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THE COST OF QUALITY INTRODUCTION
A manufacturer stays in business only as long as his product quality satisfies his customers at the price they are prepared to pay.
Failure to maintain an adequate quality standard can therefore be disastrous. But maintaining an adequate standard of quality also costs effort. From the first investigation to find out what the potential customer for a new product really wants, through the processes of design, specification, controlled manufacture and sale, to the arrangements for aftersales service to the customer, effort is being spent on ensuring that the company's product - and reputation - are good. If it is spent wisely, it can result in savings greater than the increase in costs, and hence in an improvement to profits.
As products become more and more complex, and as customers - both Government Departments and individuals - become more conscious of the effects on their own economics of receiving a proportion of defective items, the effort required must continually increase.
The costs represented by this effort can be a significant proportion of the products sales value (Do you know what the total is in your Company? In some instances the cost of scrap, rework and inspection costs alone has been found to be as high as 20% of turn-over) and any manufacturer should be interested in making sure that he is getting good value for his expenditure. He cannot feel sure unless he has studied what the costs are, how they are incurred and what they ought to be. If they are higher than they should be, he must consider ways in which they can be reduced.
Here we describe the nature of the costs incurred in ring product quality and reliability and shows how costs can be reduced whilst quality and reliability are maintained or improved.
THE NATURE OF QUALITY COSTS
Quality costs fall naturally into three main groups. First there are Costs associated with attaining or setting an adequate quality standard, sometimes called Prevention Costs. They are incurred largely in advance of production, when the quality standard is set. Insufficient money spent at this stage on, for example, design and development may well give rise to unnecessarily high costs later.
The second group is costs associated with maintaining an adequate quality standard, sometimes called Appraisal Costs. These are the costs associated with keeping the work manufacturing and buying functions up to the quality specified in the design.
The third category covers Failure Costs, or the costs associated with putting right any departure from standard. These include the costs of scrap, reprocessing, and guarantee claims. They are the costs, which arise as a result of shortcomings in, or insufficient expenditure on, the other two phases. They may be caused on the one hand by poor design, poor product engineering, poor operative training or, on the other, by bad workmanship, or slipshod inspection at the appraisal stage.
A list of the types of cost connected with quality and reliability will be found in the Appendix. Some difficulty may well be experienced in separating costs associated with quality and reliability from those more directly concerned with achieving the function of the product, for example, design and development. It is more important to recognise the changes deliberately made in these costs as action is taken to bring quality under control.
THE ATTACK ON COSTS
Obviously, the most significant improvements will usually be achieved by concentrating effort on the areas of high cost. For this purpose an analysis of the principal costs is required. Studies have shown that a fairly typical ratio between the three main groups of costs in a manufacturing company is: -
Prevention Costs 5% Appraisal Costs 30% Failure Costs - 65% Failure Costs, because they are typically the largest, will usually give the largest return for the effort involved in reducing them. An effective way of attacking Failure Costs is through a temporary increase in prevention and appraisal costs.
Appraisal Costs - for example, the cost of production and inspection - might be reduced by more attention to Value Engineering, which would to some extent increase prevention costs, and a closer control of the manufacturing process, which would increase appraisal costs.
Appraisal Costs will usually be the next to come under attack. An analysis of all essential quality control operations will often show opportunities for reducing expenditure without reducing effectiveness. For example, statistical sampling techniques may be used as a means of control, indicating trends in performance and assisting to maintain quality. By improving the control of the process, 100 per cent inspection may no longer be necessary.
Total costs will be lowest when design staff are aware of the cost implications of their work. Good design saves cost not only at the design stage itself but throughout production and testing: products become easier to make "right first time". Good design is needed not only when conceiving the product but also when conceiving systems for production and quality control. After failure and appraisal costs have been reduced by attention to the prevention aspect, it may be possible to reduce prevention costs as well.
We have seen that the process of reducing failure costs may well involve increasing expenditure on the design, developing, testing, manufacturing and inspecting processes. However, there must clearly be a point beyond which it would be uneconomic to incur additional expense. Failure costs might possibly be eliminated but at considerable, possibly prohibitive, costs in other areas. There is a point at which the aggregate of all costs is at a minimum for the intended selling price. Achieving this minimum cost will involve reviewing product designs, and improving planning processes, facilities and methods.
When the initial attack on costs has been successful, it will be logical to provide a means for analysing costs and for reporting on them in order to keep a close watch on progress so that, firstly, a worthwhile reduction in the attacked cost is achieved; and secondly, the expected increase in other costs is not exceeded.
SETTING STANDARDS OF COST
This can be done by setting a standard or budget for each cost item affected by the action, and by comparing periodically the actual cost with the standard. Differences between standard and actual cost are then notified to appropriate executives who can modify the tactics of the attack as necessary to ensure that the differences are reduced or eliminated.
Standards may be of two kinds: -
- They may be set on the basis of the calculations made during the preliminary study. In this case, they will be agreed, by the quality controller, with all the executives responsible for ensuring that the study expectations will be realised.
- They may be set by the more-or-less arbitrary decision of top management to reduce overall quality costs by - say - 5% or 10%.
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