Mark Crawford, Contributing Writer11.10.21
Additive manufacturing/3D printing (AM/3DP) is a widely adopted manufacturing process that is used to fabricate millions of medical devices and healthcare products every year. AM enables medical device engineers and surgeons to develop next-generation, innovative instruments and devices quickly and cost-effectively, which can be manufactured to scale to meet changing production demands.
“AM is used to create medical education models that represent patient anatomies, patient-specific surgical instruments derived from imaging data, and metallic implants and instruments with features that are impossible to fabricate using traditional subtractive manufacturing,” said Benjamin Johnson, vice president of portfolio and regulatory for 3D Systems in Littleton, Colo., which develops innovative additive manufacturing solutions across hardware, materials, software, and services for the medical device industry.
The advantages of AM are many, including greater design freedom, rapid prototyping, product customization, creating surface structures and textures that promote bone growth, and the ability to scale and manufacture on the same machine that does the development and prototype work.
“3D printing enables healthcare professionals and medical device manufacturers to move from a virtual model to printing and prototyping to production runs of thousands of pieces, seamlessly,” said Shon Anderson, CEO for B9Creations, a Rapid City, S.D.-based provider of 3D printing hardware, software, materials, and services platforms for the medical device industry.
Because of these advantages, AM/3DP is more deeply developed in the medical device industry than almost any other industry, with the possible exception of aerospace. “Most medical device companies either have AM products currently, AM products in the pipeline, or prototype in AM,” said Jeff Hutchens, business development manager for healthcare for AddUp Solutions, a Cincinnati, Ohio-based provider of additive manufacturing equipment and consultation services for the medical device market.
As a result, the AM/3DP medical device market is also rapidly expanding. According to Research and Markets, the global 3D printing medical devices market is projected to increase from about $2.4 billion in 2021 to $5.1 billion in 2026, a compound annual growth rate of 16.3 percent during the forecast period.1
Perhaps the greatest advantage of AM is the design freedom it provides medical device engineers. Digital manufacturing enables them to design without the constraints of traditional manufacturing and to create an array of medical devices, including ones that require microscale or complex features, or are customized to patients. “Also, replacing the costly set-up and tooling of traditional injection molding or CNC machining with 3D printing gives engineers a quick and cost-effective path forward through iteration,” said Anderson. “Bringing 3D printing in-house also lowers the barrier of access to bridge tooling for design and market validation before making a capital investment in tools.”
It has only been in the last three to five years that AM technologies have matured to the point where they are today, with many improved capabilities and material choices. Despite these advancements, however, most AM-made products are still not production-ready. Although AM technologies are suitable for the generation of low-volume complex geometries, the greater challenge for a finished component is to achieve the fine resolution, dimensional accuracies, and surface features required for many components, without secondary processing.
“To that degree, AM/3DP is not a replacement for turning, milling, and drilling, but rather a complement to subtractive manufacturing methods,” said Joseph A. DeAngelo, director of new product development for Weiss-Aug, a Fairfield, N.J.-based provider of development, prototyping, and sub-assembly services for medical devices. “Many components produced from AM/3DP technology require value-added processes to complete. For the price point of AM/3DP technology today, a justification of the equipment and return on investment becomes the largest issue.”
Latest Trends
AM continues to gain widespread adoption in the medical device market, especially for orthopedic devices. Medical device components such as spinal cages, acetabular cups for total hip arthroplasty (THA), and tibial base plates for total knee arthroplasty (TKA) are routinely printed using electron beam and laser powder bed fusion processes. AM has also extensively penetrated the spine market, generating positive clinical results. Emerging trends such as printing custom patient-specific surgical guides and instrumentation have been explored, wherein medical device manufacturers (MDMs) do not need to invest in specialized tooling and subtractive manufacturing processes for low-rate customized production runs.
“Over the last decade, AM technology has matured, and OEMs are exploring next-generation solutions such as printing on-hospital-site for quick turnaround and targeting challenging applications such as printing femoral stem components for THA, femoral knee components for TKA, and expanding interbody cages,” said Gaurav Lalwani, global medical applications engineering lead for Carpenter Technology, a Philadelphia-based provider of high-performance specialty alloy-based materials and process solutions for the medical device market.
