of the equipment that are not noticed during the manufacturing process.
4. Operator/Human Error in Manufacturing: Operators play a vital role in manufacturing quality products. A wrong timer setting for any production operation, using the wrong sieve or screen, following a wrong process, omitting any production process or the like can cause serious problems in the batch being made. This happens when the operator does not follow the instructions given in the batch production record. It is always very difficult to find a human error responsible for out-of-specification results because it is a human tendency to hide the errors made by him and sometimes it is done unknowingly and found correct in the document.
During manufacturing, many process steps are followed and any error can lead to defects in product making hence careful handling of materials and equipment is required. The points mentioned above can help you easily find out-of-specification root causes.
