A move from acceptance sampling to 100% inspection would be caused by the circumstance of downstream operators encountering recurring defects. Acceptance sampling is a quality control technique that uses statistical sampling to determine whether to accept or reject a production lot of material. It is employed when one or several of the following hold: testing is destructive; the cost of 100% inspection is very high; and 100% inspection takes too long1. 100% inspection is a quality control technique that examines every item in a production lot for defects or nonconformities. It is employed when the cost of passing a defective item is very high; testing is nondestructive; and 100% inspection does not take too long2.
Downstream operators are the workers or machines that perform the subsequent operations or processes on the products after they have been inspected or tested. Downstream operators encountering recurring defects means that the products that have passed the acceptance sampling or testing are still found to be defective or nonconforming by the downstream operators. This can indicate that the acceptance sampling or testing is not effective or reliable in detecting or preventing defects or nonconformities. This can also result in negative consequences, such as rework, waste, delays, customer complaints, or safety issues. Therefore, this circumstance would cause a move from acceptance sampling to 100% inspection, as it would require a more thorough and rigorous quality control technique to ensure that no defective or nonconforming products are passed to the downstream operators.
The other options are not circumstances that would cause a move from acceptance sampling to 100% inspection. History shows that the quality level has been stable from lot to lot is not a circumstance that would cause a move from acceptance sampling to 100% inspection, but rather a circumstance that would support the use of acceptance sampling. Quality level is the proportion of conforming items in a production lot. Quality level being stable from lot to lot means that there is little variation or fluctuation in the quality of the products over time. This can indicate that the production process is under control and consistent in meeting the quality standards or specifications. Therefore, this circumstance would support the use of acceptance sampling, as it would reduce the risk of accepting a defective lot or rejecting a conforming lot.
The company uses one of its qualified suppliers is not a circumstance that would cause a move from acceptance sampling to 100% inspection, but rather a circumstance that would support the use of acceptance sampling. A qualified supplier is a supplier that has met certain quality, delivery, and service standards and has been approved by the company to supply goods or services without inspection or testing. A qualified supplier is expected to maintain a high level of performance and reliability, as well as to report any issues or deviations that may affect the delivery process. Therefore, this circumstance would support the use of acceptance sampling, as it would reduce the need for 100% inspection by relying on the supplier’s quality assurance system.
The percent of defects is expected to be greater than 5% is not a circumstance that would cause a move from acceptance sampling to 100% inspection, but rather a circumstance that would require a change in the acceptance sampling plan. The percent of defects is the proportion of defective items in a production lot. The percent of defects being expected to be greater than 5% means that there is a high probability of finding defective items in the production lot. This can indicate that the production process is out of control or inconsistent in meeting the quality standards or specifications. Therefore, this circumstance would require a change in the acceptance sampling plan, such as reducing the acceptable quality limit (AQL), increasing the sample size, or decreasing the acceptance number, to increase the likelihood of rejecting a defective lot.
References := Acceptance Sampling - an overview | ScienceDirect Topics, What Is Acceptance Sampling? Definition And Examples
