Quality control (QC) is a process through which a business seeks to ensure that product quality is maintained or improved. Quality control requires the business to create an environment in which both management and employees strive for perfection. This is done by training personnel, creating benchmarks for product quality and testing products to check for statistically significant variations.
A major aspect of quality control is the establishment of well-defined controls. These controls help standardize both production and reactions to quality issues. Limiting room for error by specifying which production activities are to be completed by which personnel reduces the chance that employees will be involved in tasks for which they do not have adequate training.
Meaning and Importance
Present era is the ‘Era of Quality’. In this age of cutthroat competition and large scale production, only that manufacturer can survive who supplies better quality goods and renders service to-the consumers. In fact quality control has become major consideration before establishing an industrial undertaking. Proper quality control ensures most effective utilization of available resources and reduction in cost of production.
The word quality control comprises of two words viz., quality and control. It would be appropriate to explain these two words separately to understand clearly the meaning of quality control.
According to Dr. W.K. Spriegel “The quality of a product may be defined as the sum of a number of related characteristics such as shape, dimension, composition, strength, workmanship, adjustment, finish and colour”.
In the words of John D. McIIellan, “Quality is the degree to which a product conforms to specifications and workmanship standards”.
It is clear from these definitions that quality refers to various characteristics of a product and their excellence. Quality is a relative term and is never absolute depending upon the use of the product and circumstances under which it is used.
To achieve and maintain a satisfactory level of quality of products is a very difficult task.
It involves many steps to be undertaken viz:
(a) Product must possess a minimum level of quality so that it could be easily sold in the market.
(b) In order to measure quality, accurate standard measurements must be established.
(c) Reasonable deviation from the pre-determined standards must be determined.
‘(d) Satisfactory level of quality must be achieved with a minimum cost.
Control refers to the use of all the ways and means whereby quality standards could be maintained. Control precisely aims at bringing the product up to predetermined standards by minimising deviations from established and present standards.
According to Henry Fayol, “Control consists in verifying whether everything occurs in conformity with the plan adopted, the instructions issued and principles established. It has objected to point out weaknesses and errors in order to rectify them and prevent recurrence. It operates on everything things, people, actions”.
In the words of Theo Haimann, “control is the process of checking to determine whether or not, proper progress is being made towards the objectives and goals and acting if necessary to correct any deviation”.
From the above mentioned definitions, it is clear that a good control system should be such which suggests corrective remedies so that negative deviations may not re-occur in future. The scope of the term ‘control’ is wider, including not only product to be produced but also extending to workmen and their methods of operations.
Objectives of quality control
Following are the important objectives of quality control:
- To establish the desired quality standards which are acceptable to the customers?
- To discover flaws or variations in the raw materials and the manufacturing processes in order to ensure smooth and uninterrupted production.
- To evaluate the methods and processes of production and suggest further improvements in their functioning.
- To study and determine the extent of quality deviation in a product during the manufacturing process.
- To analyze in detail the causes responsible for such deviation.
- To undertake such steps which are helpful in achieving the desired quality of the product.
Quality Control Tools
There are many approaches to quality control. The type you use depends on your specific product and should be determined before any quality control inspection begins. There are seven primary quality control tools which include:
- At its most basic, quality control requires you to check off a list of items that are imperative to manufacture and sell your product.
- Fishbone diagram. This visual is helpful for determining what causes a specific problem, be it materials, machines, methods or manpower.
- Control chart. This helps you see how processes historically change using controls. The chart helps you find and correct problems as they happen, predict a range of outcomes and analyze variations.
- Instead of looking at all factors together, stratification separates data so you can identify patterns and specific problem areas.
- Pareto chart. This type of bar chart provides a visual analysis of problems and causes so you can focus on the most significant issues.
- A common graph that uses bars to identifies frequency distributions that indicate how often defects occur.
- Scatter Diagram. Plotting information along two axes on this graph can help visually identify relationships between variables.
A quality control inspector uses one or more of the available tools or methods to do a complete analysis of a product or service to determine where improvements can be made. An inspector typically gets training to know what method to use and how to properly use it.
Internal vs. External Quality Control
Depending on the product you manufacture and sell, you may opt for internal or external quality control inspections. If you establish an in-house protocol to check your system, this is called internal quality control. It can range from routine checking of equipment, having a coworker go over another employee’s data analysis or running standards and controls on a regular basis. It is generally up to management to decide if internal quality control measures are reliable and performed as needed.
When products or data are sent to an outside business not affiliated with your company, this is external control. One example of external control is in food production. A food company may routinely analyze the nutritional value or shelf life of a food item it produces in its own lab, but to verify the results, the same food item will also be sent to an outside lab. This verification by a third party is important to obtain Food and Drug Administration labeling and to prove to the FDA that the food company’s production methods are sound.