Devices manufactured for the medical community

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1 Image courtesy Jesse Garant Metrology Center The result of First Article Inspection performed on a medical device using Industrial CT Scanning. Medical Metrology Advances The world of medical manufacturing is making steady, significant advances, and metrology providers are keeping pace with devices that meet evolving needs Bruce Morey Contributing Editor Devices manufactured for the medical community have always presented unique challenges. Medical devices tend to be small and intricate, human compatible, and need to follow strict regulatory guidelines. Adding to the challenge today is that demand for these devices is growing, as are pressures to make the devices in the most cost-effective manner. We are seeing two trends in medical device manufacturing right now, said Jeff Petersen, vice president, sales for Fowler Precision (Newton, MA). Device manufacturers, he said, want to perform all of their own calibration in-house, rather than contracting that out. They are equipping their own calibration laboratories to do that. Fowler Precision offers a broad range of products that can fill those needs, according to Petersen. We have a small benchtop calibration device to a full CNC calibration device to calibrate instruments. 92 AdvancedManufacturing.org February 2016

2 The second trend Petersen is seeing is his customer s desire to perform more measurements near the point of the company recently introduced a profile-fitting capability production. That means near or even on the machine tool that transforms the old go/no-go capability into a quantified cutting the parts. They want shop-floor operators Half Pg to Magnum make Lathe whisker Ad M.E._Layout chart of deviations 1 1/6/16 12:49 of the AM part Page along 1 the profile. It is those measurements without waiting for the quality lab to make the measurements and send them back, he said. It saves time and provides a Feature Machines of the Month better product. While the instruments they provide seem to fill the need for accuracy and repeatability, there is always the inconsistency that comes from human error. You can have quite a difference in repeatability as a result of an operator, he said. That is where the company s new, highly portable zcat CMM comes in, using a program to perform measurements and taking the human element out of the equation. It weighs 30 lbs and you can operate it on a desk, though it is better on a surface plate, said Petersen. It measures to (L / 100 mm) microns when equipped with a Renishaw TP20 touch probe, according to its spec sheet. What our medical customers like about it is that they use it to measure parts near or even on the machining center, or in reverse engineering prototype parts created using a 3D printer, said Fowler. 30Hp Spindle Motor with 3-Range Headstock provides exceptional machining power Video Comparison Another company that is refining an old standby with new digital technology is Starrett Kinemetric Engineering (Laguna Hills, CA), upgrading the venerable optical comparator with a digital version. We replaced the old mylar overlays with digital profiles created from CAD files provided in.dxf format, explained Mark Arenal, managing director for Starrett. The digital files include a tolerance band so that parts can be compared digitally with an image captured through a video camera. While available since about 2013, Arenal noted that Magnum Series Has Returned From the Unrivaled Leader in Turning The Clausing/Colchester Magnum 26" & 32" Swing Variable Speed Lathes are back... with Unbeatable Features: Clausing/Colchester Magnum Heavy Duty engine lathes are engineered for the accurate and efficient machining of large components. A wide range of optional accessories make these machines ideal for job shops, oil field, power utilities, ship building and much more. State-of-the-art AC Spindle Drive, rpm, allows optimum cutting speeds for a wide range of machining applications Carriage Ways are coated with Moglice, an anti-friction PTFE material for improved surface finish and extended machine life 4.1 Spindle Bore standard, Optional 6 and 9 available Rollout Chip Pans for easy chip removal and clean-up; Optional Chip Conveyors available. Machines built to CE safety standards Clausing Lathes Are Available With 13"Thru 100" Swings and 25" Thru 482" Distance Between Centers Larger Custom Designed Machines Are Available Call or visit Over A Century in the Machine Tool Business February 2016 AdvancedManufacturing.org 93

