Medical

Additive manufacturing (AM) has undergone a major evolution since the early 2000s, when it was first used to produce dental implants and custom prosthetics. Today, with its ability to fast-track the creation and production of complex geometries that mimic the form and function of natural biomechanics, AM is rapidly transforming healthcare.

In recent years, 3D printing has solved some of the biggest challenges in the field of orthopedics. Before it was possible to quickly produce custom implants, surgeons often needed to modify standard implants to fit some patients by conforming the patient’s body to match the implant. Today, we are getting closer to producing implants that match the patient before going into surgery.

Now, AM is making it possible for surgeons to accomplish tasks that were previously impossible. After creating digital print files from patient x-rays, CT or MRI scans, production of a complex, patient-specific metal implant can be completed, often in less than 24 hours.

Throughout the history of AM, there have been many commercial and clinical successes. In 2012, researchers at the BIOMED Research Institute in Belgium implanted a 3D-printed titanium mandibular prosthesis in an 83-year-old patient. 2013 saw the first successful implantation of a 3D-printed polyetherketoneketone (PEKK) skull implant. Fast-forward to 2024: AddUp Solutions and Anatomic Implants are collaborating on the first 3D printed toe joint replacement. 

With all the benefits it offers for the future of personalized healthcare and improved patient outcomes, the application of AM in orthopedics promises to be a game-changing development. 

From subtractive to additive manufacturing

Traditional subtractive manufacturing methods have always had limitations in the geometries they can produce. They also require significant amounts of time for machining, particularly when working with materials like titanium. 

By enabling the layering of materials to manufacture objects from 3D model data, AM makes it possible to create complex shapes and structures not possible before. It has provided a cost-effective new approach to producing medical implants tailored to the unique anatomy of individual patients, providing significantly greater design freedom and control without the need for tooling or molds.

“With traditional processes, there is a need for post-production surface treatments with porous sprays, whereas 3D printing makes the production of implants with highly porous structures possible,”  says Tyler Antesberger, medical application engineer at AddUp Solutions. “So, it’s definitely a value-add that with AM, you have complete control of the device down to the micron—not just applying something to the surface and hoping that it works.” 

From metals to biocompatible materials

The use of metal-based AM for producing medical implants has been on the rise for many years. Materials used in manufacturing medical implants must meet many requirements, including high strength for functioning for long periods, corrosion and wear resistance, and biocompatibility and biodegradability.

“There’s a lot of talk around biocompatibility,” says Antesberger. “There are a lot of studies about cell scaffolds and things like that—how does bone actually grow into these devices and become part of the body?” AM makes it possible to design highly complex, customized designs that match a patient’s anatomy—and to create lattice structures that are needed to create the porous surface needed to improve bone integration in the human body. AddUp’s roller coater technology makes it possible to create an implant with a smooth surface finish with fine features and lattice resolutions.

While many advances have been made in the use of 3D-printed metallic biomaterials for use in implants, there are currently only a few metals that can be used. Today, about 75% of medical implants are made from stainless steel, titanium alloys, cobalt-chromium alloys, niobium, nitinol and tantalum—with the use of magnesium, zinc, iron, and calcium on the rise.^[1]

“The primary material used now for medical implants is Grade 23 titanium,” Antesberger says. “It has a lower oxygen content than other titanium on the market and good biocompatibility. A few other materials used in 3D printing are stainless steel alloys.”

Expanding what’s possible

The promise of 3D-printed implants for the future of personalized medicine is bright. Healthcare institutions like the Mayo Clinic already have launched large-scale 3D printing labs where they produce patient-specific 3D-printed orthopedic braces and surgical tools. And we may soon see a future in which hospitals are producing 3D-printed, patient-specific medical devices on-site at the point of care.

“Hopefully, in the future, additive manufacturing in healthcare will allow us to create a customized design for every individual—to help reduce the time in the hospital, reduce recovery time, and increase the life of the implant,” Antesberger concludes.

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^[1] https://www.sciencedirect.com/science/article/pii/S266652392300096X

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AddUp’s FormUp 350 additive manufacturing technology revolutionizes acetabular cup production by offering efficient Laser Powder Bed Fusion (LPBF) capabilities that outperform traditional methods and Electron Beam Technology (EBM).

Introduction

Acetabular cups, essential components of total hip replacements, have traditionally been manufactured through casting and forging. Although effective, this method was cumbersome and costly, necessitating long lead times and complex validations. However, AddUp’s groundbreaking FormUp 350 has transformed this narrative, showcasing how additive manufacturing technologies can revolutionize the field.

Traditional Manufacturing Process

Historically, the production of acetabular cups relied on the lost wax method, a labor-intensive process resulting in slow turnaround times and additional, costly processing stages. The final product required a porous structure that was both expensive to manufacture and challenging to validate, posing a significant hurdle to progress in the field.

The Advent of Additive Manufacturing and the Limitations of Electron Beam Technology 

Additive manufacturing brought a significant shift in acetabular cup production, with Electron Beam Technology (EBM) offering a promising alternative to traditional methods. However, EBM presented challenges, such as unpredictable failures and complex validation processes, which could escalate the overall time and cost of production.

