Mark Crawford, Contributing Writer09.17.19
Machining for orthopedic devices, instruments, and other products remains a highly competitive field, where vendor selection is often determined by cost and delivery speed. Many small specialty companies are consolidating to focus on commodity machining, orthopedic implants and related trays, and advanced surgical/robotic components. Medical device manufacturers (MDMs) continue to outsource their machining needs as their devices become more complex and tougher to manufacture—which makes for good business for contract manufacturers (CMs).
“We have experienced double-digit growth in our business and our new customers are designing some incredibly innovative instruments,” said David Cabral, president of Five Star Companies, a full-service contract manufacturer of instruments and implants for the orthopedic, spine, and sports medicine markets.
With the customer’s focus on speed—not just making the device but also getting it to market—a top challenge for CMs is lead time, especially for receiving raw materials and consumable tooling in a timely manner to meet customer demands. To achieve shorter lead times, manage costs, and be ready to make whatever their OEMs bring them, CMs must have a wide range of tooling and technology options and be an expert in their use—from standard machining tools like computer numeric control (CNC) machines to the latest innovative technologies such as additive manufacturing.
For the most part, many MDMs and their CMs feel more comfortable with existing technologies and prefer to use them whenever they can.
“Although new technologies are slowly entering the market—in particular, various additive manufacturing processes—the industry still relies heavily on traditional CNC machine tools to produce the vast majority of components, whether for implants or instruments,” said Daniel Gerbec, founder and president of Nibley, Utah-based Zigg Design, a provider of contract design and manufacturing services to the medical device industry.
However, as parts get more complex, they also challenge the limits of traditional machining methods. This is where CMs need to be on top of the latest machining methods and how they can be used to produce the needed specs—whether it is a new technology or hybrid equipment that combines one or more methods to improve quality and efficiency.
“The complexity of parts is requiring contract manufacturers to have a full suite of complementary machining technologies, including Swiss turning, milling, outside diameter grinding, and tool grinding, in order to quickly and competitively quote complex parts,” said Ric Medeiros, engineering manager for the Rhode Island facility for Cadence, a Staunton, Va.-based full-service contract manufacturer for medical device and diagnostics companies.
Depending upon the project requirements, sometimes CMs must come up with their own innovative ways to meet the product requirements and capabilities, while still holding down costs. They can simply buy the equipment they need (if it exists), combine equipment to eliminate steps and improve efficiencies, co-develop a machine with an equipment manufacturer, or use their own skills and expertise to build proprietary, in-house equipment to meet challenging client requirements that standard equipment cannot produce. This is especially true for innovative product designs made with advanced or sensitive materials.
“OEMs regularly come to us with their own ideas for machines and fixtures that we can design, build, and operate in cleanroom settings,” said Richard Ponton, chief of operations for Danbury, Conn.-based RK Manufacturing, a contract manufacturer for the medical device industry. “We have built dozens of one-of-a-kind, customer-requested machines and fixtures over the years to enable manufacturing procedures or product testing methods that are unique to our customers’ finished products.”
What OEMs Want
OEMs seek smooth, fast, efficient machining with a minimal number of steps, with advanced machining capabilities at hand if needed to meet challenging designs and tight tolerances. For example, laser micromachining can provide high precision, cleanliness, accuracy, and burr-free parts, which eliminate secondary steps—saving time and money.
“OEMs are interested in laser ablation that leaves parts contamination-free and burr-free, while also providing more freedom of design—for example, the ability to design their own textures and incorporate unique device identifiers and their own logos,” said Erik Poulsen, medical segment manager for GF Machining Solutions, a Lincolnshire, Ill.-based provider of milling, electrical discharge machining, laser micromachining, and metal additive manufacturing services for the medical device industry.
As highly engineered, complex devices become the standard over “single-duty” instruments and devices within the medical market, OEMs are asking for more services and higher value from their CMs, that go beyond basic production.
