INDU 6331 Assignment 1 Advanced Quality Control

What are the three primary technical tools used for quality control and improvement? The three primary technical tools used for quality control and improvement are: 1. Statistical process control (SPC): On-line tool useful for process monitoring and reduction of variability. 2. Acceptance sampling: Connected to inspection and testing of samples selected at random from larger batch. 3. Design of experiments (DOX): Off-line tool useful to discover key variables influencing characteristics of interest. Allow to vary input controllable factors and determine effect on output parameters. 1.15. What is a six-sigma process? Products and services normally consist in different components that typically have many opportunities for failure to occur. Six sigma is a quality methodology that focus in reducing variability in key product/service quality characteristics to the level at which failure is extremely unlikely. In six sigma process variability in process is reduced so that specification limits are at least six standard deviations from the mean. In this process it is considered to have only 3.4 of defects per million of opportunities. 3.1. The content of liquid detergent bottles is being analyzed. Twelve bottles, randomly selected from the process, are measured, and the results are: 16.05 16.03 16.02 16.04 16.05 16.01 16.02 16.02 16.03 16.01 16.00 16.07 a) Calculate the sample average ´x= ∑ xi n = 16.05+16.03+…+16.00+16.07 12 ´x=16,029 b) Calculate the sample standard deviation S 2= ∑(xi−x´ ) 2 n−1 = (16,05−16,029) 2 +…+(16,07−16,029) 2 12−1 INDU 6331 Assignment 1 Advanced Quality Control S 2=4,08∗10−4 S=0,020 3.2. The bore diameters of eight randomly selected bearings are shown (in mm): 50,001 50,002 49,998 50,006 50,005 49,996 50,003 50,004 a) Calculate the sample average ´x= ∑ xi n = 50,001+50,002+…+50,004 8 ´x=50,002 b) Calculate the sample standard deviation