Bal Seal Engineering canted coil spring improves instruments for hip and shoulder surgeries.
When a medical device is profitable, popular, selling well, and meeting all regulatory requirements, it can be tempting to leave well enough alone and focus on new product development instead of improving existing lines through iterative changes.
At Innomed Inc., a Savannah, Georgia-based manufacturer of surgical instruments for orthopedic surgery, founder and president Jim Anderson takes seriously the company’s commitment to continuous improvement. Innomed recently rolled out two revised products to prevent cleanability issues and stay ahead of regulatory guidelines.
Innomed uses ball plungers and ball-and-spring designs with blind holes in its products. Many of those products are designed by orthopedic surgeons to facilitate or expedite specific tasks, and Innomed aspires to foster new and ongoing relationships with surgeons to develop and originate innovative products. Seeking to eliminate – or at least minimize – the inherent potential for contamination in reusable instruments, Innomed began investigating alternative locking mechanisms for two of its best-selling interchangeable instruments – the CupX Acetabular Cup Extraction System and the Kolbel Self-Retaining Glenoid Retractor.
Those very different products – one is used for hip revision surgery, the other retracts soft tissue during shoulder surgery – were improved with Bal Spring canted coil springs made by Foothill Ranch, California-based Bal Seal Engineering Inc.
In 2015, Jim Anderson approached Innomed’s manufacturing partner, Warsaw, Indiana-based Instrumental Machine & Development Inc. (IMD), seeking a solution that could replace the ball plunger in the CupX and the Kolbel without requiring instrument redesign.
Innomed and IMD began investigating alternatives with comparable mechanical holding capability and superior cleanability. While both products have been on the market for years with no complaints about contamination, Innomed was committed to upgrading the instruments so they could be cleaned with no chance of contamination. With the Kolbel, the system would have to accommodate all existing legacy instruments sold throughout the years.
IMD product engineers worked with the engineers at Bal Seal Engineering to consider solutions based on features that could not change, and those that could be slightly modified, as well as the insertion and removal force requirements. The recommendation was a customized version of its canted coil spring. After prototyping, it was an immediate success in both instruments.
The Kolbel with a Bal Seal Engineering- developed retaining spring was introduced to market in December 2016. The updated CupX was introduced in January 2017.
Joe Beard, prototype/engineering manager at IMD says, “Bal Seal Engineering worked with us to develop the correct spring and groove setup we needed. In the end, it yielded great results, and the collaboration allowed us to improve functionality while being proactive about cleanability.”
The U.S. Food and Drug Administration (FDA) has noted that inadequate reprocessing can result in the retention of biological debris or soil in certain types of reusable medical devices, allowing microbes to survive disinfection or sterilization.
The original CupX and Kolbel instruments met all FDA specifications for material, cleaning, and traceability, yet Innomed and IMD saw opportunities for improvement. The Bal Spring’s ability to withstand repeated cleaning and sterilization processes made it attractive. An independent test report released in 2017 (Cleaning Evaluation R&D Report, test report for Bal Seal Engineering, Nelson Laboratories, May 12, 2017) proved that a sampling of Bal Spring canted coil springs were cleanable and reusable, meeting medical device industry standards as well as FDA regulations.
Conducted under worst-case conditions, testing validated that a device containing a canted coil spring in various groove geometries can be properly cleaned with manual or automated processes, withstanding stringent cleaning methods from manual scrubbing to automated dishwasher systems.
Innomed and IMD are committed to continuous product improvement, meeting or exceeding FDA regulations, and preventing issues before they occur. Because of questions about the cleanliness of the blind hole on the back side of the ball and spring setup in two surgical instruments, the designs were enhanced with Bal Spring canted coil springs, and IMD and Innomed are applying similar design concepts in developing other instruments.
Innomed says it is committed to a quality management system that endeavors “to consistently meet or exceed customer and regulatory requirements and expectations” and “to focus on exceptional customer service, quality products, and continuous improvement.”
With its integration of the Bal Spring canted coil spring in the CupX Acetabular Cup Extraction System and Kolbel Self-Retaining Glenoid Retractor, the company seems intent on fulfilling its promise.
