Meaning and Definition of Quality Control: According to Dr.William Spriegel, "The quality and type of any good mean its characteristics regarding size, shape, colour, durability, workmanship, Construction and adjustment." Quality control means the merits of the goods, for achieving this, the control on materials and manufacturing plants and circumstances is done in such a way that it could affect the merits of the goods. 

All materials are obtained from the nature directly or indirectly to manufacture the goods, by which there comes the changes in the construction and characteristics of those materials due to nature causes, on the other side there comes the changes in their adjustments due to temperature, moisture, dust, polluted hot air, running of machines and deterioration of measuring instruments in the manufacturing circumstances. Therefore, the control on these changes in the quality maintenance should be kept in such a way so that it should not affect quality of the goods. 

Principles of Quality Control

Following are the principles of Quality control: 

(i) The standard of the quality should be determined in such a way that all the customers satisfying characteristics present in the goods. 

(ii) The manufacturing of the goods should be done according to prescribed descriptions so that it contains the quantity of standard goods or type.

(iii) There should be comprehensive control on the changing factors affecting the perfection of the quality so that the quality in the goods should be present according to the prescribed standard. 

(iv) For the right quantity of every merit of the quality of a product should be prepared by a efficient designer.