27 QUALITY CONTROL

S. Alamelu Mangai

1.   INTRODUCTION

The market of food service industry has become more competitive in this era of globalization. Due to this, a need has been created in order to cater greater customer loyalty, greater suitability of the product to the suit the customers need and greater concern on the social image of the food industry. And this depends on the quality of their own products and services in order to meet the challenges in the new markets. The word ‘quality’ refers to the degree of excellence of a product. This module is to discuss the significance and the methods and technique of quality control.

2.  LEARNING OBJECTIVES

At the end of this lesson the learner will be able to

Understand the integral component of quality control, methods of quality control. Gain knowledge on the techniques of quality control.

3.   MEANING AND DEFINITION

The word ‘control’ denotes the process of setting standards, measuring the performance and taking corrective action. “Quality Control deals with the determination of quality standards and measurement and control necessary to see that the established standards are maintained and practiced.”

Alford and Beatty defines quality control as” that industrial management technique or group of techniques by means of which products of uniform acceptable quality are manufactured”. JA. Shubin feels that quality control means the recognition and removal of identifiable causes or defects and variations from the set standards.

Quality control refers to the systematic control of various factors that affect the quality of the end product. The end product quality depends on the raw materials quality , the manufacturing tools and equipment, the degree of skill and proficiency of the workers, working conditions, etc. The purpose of quality control is to regulate these factors to the extent that the end product conforms to the predetermined standards.

A good quality control programme involves the following steps:

i) Establishing the standards and specifications of products on the basis of the preferences of the customers and the cost of manufacture.

ii)Design and use of measures for making production conform to the standards.

iii)Selection of the process of manufacture.

iv) Establishing a logical inspection plan and collection and analysis of data. It also includes evaluation of methods and processes of manufacture.

v)Coordination of activities to improve the quality.

4.  OBJECTIVES OF QUALITY CONTROL

It aims at achieving the following objectives:

a) To establish the quality standards which are economical.

b) To establish standards of raw materials which are to be purchased.

c)To evaluate the methods of production and suggest improvements, if necessary.

d)To determine the extent or degree of quality deviations in a product during its various stages of production.

e) To identify causes of deviations from the product standard.

f) To suggest remedial measures to improve the quality of the product.

5.    SIGNIFICANCE OF QUALITY CONTROL

An efficient system of quality control can lead to the following benefits;

i) Quality control brings quality consciousness in the enterprise which discourages the manufacture or production of standard products.

ii) Quality control ensures better utilisation of resources.

iii) Quality control helps in providing greater satisfaction to customers. If the customers are satisfied, the sales are increased.

iv) Since there is less waste, the cost of production is reduced

v)The morale of the employees is increased. They feel that they are working in an enterprise producing goods of higher quality.

vi)Quality control creates a good public image of the enterprise by helping it to provide goods and services of the higher quality to the society.

6.  RESPONSIBILITY FOR QUALITY

Organization of quality control varies with the type of organization depending on its top management, policy, nature of products and state of competition. The chief of quality control of is designated as quality control manager, chief-Inspector, quality assurance manager, quality manager etc. Being a staff department it inspects raw materials, work-in-process and finished products.

Quality control discriminates between chance (uncontrollable) and assignable (controllable) variations from standards. Also locates the points of deviations from standards, analyzes its causes and advises line managers on the standard or quality to built-in products.

The strategic quality decisions are made by top management. Along with approval of a new product proposal, features and other aspects of quality such as the level of quality desire of customers, quality of the competing products are also approved. It bears the success of the marketing efforts enhancing the purchase decision of customers.

Whereas the quality decision is complicated by the relationships of quality with cost and prices. Customer may not always want the best quality. He would prefer a minimum quality control at a price that he is willing to pay. If the price is more even a high quality product may fail to attract the customer. Price is related to cost, and cost goes up with very improvements in quality controls and beyond a certain point, it increases disproportionately. The higher the quality requirements, the tighter becomes the control of manufacturing process that might result in longer production time of the finished product,

Once the top management has made the strategic quality decision considering the above points the focus now lay on production department. In designing the product and establishing quality standards, following factors have to be considered:

(i) end-use of the item (ii) design of competing products. (iii) customers’ requirements, (iv) manufacturing capability to adhere to standards, (v) need of human skills, (vi) inter-changeability of parts, (vii) chance and assignable factors which cause variations from standards, and (viii) cost and price of the product.

Generally the production department works in close collaboration with quality control, manufacturing, purchasing, sales, industrial engineering, etc. This department establishes methods in order to enhance standard performance with speed maintaining quality. The final quality is based on the raw material used, hence purchasing department too has to maintain quality. Thus all in the industry work together to reach the expected quality of the finished product or service.

Although quality control does not directly build quality in products, it assists line managers in the determination of quality standards and by identifying the areas and reasons of deviations from established quality standards. It also helps in maintaining the standards by conducting inspections and tests of materials, work-in-progress and finished products.

