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Roundtable Q&A: Testing & Inspection

Tue, 07/10/2012 - 2:01pm

Question 1: What are the common missteps OEMs make when planning a testing solution for their medical devices?

Greg Crouch
Life Sciences Business Director, National Instruments
The single most common mistake we see is the lack of attention to the fact that the test systems often must be validated to the same quality standards as the product itself. By this, we mean documented artifact and system software traceability of the test system, primarily in FDA Class II/III products. Those lagging their best-in-class competitors think of this step late, and still often use manual procedures that depend upon text-based documents and manual spreadsheets to map test system requirements to test code implementation. We hear companies say they transitioned from person-months to person-days per revalidation of test systems by automating the linking of rapidly changing test code to defined end-system requirements.

Jacques E. Hoffmann
President, InterTech Development Company
The apples and oranges problem. When one leak testing method is selected for the prototype designs and another for production assembly. Generally, the same leak testing methods that are used in prototype designs are also the best ones for assembly processes.

The hot and cold problem. If one is testing newly cast prototypes that are still warm from the casting process, you need a means to automatically compensate for temperature variations. [Conversely], waiting until parts cool is inherently fraught with error, since testing environments are constantly changing depending on current conditions.

Question 2: How early in the product development lifecycle should testing come into play?

GC: Test can improve a product’s performance, increase quality and reliability, and lower return rates. It is estimated that the cost of a failure decreases by 10 times when the error is caught in production instead of in the field and decreases 10 times again if it is caught in design instead of production. With that said, a best practice we see within companies that lead their respective industry segment is the addition of test engineering by augmenting concept proposal teams with design verification and production test engineers. These persons help eliminate a lot of pain that would have shown up later. We see no single silver bullet to make the integration successful, as it requires a strategy that spans people, processes, and technology. Organizations may need improvement in some areas more than others.

JH: The more challenging aspect of prototype development involving leak testing is in quantifying the leaks such that design iterations are truly tested. For that process, consulting with proven experts in leak testing is a recommended first step for all product designers of appliances with tanks, tubes, valves, filters, or other components that need to be “leak-proof.” Such consultations have repeatedly helped product designers save up to 10% in product development costs and significantly cut time-to-market by up to 15%.

Question 3: When dealing with supply partners, what best practices should OEMs follow to inspect the product?

GC: As a company that focuses on moving commercial technology into the test and measurement industry, our R&D investment is leveraged many times over in the commercial technologies we adopt. Thus, we must maintain close, strategic relationships with our suppliers. We force ourselves to conduct executive and lead engineer level biannual technology exchanges with key suppliers that build PC technologies, data converters, and software components to get their outlook on upcoming technologies and the ways these suppliers are investing their research dollars. It is so easy to let time go by, until you find yourself in a bind with a key supplier.

Question 4: Any thoughts/comments on testing, inspection, or another related area that you would like to share with medical device manufacturers to aid them?

GC: Other trends we see being leveraged by the best-in-class relates to how software in automated test has grown significantly and how properly architected modular test hardware components can scale with the testing need. Software development costs are often 2X to 10X more than capital costs in most test systems today. The industry leading companies we visit emphasize designing a robust test system software stack to ensure maximum longevity and reuse. The software abstracts the underlying hardware.

Modular test hardware components allows the ability to leverage heterogeneous computing in a system to distribute data, processing, and program execution among different computing nodes that are each best suited to specific computational tasks. For example, an RF test system that uses heterogeneous computing may have a CPU controlling program execution with an FPGA performing inline demodulation and a GPU performing pattern matching before storing all the results on a remote server. This level of control in a test system may sound difficult to implement, but higher-level test engineering focused programming tools such as NI LabVIEW Real-time and LabVIEW FPGA abstract all the lower-level details. After all, how many test engineers know how to program a FPGA or efficiently in low-level C languages, when their day-to-day task list is not programming?

JH: Typically at issue is how to design test fixtures and how to integrate software and hardware at the system level. Competence in hardware design results in fixtures that will prevent seal creep, manage temperature-related effects, minimize testing volumes for quick response, and eliminate part distortion during testing. Customizing software to work in real time and experience in handling comparable challenges can make or break the success of prototype leak testing.

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