“Tight tolerances are part of complex devices today and assembly can be challenging,” said Cabral. “This is where design for manufacturability [DFM] skill plays a significant role in understanding how the device will be used, as well as the customer’s expectation and intent for performance and functionality. This collaboration is essential for achieving success and determining the most efficient and cost-effective production process possible.”
Technology Trends
Smaller, more complex products with unique geometries and special materials usually require custom design tooling. Requirements for tighter tolerances and high finish requirements continue to drive up production costs. These higher costs can be at least partially offset by the improved efficiencies that result when “hybrid” equipment is used to make these devices. Hybrid machines combine laser cutting or welding with conventional multi-axis CNC Swiss milling to create a single platform where the operator can easily switch from one technology to the other as needed—a vast improvement over the standard approach of cutting first on a traditional lathe and then moving to a laser machine for cutting. Popular platforms are five- to six-axis systems that support multiple laser types. Hybrid systems are ideal for micro-hole drilling and cutting fine features with no heat-affected zones, producing precision parts in seconds, with positional accuracy in the ±1.0 µm range and ±0.5 µm repeatability.
“Combining traditional machining and laser processing into one machine reduces set-up time and parts handling and provides better precision with less variation,” said Gary Francoeur, director of engineering at Cadence’s Connecticut manufacturing facility.
Savings can be significant, added Cadence CEO and president Alan Connor. “Converting complex, multi-step parts to drop off a LaserSwiss machine in a single set-up at 60 to 70 percent of the original cost is impressive,” he said. “Savings are largely realized through reduced part handing and fewer machine set-ups.”
Another trend is the push toward merging multi-axis CNC machining with additive manufacturing (AM) methods, a process known as “hybrid manufacturing.” In this approach, additive processes—such as direct metal laser sintering—are combined with subtractive processes, such as milling, in a single machine system. The system creates its own near net part shape using the on-board AM method, which is then precision machined into dimensional tolerance with the CNC portion of the machine.
Even though AM is still high on everybody’s radar, many MDMs are slow to adopt the design paradigm shift that is required to take advantage of all the design and manufacturing opportunities that AM can offer. So far, AM is mostly used in the orthopedic market for prototypes, fixtures, and patient-specific implants. Challenges with AM that make engineers cautious are the lack of dimensional control and strength, where parts are often not strong enough for many applications. Validation of the materials used can also be a problem.
Despite these AM concerns, engineers are intrigued by the expanded freedom of design that AM offers, which is not possible with traditional processes—for example, the ability to design and create their own lattice structures.
“Additive manufacturing has always provided the temptation of producing gloriously complex parts with a minimum of fuss,” said Gerbec. “The obvious application has always been the custom fabrication of patient-specific implants and implant components. Considerable energy [is] being spent trying to figure out other applications of the AM technology—for example, the quick and efficient manufacture of fixtures.”
As promising as the upside is, the introduction of new materials and novel geometries that can be used with AM also creates more risk for new, unexpected failure modes—another reason engineers are reluctant to stray from tried-and-true standard machining methods. “When using AM, design and manufacturing engineers must be diligent to ensure that these failure modes are understood and that their associated risks have been addressed,” added Gerbec.
Smaller, more complex parts with tighter tolerances often require advanced automated vision systems. As tolerances get tighter, the CM’s ability to measure the dimensioned features becomes more challenging. What used to be measured easily with an optical comparator now often requires an automated coordinate measuring machine (CMM), or even more advanced equipment.
With a steady increase of clients bringing in smaller and more complex device designs loaded with finer features, Five Star Companies decided to review and upgrade its inspection criteria and methodologies. “Optical vision inspection is nearly error-free and absolutely critical to manufacturing throughput,” said Cabral.
