Quality Control Engineering

Introduction Of Quality And Quality Control

Quality

Different meaning could be attached to the word Quality under different circumstances. The word Quality does not mean the Quality of manufactured product only. It may refer to the Quality of the process (i.e., men, material, machines) and even that of management. Where the quality of manufactured product referred as or defined as ‘‘Quality of product as the degree in which it fulfills the requirement of the customer. It is not absolute but it judged or realised by comparing it with some standards’’.

It is usually determined by some characteristics namely design, size, material, chemical composition, mechanical functioning workmanship, finish and other properties. In the final analysis the Quality standards for the products are established by the customer.

Example : Gear used in sugarcane extracting machine through not of the same material and without possessing good finish, tolerance and accuracy as that of gear used in the hand stock of a teeth may be considered of good quality if it work satisfactory in the juice extracting machine.

Quality begins with the design of a product in accordance with the customer specification further it involves the established measurement standards, the use of proper material, selection of suitable manufacturing process and the necessary tooling to manufacture the product, the performance of the necessary manufacturing operations and the inspection of the product to check the manufacturing operations and the inspection of the product to check on performance with the specifications. Quality characteristics can be classified as follows :

(1) Quality of design

(2) Quality of conformance with specifications

(3) Quality of performance.

Control

The process through which the standards are established and met with standards is called control. This process consists of observing our activity  performance, comparing the performance with some standard and then taking action if the observed performance is significantly to different from the  standards.

The control process involves a universal sequence of steps as follows :

(1) Choose the control subject.

(2) Choose a unit of measure.

(3) Set a standard value i.e., specify the quality characteristics

(4) Choose a sensing device which can measure.

(5) Measure actual performance.

(6) Interpret the difference between actual and standard.

(7) Taking action, if any, on the difference.

Quality Control

Quality control can be defined as that Industrial Management technique by means of which product of uniform acceptable quality is manufactured. Factors Affecting Quality

(1) Men, Materials and Machines

(2) Manufacturing conditions

(3) Market research in demand of purchases

(4) Money in capability to invest

(5) Management policy for quality level

(6) Production methods and product design

(7) Packing and transportation

(8) After sales service

Objectives of Quality Control

(1) To decide about the standard of Quality of a product that is easily acceptable to the customer.

(2) To check the variation during manufacturing.

(3) To prevent the poor quality products reaching to customer.