D
MSA manual page 85 states “…select a production part that falls in the mid-range of the production measurements and designate it as the master sample for bias analysis. Measure the part n≥10 times in the tool room, and compute the average of the n readings. Use this average as the “reference value”.
I have no measuring equipment with better sensitivity. Our workplace is in an air-conditioned clean room. I don’t know what a tool room environment is like. I presuppose our clean room environment match that of a tool room. So I asked an operator to measure one sample 10 times, calculated the average, used it as the reference value, then asked the same operator to measure the sample 15 times, and then I followed the formulates given in the manual to decide if the bias is acceptable.
I did this because I believe bias is an important factor that no reason can justifiably exclude it. I used the same operator to decide the reference value because she used the equipment best, and she usually performed the measuring.
I question is, since I used the same operator, sample, environment, method, equipment, there is no reason why the averages would be different. So the bias analysis was reduced to a ritual.
Do you think my method acceptable? If you are in my shoe, what will you do?
I have no measuring equipment with better sensitivity. Our workplace is in an air-conditioned clean room. I don’t know what a tool room environment is like. I presuppose our clean room environment match that of a tool room. So I asked an operator to measure one sample 10 times, calculated the average, used it as the reference value, then asked the same operator to measure the sample 15 times, and then I followed the formulates given in the manual to decide if the bias is acceptable.
I did this because I believe bias is an important factor that no reason can justifiably exclude it. I used the same operator to decide the reference value because she used the equipment best, and she usually performed the measuring.
I question is, since I used the same operator, sample, environment, method, equipment, there is no reason why the averages would be different. So the bias analysis was reduced to a ritual.
Do you think my method acceptable? If you are in my shoe, what will you do?