One of the systems Cabral is considering is the Keyence IM-7000 Image Dimension Measurement System. Capabilities include automatic recognition of position and orientation of multiple parts. Up to 99 dimensions on up to 100 parts can be measured with a single button press. “Essentially, the IM-7000 is similar to a CMM, but when the parameters of the part being measured [such as feature dimensions and tolerances] are programmed in, the system scans the part in seconds and determines whether it is within specification or not, and highlights any dimensions that are non-conforming,” said Cabral. “This technology can also measure multiple parts within the focal area, greatly reducing inspection times and potential errors.”
In addition, measurement data from the IM-7000 is automatically saved; inspection reports can be created at any time, increasing post-measurement work efficiency.
Sometimes confusion regarding tolerances, and being in or out of spec, can result when an OEM and CM use different measurement techniques for a given feature. It is best to resolve this potential issue during the design for manufacturability stage. For example, there may be disagreement between parties regarding whether or not a part is acceptable, particularly when a given feature dimension is running near one of its limits. “The best results are achieved when the CM and OEM agree exactly how a given measurement will be made,” said Gerbec. “This ensures that the proverbial ‘apples to apples’ comparison is being made.”
Gerbec regularly sits down with clients to ensure the techniques they employ to measure their critical dimensions during incoming inspections will produce similar results to the in-house measurements Gerbec makes as the CM. The tighter the tolerance on a dimension, the more important the discussion becomes. “While this may not be very important for a standard ±0.005-inch tolerance, it becomes absolutely vital when the tolerance drops below ±0.002 inches,” he said. “Working this out up front minimizes the impact this potential back and forth would have on the delivery of the final product.”
Machine Improvements Boost Production Efficiency
Real-time data—made possible by the Internet of Things (IoT)—is the driver behind the improved accuracy and efficiency of new CNC machines being brought to market. In the CNC machine world, many machines are now equipped to collect data on their own operation and interactions with other machines that, when analyzed in real time, allows for on-the-fly adjustments to maintain micron accuracy. For example, sensors enable built-in temperature compensation systems in CNC machines that help produce consistent parts early in the day, while the machine is still coming up to operating temperature.
An example of a thermal compensation/stability system is the multiple Willemin Macodel 408MT multi-axis bar-fed CNC machine. “The latest version has a dynamic thermal stability [DTS] system based on hundreds of tiny sensors in the equipment that ensures the elimination of all thermal growth of the machine, generating extremely high dimensional capabilities, some down to 5.0 µm [for comparison, a human hair is about 70 µm in diameter],” said John Cross, director of advanced machining for MICRO, a Somerset, N.J.-based full-service contract manufacturer of medical devices. “A CNC without thermal compensation cannot achieve this kind of dimensional control at such small scales.”
Another IoT-enabled machine is the hybrid Swiss/laser processing Citizen L2000 system, manufactured by Marubeni Citizen-Cincom. The laser system offers low frequency vibration machining technology to control chip formation and handle the difficult machining that can result with certain materials, and still maintain tolerances as tight as 0.00001 inches. “This machine also has new sensor technology and controls, allowing the implementation of real-time machine utilization, tool wear detection, preventative maintenance controls to deter and predict problems before they occur, and new smart cameras and probing technology inside the machine that provides real-time quality inspection,” said Francoeur.
Changing grinding wheel material is a simple yet effective way to improve production efficiency. For artificial knee implant grinding, especially the femur portion, more CMs are using state-of-the-art super-abrasive grinding wheels, rather than conventional aluminum oxide grinding wheels. “This reduces grinding cycle times and the frequency of changing tools, which saves time and prolongs the lifetime of the grinding tool,” said Florian Dierigl, marketing manager for the medical industry for Tyrolit, an Austrian manufacturer of bonded grinding, cutting, sawing, drilling, and dressing tools.
Another way to reduce costs is by using carbon fiber instead of steel in the core of the grinding wheel, which drastically reduces weight, compared to steel material. “This simplifies the handling of the wheel and also reduces cycle time and boosts productivity, greatly reducing cost per part,” added Dierigl.
