Unit 30 Mechanical Measurement and Inspection Technology

25-01-18 cheapnisha 0 comment

Unit 30 Mechanical Measurement and Inspection Technology

nit 30 Mechanical Measurement and Inspection Technology

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The company produce a small component that has a hole in it that is critical and checked with a plug gauge.  The company produce these in batches of 50 and initially carries out 100% inspection. The company are concerned that the process is not in control and have asked you to investigate.

Table One gives the defects for 50 batches which you need to use to produce attribute control charts, np and p charts.

Table Two gives the next 100 batches. You are expected to:

1.    construct the control charts np and p using table one,

2.    document your research into ways in which the data can be used to inform the company about the process;

3.    determine the extent that the process is under control using that data in table two

The tables on following pages give the actual sizes of the diameter “A” and length “B” of a stud that the company produces on one of their CNC machines.

Design statistical variable control charts involving the mean and range, X and R charts for diameter A.  The measurements were taken in batches of 5 and recorded on the table as 1-5 first batch, 6-10 second batch etc.  Use the first 50 entries [10 batches] to do this.

1.    construct the control charts X and R using this data,

2.    document your research into ways in which the data can be used to inform the company about the process;

3.    determine the extent that the process is under control using the rest of the data in the table for diameter A, remember these are in batches of 5.

Using the data in the table for the length B of the stud produce:

1.    a statistical process capability chart for length B for the  first 100 studs.

2.    an evaluation regarding the machine’s capability based on a calculation of Cp and Cpk for the length of the stud, and how the process can be improved.

3.    produce a modified control chart and plot the rest of the data from the table for the length B of the stud

Produce a report that includes:

An evaluation of the use of the statistical methods possible and how they have influenced the design and successful use of process control charts.

A Process Capability Study based on your outcomes from the data used from the table for the length B of the stud

The size for dimension A is 12.5mm ±0.3. The sizes given in the table are in millimetres. The size for dimension B is 20.2mm ±0.2. The sizes given in the table are in millimetres.