Printing Medtech’s Future: A Look at Medical Additive Manufacturing

Additive manufacturing/3D printing (AM/3DP) has emerged as a transformative technology in the medical field, revolutionizing various aspects of patient care. By leveraging advanced AM/3DP processes, healthcare professionals can now create highly customized and patient-specific medical solutions, ranging from medical devices to surgical models, with the goal of improving patient outcomes. “3D printing provides flexibility of design and is a perfect fit for customization and personalization,” said Ido Bitan, director of products and medical solutions for Stratasys, an Eden Prairie, Minn.-based provider of 3D printing equipment and 3D-printed parts on-demand. 

“AM/3DP also thrives in low-volume, high-value applications, making it ideal for the medical device industry,” added Ethan Rejto, director of marketing for Mantle, a San Francisco, Calif.-based 3D printing startup that uses metal 3D printing to make ultra-precise steel injection molds.

Additive manufacturing applications continue to expand at a rapid rate, especially the use of advanced materials and rapid prototyping. In fact, AM is now readily used throughout the entire product development lifecycle for medical devices.

“Understanding the design freedoms, consistency, and material properties allows companies to leverage 3D printing in a variety of applications,” said Chris Martinez, CEO for 3DPX, a Chicago, Ill.-based AM manufacturer that specializes in laser sintering technology and CNC machining. 

AM/3DP, especially powder-based printing, has evolved to the point where it can be used to achieve mass customization in some cases, as well as create multi-part complex tools from nothing more than a computer-aided design (CAD) model. Disposable single-use products and devices, personalized devices, implants, and even products designed for bioresorbable materials can all be created using AM/3DP. These technologies are also essential for the prototyping of surgical robotics, as well as for printing realistic anatomical models for testing and training. Direct metal laser sintering (DMLS) and E-beam are common methods for making metal implants. “3D-printed components are often used in surgical devices—typically as complex parts or parts that are very specific to a particular patient’s anatomy,” said Eric Utley, applications engineering manager for Protolabs, a Maple Plain, Minn.-based manufacturer of custom parts via 3D printing, computer numerical control (CNC) machining, injection molding, and sheet metal.

Even though a vast number of use cases have been established for AM/3DP, “the industry continues to evolve, searching for greater efficiencies and easier adoption,” said Gary Turner, managing director of additive manufacturing for Ricoh USA, an Exton, Pa.-based medical device manufacturer (MDM) that specializes in the production of patient-specific 3D-printed anatomic models.

Latest AM/3DP Trends

Due to rapid advances in software and process controls, quality improvements, and new materials, AM/3DP is the hottest technology in the medical device space. It can be integrated with other technologies such as artificial intelligence (AI) and robotics to create highly sophisticated medical solutions. AM/3DP is increasingly the technology of choice for customized medical devices based on individual patient anatomy and needs, driving a trend toward more personalized treatments. Advanced materials are also expanding the functionality and longevity of new medical devices. “The development of new biocompatible and functional materials is expanding the range of applications for 3D bioprinting in medicine, including tissue engineering and drug delivery,” said Bitan. 

A growing trend in AM/3DP is on-site production by healthcare facilities. “Hospitals and clinics are increasingly adopting in-house 3D printing capabilities to streamline production, reduce costs, and ensure faster turnaround times for patient-specific medical devices,” said Bitan. “On the business side, although reimbursement for 3D-printed medical devices is still a challenge, there are ongoing efforts to develop clear guidelines and reimbursement codes to facilitate wider adoption.”

Newer versions of CAD software enable designers and engineers to make better products using generative tools and texturing. “Design software is catching up to the freedom that is made possible by 3D printing technology,” said Utley. “Generative design is growing in popularity and designs are becoming more optimized for both function and manufacturability.”

Sustainability is a key initiative for almost every company that looks to conserve resources and reduce waste. Traditional manufacturing methods such as injection molding have been a large source of plastic waste due to the amount of parts required to make the manufacturing process viable. “3D printing is always known as a minimum quantity of one,” said Martinez. “This allows companies to produce what is needed based on demand and not overproduce large amounts of scrap. Companies also have freedom to change the designs or skews by simply modifying CAD models, rather than expensive and time-consuming changes in tooling.”