Lasers continue to be used in creative ways to make tiny, high-precision features. Laser micromachining can remove material in nearly any shape or pattern. Features as small as a few microns in diameter are achievable and sub-micron kerfs are possible for very thin materials. Femtosecond laser machining is especially useful for the production of precision components with complex patterns. These laser systems are good choices for prototyping, low-volume production of intricate parts, and high-volume manufacturing of less-complex parts.
An increasing number of orthopedic device companies utilize femtosecond lasers to texture surfaces of orthopedic implants, such as hip joints and dental implants, to aid osseointegration. Some laser systems, such as the Agiecharmilles Laser S Series, can laser-machine complex designs onto three-dimensional surfaces without distortion, even near critical features—something that is difficult to do with the chemical etching techniques. Digital laser texturing techniques can virtually apply the texture to any part, giving the operator the ability to visually inspect the layout and position prior to machining.
Lasers can also be integrated with hybrid Swiss milling machines or AM systems to boost production efficiencies. For example, in 2018 GF Manufacturing collaborated with 3D Systems to develop the DMP Factory 500 machine, a metal 3D-printer equipped with three lasers for faster processing speeds. A smaller version—the DMP 350—is ideally suited for medical device manufacturing.
“The DMP Flex/Factory 350 machine has a modular system for metals [stainless steel, titanium, and others] to help reduce contamination and porosity in medical components,” said Jon Carlson, product manager for advanced manufacturing for GF Machining Solutions.
The system enables the efficient production of dense metal parts and is equipped with advanced gas flow technology to improve uniform part quality across the entire build area. Parts can be as large as 275 mm x 275 mm x 380 mm. A consistently low oxygen environment (fewer than 25 parts per million) is helpful for the production of microstructures with stable mechanical properties.
Moving Forward
As orthopedic devices become more complex and include more advanced or sensitive materials, machinists must stay ahead of the technology curve and have the know-how to deliver the high-precision, tight-tolerance machining these devices require. OEM engineers continue to design products with finer features (for example, laser cuts as narrow as 0.0001 inches) and challenging geometries, which may require innovative and even one-of-a-kind machining solutions—exactly the kind of versatility that OEMs want in a machining partner. A CM that combines that versatility with speed of process will never be short of work.
Technology continues to evolve with new devices, materials, and specific procedures. To keep pace, machine manufacturers are improving their cutting tool technologies, work-holding methods, and overall machine capabilities (many of which are IoT-enabled and data-driven). Laser manufacturers continue to improve laser capabilities for a wider range of materials, including metals/alloys, ceramics, polymers, multilayered materials, semiconductors, composites, and rubber, without creating heat damage in the material.
“As LaserSwiss technology evolves, we are looking at using different types of laser sources and technologies to further explore other markets and provide more opportunities to combine operations to reduce costs,” said Francoeur. “We are also working closely with OEMs such as Marubeni Citizen to specifically design machines with the hybrid process in mind. Swiss machines custom-designed for the laser processes could provide significant advantages for machining.”
New, advanced devices are constantly pushing the limits of current machining technology, including developing unique tooling to support product manufacturing. “What makes a difference to our customers is the ability to custom-design tooling and to be able to make changes on the fly as needed, for both improved manufacturability and quality enhancement,” said Ponton.
With the booming machining market, there is no shortage of new customer challenges and new product development opportunities. A key factor to successful design development is keeping an open mind to new ideas and the willingness to fail, noted Ponton. “Keeping the final product design in mind is the primary objective for overcoming challenges, especially when working with smaller or more complex products, which are quite often the norm these days in the medical field,” he said.
Connor agreed that creative vision is a must when taking on challenging customer projects.
“We routinely manufacture many ‘impossible’ parts at Cadence,” said Connor. “OEMs often define products based on the current known state-of-the-art technology and their own knowledge and experience before engaging their supply partners. OEMs that engage their partners early in the design process, before designs are specified and manufacturing technologies selected, often find that the ‘impossible’ is actually quite possible.”