3 a comparator version of the deviation color map one often While choosing the right device is a balance between sees with scanning systems. accuracy requirements, size of the part, speed and cost, he We recognize it is cumbersome to match parts manually, also observes that increasing concerns over product liability like knee or hip joint replacements, against Mylar overlays, is driving attention towards more accurate measurements. he said. There is also the management overhead of managing those overlays. Human error is always a possibility when ing more useful. Something like a Romer Arm is ideal for In the context of medical devices, CT scanning is becom- matching parts to overlays. New overlays need to be plotted measuring engineered joints, where tolerances are actually a as parts change. Medical applications include replacement little more forgiving, explained Solberg. But, there are many hips, knees, or bone screws. All of these parts from a medical instances where the CT scanner is absolutely the only way manufacturer need inspection to 100%, said Arenal. The to go because of its accuracy. A Romer Arm and scanner is video comparator improves the processing speed as well as capable of holding ±50 microns (0.002"), while our CT Scanner is certified to ±2 microns ( "). He noted such the quality compared to the traditional optical comparator. accuracy certified for metrology is especially critical to the customer. Only recently have [some] CT scanners been certified by the German VDI/VDE group, he said, referring to the German standards organization that serves as certifying organization for many metrology processes. CT scanning is ideal for many classes of medical parts, those with small and intricate details often hidden away inside the part. This includes 3D printing, a parts manufacturing technique that seems ideal for making many medical parts, according to Solberg. It means you can measure that part without having to cut it open, he said. Exact Metrology has recently partnered with ProCon X-Ray GmbH, a German developer of X-ray inspection equipment for industrial A variety of medical implants being checked on the Renishaw Equator. applications, to sell the ProCon line of CT metrology Starrett s series of Horizontal Digital Video Comparators, devices in the United States. I think the biggest impact with or HDV series, are targeted for the shop floor, to be operated medical metrology right now is the ongoing development of next to the production tool. The most recent release in the the CT scanning, he said. CT scanners like the ProCon allow series is the HDV500, released in October It boasts an users to swap out two different power ratings, such as 160 or X/Y accuracy of L (33 mm) μm for objects that are up 225 KV, each with its own advantage. And the smaller desktop to 250-mm tall. Control is either full CNC or motorized manual models are ideal for smaller medical parts, such as stents or joystick. Stage travel is 500 mm in X and 200 mm in Y. implants, that need critical inside dimensions measured. Recently, Exact Metrology has even entered the direct Choosing the Right Device patient care business in a project to deliver systems that precisely guide radiation treatments robotically. Another applica- It would seem that variety in instruments is the spice of measurement. But, there are good reasons for this, especially in medical device manufacturing. Which device and canal procedures, according to Dr. James Gutmann, DDS tion of CT scanning somewhat directly in patient care is in root accuracy to choose is application specific, explained Dean and professor emeritus of Texas A&M University (Dallas, TX). Solberg, co-founder of Exact Metrology (Cincinnati, OH). He He recently described research that exploited the technology lists the devices his contract measurement and scanning of the Nikon Metrology XT H 225 X-Ray CT system for clinical services business uses or delivers as including metrology research. MicroCT refers to techniques for especially sharp grade CT scanning, structured light devices, and Romer images. The new technology will impact research greatly, Arms equipped with laser scanners. along with the alteration of clinical techniques. MicroCT 94 AdvancedManufacturing.org February 2016

