Our product quality is one way we compete. But "quality" is like patriotism; everyone is in favor of it and claims to have it but when pressed for details many become vague.
This article is a guide for engineers, managers of engineering, manufacturing, purchasing, and marketing who must make business choices affecting the quality of their products; for customers who must choose among competing products; for customers who write specifications for special products to be made for them, and for engineers who design those products.
Product quality is degree of freedom from defects. Assuring defect free quality is a complex problem and there is never perfection.
Other defects include outright failures such as broken parts or atypical noise, and aesthetic defects such as ugliness or uneven paint.
Some defects may be intermittent. Some may be sensitive to environment. Some may be sensitive to the way the product is treated or used. Some may be latent and occur after sale. Some may appear as a gradual deterioration. Some may appear as a sudden failure. Some may exist in every copy produced and some may appear in some percentage of copies.
Slogans about quality and new names for quality control may make effective advertising copy but they do not reduce defects except to the degree that they motivate care in those who create defects. Slogans without substance can motivate cynicism rather tham care. There are actions which reduce defects.
Product quality starts here; defects designed into the product will affect all copies made and cannot be compensated by greater effort downstream.
Designing out defects anticipates downstream sources of defect and strive to prevent them. For example a designer may choose to prevent painting defects in the factory and abrasion of paint in service by making a cabinet of molded plastic which requires no paint.
Designing out defects includes providing margins of safety to compensate for variations in materials, components, manufacturing care, inspection, shipping abuse, and use. These margins cost money, size, and weight, so their magnitudes are a challenge to management judgement.
Designing out defects includes designing for those manufacturing processes which produce few defects, and design for inspectability. The designer should consult with manufacturing and inspection personnel.
Designing out defects includes the product's human and physical environments. For example product quality for Army field use is different from product quality for medical research laboratories.
Designing out defects includes designing packaging, instruction manuals, and instruction labels as parts of the product which can constitute assets or defects.
Designing out defects is designing for available low defect materials and components. The designer should consult with purchasing personnel.
Designing out defects takes costly man-hours. Management must decide how far to go.
Even the best designers make errors, so a product design is tested and revised before it enters production. The extent of testing and revision, i.e., their budget, is another management decision which affects the number and kinds of defect in the final product.
Purchasing personnel can reduce product defects due to defective materials, components, or services by choosing and supervising vendors. They face a direct conflict between cost and absence of defects, together with other problems of vendor reliability.
Manufacturing processes can introduce defects at every step of the way. Ways to reduce manufacturing defects are:
The marketing department is the interface between the customers and the other departments. Marketers help the other departments please the customers by explaining what pleases and what displeases. It is a management responsibility to make the other departments pay attention to the marketers. Pleasing customers sells products.
Defect reduction requires investment in both money and personal relationships but the successes of our Japanese and German competitors teach that the investments are profitable in the long run.