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. His clients range from startups to global manufacturing leaders. He also writes a variety of feature articles for regional and national publications and is the author of five books.
“We have experienced double-digit growth in our business and our new customers are designing some incredibly innovative instruments,” said David Cabral, president of Five Star Companies, a full-service contract manufacturer of instruments and implants for the orthopedic, spine, and sports medicine markets.
With the customer’s focus on speed—not just making the device but also getting it to market—a top challenge for CMs is lead time, especially for receiving raw materials and consumable tooling in a timely manner to meet customer demands. To achieve shorter lead times, manage costs, and be ready to make whatever their OEMs bring them, CMs must have a wide range of tooling and technology options and be an expert in their use—from standard machining tools like computer numeric control (CNC) machines to the latest innovative technologies such as additive manufacturing.
For the most part, many MDMs and their CMs feel more comfortable with existing technologies and prefer to use them whenever they can.
“Although new technologies are slowly entering the market—in particular, various additive manufacturing processes—the industry still relies heavily on traditional CNC machine tools to produce the vast majority of components, whether for implants or instruments,” said Daniel Gerbec, founder and president of Nibley, Utah-based Zigg Design, a provider of contract design and manufacturing services to the medical device industry.
However, as parts get more complex, they also challenge the limits of traditional machining methods. This is where CMs need to be on top of the latest machining methods and how they can be used to produce the needed specs—whether it is a new technology or hybrid equipment that combines one or more methods to improve quality and efficiency.
“The complexity of parts is requiring contract manufacturers to have a full suite of complementary machining technologies, including Swiss turning, milling, outside diameter grinding, and tool grinding, in order to quickly and competitively quote complex parts,” said Ric Medeiros, engineering manager for the Rhode Island facility for Cadence, a Staunton, Va.-based full-service contract manufacturer for medical device and diagnostics companies.
Depending upon the project requirements, sometimes CMs must come up with their own innovative ways to meet the product requirements and capabilities, while still holding down costs. They can simply buy the equipment they need (if it exists), combine equipment to eliminate steps and improve efficiencies, co-develop a machine with an equipment manufacturer, or use their own skills and expertise to build proprietary, in-house equipment to meet challenging client requirements that standard equipment cannot produce. This is especially true for innovative product designs made with advanced or sensitive materials.
“OEMs regularly come to us with their own ideas for machines and fixtures that we can design, build, and operate in cleanroom settings,” said Richard Ponton, chief of operations for Danbury, Conn.-based RK Manufacturing, a contract manufacturer for the medical device industry. “We have built dozens of one-of-a-kind, customer-requested machines and fixtures over the years to enable manufacturing procedures or product testing methods that are unique to our customers’ finished products.”
What OEMs Want
OEMs seek smooth, fast, efficient machining with a minimal number of steps, with advanced machining capabilities at hand if needed to meet challenging designs and tight tolerances. For example, laser micromachining can provide high precision, cleanliness, accuracy, and burr-free parts, which eliminate secondary steps—saving time and money.
“OEMs are interested in laser ablation that leaves parts contamination-free and burr-free, while also providing more freedom of design—for example, the ability to design their own textures and incorporate unique device identifiers and their own logos,” said Erik Poulsen, medical segment manager for GF Machining Solutions, a Lincolnshire, Ill.-based provider of milling, electrical discharge machining, laser micromachining, and metal additive manufacturing services for the medical device industry.
As highly engineered, complex devices become the standard over “single-duty” instruments and devices within the medical market, OEMs are asking for more services and higher value from their CMs, that go beyond basic production.
“Tight tolerances are part of complex devices today and assembly can be challenging,” said Cabral. “This is where design for manufacturability [DFM] skill plays a significant role in understanding how the device will be used, as well as the customer’s expectation and intent for performance and functionality. This collaboration is essential for achieving success and determining the most efficient and cost-effective production process possible.”
