Additive manufacturing is ideal for producing medical devices. When designing an implant, a CAD engineer will first create a computer model based on patient data and then set the 3D printer to work. What's more, products made using this technology have excellent material properties - for example, polymer devices that are robust but elastic and shock-absorbent, or implants with a porous structure that fuse well with healthy tissue but remain stable and durable. Additive manufacturing is also suitable for producing custom-fit implants on a cost-effective basis. A further benefit is that, unlike conventional machining methods, 3D printing does not produce any waste in the form of shavings or swarf. And in the manufacture of medical implants, where the material of choice is generally an expensive titanium alloy, this means genuine savings.
Furthermore, there are none of the retooling costs of conventional methods.
Conmet, a market leader in craniomaxillofacial surgery and implantology, first looked at additive manufacturing 10 years ago. At the time, however, the technology was still insufficiently mature for such applications. In 2017, the company decided to approach TRUMPF to find out how far the technology had evolved. "TRUMPF is the only supplier on the market for 3D printing that develops its own lasers and all the optical components," explains Andreas Margolf, project manager for additive manufacturing at TRUMPF. "We also have a wealth of experience in the areas of machine tools and services. That means we're able to assist Conmet with any aspect of the process."
The first task was to determine the right machine for Conmet, along with the relevant process parameters. It was soon clear that the ideal set-up was TRUMPF's own TruPrint 1000 3D printer with the laser focused to a diameter of 30µm. Equipped with a 200W fibre laser developed by TRUMPF, the machine has no problems working with the titanium alloys generally used to produce implants. TRUMPF also proved its expertise to fine tune the focal diameter at which the laser beam hits the powder bed. "Our tests showed that reducing the focal diameter to 30µm improves the surface smoothness of the implants by around 20%," Margolf explains. This makes the process slower and slightly more expensive but reduces the cost of post-processing the surface."
Conmet has been operating with the TruPrint 1000 at its Moscow production facilities since the beginning of 2018. The company uses the new machine to produce dental components and craniomaxillofacial implants for, among others, cancer patients. Hospitals provide Conmet with CT data of patients; engineers at Conmet then design the implant, in consultation with the surgeon; and the machine prints it out. "We currently produce 60 implants a month with the TruPrint 1000, and we're planning to increase our output by 10%," says Nadeschda Morozova, project manager at Conmet. The implants not only have an especially high quality level overall - they are also substantially cheaper.
"Compared with conventional machining methods, such as turning and milling, the new process saves us 40% in production costs," Morozova reports. In the near future, Conmet intends to start producing customfit spinal fixation devices using 3D printing. The company also has plans to manufacture mass-produced prosthetics with the TruPrint 1000. For this, Conmet will be investing in new machinery and has once again opted for TRUMPF technology. As Morozova explains, the new machine will be a TruPrint 3000, with a larger construction chamber.