The Game-Changing Impact of AddUp’s FormUp 350: A Superior Leap in Acetabular Cup Manufacturing

In the pursuit of more efficient and precise manufacturing methods, AddUp’s FormUp 350 has emerged as a superior alternative to EBM. This innovative machine, operating on Laser Powder Bed Fusion (LPBF) technology, delivers closer net shape parts with no supports needed, dramatically reducing post-processing and lead times. It offers a larger build plate and more lasers than EBM printers, potentially doubling the throughput and optimizing production processes.

Notably, the FormUp 350 features a fine feature resolution and a roller recoater, enabling the printing of a lattice structure within the implant. This key feature significantly enhances osseointegration, leading to longer-lasting implants and improved patient outcomes.

Revolutionizing the Medical Device Industry: The Impact of FormUp 350 

AddUp’s FormUp 350 has profoundly impacted the medical device industry. By shortening lead times and enhancing precision, this machine enables manufacturers to respond swiftly to market demands and deliver superior quality products. The capability to print lattice structures not only enhances the performance of the implants but also improves patient outcomes. This development leads to fewer revision surgeries, resulting in cost savings for both patients and healthcare providers.

Conclusion

The FormUp 350 from AddUp delivers throughput capabilities currently unchallenged on the market. This can be seen in the below Hip Cup Productivity Study. Parts shown were printed with a compression roller technology in 30um layers of Ti6Al4V ELI. Compared to EBM technology, the AddUp 350 has a shorter run time of 12:41 compared to 15:23 (EBM) which leads to an improved annual throughput of 9,309 (16,403 LPBF, 7,094 EBM). As the medical device industry continues to evolve, this concrete evidence of the FormUp 350’s superiority underscores its transformative potential in the future of hip replacement surgeries and beyond.

The Importance of Surface Finish When Manufacturing Medical Devices and Implants

Surface finish is crucial in additive manufacturing of medical devices and implants, as it must meet or exceed the standards set by traditional subtractive manufacturing methods, ensuring better patient outcomes and reducing contamination risks.

Due to the novelty of additive manufacturing, surface finish will always be compared back to subtractive manufacturing. This is even reflected in ASTM standards for additive manufacturing. ASTM F3001 which is the standard for Ti6Al4V ELI (Extra Low Interstitial) used with Powder Bed Fusion constantly references ASTM F136 which is the standard for Wrought Ti6Al4V ELI Alloy for Surgical Implant Applications. This sets the bar for the additive manufacturing industry that the final finished good must be equivalent or better than products manufactured from bar stock.

Medical Implants: Better Surface Finish for Better Patient Outcomes

On the implant side of the medical industry, additive manufacturing has been innovative. No longer are product development engineers looking to spray their parts with plasma porous spray to gain osteointegrative benefits, they are intentionally designing complex structures that mimic bone. These complex structures cannot be traditionally manufactured and can be more easily validated unlike plasma porous spray.

Industrial metal 3D printers are steadily improving their surface finish to be closer to wrought directly from the printing process. Advances are being made in recoating systems, melt-monitoring systems, and powder handling to produce the best as-printed surfaces as possible. As additional post-printing surface treatments are developed for the additive manufacturing industry, differently manufactured parts will be indistinguishable from each other.

Surface finish is imperative for implantable medical devices for several reasons. A few are pathogen spread, implant rejection, part corrosion, surface contamination, reduced lifespan, and biocompatibility. Most of these reasons are directly related to patient well-being. The inherent process of additive manufacturing (layer by layer) creates voids in the material that can be difficult to clean and sterilize. This creates plentiful spaces for bacteria to hide in. It is of utmost importance that the implant can be thoroughly cleaned before it is in a surgical setting. Then there is always the aesthetic of the implant itself. A cosmetically good-looking implant intuitively portrays itself as clean, functional, and well manufactured.

Minimize Finishing Treatments to Reduce Cost and Lead Time

Some common surface finishing treatments for additively manufactured implants include blasting, vibratory finishing, and chemical passivation. Both blasting and vibratory finishing aim to give the implant a uniform finish. They can help to blend between manufactured and printed surfaces while helping to remove any burrs or sharp edges. Blasting is typically completed with a glass bead whereas vibratory is done with some type of ceramic media. Chemical passivation is done as a cleaning step to ensure that the implant is free of any in-process materials from manufacturing before going to . As the additive manufacturing process improves, there is optimism that secondary surface finishing operations can be minimized. This can help reduce costs and potential avenues for contamination.

Surface Finish for Surgical Instruments

Surgical instruments and trauma devices must be even closer to wrought surface finish specifications. These devices do not want any type of osteointegrative features like complex structures. Reusable instruments must be able to be cleaned between surgeries and retain their sharpness. Trauma devices like plates and screws must be able to be removed once the injury has healed. These requirements tend to lead to these types of devices being made from 316L, 17-4 PH, and 420. Technology advances are allowing these industrial 3D printers to utilize fine powders and resolve a better surface finish closer to a traditionally manufactured device.

