Total Quality Control | TQC

Total Quality Control defined as an effective system for integrating the quality development, quality maintenance and quality improvement efforts of the various groups in an organization so as to enable production and service at the most economical level which allow for full customer satisfaction.

It may be classified as a ‘‘Management Tool’’ for many industries outstanding improvement in product quality design and reduction in operating costs and losses.

Product quality is defined as ‘‘The composite product of engineering and manufacture that determine the degree to which the product in use will meet the expectations of the customer’’.

‘‘Control’’ represents a tool with four steps :

  • Setting up of quality standards.
  • Appraising conformance to these standards
  • Acting when these standards are exceeded.
  • Planning for improvements in these standards.

Quality control emerges as a based function based on the collection analysis and interpretations of data on all aspects of the enterprise.

Total quality control is an aid for good engineering designs, good manufacturing methods and conscious inspection activity that have always been required for the production of high quality articles.

Quality of any product is effected at many stages of the industrial cycle :

Marketing : Evaluates the level of Quality which customers want for which they are willing to pay.

Engineering : Reduces this marketing evaluations to exact specification.

Purchasing : Chooses, contracts with and retains vendors for parts and materials.

Manufacturing Engineering : Select the jigs, tools and processes for production.

Manufacturing Supervision and shop operators : Exert a major quality influence during parts making, sub assembly and final assembly.

Mechanical Inspection and function Test : Check conformance to specifications.

Shipping : Influences the caliber of packaging and transportation.

Installation : Helps ensure proper operations by installing the product according to proper instructions and maintaining it through product service.

 In other words, the determination of both quality and quality costs actually takes place throughout the entire industrial cycle. Quality control is responsible for quality assurance at optimum quality costs.


  • Improvements in product quality and design
  • Reduction in operating costs and losses
  • Reduction in production line bottle necks
  • Improvement in employee morale
  • Improved inspection methods
  • Setting time standards for labour
  • Definite schedule for preventive maintenance
  • Availability of purposeful data for use in co-advertising
  • Furnishing of actual basis for cost accounting for standard and for scrap, rework and inspection.

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.


Quality Control

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



(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.


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.