Technology Trends
Smaller, more complex products with unique geometries and special materials usually require custom design tooling. Requirements for tighter tolerances and high finish requirements continue to drive up production costs. These higher costs can be at least partially offset by the improved efficiencies that result when “hybrid” equipment is used to make these devices. Hybrid machines combine laser cutting or welding with conventional multi-axis CNC Swiss milling to create a single platform where the operator can easily switch from one technology to the other as needed—a vast improvement over the standard approach of cutting first on a traditional lathe and then moving to a laser machine for cutting. Popular platforms are five- to six-axis systems that support multiple laser types. Hybrid systems are ideal for micro-hole drilling and cutting fine features with no heat-affected zones, producing precision parts in seconds, with positional accuracy in the ±1.0 µm range and ±0.5 µm repeatability.
“Combining traditional machining and laser processing into one machine reduces set-up time and parts handling and provides better precision with less variation,” said Gary Francoeur, director of engineering at Cadence’s Connecticut manufacturing facility.
Savings can be significant, added Cadence CEO and president Alan Connor. “Converting complex, multi-step parts to drop off a LaserSwiss machine in a single set-up at 60 to 70 percent of the original cost is impressive,” he said. “Savings are largely realized through reduced part handing and fewer machine set-ups.”
Another trend is the push toward merging multi-axis CNC machining with additive manufacturing (AM) methods, a process known as “hybrid manufacturing.” In this approach, additive processes—such as direct metal laser sintering—are combined with subtractive processes, such as milling, in a single machine system. The system creates its own near net part shape using the on-board AM method, which is then precision machined into dimensional tolerance with the CNC portion of the machine.
Even though AM is still high on everybody’s radar, many MDMs are slow to adopt the design paradigm shift that is required to take advantage of all the design and manufacturing opportunities that AM can offer. So far, AM is mostly used in the orthopedic market for prototypes, fixtures, and patient-specific implants. Challenges with AM that make engineers cautious are the lack of dimensional control and strength, where parts are often not strong enough for many applications. Validation of the materials used can also be a problem.
Despite these AM concerns, engineers are intrigued by the expanded freedom of design that AM offers, which is not possible with traditional processes—for example, the ability to design and create their own lattice structures.
“Additive manufacturing has always provided the temptation of producing gloriously complex parts with a minimum of fuss,” said Gerbec. “The obvious application has always been the custom fabrication of patient-specific implants and implant components. Considerable energy [is] being spent trying to figure out other applications of the AM technology—for example, the quick and efficient manufacture of fixtures.”
As promising as the upside is, the introduction of new materials and novel geometries that can be used with AM also creates more risk for new, unexpected failure modes—another reason engineers are reluctant to stray from tried-and-true standard machining methods. “When using AM, design and manufacturing engineers must be diligent to ensure that these failure modes are understood and that their associated risks have been addressed,” added Gerbec.
Smaller, more complex parts with tighter tolerances often require advanced automated vision systems. As tolerances get tighter, the CM’s ability to measure the dimensioned features becomes more challenging. What used to be measured easily with an optical comparator now often requires an automated coordinate measuring machine (CMM), or even more advanced equipment.
With a steady increase of clients bringing in smaller and more complex device designs loaded with finer features, Five Star Companies decided to review and upgrade its inspection criteria and methodologies. “Optical vision inspection is nearly error-free and absolutely critical to manufacturing throughput,” said Cabral.
One of the systems Cabral is considering is the Keyence IM-7000 Image Dimension Measurement System. Capabilities include automatic recognition of position and orientation of multiple parts. Up to 99 dimensions on up to 100 parts can be measured with a single button press. “Essentially, the IM-7000 is similar to a CMM, but when the parameters of the part being measured [such as feature dimensions and tolerances] are programmed in, the system scans the part in seconds and determines whether it is within specification or not, and highlights any dimensions that are non-conforming,” said Cabral. “This technology can also measure multiple parts within the focal area, greatly reducing inspection times and potential errors.”