MDMs are also asking their AM partners for implantable devices that have lattice/porous structures to encourage osteointegration. “Medical device OEMs have been the fastest industry to adopt metal additive manufacturing and are driving innovation in their devices and implants, with intricate lattice structures and roughened surfaces for bone growth,” said Graeme Findlay, director of marketing for Precision ADM, a Winnipeg, Manitoba-based provider of additive manufacturing services for the medical industry.
Another keen focus by MDMs is fabricating a greater variety of patient-specific solutions. The medical device industry has already witnessed the success of 3D printing for patient-specific medical devices for dentistry and craniofacial medicine. More recently, the orthopedics community is “capitalizing on these patient-specific workflows to create custom surgical instruments that reduce the number of operative steps needed for prepping the bony anatomy to receive off-the-shelf implants,” said Johnson. “Similarly, the radiation oncology segment is adopting 3D printing to create patient-specific accessories to more effectively modulate dosages delivered during radiotherapy treatments.”
Devising customized surgical plans, instruments, and implants for surgeons to personalize the treatment of their patients is becoming more mainstream, whereas previously it was only done for more complex patients. However, creating an ecosystem for personalized medical devices is not an easy accomplishment—"we see the partnerships among surgeons, OEM manufacturers, and additive manufacturing solution vendors as critical for delivering the complete solution to elevate patient care,” said Johnson.
Another trend is the increased focus on productivity in hardware and software systems. 3D printers are being commercialized for large-volume manufacturing that maintains high-quality output but at faster print speeds and throughput. In software, much of the work is going into the development of manufacturing execution systems that take advantage of the digital infrastructure of additive solutions, “thereby making the operation of running a fleet of 3D printers easier for traceability and compliance purposes,” said Johnson. “The trend toward productivity will result in overall reduced costs that, in turn, will result in additional medical device applications that can be addressed with additive manufacturing.”
As additive manufacturing becomes easier to use for the production of medical devices, more clinical centers are taking an interest in manufacturing their own devices on-site. There is a long history of using 3D printing within the hospital for creating anatomic models of patient disease for use as an augment to medical education and as an additional tool in the surgical planning and treatment selection for patients. More recently, hospitals have been designing and printing their own patient specific-instruments for use in surgery and, in the future, will likely have the capability to manufacture personalized implants and other patient treatment tools.
What OEMs Want
Medical device companies are eager for rapid prototype turnaround, cost-efficient prototypes and production costs, greater inventory control, and shorter lead times.
“OEMs want accuracy and reproducibility for both prototypes and production,” said Hutchens. “They also expect productivity and reduction in costs due to print accuracy leading to reduced post processing.”
MDMs are constantly looking for ways to use additive manufacturing that will foster innovation—for example, achieving miniaturization and tight tolerances for components, which can challenge the limits of AM know-how. “Medical device manufacturers, contract manufacturers, universities, startups, and others often collaborate to produce high-resolution models in their engineering or biocompatible resin of choice, all increasingly pushing the envelope of micro-scale printing and production,” said Anderson. B9Creations, for example, uses its own AM equipment and proprietary computer-aided manufacturing (CAM) software to produce parts with dimensional tolerances within ±50 µm (±0.002 inches).
Consistent, high-quality powder, along with tools to effectively manage the recyclability and track the history of the powder, are getting more attention from MDMs. “The FDA has enhanced scrutiny on the devices produced using additive manufacturing and are asking for additional information pertaining to powder lifecycle for new device approvals,” said Lalwani. “In turn, MDMs are looking to innovate and print the next generation of device designs and want advanced powders that can help them achieve those desired higher mechanical properties.”
New Technology Advances
New technology improvements continue to advance AM design capabilities. “For example, new software, better file formats, and more computing power have combined to provide endless design opportunities,” said Ryan Kircher, senior additive manufacturing engineer for rms Company, a Coon Rapids, Minn.-based provider of high-volume precision machining and additive manufacturing for medical device OEMs.
These opportunities are advancing on a number of AM fronts, including the lightening of components, larger builds, variety of materials, improved resolution and accuracy, fewer parts within an assembly, and reduced power consumption. Other goals are detailed lattice structures within implants that mimic bone structure, matching stiffness of implants to the surrounding bone structures, and the ability to X-ray through an AM implant due to reduced density of the implant design (more porosity).
“Another interesting trend is the design for combining geometries into a hybrid manufacturing system that implements a subtractive base component, upon which an additive element is built to generate a desired device,” said DeAngelo.
