The Passionate Engineer

Avoiding Design Stress Disorder

Outsourcing Product Development for Winning Products
Randal B. Chinnock

I swear at my toaster oven. Don’t get me wrong — it’s not the kind of thing I do to amuse myself on a Saturday night. It is the result of what I call “Design Stress Disorder,” a syndrome that arises as a result of poorly designed products. It starts with confusion: Am I using this wrong? Then comes self-denigration (Am I stupid?) followed by disbelief, irritation, and the urge to fling the offending object out of high windows. The toaster oven that I hate takes several minutes to heat and cooks so unevenly that it sears a black line across my toast while leaving the rest barely warm. For an encore, the rack falls out if something as heavy as a small Pyrex bowl of lasagna is placed on it. And it is ugly to boot.

You do not want your customers to develop Design Stress Disorder when they use your products. They will write you nasty letters and never buy your products again. So how do you avoid this manufacturer’s purgatory? Design your products right the first time, using the right tools and the right people. Part of this means using the best design software applications and people who are expert at using them. If you don’t have these tools and staff in your organization, outsource the work to pros.

The current generation of product design software is amazing. At the heart of most product design efforts is a mechanical computer aided design (CAD) program. The best CAD programs, such as SolidWorks, are called “solid modelers,” because they create extremely realistic 3-dimensional parts. The parts can be viewed at any angle, rotated, cut, and examined on the computer screen. They can then be mated with other parts to create an assembly. The assemblies can be analyzed to determine how they respond to mechanical stress, extremes of temperature, and dynamic effects such as shock and vibration. Plastic parts can be analyzed to determine how well they’ll mold, what residual stresses will remain in the part after molding, and whether the part will warp or deform from these stresses as it cools after molding.

If one part in an assembly is generating heat, these finite element analysis (FEA) programs can calculate how the heat is conducted and dissipated, and whether parts that people touch will get too hot. Not long ago, massive mainframe computers were required for these kinds of tasks. Now, they are performed on high-end desktop computers. This enables the manufacturer to learn all of this information before spending a nickel on making actual products.

In the case of the toaster oven, each of the toaster’s parts – the cover, door, bottom, sides, handle, rack, knobs – could then have been modeled, mated, and toleranced to ensure proper fit. The radiation pattern from the heating elements could have been analyzed to determine not only how uniformly the toaster will cook, but how hot the outside surfaces will become, heading off potential liability suits.

To ensure that a product meets user needs, performance requirements from user- and marketing-perspectives are captured in a Product Requirements Document (PRD). If this had been done, the maximum weight that the rack should support would have been defined. Then the rack, which is made of chrome-plated steel wire, could have been subjected to an FEA analysis, which would have quickly shown that it bent too much under a reasonable load, causing it to fall out of its guide slots. Along the way, mechanical engineers work closely with industrial designers to develop an aesthetically pleasing appearance and intuitive controls, as well as ensuring that the entire product can be manufactured cost-effectively.

Design defects can have much more serious results than a morning snit over burnt toast. In the medical field, products must be designed extremely carefully to ensure that they don’t fail during use and harm a patient or doctor. Failures can be caused by parts coming loose, by software or electronic circuits that go haywire, or by poorly designed controls that lead to operator error.

In the laboratory automation field, such as Hologic’s system for the automated processing of PAP smear slides to detect cervical cancer, complex systems with optical, mechanical, electronic, and software components must work together with great precision. If not, the resulting errors can be disastrous. False positives inflict patient anxiety, while false negatives can result in disease and death.

During the development of this system, we designed and tested the optical imaging components on the computer before any lenses were ground and polished. The mechanics were subjected to repeated actuations in an FEA program to ensure that precision was maintained after millions of cycles. We put the software through extensive “validation protocols” (testing) to ensure that incipient, undetected defects would “fail safe”, i.e., in ways that cause no harm. The results from these tests were used to modify the design while it was still in the computer, saving a lot of fabrication expense – and liability exposure.

Product Development firms offer manufacturers specialized expertise for creating safe, innovative, and profit-generating products. Such firms range in size from the solo designer to the 500-person full service giant. Some firms specialize in certain market segments, such as consumer products, while others are focused on industrial design; while still others – like Optimum Technologies – offer great engineering depth and can take on the analytical and design challenges of complex medical devices.

In choosing a firm, look for one that has experience in your field. They should understand the fabrication technologies involved in the manufacture of your product, and be able to work closely with your internal resources.

Avoid Design Stress Disorder. If product development is not a core competence of your firm, outsource to a firm that listens, understands your markets and goals, and can innovate all the way to the winner’s circle.

Optimum Technologies, Inc. is the northeast’s only full service product development firm specializing in optical medical devices and instruments. OTI’s FDA-compliant facilities are located in Southbridge, MA, and their staff has collective experience of over 500 years in the design, development, prototyping, and production of innovative products. Mr. Chinnock is the company’s founder and CEO. For more information, go to  www.optimum-tech.com

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