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24. What is acceptance sampling and when should it be used?

ans. Acceptance sampling is used for parts that are being made by another manufacturer who does not provide process quality information. This technique uses random inspection of parts as they arrive to ensure conformance to quality limits.

4.9 QUALITY CONTROL PROJECTS

4.9.1 Measuring for Quality Control

Objectives:

• You will be expected to gain practice using the Metrology equipment. Beyond this the students will be expected to make sense of the numbers collected, as well as how they relate to variations caused by processes. The student should also gain an appreciation for software support tools.

Suggested Procedure:

1.Students will be assigned a set of similar parts.

2.Each part will be measured for specified dimensions/features during normal laboratory time. EACH part is to be measured by EACH student 5 times. Each measured dimension will be measured using at least two different Metrology methods.

3.The results may be analyzed using methods, such as,

-distribution for individuals, parts, overall, etc.

-calculation of parameters; σ , mean, etc.

-process capability.

-etc.

4.TurboSPC is used on the measured data, and is available on a number of computers.

5.A report and presentation (10 minutes) will be prepared for the lab session

4.9.2 Evaluation of Metrology Equipment

Objectives:

• To understand the limitations in the equipment used for Metrology.

Suggested Procedure:

1.Select a measuring machine used in Project 1. This should not have been used by any other groups in your section.

2.Measurement standards will be used to make repeated measurements, as in Project 1.

3.The capabilities of the process will be determined using known methods.

4.Comparison to results in Project 1 can be made.