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166 Part III: Inspection and Test
Final Inspection
1. Products are inspected and then classified into classes or grades,
depending on the degree of conformity to standards.
2. Nonconforming products may be classified as scrap or rework.
In some cases the cost of reworking a product is more than to
produce it.
3. Nonconforming products may be analyzed to determine the
root cause of the problem and the appropriate corrective action
to follow.
Part III.C.1
Finished product inspection is carried out to confirm that the product conforms
to customer specifications. It may include assembly, installation, and packaging.
In all cases, final inspection is thorough and complete and may be intensive and
costly, depending on the accuracy and severity of incoming inspection and inprocess
inspection.
Inspection planning also includes the preparation of a list of characteristics to
be inspected. The following guidelines may prove helpful (Raz 1992):
• Inspect characteristics that affect the performance of the product.
To the extent possible, product testing should be done under
conditions that simulate actual use.
• Select characteristics that can be measured objectively, to the
extent possible.
• Provide a seriousness classification in order to improve consistency
for characteristics that are evaluated subjectively.
• Inspect characteristics that can be related to a specific production
process in order to simultaneously obtain information about
the process.
A detailed inspection plan should be prepared and approved by the customer and
the production, engineering, and manufacturing departments prior to the start of
full-scale production. The inspection plan should include the following items:
• The location of each inspection station in the sequence of production
operations
• The type of inspection or test to be carried out, including a description
of the environment, equipment, and procedures
• Accuracy requirements for the measurements
• The conformance criteria, normally based on product specifications
• The sample size and procedure for drawing a sample in the case of
sampling inspection
• The lot size and the criteria for lot acceptance, if applicable