What OEMs Want

AM manufacturing trends reflect the needs of MDMs. Providing a broader range of biocompatible materials and more standardized procedures are top requests; this is especially true for patient-specific and biocompatible parts. “We have many requests for realistic look and feel to models,” said Turner. MDMs also demand product consistency and good surface finishes, especially for prototyping.

“MDMs want prototypes that are fast and accurate,” said Utley. “For end-use parts, they want production-quality solutions where traceability and quality are assured.”

Despite the disruptive force of AM/3DP, and hundreds of proven use cases, AM is not a “sure thing” for every device and must be carefully evaluated to ensure the ROI is viable. “The reality is that traditional manufacturing is still fast, inexpensive, and precise for many MDM needs, so finding a good fit for 3D printing can still be a challenge,” advised Rejto.

MDMs count on their contract manufacturers (CMs) to leverage the design freedom AM/3DP provides to help create specialty products, especially for newer devices where functionality and ergonomics are combined. “Much of what we see is on the macro level, with metals having more potential for end-use, reusable components,” said Greg Paulsen, director of applications engineering for Xometry, a North Bethesda, Md.-based provider of CNC machining, additive manufacturing, and assembly services for the medical device industry. “Polymer additive manufacturing is heavily used in research phases, but usually transitions to injection molding for production.”

MDMs are increasingly interested in “near net” manufacturing, a technique that produces a part close to its final shape and dimensions. 3D printing does have some limitations related to extremely tight tolerancing; however, machining has limitations in what form is required as the starting point. “Leveraging the geometry freedoms provided by 3D printing, followed up by machining these printed parts to extreme precision, allows for fast turnaround times and lower costs for highly complex parts,” said Martinez. “This is very common in metal 3D printing in the automotive and aerospace industries.

Also, from the sustainability viewpoint, near-net manufacturing helps reduce energy consumption and CO2 emissions from the production, transportation, and recycling of waste material.

To further reduce costs and improve sustainability, MDMs are always looking for better ways to manage their inventory. They are especially interested in not holding onto legacy or pre-legacy products and instead replacing them with a digital inventory system. “Instead of having product on-site as inventory, with the idea that they need to be ready if a customer orders these parts, if MDMs have a CAD file, a manufacturing partner like 3DPX can produce these parts from that file in a matter of days, for a comparable price,” said Martinez. “The concept of leveraging a digital inventory system can save companies millions of dollars and prevent massive waste if AM is properly understood within the OEM.” 

Innovative Technologies

Both additive and subtractive manufacturing provide solutions for medical device manufacturing. Hybrid machines integrate both these methods to make intricate designs with 3D printing, followed by machining to create the final product. These machines are ideal for near-net shape manufacturing, where AM gets the part to near-net shape, and subtractive machining is then used to finish the part.

“3D printing is known for its speed, geometry freedom, and ease of use, but it’s also known for its poor surface finish and tolerances,” said Rejto. “By combining 3D printing with CNC machining, you unlock the best of both worlds.”

This hybrid approach offers multiple advantages, including using less starting material and shortening cycle times, thereby reducing total production costs by eliminating rough machining processes.

Despite these advantages, “hybrid machines are still highly specialized and often not available on the service market, so they require high capital investment and R&D to utilize,” said Paulsen. “However, these machines will likely become the new normal over the next decade.”

Many AM/3DP advancements are related to material developments across the AM spectrum. For example, Ricoh 3D for Healthcare focuses on polymer 3D printing and in this space “we have seen improvements in manufacturing speed, machine reliability/replicability, and material options, all of which have improved delivery to our customers,” said Turner. “Specific to speed, there are digital light processing [DLP] processes, such as Form 4, that can deliver same-day surgical planning models to point-of-care healthcare facilities.” 

Having material options is vital for solving problems and advancing innovation in healthcare. Ricoh 3D works with a wide variety of material suppliers to tailor materials to meet specific application requirements. “Material improvements in elastomerics, ceramics, and composites are helping to drive innovation in our 3D product portfolio,” said Turner.

4D printing is a manufacturing approach that is still early in development. This method uses 3D printers to create three-dimensional objects from “intelligent” materials that can be programmed to change their size or shape when they are subjected to an external stimulus, such as heat, humidity, or light. These materials include hydrogel resins, active polymers, and even live tissues. 4D-printed devices can bend, repair, assemble, or even disintegrate themselves when they are exposed to a set of environmental conditions.