AddUp’s Solution

Achieving parts directly off the printer with optimal surface finish is a priority for AddUp. That’s because industry-leading surface finish means less post processing and therefore cost reduction for our customers. The FormUp 350 provides advanced technology with a roller recoating system that allows many parts to meet surface finish requirements as printed.

Controlling the penetration of the melt into the lower layers is a key factor in the surface quality of a 3D metal-printed part. Poorly managed, it leads to high variations in Ra index, with high sensitivity to surface angle. Using AddUp’s roller spreading system, the homogeneity of the powder bed is greatly enhanced, limiting this type of variation and allowing for a smoother surface finish as printed. Parts printed on the FormUp 350 achieve an Ra value as low as 3µm.

In addition, AddUp uses finer powder (PSD 5-25µm) instead of the widely-used industry standard medium powders (PSD 15-45µm or 20-63 µm). This makes it possible to considerably reduce the size of the voids between particles therefore improving the permeability of the powder bed, reducing erratic bath penetration and lowering laser power. The use of these fine powders not only enhances the surface finish for parts printed on the FormUp 350, but it also greatly reduces the need for support structures.

Learn more about AddUp’s FormUp 350 for medical applications here.

Driving Innovation and Advancement

Manufacturers are continuously encouraged to improve their processes and technologies. In the case of AM, certifications push for research and development in areas such as material science, process optimization, and design guidelines. By setting stringent criteria for certification, manufacturers are motivated to innovate and refine their practices. This drive for innovation not only benefits the individual companies but also contributes to the overall advancement of the manufacturing industry.

The FormUp 350 Powder Bed Fusion (PBF) machine revolutionizes the manufacturing of large spinal fusion devices, offering increased efficiency, precision, and cost-effectiveness. 

Introduction

Spinal fusion devices play a crucial role in the medical field, providing essential support and stability in spinal surgeries. Traditionally, large spinal fusion devices were produced using small format Powder Bed Fusion (PBF) machines or machined out of poly bar stock. While these methods were effective, they presented several challenges, including high costs and lengthy production times. However, the advent of advanced manufacturing technologies, such as the FormUp 350 PBF machine, has revolutionized the production process, offering enhanced efficiency, precision, and improved patient outcomes.

Traditional Manufacturing Methods: PBF and PEEK

The conventional manufacturing process of large spinal fusion devices relied on PBF or machining out of PEEK bar stock. These methods, while effective, were not without their drawbacks. The production process was slow and costly, leading to increased prices for the finished implant. Additionally, when produced using PEEK, these types of implants lacked ideal Osseo integrative features, which are crucial for the success of the implant. Moreover, the unstable material supply chain for PEEK presented further challenges in the manufacturing process.

The Advent of Additive Manufacturing

The introduction of additive manufacturing marked a significant shift in the production of large spinal fusion devices. However, the manufacturing of these devices on smaller platforms with 1-2 lasers increased the cost of the finished implant. These implants were tall in Z, leading to increased build times that were further increased with a small number of lasers. Furthermore, the use of a scraper/brush recoating process and the need for wire electrical discharge machining (EDM) to remove the LLIFs from the build plate added to the overall time and cost of production.

The FormUp 350: A Leap Forward in Spinal Fusion Device Manufacturing

The FormUp 350 PBF machine has emerged as a superior alternative to smaller platforms with 1-2 lasers. Thanks to a 350 millimeter squared build plate, the FormUp 350 can hold 1.5 times the amount of large spinal implants compared to smaller platforms. The use of 4 lasers allows for 152 large spinal implants to be printed in just 32 hours, significantly reducing production time and increasing output.

The FormUp 350 utilizes a powder roller technology which allows for geometric complexity using minimal supports and results in optimal surface finish. This technology enables the realization of intently designed complex structures and surface roughness that contributes to better patient outcomes. There is no longer a need for a plasma porous spray or sheet-based trabecular surface, and the surface roughness is not a byproduct of the process. This helps to decrease the manufacturing processes required to complete a finished product, reducing costs along all parts of the supply chain and supporting more efficient patient outcomes.

The Impact of the FormUp 350 on the Medical Device Industry

The adoption of the FormUp 350 in the manufacturing of large spinal fusion devices has far-reaching implications for the medical device industry. By reducing lead times and increasing precision, the FormUp 350 allows manufacturers to respond more quickly to market demands and produce higher quality products. Moreover, the ability to print complex structures and achieve optimal surface roughness improves the performance of the implants, leading to better patient outcomes. This is a significant advancement, as it not only enhances the quality of life for patients but also reduces the need for revision surgeries, leading to cost savings for both patients and healthcare providers.

Results

Large spinal implants produced using small build capacity, low number of lasers, and traditional recoating systems cost more than when produced using the FormUp 350.
The FormUp 350 machine is ideal for medical applications because it provides an improved and cost-effective process to mass-manufacture highly complex and/or customized medical parts.

Parts built per laser on the FormUp 350:

• 2 Laser – 76
• 4 Laser – 38

Time to build on the FormUp 350:

• 2 laser – 52.95
• 4 laser – 32.35

Annual throughput on the FormUp 350:

• running 1 shift per day for 52 weeks per year
• 1 – 1.5 from laser off to laser on (build flip)