Quality Engineering Assignment Sample

Introduction

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Question 2

The components have been formed into batches of size five using the “Honzaki CNC vertical drilling machine”. The company then acquired a “Kawda CNC vertical drilling machine” which grouped machine components into batches (Colosimo et al. 2018). The average of the values for each batch of five components has been calculated in the column named “average”. Next the mean of the values in the column “average” is calculated.

 The Range for each batch is calculated by finding the difference between the maximum and minimum value of the variable for each batch (Chakraborti and Graham, 2019). Subsequently, the mean of the range is calculated and found to be 0.154. The value of the mean of the averages of the variable for each batch of size five has been found to be 115.4039. The value of sigma which is the standard deviation has been determined as 0.066194 and the C_p has been computed as 0.292072. The average value of the Upper Control Limit has been obtained as 0.0121 and the average value of Lower Control Limit has been obtained as 0.1039. The value of C_pk  has been obtained as 0.060932 and the chart generated for the values of C_p and C_pk has been given below.

The value of the Process capability indicates that the machine components are being produced within the control limits. The higher the value of the process capability index, the more the process is capable. 

Question 3

The data has been typed into the worksheet and the average for the values of each batch of five machines has been calculated. The average is calculated by using the “AVERAGE” function of MS Excel and stored in the column named “X bar”. Then the average of “X bar” values have been calculated in the column named “X D BAR”. Then the values of the “Upper Control Limit (UCL) and the Lower Control Limit(LCL)” are calculated. The standard deviation of the “X bar” values have been calculated before calculating the LCL and the UCL. When the calculation of the values is done, the columns “X bar”, “X DBAR”, “UCL” and “LCL” are selected and then from the insert ribbon the “line chart” option is selected. This is how the chart for the UCL and LCL for x-bar chart is designed. From the chart it can be concluded that the samples are all within quality limits (Stylidis et al. 2020).

The line chart is seen to be present within the UCL and LCL in the chart and this indicates the process is under statistical control. From the same data the ranges of the batches are calculated in the column named “R”. The range is the difference between the maximum and minimum value for each batch. Then the value of “R bar” is calculated by finding the average of the Range values for the batches. The Upper Control Limit is obtained by multiplying the value of “R bar” with the value of “D₄” for batch size of 5. The value of “D₄” for batches of five machines is 2.115. The Lower Control Limit is zero. Then the columns for “R”, “R Bar”, “UCL” and “LCL” are selected. Next, from the insert ribbon the line chart option is selected and then the chart for UCL and LCL is created (Chen, Y., 2019). From the chart it can be concluded that the process is under control as the line chart is within the UCL and the LCL lines in the chart (Sheikh et al. 2021).

The R chart has been detected from the range column which is unique in this data and that has been derived. R bar chart shows the differences where the average line does not touch the UCL line and also LCL line.