“4D printing enables an object’s ability to change over time,” said Martinez. “An example is the use of a nitinol implant that will adapt to a body, once the surgery is complete. The implant can be printed and implanted and behave with a predictable change over time, to meet the required changes of the body post-surgery. Bodies are always changing and, with some new adaptive materials, these printed parts can change with the body to eliminate further surgeries.” 

Digital additive production (DAP), custom-blended materials, biomimetic trainers, and full-color and low-durometer materials that make simulators and prosthetics more realistic are all relatively new developments. RadioMatrix, a new radiopaque material from Stratasys, allows medical teams and researchers to 3D-print radio-realistic models that exhibit defined radiopacity properties under medical imaging such as X-ray or computed tomography (CT). This provides contrast between anatomical structures, making them look real under medical imaging. 3D-print labs can make targeted pathologies visible so clinicians can practice procedures that require contrast media, and researchers can test and demo medical devices. 

“This gives us the ability to print radiological phantoms that can be scanned under an MRI or CT scan and look like human anatomy,” said Turner. “Use cases include training and machine calibration/setup prior to use, which is especially beneficial for pediatric patients.”

Regulatory Considerations

The FDA faces unique challenges in regulating 3D-printed medical devices due to their innovative nature and the potential for customization. Key challenges include:

• Novelty—Many 3D-printed devices are novel, making it difficult to fit them into existing regulatory frameworks

• Customization—The ability to customize 3D-printed devices can complicate the regulatory process, as each device may have unique characteristics 

• Risk assessment—Risks associated with 3D-printed devices include material properties, printing parameters, and design complexity

• Quality control—Ensuring consistent quality and reproducibility in 3D-printed devices can be difficult due to the variability in manufacturing processes

• Intellectual property—Ease of sharing and replicating 3D models increases risks for design theft 

“To address these challenges, the FDA has been working to develop guidance documents and regulatory frameworks that specifically address 3D-printed medical devices,” said Bitan. “However, the rapid pace of innovation in this field continues to present new challenges for regulators.”

Since 3D printing is still relatively new in the medical space, standardization and quality control metrics are constantly being developed. The FDA wants to allow companies to use 3D printing because of the vast benefits from mass customization additive can provide, “while also trying to predict risks that have never even presented themselves yet,” said Martinez. “Medical device manufacturers are trying to understand what empirical data they can provide, such as biocompatibility testing, to assure the FDA that products are safe.”

With AM/3DP, the design, the material, and the manufacturing equipment are all interconnected. This can become challenging when qualifying a product through the FDA because, even if fully qualified, the FDA could lock the production to a single location. “This is different from machined or molded products, where the materials may be well characterized—as long as the process of making the part from that material is controlled, you can pass regulations more easily,” said Paulsen. “New rules and process tools are required to help streamline the process.”

The rigorous quality system and regulatory requirements of medical device manufacturing can deter hospitals and ambulatory surgical centers from bringing 3D printing on-site. To mitigate this concern, RICOH 3D for Healthcare offers a quality-controlled medical device manufacturing service that produces patient-specific anatomic models within an ISO 13485-certified quality system. This service is available from its centralized production facility or directly at the healthcare facility at the point of care, inclusive of needed quality systems and providing timely access to FDA-cleared medical devices. RICOH 3D for Healthcare has received 510(k) clearance from the FDA for its craniomaxillofacial, orthopedic, cardiovascular, neurological, gastrointestinal, genitourinary, and breast applications for patient-specific anatomic modeling.

Recent Successes

One of the most innovative AM technologies is an alternative to extrusion. Spectrum Plastics Group, A DuPont Business, has developed a proprietary additive manufacturing process that creates tubing, without the need for extrusion. Spectrum can 3D-print single- and multi-lumen tubing configurations in multiple materials with turnaround times ranging from hours to days—”a first in the industry,” said Tyler Stark, Innovation Hub Leader for Spectrum. “The proprietary tubing process allows us to create profiles and shapes that have high tolerances at any given length. We are able to continuously print with no limits.”

