TPi April 2010

Smal l diameter tubes

Pitfalls to avoid when outsourcing tubing “While such information may be convincing, it is often misleading,” says Mr Heft. “The trouble with the Internet and even some reference books is that they may encourage the selection of an exotic material that could be unavailable or inappropriate for the application. We see this all the time. Your supplier should explain such issues and then determine what you are trying to achieve. They should be knowledgeable of the application and make suggestions regarding alloys and design factors.”

Manufacturers of medical devices who outsource metal tubing should insist on validation of tubing specifications with an expert, and require realistic lead times. There is a hard price to pay for those who choosenottoconsultwithknowledgeable suppliers when outsourcing metal tubing for medical devices. Unless certain steps are taken to ensure that designs and specifications are accurate, the potential consequences include exceeded R&D budgets, exorbitant production costs, delay of FDA approval, slowed speed to market and a great deal of frustration. By qualifying and partnering with a metal tube supplier, most of the pitfalls that cause such problems can be identified and avoided. For example Lance Heft, CEO of International Tube USA, a major supplier of metal tubes to the medical device industry said: “A big pitfall that we run into is that a lot of engineers will look at tolerances in terms of the upper and lower extremes; they do not take into account tolerance stacking, effects of secondary operations, ID clearance issues etc. If these items are not specified properly and prototype runs are ordered, the engineer loses their monetary investment, and more importantly time, which translates to time to market and missed product release deadlines, or even worse – recalls.” “These are critical factors that you often run into in production runs. If this happens, you have to go back to the drawing board because perhaps just one of those specs didn’t work. So, we’ll bring those types of questions up in the initial meeting with a customer to make sure the engineers get what they want in their initial prototype run.” Here are five other pitfalls that OEMs, engineers, and procurement people can avoid when outsourcing metal tubing used in medical devices: Using unqualified input We live in the Age of Information, yet it’s essential to remember that not all information is accurate. Many engineers will refer to Internet sites for information on metals and their corresponding mechanical and chemical properties.

Mr Heft adds that the collaborative relationship is often most important to smaller and mid-size medical device manufacturers who do not have the range of experience with metallurgy and applications that the tube supplier should have. Additionally, it is important to fully understand the different manufacturing methods of tubing and how this relates to the performance of the end product. Many tube designs and configurations include fabrication challenges such as metallurgy, tube formation and configuration, tensile strengths, cost, structural characteristics and coatings. These may include bulges, flairs and swages that are difficult to perform, yet may be vital to the performance of a device. So, it is important to confirm that your supplier has experience with such configurations. Over-estimating requirements Prospective vendors should be qualified according to their experience with an application to validate tubing requirements. For instance, small- diameter tubing is becoming increasingly important because medical devices continue to become more miniaturised. “This creates a need to put more materials or devices through a smaller ID tube,” Mr Heft explains. “When you put multiple devices, such as fibre optics, other tubes, guidewires and even stents, through a narrow laparoscopic or endoscopic tube, for example, you get a ‘stack-up’ of tolerances. That results in costly problems. So, it becomes much more important that the ID is accurate, the inner surface is smooth without burrs, roughness or debris which could cause damage to the materials, and that

High precision tubing

the instrument is engineered so that it does not develop kinks.”

“Our knowledge comes in right from the start. It’s scary to say but it has happened to us that the customer will come to us and ask for 316 or 304 stainless and then we find out that they are using it for an implanted device,” says Heft. “That is not implant-grade material, so we have to make them aware that they need an implant-grade material, and help them understand the properties and why they are important.” Fully understanding the tube application can lead to optimum functionality plus costsavings.Havingaccesstospecialised engineers at the vendor level helps to define device quality requirements and also ensures consideration of solutions to both current and future requirements in an environment of constant technological change. “If your supplier does not have engineers on staff, look somewhere else,” Mr Heft states. Taking quality correlation for granted It is vital for the vendor to ensure that the tube can perform to the level of quality expected and it is extremely important to find a provider that makes sure that quality measurement techniques are correlated between both parties, products are being inspected properly, and products are being run through the necessary tests to make sure they perform. “The subject of correlation doesn’t come up as often as it should,” Mr Heft says. “In some cases engineering handles the mechanics and functionality of the device. But there is a separate quality

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Tube Products International April 2010

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