Xbar/R Chart for C6-C9
The revised charts do not show any out-of-control phenomenon. Based on all the given data and information,
4.1) Identify the average length of the beams Best-Wood produced when the process is in statistical control
4.2) Estimate the process standard deviation of the beam production process.
4.3) Calculate Process Capability Ratio if the design specifications of the beam length is 24 2.2cm .
4.4) Based on the given data and your calculation, briefly explain to Best-Wood management that the following steps should be taken or should not be taken in improving the process:
4.4.1) Use a more accurate measuring device to make the centering of the process closer to the targeted value of 24.00 cm.
4.4.2) Eliminate the impact of certain factors such as machine vibration to reduce process standard deviation.
4.4.3) Increase the range of the design specifications in order to improve Process Capability Ratio in achieving a 6-sigma process
You may need the following equations and table in answering this question.
̑ = R/d2 , Cp = (USL - LSL )/(6 x ̑), where USL and LSL are upper and lower specification limits.