Metal additive manufacturing is becoming more productive for medical devices through software and print strategies as well as hardware advancements. For example, additional lasers can be added to a printer to increase productivity. “Automated powder handling also helps reduce print time and time in between builds,” said Hutchens. “As part of our AddUp FormUp 350 process, we also have a roller powder spreader with the ability to print with fine powder, leading to improved surface finishes and less post-processing costs.”
Materials Science
Materials are key to the growth of additive manufacturing. Titanium alloys, stainless steels, and cobalt-chrome are the most popular metals for AM. For plastics, nylon and acrylate materials are frequently used to create patient-specific instruments for short-duration use.
AM materials in the medical device industry have evolved from materials that were developed to support the prototyping of products to materials intended for use in the production of the final product. “In the prototyping environment, it was acceptable to develop materials similar in capability to traditionally used materials, but not similar chemically,” said Johnson. “These materials helped engineers quickly iterate product designs, but then required separate material choice considerations for the end-product. Today, we select materials with the required mechanical, chemical, biocompatibility, and sterilization capabilities needed for the final commercialized product.”
Material consistency is critical for the 3D printing of medical devices. The FDA has become more knowledgeable about AM for medical devices and has more reporting requirements, including for material consistency and biocompatibility. “Materials are regularly tested for consistency and materials companies continue to advance a greater array of different AM material powders and grain sizes,” said Hutchens.
About 200 3D-printed devices have already been cleared by the FDA and are on the market today. Another critical focus by the FDA is on cleaning and the overall process validation for AM products. “Cleaning includes removing powder, which means a device needs to be designed in a way that all the powder can be removed,” noted Brian R. McLaughlin, president of Amplify Additive, a Scarborough, Me.-based provider of additive manufacturing services for 3D-printed titanium orthopedic implants.
Another concern is the quality of recycled powder. There are good reasons for wanting to reuse powder, such as reduced environmental impacts and lower costs, but these must be weighed against the chemical and physical changes that occur in powder material during AM and how they affect end-part quality.
“Our additive manufacturing research team has conducted in-depth analyses on powder recycling and the impact each reuse has on the materials,” said Findlay. “We have discovered that powder reuse can potentially have a big impact on the part quality. Recycling over time can alter the powder’s chemical composition, which in turn, will affect the final part composition and its mechanical properties. For materials such as titanium-based alloys, we have observed that higher recycle counts can increase elements such as oxygen and nitrogen, which can improve the strength of the material, but also reduce its ductility.”
With the FDA’s sharper focus on AM, powder management has become of paramount importance to MDMs. Recent market feedback outlining the need for a more robust powder management and handling led Carpenter Technology to develop PowderLife, which provides a combination of products that enables higher productivity and quality in AM by providing traceability from starting feedstock to the final-built component. This allows for easy product recall should a defective powder lot be discovered via simple powder inventory tracking. “PowderLife provides safer powder handling and comprehensive data collection of key process variables such as oxygen, temperature, humidity, and pressure,” said Lalwani. “This software and hardware solution allows for efficient management of powder and enables medical OEMs and contract manufacturers to effectively provide validation and traceability information to the regulatory bodies for 510(k) or premarket approvals.”
The availability of AM-optimized non-titanium powders is also an important positive step to enable widespread adoption of AM beyond the regular use of titanium alloys. Cobalt-chrome-molybdenum (CCM) alloy is widely used in conventional manufacturing of implants. However, the standard chemistry of CCM results in brittleness and cracking when used in the AM process. To meet this challenge, Carpenter Technology has identified and optimized the trace elemental composition within the ASTM-approved limits and developed a CCM powder optimized for 3D printing. The company is also working on development of next-generation materials for AM such as BioDur 108 (cobalt- and nickel-free FDA-approved implantable alloy) and Nitinol powders.
Moving Forward
Even though 3D printing has already come a long way in the medical device market, “we have only scratched the surface of what 3D printing can do for patient outcomes, reducing time to market, and reducing overall costs,” said Hutchens.
For example, engineers are researching how 3D printing in different materials can have positive patient benefits such as reducing infection, lessening wear debris, and matching local bone structures of osteoporotic patients. Electron beam (powder-based) additive manufacturing is being studied as a way to create in-situ alloys from different powders, with improved properties, compared to pre-alloyed powders, which tend to have narrow composition ranges and are expensive to make. However, in AM-made, in-situ alloying, pure elemental blends of metal powders are combined to form the alloy during the heating/welding process. In-situ alloys can be harder and have greater tensile strength than pre-alloyed metals. Plastic composites can also be formed in-situ during AM.