7.  METHODS OF QUALITY CONTROL

The methods of quality control include (i) inspection; and (ii) statistical quality control.

These methods are discussed below:

7.1 INSPECTION

Inspection is an important part of any system of production control. It is concerned at getting the products of the right quality starting from the point of purchase until the delivery of final product. Inspection may be either remedial or preventive. Preventive inspection takes place at various stages of production in order to avoid the production of substandard products. Remedial inspection is carried after the goods have been produced or manufactured in order to separate defective goods from the right quality goods. Inspection is used at the time of purchase of raw materials also.

7.1.1 Responsibilities of Inspection: Inspection is responsible for the following functions :

1.It inspects and tests the quality of all materials and purchased parts to ensure that they conform to prescribed specifications and standards.

2. It checks in-process manufacturing to ensure that manufactured parts and sub-assemblies conform to standards so as to prevent farther processing of detective pieces.

3. It checks the quality of finished products to ensure that goods of acceptable quality are dispatched for sale.

4. It provides data for future decisions relating to product designing, tooling, product engineering and production planning and control.

5. It is responsible for the maintenance and periodic testing of inspection devices, such as gauges and other instruments.

6.It advises line management on the disposal of scrap, and ensures that rejected materials or parts do not re-enter the production process.

7.1.2 Types of Inspection. Following types of inspection may be carried out in any food service organization:

i)Remedied inspection. This is done to separate useable raw materials or work-in-progress from defective raw materials or work-in-progress.

ii)Preventive inspection. This is done to find out the causes responsible for defective workand to suggest measures to overcome these causes.

   iii)Operative inspection or In process inspection. This is done to check and control the quality standards in the production process.

iv)Centralized and decentralized inspection. It may be done at specified central points in the organization or at the place where actual operations are being carried out. The former is known as centralized inspection and the later as decentralized or floor inspection.

Under centralized inspection, raw materials or products are moved to the inspection centre where the inspectors apply various kinds of tests. This inspection has advantage such as : (i) permits more intensive utilization of inspecting personnel and testing equipment; (ii) makes possible use of sensitive testing devices which need standard testing conditions (iii) saves cost by obviating the need of investment in multiple units of measuring devices which will have to be made in ease of decentralized inspection; (iv) permits relatively closer supervision of inspecting staff, and more efficient maintenance of instruments; (v) inspectors can have easy access to records, books, journals and reference material which would not be available to them on the shop floor; (vi) finally, inspection may be more objective and impartial as inspectors are spatially removed from operatives and supervisors whose work they inspect.

Disadvantages of centralized inspection are: (i) increased cost and delays involved iii transportation of materials, parts, etc., to centralized locations; (ii) lack of touch with real operating situations; (iii) piling up of defective work until the lot is ready to be dispatched for inspection and (iv) delays in corrective action which will have to wait the receipt of inspection report.

But under decentralized or floor inspection, the inspectors move from department to department and inspect raw materials, work-in-progress and finished products then and there. This is also known as patrolling inspection.

Decentralized inspection on the shop floor and in the stores department has the following advantages : (i) saves time and cost of transportation and handling of materials which will have to be incurred an case of centralized inspection; (ii) materials move faster, in the |plant from one operation to another; (iii) workers do not have to wait for inspectors to approve setup of machines, and for starting processing operations; (iv) avoids possible accumulator of defective materials and parts; (v) inspectors can promptly detect adverse trends and infinite action for improving machine alignments and operations; (vi) finally, inspectors can demonstrates and explain the defects to operatives and supervisors.

Decentralized inspection has its disadvantages also: (i) In Case there is insufficient inspection work at a work station, it may result in under-utilization of inspecting personnel and testing instruments.(ii) involves extra cost in multiple units of inspecting devices; (iii) finally, some items need the use of special testing equipment which may be available only centrally.

7.1.3 Inspection policies

Inspection department formulates a number of policies and procedures to aid its inspection in performing their functions. These policies and procedures commonly relate to the determination of the points of inspection, location of inspection and methods of inspection.

7.2 STATISTICAL QUALITY CONTROL

A landmark in the development of statistical quality control came in 1924 as a result of the work of Dr. Walter Shewhart during his employment at bell Telephone Laboratories. He recognized that there will always be variation in the resulting products in the manufacturing process . He also recognized that this variation can be understood, monitored, controlled by statistical procedures. Other leading pioneers in the field of quality control were Dr. H. Dodge and Dr. H. Romig. Shewhart, Doge and Romig were responsible for much of the development of quality control based on sampling techniques. These techniques formed what has become known as ‘acceptance sampling.’

Although the techniques of acceptance sampling and control charts were not widely adopted initially outside Bell, during the 1920s many companies had established inspection departments as a means of ensuring quality. During the Second World War, due to the need for mass produced products, statistical sampling and inspection methods became very successful and Dr. W.E. Deming and Dr. J.M. Duran spread the use of such techniques further into U.S. industry.

