statistical process control 2

8/8/2019 Statistical Process Control 2

1/14


2/14

Statistical process control is applied after a processhas been stabilized so that any deviation from the

stability can be handled easily.

There are four types of attribute charts used for non

measurable defect and defective controlling

N and NP Charts for the control of number of

defectives or non- conforming C and U Charts for the control of the defects or non-

conformities


3/14

Used at places where various defectscould occur in a single product that is

being manufactured

The sample size of inspection is fixed

for this chart.


4/14

Standard Deviation is given by (np (p-1))

Upper Control Limit

np + 3(np (p-1))

Lower Control Limit

np - 3(np (p-1))

Where

p = fraction of defectives

n = sample size


5/14


6/14

Used at places where various defectscould occur in a single product that is

being manufactured

The sample size of inspection is variable

for this chart.The proportion of defectives are plotted

and analyzed for improvement of the

rocess


7/14


8/14


9/14


10/14


11/14


12/14


13/14


14/14

IMPLEMENTATION CHART
http://j/FOR%20PRINT/C%20CHART%20IMPLEMENTATION%2030.6.10.xlshttp://j/FOR%20PRINT/C%20CHART%20IMPLEMENTATION%2030.6.10.xls

statistical process control 2

Documents