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Quality, Speed, Price: Pick Three

We’ll use “quality” to mean excellent fit, form and function—in addition to the absolute requirements of safety and effectiveness. For too long, the standard practice in the medical device industry has been to optimize only cost. Manufacturers waste time by struggling half-blindly through an inefficient iteration sequence until they stumble onto a passable part. Conjecture is risky when one is working with inadequate decisionable information.

For new products being brought to market, some orthopaedic manufacturers have estimated the cost of each day’s delay at $75,000 (and more) in lost profit. Time is, indeed, a lot of money! Speed is of paramount importance. That has never been more true than now, when foreign manufacturers are demonstrating greater adeptness than ever before.

In the 21st century, manufacturers who take advantage of advanced technological tools can secure the needed quality, while improving both schedule and cost. Manufacturers can thus optimize all three of the seemingly elusive objectives of quality, speed and price, while actually increasing confidence.

The Inadequacy of 20th Century Metrology Data

I have a saying: CMMs fool you—optical comparators lie. Most users and managers understand this painful reality, but have too long accepted this status quo.

Coordinate measuring machines (CMMs) are still seen by some in the medical device industry as the gold standard in inspection. This belief persists despite the fact that FDA allows no special privilege of place for CMMs. FDA’s ultraconservative ethos requires quality departments to verify CMM data with handheld calipers and micrometers. The failings of CMMs far outweigh the few merits. At best, CMMs provide inadequate information, demand too much effort, require many questionable assumptions and yield scant decision support value.

One failing, which obliterates claims of accuracy, is vulnerability to human judgment. A CMM operator will always be susceptible to human error, regardless of experience. (One CMM programmer who had more than 30 years of experience in the medical device supply chain frankly admitted this in my office earlier this year.) And in our correlation studies of advanced metrology to CMMs, we discover latent CMM programming errors more often than you would like to believe.

Even more disturbing than the CMM’s human component is its inherently primitive treatment of exceptionally limited data. The shoulder dome in Exhibit 2. was inspected both with a CMM and a modern, 21st-century White Light Scanner (WLS). In this color plot visualization, green areas show surfaces that are within the tolerance band, while blue areas indicate minus material beyond the allowable tolerance band. (This deviation spectrum illustration is very typical, but configuration options are practically limitless.)

Exhibit 2: White Light Scanned Shoulder Dome, with CMM Points Superimposed

White Light Scanned Shoulder Dome, with CMM Points Superimposed

 

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