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IE 405 QUALITY MANAGEMENT. RECITATION 6. Rec 6 Q1. The highest contributors of defects is excess flash, missing cap and flow lines. Excess flash also has the highest defect rate in the individual c chart.
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IE 405QUALITY MANAGEMENT RECITATION 6
The highest contributors of defects is excess flash, missing cap and flow lines. Excess flash also has the highest defect rate in the individual c chart. • Excess flash can be reduced by maintaining the machinery or equipment, in order to reduce the flash rate. • An important parameter missing cap, can be avoided by warning the worker(s) who are responsible for putting on the cap. It is simpler and easier to maintain the caps on the bottles than is to reduce the other defects.
Rec 6 Q2 • USL=12.55mm • LSL=12.45mm • Derive Z value from • 12.45-12.50/0.02= -2.50 • a) Scrap rate of 0.0062 or 0.62% • Rework rate (due to symmetry) is 0.62% also.
b) Area= The value is with respect to LSL not USL.Because the z=-3.59 value is calculated with respect to scrap not rework. • -3.59= 12.45- m/0.02 • m=12.52mm c) Rework 12.55-12.52/0.02= 1.50 1- 0.9332= 6.68%
Rec 6 Q3 • Cp measures POTENTIAL CAPABILITY • Why? • Does not take into account where the process mean is located relative to the specifications • Cpk measures ACTUAL CAPABILITY • It takes process centering into account
Specifications: • LSL:-50 • USL: 50 with respect to formula • From chart derive Rbar/d2= 3.035 Cp=100/3.02*6= 5.50 • 1/5.50 = 0.1818 Covers 18% of the specification band.
Cpk= min(Cpu, Cpl) • Cpu= (50-10.375/3*3.03)=4.359 • Cpl= (10.375- (-50)/3*3.03)=6.64 • Min (4.359, 6.64)= Cpk • Choose 4.359 • Since Cp>Cpk process is out of center