In addition, measurement data from the IM-7000 is automatically saved; inspection reports can be created at any time, increasing post-measurement work efficiency.
Sometimes confusion regarding tolerances, and being in or out of spec, can result when an OEM and CM use different measurement techniques for a given feature. It is best to resolve this potential issue during the design for manufacturability stage. For example, there may be disagreement between parties regarding whether or not a part is acceptable, particularly when a given feature dimension is running near one of its limits. “The best results are achieved when the CM and OEM agree exactly how a given measurement will be made,” said Gerbec. “This ensures that the proverbial ‘apples to apples’ comparison is being made.”
Gerbec regularly sits down with clients to ensure the techniques they employ to measure their critical dimensions during incoming inspections will produce similar results to the in-house measurements Gerbec makes as the CM. The tighter the tolerance on a dimension, the more important the discussion becomes. “While this may not be very important for a standard ±0.005-inch tolerance, it becomes absolutely vital when the tolerance drops below ±0.002 inches,” he said. “Working this out up front minimizes the impact this potential back and forth would have on the delivery of the final product.”
Machine Improvements Boost Production Efficiency
Real-time data—made possible by the Internet of Things (IoT)—is the driver behind the improved accuracy and efficiency of new CNC machines being brought to market. In the CNC machine world, many machines are now equipped to collect data on their own operation and interactions with other machines that, when analyzed in real time, allows for on-the-fly adjustments to maintain micron accuracy. For example, sensors enable built-in temperature compensation systems in CNC machines that help produce consistent parts early in the day, while the machine is still coming up to operating temperature.
An example of a thermal compensation/stability system is the multiple Willemin Macodel 408MT multi-axis bar-fed CNC machine. “The latest version has a dynamic thermal stability [DTS] system based on hundreds of tiny sensors in the equipment that ensures the elimination of all thermal growth of the machine, generating extremely high dimensional capabilities, some down to 5.0 µm [for comparison, a human hair is about 70 µm in diameter],” said John Cross, director of advanced machining for MICRO, a Somerset, N.J.-based full-service contract manufacturer of medical devices. “A CNC without thermal compensation cannot achieve this kind of dimensional control at such small scales.”
Another IoT-enabled machine is the hybrid Swiss/laser processing Citizen L2000 system, manufactured by Marubeni Citizen-Cincom. The laser system offers low frequency vibration machining technology to control chip formation and handle the difficult machining that can result with certain materials, and still maintain tolerances as tight as 0.00001 inches. “This machine also has new sensor technology and controls, allowing the implementation of real-time machine utilization, tool wear detection, preventative maintenance controls to deter and predict problems before they occur, and new smart cameras and probing technology inside the machine that provides real-time quality inspection,” said Francoeur.
Changing grinding wheel material is a simple yet effective way to improve production efficiency. For artificial knee implant grinding, especially the femur portion, more CMs are using state-of-the-art super-abrasive grinding wheels, rather than conventional aluminum oxide grinding wheels. “This reduces grinding cycle times and the frequency of changing tools, which saves time and prolongs the lifetime of the grinding tool,” said Florian Dierigl, marketing manager for the medical industry for Tyrolit, an Austrian manufacturer of bonded grinding, cutting, sawing, drilling, and dressing tools.
Another way to reduce costs is by using carbon fiber instead of steel in the core of the grinding wheel, which drastically reduces weight, compared to steel material. “This simplifies the handling of the wheel and also reduces cycle time and boosts productivity, greatly reducing cost per part,” added Dierigl.
Lasers continue to be used in creative ways to make tiny, high-precision features. Laser micromachining can remove material in nearly any shape or pattern. Features as small as a few microns in diameter are achievable and sub-micron kerfs are possible for very thin materials. Femtosecond laser machining is especially useful for the production of precision components with complex patterns. These laser systems are good choices for prototyping, low-volume production of intricate parts, and high-volume manufacturing of less-complex parts.