Bal Seal Engineering Inc. www.balseal.com
Innomed Inc. www.innomed.net
Instrumental Machine & Development Inc. (IMD) www.imdortho.com
About the author: David Wang is a global market manager for Bal Seal Engineering’s medical device business. An engineer with more than 10 years of design experience, he collaborates with OEMs and tier suppliers to create sealing, connecting, conducting, and EMI shielding solutions that help set new standards for device performance. Wang can be reached at 949.460.2147 or dwang@balseal.com.
The CupX Acetabular Cup Extraction System quickly and precisely removes an acetabular cup with minimal bone loss. The product was brought to market in 2003, employing a ball-and-spring setup to hold the pivot ball onto the instrument’s end. Though the product performed exactly as intended with no cleanability issues reported, surgeons and product engineers alike were concerned about the cleanliness of the blind hole on the back side of the ball-and-spring setup.
Up 6.1% from September’s $210.58 million and up 12.9% when compared with the $197.99 million reported for October 2017.
October 2018 U.S. cutting tool consumption totaled $223.46 million according to the U.S. Cutting Tool Institute (USCTI) and AMT – The Association For Manufacturing Technology. This total, as reported by companies participating in the Cutting Tool Market Report collaboration, was up 6.1% from September’s $210.58 million and up 12.9% when compared with the $197.99 million reported for October 2017. With a year-to-date total of $2.07 billion, 2018 is up 12.8% when compared with 2017.
These numbers and all data in this report are based on the totals reported by the companies participating in the CTMR program. The totals here represent the majority of the U.S. market for cutting tools.
“October results continue the trend we have seen all year. There are some monthly fluctuations but the year over year and year to date remain over 12% ahead of last year. The market buzz continues to be positive and it appears 2018 will be the best year in over 6 years,” notes Phil Kurtz, president of USCTI.
According to Scott Hazelton, managing director, Economics & Country Risk at IHS Markit, “Higher oil prices, fiscal stimulus, particularly for investment goods, and consumer demand for durable goods will make 2018 a strong year for manufacturing in general, and cutting tools in particular. Business confidence ebbed towards the end of 2018, with uncertainty over trade and the duration of strong economic growth increasing. Combined with a declining tailwind from tax reform, and increasing wages in a tight labor market, we expect some slowing of manufacturing growth next year, with cutting tool demand growth likely downshifting from over 13% in 2018 to just under 7% in 2019. This still suggests another strong year in 2019, but growth will moderate further in 2020 as the broad economy slows.”
Options from NSK America can accelerate micro-machining speeds while limiting wear on the machine spindle.
Medical part manufacturing continues to grow at a healthy pace, and projections are for the global market for medical device outsourcing to reach $40.8 billion this year. Lately there have been increasing opportunities to bid on medical part micro-machining jobs, but your shop is having a tough time winning against the competition. The micro-tools just aren’t turning fast enough to get to that price-per-piece sweet spot and win the job.
Ultra-precision, high-speed spindles; Shank compatibility: BT/CAT/NT/HSK/R8
Max. output power: 340W (0.45hp)
Air line kit (AL-C1204): For Control Unit NE211
Collet (CHK-): 0.50mm to 6.35mm
Motor cord (EMCD-810-): 13ft/26ft; Provided with 4mm air cooling hose
Ultra-precision, high-speed spindles; Shank compatibility: BT/CAT/NT/HSK/ST
Ideal operating speed: 50,000rpm to 80,000rpm
Air line kit (AL-C1204): For control unit NE211
Collet (CHA-): 0.5mm to 4.0mm
Motor cord (EMCD-810-): 13ft/19ft/26ft; Provided with 4mm air cooling hose
If money is no object, invest in a new machine, perhaps a dedicated micro-cutter. What do you do if you don’t have a massive capital expenditure plan?
One suggestion is to adapt what’s already in the shop and use an auxiliary spindle attachment, often referred to as a speeder. Speeders use planetary gears interfaced with the machine’s main spindle amplify rotational motion, often multiplying existing speeds up to 6x. However, speeders can push a machine’s main spindle beyond its wear limits when running at or near maximum revolutions per minute (rpm) for extended periods of time. The resulting thermal expansion can destroy gears and bearings as extra speed generates extra friction. This, in turn, requires more frequent replacement and machine downtime. Speeder use can also induce problems with vibration, tool life, and runout.
