Statistical Quality Control (SQC)
A Quality control system performs inspection, testing and analysis to conclude whether the quality of each product is as per laid quality standard or not. It’s called ‘‘Statistical Quality Control’’ when statistical techniques are employed to control quality or to solve quality control problem. SQC makes inspection more reliable and at the same time less costly. It controls the quality levels of the outgoing products.
SQC should be viewed as a kit of tools which may influence related to the function of specification, production or inspection.
A successful SQC programme is expected to yield the following results :
(1) Improvement of quality.
(2) Reduction of scrap and rework.
(3) Efficient use of men and machines.
(4) Economy in use of materials.
(5) Removing production bottle-necks.
(6) Decreased inspection costs.
(7) Reduction in cost/unit.
(8) Scientific evaluation of tolerance.
(9) Scientific evaluation of quality and production.
(10) Quality consciousness at all levels.
(11) Reduction in customer complaints.
Tools of SQC
The principle tools of SQC are as follows :
(1) Frequency distribution.
(2) Control charts for measurement and attribute data.
(3) Acceptance sampling techniques.
(4) Regression and correlation analysis.
(5) Tests of significance.
(6) Design of experiments.