Other recent successes/advances include:

• Printing implantable materials that are also bioresorbable is a large step forward in creating patient-specific implants. For breast cancer, developing elaborate 3D-printable implants that can be absorbed into the body creates a third reconstruction method as new breast tissue forms. Stratasys and CollPlant Biotechnologies are working together on a new type of 3D-printed breast implant that is made with a special bioink that encourages natural tissue to grow as it dissolves over time.¹

• Westminster Tool, a machine shop in Westminster, Conn., used its Mantle metal 3D printer to print prototype tooling for a leading medical device company. The part had over 40 swipe-by shut-offs. Westminster Tool printed the tooling and delivered more than 7,000 molded parts to the customer, reducing the lead time by over four weeks. Additionally, since the tool was printed in H13 tool steel (a production tool steel), the molded parts were production-representative prototypes.

• The RICOH 3D for Healthcare team collaborated with Orlando Health in Florida to create novel material blends for a self-infusion product. Orlando Health had been working on building task trainers using 3D-printed tissue blocks that would allow patients with bleeding disorders to practice self-infusion safely. The Ricoh and Orlando Health teams collaboratively redesigned and perfected the skin sleeves—achieving a safe way to teach patients how to infuse their medication when they have a bleeding disorder.²

• 3DPX has customers in the medical space that develop patient-specific instrumentation. They scan patients, create surgery plans digitally, and send the CAD model to 3DPX, which then uses EOS selective laser sintering (SLS) machines to print the parts, followed by post-processing. The parts are then shipped and ready at the hospital in just a few days. Surgeons who use these devices state there is usually an average reduction of about 40 minutes in their surgical procedures.

Xometry’s marketplace provides comprehensive access to all types of AM for plastics and metals, as well as options to scale in machining or molding, to support this type of leading innovation. Medical device manufacturers count on Xometry to provide popular technologies such as DMLS, SLS, and SLA (stereolithography). “We celebrate the innovative designs our customers provide and work to build their products to the specifications demanded,” said Paulsen.

Moving Forward

AM/3DP technology continues to move forward at a rapid pace, making it difficult for MDMs to keep up. “Most newer advancements in AM have been in materials and material science, rather than processing,” said Stark. “These include highly engineered materials, photopolymer resins that mimic thermoplastics, and new additives that make layer adhesion even higher.”

“MDMs are very used to the misconception that if you want something done accurately, you need to have it injection molded or machined,” said Martinez. “This is not the case anymore. AM machines like the FDR [Fine Detail Resolution] from EOS can provide tolerances that rival many CNC machines and are just as repeatable.” Because of FDR’s ultra-thin CO laser beam, the process’ accuracy is comparable to SLA—at far more efficient production rates. An accuracy of ±40 microns makes it comparable to injection molding. FDR can easily manufacture ultra-thin threads, intricate lattice structures, and complex interlocking components like meshes. 

AM companies continue to upgrade their machines, especially software or hardware-driven connections. “For example,” said Paulsen, “instead of just monitoring a build, there are newer technologies that do in-situ corrections based on the intended outcome. Digital twin production helps reduce scrap before parts are even made, and the more of these process steps that are bridged, the better the outcomes will be for this process within the medical device industry.”

Design has always been a limiting factor in the application of digital manufacturing to real-world problems. While there has always been plenty of hype about being able to “print anything” or pursuing design freedoms where “complexity is free” in AM, “the reality is much more nuanced,” said Turner. “All machines have geometric limitations, so you really can’t print absolutely everything, and making use of the game-changing capabilities of building an object layer by layer often conflicts with software limitations and the competency and know-how needed to employ efficient design for AM techniques.”

Ricoh’s ultimate goals are to provide wider access to AM/3DP personalized devices, reduce lead times, and improve communication between MDMs and patient-care teams. To accomplish this, Ricoh has leveraged newer AM/3DP technologies to bring the manufacturing facility to the point-of-care, at or near where the patient will be treated. “We are working to expand our point-of-care network across the country, leveraging hospital partners to drive adoption,” said Turner.

References

¹ tinyurl.com/mpo241131

² tinyurl.com/mpo241132

Mark Crawford is a full-time freelance business and marketing/communications writer based in Corrales, N.M. His clients range from startups to global manufacturing leaders. He has written for MPO and ODT magazines for more than 15 years and is the author of five books.