Feedstock materials for additive manufacturing processes will continue to evolve and offer a greater range of engineered properties—these include nickel-titanium, polyetheretherketone (PEEK), ultra-high molecular weight polyethylene (UHMWPE), and fluorinated polymers. Even more exciting is the development of bioresorbable materials. For example, magnesium alloys are promising materials for use in absorbable implants.
Biodegradable magnesium materials offer significantly enhanced mechanical properties for orthopedic applications compared to their biodegradable plastic counterparts; however, the degradation rates of magnesium and magnesium alloys in the body must be carefully controlled. 3D-printed bioceramic implants, made using a digital light processing (DLP) technique, can now replace both cortical and cancellous bone.
Another capability that is gaining traction is customization.
“Many medical manufacturers have unique needs and applications, and we’ve partnered with an increasing number of them, looking to pair our commercial additive manufacturing technology with custom hardware, software, materials, and services to equip them to deliver better products to market faster and cost-effectively, and production as needed,” said Anderson.
Over the next decade, Lalwani expects to see continuous improvement in AM technologies, driven largely by advances in materials and printing platforms. “The availability of good-quality powders at competitive costs will drive large-scale adoption in the industry,” he said. “Patient-specific implants printed at surgical sites will also become a common practice. Development of next-generation implants with tunable functional properties and multi-material functionally graded implants will enable complex surgeries and improve patient outcomes.”
McLaughlin looks forward to the day when “we can select a region of the human body, leverage AI and various software tools to develop the ideal implant for a particular patient, and manufacture that implant solution using the right AM technology,” he said. “We have the technology, but we mostly manipulate by hand to get parts from CAD onto an AM platform for manufacturing, and the knowledge to do that efficiently and successfully needs to continue to be built.”
Anderson believes the best way to achieve this is through an industry-wide collaborative approach.
“Additive manufacturers will need to develop research and development centers on both the expertise and technological capability to partner with customers to drive products through the value stream,” said Anderson.
“Partnering with medical manufacturers to help them navigate that product lifecycle requires not only scalable additive manufacturing technology, including print preparation, management, and monitoring software, hardware, and post-processing, but also deep expertise in lean manufacturing and value stream mapping, systems integration, the regulatory environment, and production.”
References
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.
“AM is used to create medical education models that represent patient anatomies, patient-specific surgical instruments derived from imaging data, and metallic implants and instruments with features that are impossible to fabricate using traditional subtractive manufacturing,” said Benjamin Johnson, vice president of portfolio and regulatory for 3D Systems in Littleton, Colo., which develops innovative additive manufacturing solutions across hardware, materials, software, and services for the medical device industry.
The advantages of AM are many, including greater design freedom, rapid prototyping, product customization, creating surface structures and textures that promote bone growth, and the ability to scale and manufacture on the same machine that does the development and prototype work.
“3D printing enables healthcare professionals and medical device manufacturers to move from a virtual model to printing and prototyping to production runs of thousands of pieces, seamlessly,” said Shon Anderson, CEO for B9Creations, a Rapid City, S.D.-based provider of 3D printing hardware, software, materials, and services platforms for the medical device industry.
Because of these advantages, AM/3DP is more deeply developed in the medical device industry than almost any other industry, with the possible exception of aerospace. “Most medical device companies either have AM products currently, AM products in the pipeline, or prototype in AM,” said Jeff Hutchens, business development manager for healthcare for AddUp Solutions, a Cincinnati, Ohio-based provider of additive manufacturing equipment and consultation services for the medical device market.
As a result, the AM/3DP medical device market is also rapidly expanding. According to Research and Markets, the global 3D printing medical devices market is projected to increase from about $2.4 billion in 2021 to $5.1 billion in 2026, a compound annual growth rate of 16.3 percent during the forecast period.1
Perhaps the greatest advantage of AM is the design freedom it provides medical device engineers. Digital manufacturing enables them to design without the constraints of traditional manufacturing and to create an array of medical devices, including ones that require microscale or complex features, or are customized to patients. “Also, replacing the costly set-up and tooling of traditional injection molding or CNC machining with 3D printing gives engineers a quick and cost-effective path forward through iteration,” said Anderson. “Bringing 3D printing in-house also lowers the barrier of access to bridge tooling for design and market validation before making a capital investment in tools.”