While those are options often heard, NSK America’s Michael Shea, product sales manager – industrial; and Greg Nottoli, senior product manager, suggest another solution – auxiliary electric spindles that excel in handling the small features and intricate work of micro-machining.
“When we’re talking about micro-machining, it’s really any tool under 1/8", and more frequently, the end mills, drills, etc., that machinists are using have diameters all the way down to 0.005", so high rpm is necessary for this precision work,” Shea says. “This is where NSK high-speed electric spindles are designed to perform.”
Tool: 0.8mm ball nose end mill
Unlike speeders that require existing gears, wearing them down prematurely, NSK high speed electric spindles feature an integrated motor and spindle, so there are no gears to wear out.
“People are more aware of spindle speeders and often they think they can only achieve the required rpms using this gear-driven tool,” Nottoli says, “NSK offers the HES series of integral motor electric spindles that take away abuse of the machine spindle and the need for gears, removing heat and vibration issues. Machinists using speeders are getting more speed, but by adding in issues of heat and vibration, there are issues with tool life, speeder longevity, and runout.”
When added to machining centers, NSK’s HES series of spindles – HES510 and HES810 – enable high-speed micro-machining, milling, and small-diameter drilling with improved accuracy, surface finish, and tool life, and less machine abuse. And they are quiet, with some users noting they can’t even hear it running.
“Our high-speed electric spindles interface with BT, CAT, NT, and HSK tool holders, so compatibility is no issue,” Shea notes. “Tool speeds can be increased in 1,000rpm increments up to the spindle’s maximum – HES510 to 50,000 rpm, HES810 to 80,000rpm.”
It should be noted the HES510 is also available in an R8 shank, while the HES810 is compatible with 32mm straight shanks.
Established in 1984 as a wholly owned subsidiary of NSK Nakanishi Inc., NSK America Corp. serves as the North American Headquarters in Nakanishi’s global network, providing application support, sales, and repair service for high speed motors, spindles, and micro-grinders in the North, Central, and South American markets.
And it’s simple to use.
“The HES inserts into the spindle just like a toolholder. The operator connects the electrical cord and air hose – required for cooling the ceramic bearings and delivering air purge to keep chips and contaminants out – and they are set to run,” Nottoli explains. “We are delivering the speed they need, in an easy-to-use system that increases tool life and surface finish while resting the machine’s main spindle. It typically takes less than a minute to hook up the spindle and be ready to run.”
The main spindle must be switched off prior to use. An emergency breakaway connector prevents damage if the machine spindle is switched back on by accident. Design of the completely self-contained high-speed spindle eliminates gears, removing the risk of heat buildup, so it’s able to run at higher speeds for longer periods.
Helping protect cutting tools, the system also has a load meter on the unit’s control box that uses green, yellow, and red lights to determine when parameters require adjustment. If the load becomes too great, the system can automatically shut off the spindle and report back to the CNC control.
Micro-milling applications require small cutting tools run at high rpm to minimize tool breakage and maximize machine quality.
“Micro-machining means small features and tight tolerances,” Shea says. “High spindle speed reduces the chip load which reduces the forces between the tool and the material. High-speed/low-force machining yields less heat, reduces tool deflection, and allows machining of thinner walled workpieces.”
Nottoli agrees, adding that “All this results in cooler machining, superior surface quality, and better accuracy. A micro-tool needs a high rpm value to realize both efficient cutting speed and productive metal removal rate. This is where HES510 and HES810 high speed electric spindles show what they can deliver.”
NSK America Corp. www.nskamericacorp.com
About the author: Elizabeth Engler Modic is editor of Today’s Medical Developments and can be reached at emodic@gie.net or 216.393.0264.
The AL-C1204 air line kit delivers clean, dry air to electric motors via the control unit. The filter removes debris while the adjustable regulator provides the correct air pressure for cooling and purging.
Precision cutter technology optimizes sample cutting for higher efficiency and consistency in medical device manufacturing.
Precision sample preparation of metals and composites is key for reliable high-volume product testing and diagnostics in medical manufacturing. Along with the need for flawlessly cut samples for dimensional specifications, changing conditions in the quality control/quality assurance (QA/QC) environment include meeting the need for ever-increasing precision.
In high-volume medical parts production, hundreds of samples from production batches need to be run through the lab daily. For metallographic studies, the process often requires parts to be sectioned, an often-unavoidable destructive technique. Sectioning, the first step in the metallographic preparation procedure, produces a damaged layer at the cut surface.