4 technology has been a part of dentistry for a few years, said Gutmann, but with newer machines such as the XT H 225 we can go to greater depths of anatomical evaluation. While not envisioning MicroCT for use directly on patients, using it has opened our eyes and minds to a different way of looking at the environment where we work. The Benefits of CT Scanning In fact, Jesse Garant, founder of Jesse Garant Metrology Center (Windsor, ON, Canada) saw such an opportunity in CT-based metrology services that this has been the company s primary offering since inception. We have ten different industries that we work for right now but medical device is one of our top four for our revenue for CT, he said. Since CT metrology is still relatively new, he observed that medical device manufacturers new to the technique tend to start using it to diagnose failures. They are looking to troubleshoot a device, either in preproduction or in production for a given flaw that they re experiencing, Garant explained. They are looking for hidden flaws due to the material, such as porosity or uneven wall thickness, or mechanical failure. Once they are educated on the value of CT, we can start to pull them into product qualification in preproduction, he said. This includes product qualification such as first article inspection or product validation after testing such as for temperature, vibration testing, mechanical testing on prototypes and qualifying the internals of parts before production begins. CT is especially useful for clear molded parts, a common item in medical manufacturing. A vision system would have difficulty measuring some of those parts because they are often clear and reflective, he explained. Somewhat surprisingly, they use their own purpose-built CT machines all calibrated to NIST traceable artifacts. We started out years ago acquiring different systems, but we have since become quite tech-savvy and build or modify all of our in-house CT systems, he said. It gives us a lot more versatility on the systems than a standard off-the-shelf system you would buy because we are a service provider and we see thousands of different parts a year now. We want to pair the proper machine with the part coming in, to always give the client the best result. High-Speed Inspection There are numerous places for metrology and inspection in production as well as analysis and design. Zeiss Industrial Metrology (Maple Grove, MN), a provider of metrological CT systems with its Metrotom series, is also seeing the value of more tailored, purpose-built high-speed inspection systems built around CT. Their new offering is the VoluMax inline CT system. VoluMax is something in-between non-destructive testing and metrology, explained Dr. Marcin Bauza, director of new technology and innovation for Zeiss. It resembles the high stability and repeatability of metrological system while providing high speed, enabling 100% inspection capabilities. Each VoluMax installation is unique for the customer and circumstances. VoluMax was introduced by Zeiss to North America in the last year, according to Bauza. The CT-XPRESS is equipped with a high productive 65W X-ray tube and a high-resolution flat panel detector, making it a truly transportable, desktop CT scanner ideal for medical parts. It can perform metrological tasks when necessary because its technical base is similar to the Metrotom CT, he explained. The key advantage is I do not have to calibrate this machine during each scan with, say, NIST traceable artifacts, such as in a master gauge process. I can inspect a part and provide detailed analysis of internal defects and compare the part geometry to a solid model of nominal part. He also noted that with its emphasis on speed critical for in-line inspections it may not have the same level of resolution as Metrotom. However, it can measure and inspect parts in seconds or even obtain subsecond throughput with multiple part scans. It measures certain metals such as cast aluminum, even titanium, as well as the common plastics often used in medical devices. Another Zeiss offering in customized inspection systems that Bauza noted would be useful for medical devices is their SurfMax line of surface defects inspection systems. Using optics, automatic loading and a white light based approach, defects, blemishes, cavities or pores typically hard to observe by human inspectors as well as vision systems February 2016 AdvancedManufacturing.org 95

5 is a high-speed comparative gauge for inspection of high-volume manufactured parts. We do metrology based on the hard gauging technique of the master measure process, said Emmett, it takes a little preparation, but is well worth it in a production setting. Its parallel kinematic machine design allows for high-speed scanning and rapid moves between features, while retaining stiffness. In the medical industry, there are a number of ideal applications that are currently using the Equator, said Emmett. One such application is measuring bone screws, since they are made in high volume, are uniform in size and shape, and have unique and varied precision features. Another are the components within X-ray and CT scanning machines that are becoming more popular, as previously noted. They want more resolution out of the detectors, he said, which means finer, even more precise parts. Measuring syringes today is particularly interesting. Now that the medical community is starting to use these as automatic and mobile means for delivering controlled dosages, small sizes and extremely tight tolerances go hand in hand. Maintaining the repeatability of the swept volume of the syringe is extremely important. It may only be a one millimeter stroke, but if you vary by even a couple of microns, that could be quite detrimental to the patient, he said. The Equator is capable of repeatable measurements from a master to ±2 μm. It is often capable of even more. We Starret Kinemetric Engineering Horizontal Digital Video Comparator are detected on a wide range of surfaces and materials. have had gauge R&R studies that exceed that specification These include matte to gloss surface finish and plastics to on well-formed diameters, he said. metals. Knee implants and other devices where surfaces free of inflections and defects are critical would be an ideal application. It does not measure surface roughness so much?exact Metrology / exactmetrology.com as it analyzes the entire surface for abnormalities, explained Fowler High Precision / fowlerprecision.com Bauza. The intent is to remove variance in today s human inspection while dramatically improving consistency of judgment and throughput all in a manufacturing environment Jesse Garant / jgarantmc.com Nikon Metrology enabling 100% inspection / nikonmetrology.com/ en_us/ The Equator Another production intent metrology device is the Equator gauging system from Renishaw (Hoffman Estates, IL). Unique since its introduction in 2012, it looks and feels like a CMM, since it drives a little stylus around, explained Dave Emmett, business manager, Gauging Products. However in reality it Renishaw Inc / renishaw.com Starrett Kinemetric / starrett.com Carl Zeiss Industrial Metrology, LLC / zeiss.com/metrology 96 AdvancedManufacturing.org February 2016