It has only been in the last three to five years that AM technologies have matured to the point where they are today, with many improved capabilities and material choices. Despite these advancements, however, most AM-made products are still not production-ready. Although AM technologies are suitable for the generation of low-volume complex geometries, the greater challenge for a finished component is to achieve the fine resolution, dimensional accuracies, and surface features required for many components, without secondary processing.
“To that degree, AM/3DP is not a replacement for turning, milling, and drilling, but rather a complement to subtractive manufacturing methods,” said Joseph A. DeAngelo, director of new product development for Weiss-Aug, a Fairfield, N.J.-based provider of development, prototyping, and sub-assembly services for medical devices. “Many components produced from AM/3DP technology require value-added processes to complete. For the price point of AM/3DP technology today, a justification of the equipment and return on investment becomes the largest issue.”
Latest Trends
AM continues to gain widespread adoption in the medical device market, especially for orthopedic devices. Medical device components such as spinal cages, acetabular cups for total hip arthroplasty (THA), and tibial base plates for total knee arthroplasty (TKA) are routinely printed using electron beam and laser powder bed fusion processes. AM has also extensively penetrated the spine market, generating positive clinical results. Emerging trends such as printing custom patient-specific surgical guides and instrumentation have been explored, wherein medical device manufacturers (MDMs) do not need to invest in specialized tooling and subtractive manufacturing processes for low-rate customized production runs.
“Over the last decade, AM technology has matured, and OEMs are exploring next-generation solutions such as printing on-hospital-site for quick turnaround and targeting challenging applications such as printing femoral stem components for THA, femoral knee components for TKA, and expanding interbody cages,” said Gaurav Lalwani, global medical applications engineering lead for Carpenter Technology, a Philadelphia-based provider of high-performance specialty alloy-based materials and process solutions for the medical device market.
MDMs are also asking their AM partners for implantable devices that have lattice/porous structures to encourage osteointegration. “Medical device OEMs have been the fastest industry to adopt metal additive manufacturing and are driving innovation in their devices and implants, with intricate lattice structures and roughened surfaces for bone growth,” said Graeme Findlay, director of marketing for Precision ADM, a Winnipeg, Manitoba-based provider of additive manufacturing services for the medical industry.
Another keen focus by MDMs is fabricating a greater variety of patient-specific solutions. The medical device industry has already witnessed the success of 3D printing for patient-specific medical devices for dentistry and craniofacial medicine. More recently, the orthopedics community is “capitalizing on these patient-specific workflows to create custom surgical instruments that reduce the number of operative steps needed for prepping the bony anatomy to receive off-the-shelf implants,” said Johnson. “Similarly, the radiation oncology segment is adopting 3D printing to create patient-specific accessories to more effectively modulate dosages delivered during radiotherapy treatments.”
Devising customized surgical plans, instruments, and implants for surgeons to personalize the treatment of their patients is becoming more mainstream, whereas previously it was only done for more complex patients. However, creating an ecosystem for personalized medical devices is not an easy accomplishment—"we see the partnerships among surgeons, OEM manufacturers, and additive manufacturing solution vendors as critical for delivering the complete solution to elevate patient care,” said Johnson.
Another trend is the increased focus on productivity in hardware and software systems. 3D printers are being commercialized for large-volume manufacturing that maintains high-quality output but at faster print speeds and throughput. In software, much of the work is going into the development of manufacturing execution systems that take advantage of the digital infrastructure of additive solutions, “thereby making the operation of running a fleet of 3D printers easier for traceability and compliance purposes,” said Johnson. “The trend toward productivity will result in overall reduced costs that, in turn, will result in additional medical device applications that can be addressed with additive manufacturing.”
As additive manufacturing becomes easier to use for the production of medical devices, more clinical centers are taking an interest in manufacturing their own devices on-site. There is a long history of using 3D printing within the hospital for creating anatomic models of patient disease for use as an augment to medical education and as an additional tool in the surgical planning and treatment selection for patients. More recently, hospitals have been designing and printing their own patient specific-instruments for use in surgery and, in the future, will likely have the capability to manufacture personalized implants and other patient treatment tools.
What OEMs Want
Medical device companies are eager for rapid prototype turnaround, cost-efficient prototypes and production costs, greater inventory control, and shorter lead times.