The extent of this damage is a function of the sectioning technique and machine chosen, the material being cut, the nature of the wheel or blade selected (abrasive type, size and distribution, bonding agent, thickness), and cutting parameters (feed rate, rpm of blade, coolant flow).
Sectioning necessarily causes some specimen damage. Increasing demand for higher quantity and quality of samples is forcing medical manufacturers to seek ways to minimize the damage caused by sectioning. Precision sectioning minimizes the kerf loss, is exact enough to be used when specimens must be sectioned at very precise locations, and is delicate enough for use with fragile or friable specimens.
The surface finish is also better than that produced by other cutting methods, and the steps following precision sectioning do not include time spent using excessively coarse abrasives to remove damage produced with other sectioning techniques.
The goal with precision cutting is to minimize damage to the sample and to maximize the amount of flawless surface available for analysis. Other benefits include:
Three factors can maximize the sample cutting process – speed, blade composition, and load.
Other cutting system advancements have been developed to enhance precision and efficiency for medical parts testing:
Power hack saws, band saws, and shop abrasive saws (generally run without a coolant) are very aggressive sectioning devices that generate considerable damage at the cut interface, as do metal shears. This damage must be removed to expose the true material microstructure.
Laboratory sectioning devices, when properly used, produce less damage than machine shop devices. Two types of laboratory cutting devices used by metallographers are:
Abrasive cutters – Generally use consumable wheels with diameters from about 9" to 14" (229mm to 356mm); laboratory style cutters with larger diameter wheels (up to 18"/457mm diameter) are generally used outside the laboratory due to their large size.
Low-speed saws – Evolving throughout the last 30 years into the precision saw; early versions had a maximum speed of 300rpm and gravity feed. Current models have a 500rpm max. speed and linear feed, along with options such as automated blade dressing and automated serial cutting. Saws use both non-consumable and consumable blades.
Metal-bonded diamond blades are available with either high or low diamond concentrations and with various particle sizes. High-concentration diamond blades are best for metals and polymers – ductile materials – cut by a ploughing mechanism. The diamonds plough through the sample and hardened strips of material become brittle and break off. Low-concentration diamond blades are recommended for cutting hard ceramics – brittle materials – cut by a brittle fracture mechanism.
Blades are made using a variety of mean diamond particle sizes using an arbitrary scale from 5 (finest) to 30 (coarsest). A blade with a 10 rating will have larger abrasive particles than one with a 5 rating, yet they are not necessarily twice as large. A general rule for cutting is the smaller the abrasive, the lower the resulting deformation.
A rigid, uncoated component, such as a titanium hip prosthesis, can be sectioned directly using a larger abrasive cutter, taking precaution on how the samples are clamped to avoid damage.
Sectioning should be performed using an appropriate diamond blade for titanium alloys or using a recommended ferrous abrasive blade. After sectioning, coated samples can be mounted and ceramic- coated samples can be re-mounted, using castable and hot compression mounting.
Heat generated by the friction from the cutting process itself damages the sample surface. Controlling the amount of heat generated can effectively minimize damage.
Very thin diamond cutting blades combined with good lubrication can reduce heat, but so can applying just the right amount of cutting head load when cutting. By keeping the load low and the cutting capability high, along with proper blade selection, the sample can be moved to analysis under a macro/microscope, depending on the structure and/or depth of analysis being investigated, with virtually no surface damage.
An experienced lab technician can determine if the cutting load is being properly applied, but consistency is difficult to maintain throughout a long day of testing. Newly developed software can monitor motor current and translate that reading into cutting head load.
The software lets the load reach a certain point and then prevents it from increasing by having the saw back off the rate of cut. Because the software is reading motor current, the operator does not have to consider factors such as material composition or sample thickness.
In-house QA/QC labs for medical manufacturing are facing many challenges around the ability to provide accurate testing, working in a high-volume sample-testing environment with various materials. In addition to advancements in cutting saw technology, local metallurgical equipment reps can determine which system is suitable.
Buehler, a division of Illinois Tool Works Inc. www.buehler.com
About the author: Dr. Evans Mogire, EMEA Technical and Labortory manager for Illinois Tool Works division Buehler, can be reached at 847.295.6500.
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