The basic and most significant reason is the fact that the method can be applied in a variety of situations related to quality management, complying with contractual terms, preventing unexpected situations, etc. Moreover, it delivers results or conclusions of sufficient accuracy for a wide variety of purposes.
The method is applied in situations where:
* The inspection results in damage or destruction to the product. If instead of this method (AS) a 100% inspection is applied, this will destroy the entire amount of finished produce. Example: Inspection of batches of ammunitions (cartridges, shells, etc.) or melting electrical fuses (for 10A)[J].
- Since 100% inspection of products would involve additional cost this would add to the cost of the final products (quality control inspections are included in the cost of the product).
- When a large variety of similar products have to be inspected (a wide product range based on a single type of product or principle) sampling will produce as good, if not better results than 100% inspection. Such mass inspections cause fatigue to quality control personnel due to the monotonous work which might in turn result in more errors than the average accepted percentage when using the Sampling acceptance method.
- When the x and R and p indicators are not provided in the information relating to quality – no diagrams are available (Paretto chart, etc.)
- When no automated means of control are provided and products are inspected manually or visually.
Besides all said above, the AS method has the following additional advantages compared to 100%
1. It is less costly owing to fewer inspections
2. Less handling damage during inspection
3. Fewer inspectors are involved, thereby simplifying recruiting, training and supervising.
4. Upgrading the inspection job from monotonous piece-by-piece decisions to lot-by-lot decisions.
5. Rejection of entire lots, rather than the return of defectives, thereby providing stronger motivation for improvement.