Basic concepts of quality

The Meaning of "Quality"

          Quality is a relative term and it is generally used with reference to the end use of the product. For example, a gear used in sugarcane juice extracting machine may not possess good surface finish, tolerance and accuracy as compare with the gear used in the head stock of a lathe, still it may be considered of good quality if it works satisfactorily in the juice extracting machine. The quality is the thus defined as the fitness for use/purpose at the most economical level.

          The quality depends on the perception of a person in a given situation. The situation can be user-oriented, cost-oriented or supplier-oriented. Since, the item is manufactured for the used of the customer, the requirements of the customer dictates the quality of the product. Quality is to be planned, achieved, controlled and improved continuously.

          The word "Quality" has variety of meanings:

1.     Fitness for purpose: The component is said to possess good quality, if it works well in the equipment for which it is meant. Quality is thus defined as fitness for purpose.

2.     Conformance to requirement: Quality is the ability of the material/component to perform satisfactorily in an application for which it is intended by the user. Quality of a product, thus, means conformance to requirements. Customer needs have to be assessed and translated into specifications depending upon the characteristics every application has its own characteristics.

As an example, let us consider a fountain pen. The application of the fountain pen is to write on the paper in order to perform this function satisfactorily, the required characteristics are:

•    It should hold sufficient quantity of ink, so that frequent refilling is avoided.
•     It should regulate the flow of ink into the rib.
•     It should mark the characters on the paper. The marking should be neither too thin nor too broad.
•     It should not tear the paper.
•     It should be of convenient size to hold between fingers.
•     It should have a good appearance.
•     It should prevent ink from drying when not in use.
•     It should not be slippery nor it should hurt fingers.
•     It should hold securely to the pocket.
•     It should not be too expensive.
•     It should have a reasonable life. It should sustain reasonable shocks (unbreakable).

Depending on these demands, it is necessary to decide the length, diameter, material, tip of the nib etc. Hence, the demands of the application are translated into he requirements and the requirements are quantified. These quantified requirements are called specifications.

3.     Grade: Quality is a distinguishing feature or grade of the product in appearance, performance, life, reliability, taste, odour, maintainability etc. This is generally called as quality characteristics.

4.     Degree of preference: Quality is the degree to which a specified product is preferred over competing products of equivalent grade, based on comparative test by customers, normally called as customer's preference.

5.     Degree of excellence: Quality is a measure of degree of general excellence of the product.

6.     Measure of fulfillment of promises: The quality of a product is a measure of fulfillment of the promises made to the customers.

7.     In terms of product characteristics, Feigenbaum defines quality as: "The total composite product and service characteristics of Enginering, Manufacturing, Marketing and Maintenance through which the product and service is use meet the expectation of the customers"

The key point of the definition is that Quality depends mainly on customer's perception as described earlier. hence, it is essential that all these features must be built in the design and maintained in manufacturing which the customer would like to have and is willing to pay for it.

For example, the product must perform its intended function repeatedly as called upon, over its stipulated life cycle under normal conditions of use. Many times it is required that the product must look attractive and be safe in handling. It should last for a longer period and be economical. it should be easy to operate or use.

Thus we conclude that the product should have certain abilities to perform satisfactorily in a stated application. These abilities may be categorized into ten factors as under:

1.                 Suitability. For specific application.

2.                 Reliability. It should give efficient and consistent application.

3.                 Durability. It should have desired life.

4.                 Safe and foolproof workability.

5.                 Affordability. it should be economical.

6.                 Maintainability. It should be easy to maintain.

7.                 Aesthetic look. It should look attractive.

8.                 Satisfaction to customers. it should satisfy the customer's requirements.

9.                 Economical. It should have reasonable price.

10.            Versatility. It should serve number of purposes.

A product can be said to possess good quality if all above requirements are properly balanced while designing and manufacturing it.

Quality of Design

          The quality of design of a product is concerned with the tightness of the specifications for manufacture of the product. For example, a part which has a drawing tolerance of ± 0.001 mm. would be considered to have a better quality of design that another with a tolerance of ± 0.01mm.

          A good quality of design must ensure consistent performance over its stipulated life span stated in terms of rated output, efficiency, and overload capacity, continued or intermittent operation for specified application or service.

          It should consider possible modes of failure due to stress, wear, distortion, corrosion, shocks, vibrations, high or low temperature, altitude or pressure, environmental conditions etc.

          However, product design and development is a continuous process which results into evaluation of product, based on assessed user needs, their feedback after use and development in technology at a given point of time, in a given environment.

Factors Controlling Quality of Design

1.  Type of customers in the market: For customer goods the important factor which governs the quality of design, is the type of customers in the market. the study of optimum of design involves "market survey". it is the study of :

a)  consuming habits of people. (This factor is particular important for consumer goods).

b)        the prices they are willing to pay or various products and services.

c)       the choice of design of the product which meets the needs of the customers. (User needs based on feedback and specific application).

For example, variety of vehicles with difference in size, capacity, performance and capability are found in the market to suit various applications e.g., for passengers transport, goods transport, ambulance for hospitals and vehicles for defence service etc.

The quality of design, thus, depends upon the type of customers rich, middle, poor etc. to provide the intended function with the greatest overall economy.