An increasing number of orthopedic device companies utilize femtosecond lasers to texture surfaces of orthopedic implants, such as hip joints and dental implants, to aid osseointegration. Some laser systems, such as the Agiecharmilles Laser S Series, can laser-machine complex designs onto three-dimensional surfaces without distortion, even near critical features—something that is difficult to do with the chemical etching techniques. Digital laser texturing techniques can virtually apply the texture to any part, giving the operator the ability to visually inspect the layout and position prior to machining.
Lasers can also be integrated with hybrid Swiss milling machines or AM systems to boost production efficiencies. For example, in 2018 GF Manufacturing collaborated with 3D Systems to develop the DMP Factory 500 machine, a metal 3D-printer equipped with three lasers for faster processing speeds. A smaller version—the DMP 350—is ideally suited for medical device manufacturing.
“The DMP Flex/Factory 350 machine has a modular system for metals [stainless steel, titanium, and others] to help reduce contamination and porosity in medical components,” said Jon Carlson, product manager for advanced manufacturing for GF Machining Solutions.
The system enables the efficient production of dense metal parts and is equipped with advanced gas flow technology to improve uniform part quality across the entire build area. Parts can be as large as 275 mm x 275 mm x 380 mm. A consistently low oxygen environment (fewer than 25 parts per million) is helpful for the production of microstructures with stable mechanical properties.
Moving Forward
As orthopedic devices become more complex and include more advanced or sensitive materials, machinists must stay ahead of the technology curve and have the know-how to deliver the high-precision, tight-tolerance machining these devices require. OEM engineers continue to design products with finer features (for example, laser cuts as narrow as 0.0001 inches) and challenging geometries, which may require innovative and even one-of-a-kind machining solutions—exactly the kind of versatility that OEMs want in a machining partner. A CM that combines that versatility with speed of process will never be short of work.
Technology continues to evolve with new devices, materials, and specific procedures. To keep pace, machine manufacturers are improving their cutting tool technologies, work-holding methods, and overall machine capabilities (many of which are IoT-enabled and data-driven). Laser manufacturers continue to improve laser capabilities for a wider range of materials, including metals/alloys, ceramics, polymers, multilayered materials, semiconductors, composites, and rubber, without creating heat damage in the material.
“As LaserSwiss technology evolves, we are looking at using different types of laser sources and technologies to further explore other markets and provide more opportunities to combine operations to reduce costs,” said Francoeur. “We are also working closely with OEMs such as Marubeni Citizen to specifically design machines with the hybrid process in mind. Swiss machines custom-designed for the laser processes could provide significant advantages for machining.”
New, advanced devices are constantly pushing the limits of current machining technology, including developing unique tooling to support product manufacturing. “What makes a difference to our customers is the ability to custom-design tooling and to be able to make changes on the fly as needed, for both improved manufacturability and quality enhancement,” said Ponton.
With the booming machining market, there is no shortage of new customer challenges and new product development opportunities. A key factor to successful design development is keeping an open mind to new ideas and the willingness to fail, noted Ponton. “Keeping the final product design in mind is the primary objective for overcoming challenges, especially when working with smaller or more complex products, which are quite often the norm these days in the medical field,” he said.
Connor agreed that creative vision is a must when taking on challenging customer projects.
“We routinely manufacture many ‘impossible’ parts at Cadence,” said Connor. “OEMs often define products based on the current known state-of-the-art technology and their own knowledge and experience before engaging their supply partners. OEMs that engage their partners early in the design process, before designs are specified and manufacturing technologies selected, often find that the ‘impossible’ is actually quite possible.”
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. His clients range from startups to global manufacturing leaders. He also writes a variety of feature articles for regional and national publications and is the author of five books.