Additive manufacturing makes complex and innovative medical devices possible

Many innovative next-generation medical devices and components can only be made with additive manufacturing

By Tyler Stark, Senior Director of Additive Manufacturing and Innovation, Spectrum Plastics Group

Additive manufacturing (AM), also known as 3D printing, comprises an innovative suite of advanced technologies that enable the manufacture of a variety of components and products, with remarkably complex, high-resolution features that cannot often not be made within the constraints of traditional manufacturing. methods. New specialized AM technologies, equipment and materials continue to enter the market at a rapid pace. Ultimately, advanced AM drives creative engineering, innovative rapid prototyping, and the seamless transition to high-volume manufacturing, advancing medical device design.

Popular AM technologies include:

  • Selective laser sintering (SLS) – thin layers of powdered material are fused together (also called direct metal laser sintering and selective laser melting)
  • Molten Deposition Modeling (FDM) – granular or filament feedstock is dispensed through a nozzle (also known as Molten Filament Manufacturing)
  • Stereolithography (SLA) – a liquid photopolymer is cured in a vat using ultraviolet light (also called vat photopolymerization or digital light projection)
  • Material projection (Polyjet) – droplets of photosensitive material are distributed and solidified under ultraviolet light, layer by layer
  • Multi-jet fusion (MJF) – also known as binder jetting, a liquid bonding agent is selectively deposited on layers of powdered material to create a solid structure
  • Direct laser metal sintering (DLMS) – also known as directed energy deposition, a laser beam or electron beam fuses materials together, melting them as they are deposited

Medical applications for AM

Additive manufacturing technologies enable medical device companies to rapidly develop innovative next-generation devices, which can also be scaled to meet changing production demands.

The advantages of additive manufacturing over traditional manufacturing methods such as machining, injection molding and extrusion include:

  • Equipment and materials can be customized for a wide range of medical applications
  • Rapid prototyping that delivers production-ready prototypes in days instead of weeks or months, accelerating product development and informed decision-making
  • Creation of innovative and one-of-a-kind products or components, especially for minimally invasive surgical processes
  • Bridge manufacturing that uses AM to test low-volume production runs of a product before investing heavily in a mass-production process using standard manufacturing methods.

Proprietary/customized processes

AM in the medical industry continues to progress, especially the number of new AM materials with very specific technical properties. Advances in software and hardware are also improving accuracy and flow control, resulting in highly accurate parts. Depending on the geometry and complexity of the part, tolerances can be as tight as +/-0.0005 inch.

AM has become commonplace, but with limited capabilities and offerings to incorporate high performance thermoplastics, which can offer much greater design flexibility than metals due to the large number of thermoplastic materials available, such as acrylic , ABS, nylon, PLA, polycarbonate, polyether sulfone, PEEK, polyethylene, urethanes and custom materials. These materials can be modified by chemical or mechanical manipulation to improve physical properties such as impact resistance, mechanical strength, heat resistance, chemical resistance, lubricity, abrasion resistance, resistance to sterilization, biocompatibility, transparency and low water absorption.

Spectrum uses AM to process all medical grade thermoplastic materials. Material consistency is essential for AM reliability and repeatability. To achieve the greatest control over material quality and consistency, Spectrum manufactures its own filaments in-house. All products are made from USP Class VI and/or ISO 10993 medical grade materials and additives that are biocompatible, traceable and certified.

Spectrum Additive Manufacturing

Spectrum has developed Spec+ Additive Manufacturing, its own proprietary AM equipment and processes to create medical products that other companies cannot, such as high precision medical grade single and multi-lumen tubing, an industry first . This proprietary technology produces prototype multi-lumen tubing, pushing the boundaries of medical-grade tubing design, materials, and speed. The Spec+ system can create a full-length multi-lumen tube to specification in a single day (compared to the standard extrusion process, it can take up to three or more die iterations and weeks to refine a prototype multilumen extrusion). Spec+ simply prints the full extrusion profile from the first designated material stroke.

Future progress

Miniaturization is a dominant trend in the medical device industry. Integrated additive manufacturing processes and materials, combined with careful system controls, can produce ultra-high precision microscopic parts that are suitable for both rapid prototyping and production. Spectrum AM technologies can print incredibly small parts from almost any type of thermoplastic, even multiple materials together in a single print. Parts can be so small that they are often difficult to see with the naked eye.

The benefits of AM are numerous, including rapid prototyping, product customization, and the creation of complex surface structures and textures that reduce weight and improve performance at the micro scale. AM also does not require the expensive setup and tooling required by traditional injection molding or CNC machining. It also makes it easier to access deck tooling to test short runs before making expensive investments in tools.

AM materials will continue to evolve at a rapid pace, including bioresorbable materials. Implantable components are tested with different AM systems to see how various materials influence product performance, especially wear and durability. Materials are also mixed during the additive manufacturing process to form “in situ” alloys. In-situ alloys can have better mechanical properties than individual pre-alloyed metals. Plastic composites can also be formed in situ during AM, creating exciting opportunities for performance enhancement.

Perhaps the greatest advantage of AM is the design freedom it offers medical device engineers, allowing them to choose from a wide range of medical-grade plastics, with material characteristics and components of design specifically designed for multi-material and multi-dimensional constructions. The ultimate benefit of AM is that medical device companies can invent innovative new products that offer dramatically improved time to market.

Partner with Spectrum’s AM technical team

For more information about Spectrum’s advanced Spec+ additive manufacturing technologies for medical devices, visit www.spectrumplastics.com or call 404-564-8560 to speak directly with our technical experts.

Content sponsored by Spectrum Plastics Group

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