In almost all industries, purchasing of raw materials and other components is made from the outside sources. It is therefore very important the material purchased is carefully inspected in order to maintain the quality of production. It is not possible and practicable to carry out 100 percent inspection of the material received. Under such condition, the material received will be accepted on the basis of sampling inspection. This procedure is called as acceptance sampling. It can be defined as “the acceptance of the whole lot of items on the basis of a small sample of the lot”. This method is economical and widely used in industries.
In this process, a few samples from the lot are randomly taken and they are inspected. In case the number of defective pieces in the sample is more than the agreed numbers, the whole batch (lot) is rejected. On the other hand, if the number of the rejected pieces is less than the agreed number, the whole lot is accepted. In this method, the supplier always has a chance of running the risk of having the good lot rejected and the buyer also always runs some risk of accepting a bad lot. Acceptance sampling method is an inspection technique. By sampling it is not a quality control method. It requires the knowledge of the past inspection data and the record of the production. A sample can be defined as a product that shows an evidence of the quality of the whole log. Sampling can be conducted on “Go” and “Not Go” basis.
Following steps are required to be taken in the process of acceptance sampling:
· To Divide the products into inspection lots.
· To draw a random sample from each prepared lot.
· To carry-out inspection and to determine their quality.
· To Accept or reject lot on the basis of the inspection results.
ADVANTAGES OF ACCEPTANCE SAMPLING
· It is an economical inspection technique.
· It is easy an convenient.
· It is suitable for mass production.
· It is useful for avoiding 100% inspection.
· It causes less fatigue.
· It is useful where cost of inspection is high.
· It is useful when 100% inspection is not possible due to destructive testing.
· It is useful when the time available for inspection is less.
Disadvantages
· The suppliers run the risk of having a good lot rejected.
· Buyers also run the risk of having a bad lot accepted.