What are the forms of quality inspection?

[la ling]

Full inspection, sampling inspection, counting inspection, physical and chemical inspection, destructive inspection, etc.

1. Total inspection
Full inspection is generally applied to: important, critical and valuable products; Items that have a decisive impact on subsequent process processing; Processes and products with seriously uneven quality; Non interchangeable assembly parts; Products with small batch and without sampling inspection. For example, it is suitable for the refrigeration effect of freezer, not suitable for the life test of TV, the strength test of steel pipe and the thread of a large number of nuts.

2. Sampling inspection
Sampling inspection, also known as sampling inspection, is a statistical method and theory to randomly select a small number of products (samples) from a batch of products for inspection, so as to judge whether the batch of products are qualified or not. It is different from comprehensive inspection in that the latter needs to inspect the whole batch of products one by one and pick out the unqualified products, while sampling inspection infers the quality of the whole batch of products according to the inspection results of the products in the sample.

If the inference result shows that the batch of products meets the pre-defined qualification standards, they will be accepted, otherwise they will be rejected. Therefore, a batch of products that are considered qualified through sampling inspection may also contain some unqualified products. The main sampling methods include simple random sampling, systematic sampling and stratified sampling.

3. Counting test
For each unit product in the sampling group, only qualified products or unqualified products are determined by measuring the inspection items, so as to infer the unqualified product rate of the whole batch of products. This kind of inspection is called counting inspection. The count value and quality data of counting inspection cannot be taken continuously, such as the number of nonconformities, the number of defects, the number of defects, etc.

4. Physical and chemical test
The methods of quality inspection can be divided into physical and chemical inspection and functional inspection according to the nature of inspection. Physical and chemical inspection, also known as “instrument inspection”, is the inspection carried out by using some measuring tools or instruments and equipment, such as micrometer, dial indicator, inspection gauge, microscope, etc. with the help of physical and chemical methods.

5. Destructive inspection
A destructive inspection is an inspection form or method that changes the form of the inspected product and destroys the use function or performance of the product to a certain extent.
Non-destructive inspection refers to the inspection form or method in which the form of the inspected product has not changed and the performance and use function of the product have not been affected after the product has been inspected.

[Li wu]

Quality inspection methods can be classified according to different marks.
(1) It is divided into full inspection according to the inspection quantity; Sampling inspection.
(2) It is divided into counting inspection according to quality characteristic value; Metrological Inspection.
(3) It is divided into physical and chemical inspection according to inspection techniques and methods; Sensory examination; Biological examination.
(4) It is classified as destructive inspection according to the integrity of the inspected object after inspection; Non destructive inspection.
(5) Classified as fixed inspection according to the inspection location; Flow inspection.
(6) According to the inspection purpose: production inspection, acceptance inspection, supervision inspection, verification inspection and arbitration inspection
(7) According to the supply-demand relationship: first-party inspection, second-party inspection and third-party inspection.

[wy zw]

Several forms of quality inspection:
1. Check the original quality certificate;
Under the conditions of large purchase batch, stable quality of the supplier and sufficient reputation, quality inspection is often closely combined with product verification. Is to check the original quality certificate. Specific original quality certificates such as quality certificate, certificate of conformity, inspection (test) report, etc. are used to identify the quality.

Check the original quality certificate to determine its quality status. Generally:
A. It can confirm that the original documents of the supplier are complete;
B. The certificate quality characteristic data are complete and meet the requirements of technical performance and relevant standards;
C. Signature and seal procedures shall be complete;
D. The physical quantity is consistent. After confirmation, perform the signing procedures of the specified procedures, and distribute the vouchers to the relevant functional management departments. If necessary, physical quality inspection shall be carried out for the final performance of the product and the decisive material and quality characteristics.

2. Physical inspection
The full-time inspector of the unit or the external inspection unit entrusted by the unit shall issue inspection records after observation, test and measurement according to the specified procedures and requirements as evidence of product conformity.

3. Send personnel to the factory (resident) for acceptance
The purchaser shall send personnel to the supplier for on-site inspection and acceptance of its products and product components. Supervise the operation process and quality control of product formation and identify the quality of finished products, verify that the supplier’s quality is under control, and provide relevant inspection reports to confirm that the inspection results meet the specified requirements. The original vouchers for release and delivery are complete and the products are qualified, and they are accepted.

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