2.  For capital goods, the decision is usually governed by such considerations as intended life, environmental conditions, reliability, importance or continuity of service, maintainability etc.

3.  Profit consideration. From company's point of view, profit is more important. It is not necessary that the company should manufacture 100 percent quality products. The market segment to which management desires to cater should be considered. Profit can be maximized by producing products in different grades to suit different types of customers.

4.  Environmental Conditions. It also plays an important role in deciding quality of design. For example, a car radiator designed for use in equatorial regions should be for increased ambient temperature. A well designed bus body known for its good performance abroad has failed to withstand both, road conditions and loading pattern in our country.

5. Special requirements of the product. Generally, greater the requirements for strength, fatigue resistance, life interchangeability of manufacture of item, closer should be the tolerance o given better quality goods.

6.  Higher quality of design means higher cost, quite often it also means higher  values.

     However, human ingenuity often finds ways to make design both better and cheaper.

Quality Control

Control: Control can be defined as a process by means of which we observe the actual performance and compare it with some standard. If there is a deviation between the observed performance and the standard performance then it is necessary to take corrective action.

Quality Control: The term quality control has variety of meaning:

1.   Quality control is the process through which we measure the actual quality performance, compare it with the standards and take corrective action if there is a deviation.

2.    It is a systematic control of various factors that affect the quality of the product. it depends on : Material, Tools, Machines, type of labour, working conditions, measuring instruments, etc.

3.  Quality control can be defined as the entire collection of activities which ensures that the operation will produce the optimum quality products at minimum cost.

4.     It can also be defined as the tools, devices or skills through which quality activities are carried out.

5.     It is the name of the department which devotes itself full time to quality functions.

6.      The procedure for meeting the quality goals is termed as quality control.

7.       It is a system, plan or method of approach to the solution of quality problems.

8.       As per A.Y. Feigenbaum Total Quality control is:

"An effective system for integrating the quality development, quality maintenance and quality improvement efforts of the various groups in an organization, so as to enables production and services at the most economical levels which allow full customer satisfaction."

Steps in quality control program:

1.  Formulated quality policy.

2. work out details of product requirements, set the standards (specifications) on the basis of customers preference, cost and profit.

3.    Select inspection plan and set up procedure for checking.

4.    Detect deviations from set standards or specifications.

5.    Take corrective action through proper authority and make necessary changes to achieve standards.

6.    Decide on salvage method i.e. to decide how the defective parts and disposed of, entire scrap or rework.

7.     Co-ordination of quality problems.

8.  Developing quality consciousness in the organization. Quality control is not a function of any single department or a person. It is the primary responsibility of any supervisor to turn out work of acceptable quality.

Aims or Objectives of Quality Control:

1. To improve the company's income by making the product more acceptable to the customers ; by providing long life, greater usefulness (versatility), aesthetic aspects, maintainability, etc.

2.   To reduce company's cost through reduction of the losses due to defects. For example, to achieve lower scrap, less rework, less sorting, fewer customer returns etc.

3.      To achieve interchangeability of manufacture in large scale production.

4.       To produce optimum quality at minimum price.

5.    To ensure satisfaction of customers with products or services of high quality level, to build customer's goodwill, confidence and reputation of manufacturer.

6.    To make inspection prompt to ensure quality control as proper stages to ensure production of non-defective products.

7.       Judging the conformity of the process the established standards and taking suitable action when there are deviations.

8.        To improve quality and productivity by process control, experimentation and customers feedback.

9.         Developing procedure for good vendor-vendee relations.

10.      Developing quality consciousness in the organization.

Optimum Cost of Performance:

          The interaction among the cost categories can lead to an optimum level of total quality costs. Figure 1.4 illustrates this graphically. The sum of the appraisal and prevention costs rises from zero to infinity as perfection is approached. The failure cost drop from infinity to zero as perfection is approached. The total quality costs as shown in figure have a minimum or optimum between two infinites.

          From the figure it is clear that when the failure costs dominate (left hand zone) the total cost can be reduced by reducing the cost of failure. This recessitates attack on main defect concentration areas ; on the other hand when the appraisal costs dominate (right and zone) the total cost can be reduced by widening the tolerances, reduction of more effective inspection, test procedure etc.

Factors affecting quality-5 WH

Model

100    -        Why? Market Compulsion, Product Complexities

200    -        What? Money, Men Machines

300    -        When? All the time

400    -        Where? Shop / floor, point of delivery

500    -        Whom? Responsible, Management

600    -        How? Information system, Motivation techniques.

ISO 9000 and TQM

ISO 9000 is quality management system. Organization has to prepare quality manual. Quality manual deals with organizations activities, procedures so that organization can supply quality products and services. Organization that have received ISO 9000  certificate will not necessarily produce quality products and services.

Organizations which have decided to adopt TQM, will produce quality products and services today and in near future. TQM journey will never end. Organizations have to produce better quality products and services than competitors.

ISO 9000

a)       is a basic building block of TQM.

b)      setting the framework for a culture that nourishes TQM.

c)       is method of maintenance of standards facilitating TQM.

It is not necessary for organization to go first for ISO 9000 accredition. Organization can move on the road of TQM independently and will survive in future.

Buyer Beware

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Predispatch Inspection

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In process inspection

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SPC

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ISO 9000

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TQM