“OEMs want accuracy and reproducibility for both prototypes and production,” said Hutchens. “They also expect productivity and reduction in costs due to print accuracy leading to reduced post processing.”
MDMs are constantly looking for ways to use additive manufacturing that will foster innovation—for example, achieving miniaturization and tight tolerances for components, which can challenge the limits of AM know-how. “Medical device manufacturers, contract manufacturers, universities, startups, and others often collaborate to produce high-resolution models in their engineering or biocompatible resin of choice, all increasingly pushing the envelope of micro-scale printing and production,” said Anderson. B9Creations, for example, uses its own AM equipment and proprietary computer-aided manufacturing (CAM) software to produce parts with dimensional tolerances within ±50 µm (±0.002 inches).
Consistent, high-quality powder, along with tools to effectively manage the recyclability and track the history of the powder, are getting more attention from MDMs. “The FDA has enhanced scrutiny on the devices produced using additive manufacturing and are asking for additional information pertaining to powder lifecycle for new device approvals,” said Lalwani. “In turn, MDMs are looking to innovate and print the next generation of device designs and want advanced powders that can help them achieve those desired higher mechanical properties.”
New Technology Advances
New technology improvements continue to advance AM design capabilities. “For example, new software, better file formats, and more computing power have combined to provide endless design opportunities,” said Ryan Kircher, senior additive manufacturing engineer for rms Company, a Coon Rapids, Minn.-based provider of high-volume precision machining and additive manufacturing for medical device OEMs.
These opportunities are advancing on a number of AM fronts, including the lightening of components, larger builds, variety of materials, improved resolution and accuracy, fewer parts within an assembly, and reduced power consumption. Other goals are detailed lattice structures within implants that mimic bone structure, matching stiffness of implants to the surrounding bone structures, and the ability to X-ray through an AM implant due to reduced density of the implant design (more porosity).
“Another interesting trend is the design for combining geometries into a hybrid manufacturing system that implements a subtractive base component, upon which an additive element is built to generate a desired device,” said DeAngelo.
Metal additive manufacturing is becoming more productive for medical devices through software and print strategies as well as hardware advancements. For example, additional lasers can be added to a printer to increase productivity. “Automated powder handling also helps reduce print time and time in between builds,” said Hutchens. “As part of our AddUp FormUp 350 process, we also have a roller powder spreader with the ability to print with fine powder, leading to improved surface finishes and less post-processing costs.”
Materials Science
Materials are key to the growth of additive manufacturing. Titanium alloys, stainless steels, and cobalt-chrome are the most popular metals for AM. For plastics, nylon and acrylate materials are frequently used to create patient-specific instruments for short-duration use.
AM materials in the medical device industry have evolved from materials that were developed to support the prototyping of products to materials intended for use in the production of the final product. “In the prototyping environment, it was acceptable to develop materials similar in capability to traditionally used materials, but not similar chemically,” said Johnson. “These materials helped engineers quickly iterate product designs, but then required separate material choice considerations for the end-product. Today, we select materials with the required mechanical, chemical, biocompatibility, and sterilization capabilities needed for the final commercialized product.”
Material consistency is critical for the 3D printing of medical devices. The FDA has become more knowledgeable about AM for medical devices and has more reporting requirements, including for material consistency and biocompatibility. “Materials are regularly tested for consistency and materials companies continue to advance a greater array of different AM material powders and grain sizes,” said Hutchens.
About 200 3D-printed devices have already been cleared by the FDA and are on the market today. Another critical focus by the FDA is on cleaning and the overall process validation for AM products. “Cleaning includes removing powder, which means a device needs to be designed in a way that all the powder can be removed,” noted Brian R. McLaughlin, president of Amplify Additive, a Scarborough, Me.-based provider of additive manufacturing services for 3D-printed titanium orthopedic implants.
Another concern is the quality of recycled powder. There are good reasons for wanting to reuse powder, such as reduced environmental impacts and lower costs, but these must be weighed against the chemical and physical changes that occur in powder material during AM and how they affect end-part quality.
“Our additive manufacturing research team has conducted in-depth analyses on powder recycling and the impact each reuse has on the materials,” said Findlay. “We have discovered that powder reuse can potentially have a big impact on the part quality. Recycling over time can alter the powder’s chemical composition, which in turn, will affect the final part composition and its mechanical properties. For materials such as titanium-based alloys, we have observed that higher recycle counts can increase elements such as oxygen and nitrogen, which can improve the strength of the material, but also reduce its ductility.”
