I sat down with Theresa Smith, district sales manager for Instron at the recent North American Spine Society meeting to talk about what trends she sees for the mechanical testing apparatus industry, specific to medical device applications. Instron is a manufacturer of mechanical testing equipment and has a variety of types, from ball screw-driven for plain tensile or compression tests to servohydraulic and electrodynamic for fatigue or fracture toughness tests.
Despite the fact that her office is located just up I-95 from me, it took this conference in San Francisco for us to get our schedules coordinated. We talked about two main areas: The greening of test systems and the increased financial flexibility that Instron offers:
David Spenciner: Theresa, thanks for taking time to talk. What new trends do you see with regard to mechanical testing of medical devices and how is Instron responding?
Theresa Smith: Well, Dave, we see that, especially for large companies, their green initiative pervades all aspects of their business, including capital expenditure and R&D budgets. Three years ago, Instron first offered dynamic testing systems that use electromagnets to drive actuator motion rather than the traditional pressurized oil. More recently, Instron expanded this line to include a larger capacity frame (10 kN) and a tension/torsion frame. There are several important differences between ElectroPuls and the older technology, primarily due to the fact that we are no longer pumping hydraulic oil around. These include a smaller overall footprint, lower facilities preparation costs, less maintenance, quieter operation, decreased electricity usage and relative ease of relocation. A lot of these changes were driven by our support of our customers’ green initiatives.
DS: That’s a good point. I remember many years ago having a water-cooled pump at our test lab in Cambridge. Before the city made us install a water tank to re-circulate the cooling water, all that water just went down the drain, 24/7 and year after year.
TS: Many municipalities no longer allow this sort of waste, so a re-circulating water supply must be used. This technology uses air cooling, but it’s quiet enough that you could install it in your office. One of our customers did exactly that so he could keep an eye on his tests while attending to other work. These machines also run a lot faster and longer than servo machines. We are seeing the need for very rapid cycling being driven by cardiac stent testing, where designs need to undergo 400 million cycles prior to regulatory approval. This technology lets our customers test multiple stents in fatigue at rates up to 70 cycles per second all on one test frame.
DS: Wow, even at 70 Hz, those tests have got to take a long time — it’s nice to be able to configure the machine to test many stents in parallel. Other than the stent designers, are you seeing much demand for these machines within the medical device world?
TS: Yes, there seems to have been pent-up demand within the medical device industry for this technology. For example, the tension/torsion frame permits up to 32 full rotations of the actuator, compared with only 90 or 270 degrees for the servo technology. This increased range makes ElectroPuls much more appropriate for testing devices that need to be rotated substantially during testing. For example, the insertion and removal torque tests for bone screws typically require multiple rotations in order to complete the test.
To deal with the demand and the changing economic climate, Instron has a program that lets companies rent the machine prior to buying it. While still a small part of our business, we are seeing more companies express interest in this option. It allows them to better determine the return on investment and to get a head start on their testing program while waiting for their capital equipment budget to free up a little. A portion of the rental can go toward the eventual purchase. The ability to rent an ElectroPuls frame gives companies the option to take delivery and install a fully functioning frame in significantly less time than if they bought or leased a servo frame.
DS: I can see how delaying capital expenditures without slowing down the R&D testing process would be attractive to contract test labs as well as medical device designers. Thanks for your time Theresa and I hope you have a productive NASS.