Statistical Quality Control (SQC) applies statistical tools to testing or inspection for the maintenance of quality standards. It is based on the theory of sampling and laws of probability. By the application of sampling techniques and continuous analysis of results it aims to control quality of materials, products and processes within predetermined tolerances. The quality trend is based upon the analysis of the inspection data, variations from prescribed tolerances. This will also enable for preventive action for controlling quality.

SQC makes sample inspection more reliable. In case of sample inspection, a small part of a certain lot of products is inspected and its quality is assumed to be the quality of the lot. This is called statistical inference, the characteristics of the whole lot or population are inferred to be like the sample. Sampling may prove to be risky because of the possibility that a sample may not have exactly the same characteristics as the whole lot.

Sampling is very useful if it is reliable. It eliminates 100% inspection and is the only possible method for products which must be tested until they fail or break. Sampling saves money as well as time . The objectives of statistical quality control are to show how reliable the sample is and how to control the risk associated with sampling technique.

7.2.1 Uses of SQC

SQC has three general uses:

(1)To control the quality of work done on individual operations while the work is being done. This is called variable control .It deals with the average measurements and range of deviations.

(2)To decide whether to accept or reject lots of products already produced (whether purchased or made within the company). This is called attribute control. When not able to measure characteristics of the item, the inspector uses judgment.

(3)   To furnish management with a quality audit of the company’s products.

7.2.2 Advantages of Statistical Quality Control

Statistical quality control confers the following advantages:

i)Statistical quality control is based on sampling technique; it lowers the cost of inspection.

ii) It permits determination of tolerances on a scientific basis. When these limits are crossed, action is promptly taken.

iii)Control chart technique informs the management if things are not going as they should go. It helps in controlling the quality of work done on individual operations while the work is being done.

iv)It prevents scrap losses due to practice of process and attribute control.

v)Helps in deciding whether to accept or reject lots of products already produced or manufactured.

vi)Statistical quality control enhances the goodwill of the enterprise among the customers.

vii)It also increases the morale of the workers as they get satisfaction by working in a firm producing higher quality products.

7.3 Techniques of Statistical Quality Control

The two important techniques of statistical qualitycontrol  are Control  Chart and Acceptance Sampling. These techniques are discussed below:

7.3.1 Control Chart

A control chart is a statistical tool for indicating variations in quality from standards. Using graph it presents lines defining the range of expected variability. It gives a running record of quality measurement by which every new measurement can be graphically compared with the past performance and thus can be properly evaluated. The main purpose of controlchart is to detect the presence of assignable causes of variation. The assignable causes of deviation from the standards include (i) differences among workers, (ii) differences among machines, (iii) differences among materials, (iv) differences due to the interaction between two or three of these factors.

The basic concept behind a control chart is when a process is affected; the variations among the samples are predictable in terms of numerical limits. When the product’s characteristics exceed these limits, the assignable causes can be safely assumed. There is a number of control charts used for the purpose of process control. A firm can use chart of individual observance, chart of averages and chart of range.

7.3. 2Acceptance Sampling

Acceptance sampling technique is used to check products already completed. It is known as attribute sampling. Under acceptance sampling, the quality of outgoing products will be controlled to ensure that on the average; no more than some specified percent of defective items will pass. The inspection plan is known as ‘acceptance sampling plan based on attributes’ if the decision of acceptance or rejection of the lot is dependent on the number of defectives found in a randomly picked up sample. A limit of the number of defectives is laid down and sample is taken on random basis. If the sample contains less than the predetermined number of defectives, it is accepted and if it does not, it will be rejected. It may happen that one sample does not represent the characteristics of the lot it represents. In order to avoid the possibility of wrong decisions being taken, it is advisable to take a number of samples.

7.4 Limitations of statistical quality control

Statistical quality control is the most scientific method available for controlling quality.

(i) It fails to detect all the defective parts, products and materials because of the large numbers that inspectors are required to inspect.

(ii) Inspection tends to be monotonous resulting in ‘inspection fatigue’.

(iii) It is also subject to errors of human judgment.

(iv) Finally, inspectors often make it a practice to reject a few pieces so that they may seem to be doing a good job.

7.5 SUMMARY

Quality control is the most important part in controlling the whole process of any food service organization. A thorough understanding of the statistical techniques and implementation of will ensure that no much loss is incurred. And pave way for positive attributes of the customers and the production of quality products and services will also enable the operative workers to re4main loyal to the organization. Thus in the changing scenario of the customers need food service establishments need to adopt these techniques to compete in the market.

REFERENCES

1. Dr.T.N.Chhabra, Principles & Practice of Management , Published by Dhanpat Rai & Co.(P)Ltd,Reprint 2006,ISBN: 81-7700-032-2, p 812-816
2. R D Agarwal , Organisation and management , Published by Tata McGraw-Hill Publishing company limited, ISBN 0-07-451506-3, P-515-533