#Permute high quality vs. keep quality driver#

Then, too many products display temperamental behavior and annoying or even dangerous performance degradations. For customers, the proof of a product’s quality is in its performance when rapped, overloaded, dropped, and splashed. Of course, customers do not give a hang about a factory’s record of staying “in spec” or minimizing scrap. Most managers think losses are low when the factory ships pretty much what it builds such is the message of statistical quality control and other traditional quality control programs that we’ll subsume under the seductive term “Zero Defects.” managers and engineers have reckoned quality losses as equivalent to the costs absorbed by the factory when it builds defective products-the squandered value of products that cannot be shipped, the added costs of rework, and so on.

Competing proposals for capital equipment or competing proposals for on-line interventions may be compared by adding the cost of each proposal to the average quality loss, that is, the deviations expected from it.įor a generation, U.S.

Strive to reduce variances in the components of the product and you will reduce variances in the production system as a whole.

A concerted effort to reduce product failure in the field will simultaneously reduce the number of defectives in the factory.

Where deviation from target is consistent, adjustment to the target is possible. Catastrophic stack-up is more likely from scattered deviation within specifications than from consistent deviation outside.

Work relentlessly to achieve designs that can be produced consistently demand consistency from the factory.

Get on target, don’t just try to stay in-spec. You gain virtually nothing in shipping a product that just barely satisfies the corporate standard over a product that just fails.Overall quality loss then increases by the square of deviation from the target value, that is, by the quadratic formula L=D 2C, where the constant, C, is determined by the cost of the countermeasure that might be employed in the factory. Before products go on to manufacturing, tolerances are set.To build robust products, set ideal target values for components and then minimize the average of the square of deviations for combined components, averaged over the various customer-use conditions.In new products, average effects may be most efficiently discerned by means of “orthogonal arrays.” To set targets at maximum signal-to-noise ratios, develop a system of trials that allows you to analyze change in overall system performance according to the average effect of change in component parts, that is, when you subject parts to varying values, stresses, and experimental conditions.Robust products deliver a strong “signal” regardless of external “noise” and with a minimum of internal “noise.” Any strengthening of a design, that is, any marked increase in the signal-to-noise ratios of component parts, will simultaneously improve the robustness of the product as a whole.Quality losses result mainly from product failure after sale product “robustness” is more a function of product design than of on-line control, however stringent, of manufacturing processes.But managers will have to learn more than one principle to understand why.

#Permute high quality vs. keep quality driver#

Indeed-though not nearly so obvious-an inherent lack of robustness in product design is the primary driver of superfluous manufacturing expenses.

The “robustness” of products is more a function of good design than of on-line control, however stringent, of manufacturing processes. managers learn only one new principle from the collection now known as Taguchi Methods, let it be this: Quality is a virtue of design. How can manufacturing companies minimize them? If U.S. Taiichi Ohno, the renowned former executive vice president of Toyota Motor Corporation, put it this way: Whatever an executive thinks the losses of poor quality are, they are actually six times greater. Losses will be much greater than the costs of manufacture, and none of this expense will necessarily recoup the loss to your reputation. In either case, you must track it, transport it, and apologize for it. When a product fails, you must replace it or fix it.