With the FDA’s sharper focus on AM, powder management has become of paramount importance to MDMs. Recent market feedback outlining the need for a more robust powder management and handling led Carpenter Technology to develop PowderLife, which provides a combination of products that enables higher productivity and quality in AM by providing traceability from starting feedstock to the final-built component. This allows for easy product recall should a defective powder lot be discovered via simple powder inventory tracking. “PowderLife provides safer powder handling and comprehensive data collection of key process variables such as oxygen, temperature, humidity, and pressure,” said Lalwani. “This software and hardware solution allows for efficient management of powder and enables medical OEMs and contract manufacturers to effectively provide validation and traceability information to the regulatory bodies for 510(k) or premarket approvals.”
The availability of AM-optimized non-titanium powders is also an important positive step to enable widespread adoption of AM beyond the regular use of titanium alloys. Cobalt-chrome-molybdenum (CCM) alloy is widely used in conventional manufacturing of implants. However, the standard chemistry of CCM results in brittleness and cracking when used in the AM process. To meet this challenge, Carpenter Technology has identified and optimized the trace elemental composition within the ASTM-approved limits and developed a CCM powder optimized for 3D printing. The company is also working on development of next-generation materials for AM such as BioDur 108 (cobalt- and nickel-free FDA-approved implantable alloy) and Nitinol powders.
Moving Forward
Even though 3D printing has already come a long way in the medical device market, “we have only scratched the surface of what 3D printing can do for patient outcomes, reducing time to market, and reducing overall costs,” said Hutchens.
For example, engineers are researching how 3D printing in different materials can have positive patient benefits such as reducing infection, lessening wear debris, and matching local bone structures of osteoporotic patients. Electron beam (powder-based) additive manufacturing is being studied as a way to create in-situ alloys from different powders, with improved properties, compared to pre-alloyed powders, which tend to have narrow composition ranges and are expensive to make. However, in AM-made, in-situ alloying, pure elemental blends of metal powders are combined to form the alloy during the heating/welding process. In-situ alloys can be harder and have greater tensile strength than pre-alloyed metals. Plastic composites can also be formed in-situ during AM.
Feedstock materials for additive manufacturing processes will continue to evolve and offer a greater range of engineered properties—these include nickel-titanium, polyetheretherketone (PEEK), ultra-high molecular weight polyethylene (UHMWPE), and fluorinated polymers. Even more exciting is the development of bioresorbable materials. For example, magnesium alloys are promising materials for use in absorbable implants.
Biodegradable magnesium materials offer significantly enhanced mechanical properties for orthopedic applications compared to their biodegradable plastic counterparts; however, the degradation rates of magnesium and magnesium alloys in the body must be carefully controlled. 3D-printed bioceramic implants, made using a digital light processing (DLP) technique, can now replace both cortical and cancellous bone.
Another capability that is gaining traction is customization.
“Many medical manufacturers have unique needs and applications, and we’ve partnered with an increasing number of them, looking to pair our commercial additive manufacturing technology with custom hardware, software, materials, and services to equip them to deliver better products to market faster and cost-effectively, and production as needed,” said Anderson.
Over the next decade, Lalwani expects to see continuous improvement in AM technologies, driven largely by advances in materials and printing platforms. “The availability of good-quality powders at competitive costs will drive large-scale adoption in the industry,” he said. “Patient-specific implants printed at surgical sites will also become a common practice. Development of next-generation implants with tunable functional properties and multi-material functionally graded implants will enable complex surgeries and improve patient outcomes.”
McLaughlin looks forward to the day when “we can select a region of the human body, leverage AI and various software tools to develop the ideal implant for a particular patient, and manufacture that implant solution using the right AM technology,” he said. “We have the technology, but we mostly manipulate by hand to get parts from CAD onto an AM platform for manufacturing, and the knowledge to do that efficiently and successfully needs to continue to be built.”
Anderson believes the best way to achieve this is through an industry-wide collaborative approach.
“Additive manufacturers will need to develop research and development centers on both the expertise and technological capability to partner with customers to drive products through the value stream,” said Anderson.
“Partnering with medical manufacturers to help them navigate that product lifecycle requires not only scalable additive manufacturing technology, including print preparation, management, and monitoring software, hardware, and post-processing, but also deep expertise in lean manufacturing and value stream mapping, systems integration, the regulatory environment, and production.”
References
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.