Customizing, optimizing medical device production

With additive manufacturing (AM) offering medical technology designers great freedom, successful results require integrating manufacturing solutions from start to finish. Powder bed AM technology, a well-established supplement to conventional machining processes, is already producing medical devices ranging from dentures and bone plates to implant sets.

As the demand for AM parts grows, DMG MORI engineers know there’s the need to support customers with integrated manufacturing solutions – programming software, selective laser melting, and machining centers – to tackle their projects. This has led to the manufacturing technology company recently opening its Medical Center of Excellence in Chicago, Illinois, to develop end-to-end processes for customers’ applications.

The Center in Chicago follows upon the success of the Medical Excellence Center at Deckel Maho in Seebach, Germany, which recently handled a project for accelerated, economical production of custom titanium hip cups. DMG MORI’s integrated solution allowed them to answer the task.

Efficient production, customized implants

Since titanium medical implants are subject to rigorous quality requirements, the top priorities were to develop process-reliable manufacturing and decrease production time. The answer was a Lasertec 30 Dual SLM, featuring two 600W lasers with a scan field covering the entire build volume, generating a build rate of more than 90cm³/h.

DMG MORI engineers then tested the stability of sample components in the entire build volume and their relative density – especially at the increased production rates. Results showed that with a relative density of more than 99.95% in the final component, the tests exceeded expectations, and the bending and stress tests were also consistently successful.

“The dynamically adjustable focus diameter was further optimized and is now 50µm. In addition to the high productivity, this results in a very good surface quality. The active liquid cooling ensures outstanding long-term stability in the process,” says Dr. Uli Sutor, key account for medical industries at DMG MORI Seebach.

The system design incorporates safety. Lasertec 30 Dual SLM rePLUG powder modules prevent fine metal powder from escaping into the ambient air, while a permanent filter system ensures automatic passivation of metal dust. Modules also allow for powder change in less than two hours. Filter service life is at least 3,500 hours.

Intelligent solutions

Hip cup production is a holistic process from design to programming, from AM in the powder bed to final finishing on an NTX 1000 2nd Generation. Those processes support precision machining of the internal threads, for example. Optomet software optimizes the powder bed process parameters in the SLM product range used in this project.

“With it, process parameters can be predicted within a few minutes as well as mechanical properties of the materials,” Sutor explains.

CELOS is also a key part of the process. Integrated software offers CAM programming directly at the machine using RDesigner, controlling both machines. Camera-based monitoring tools oversee build-up and coating quality. TULIP software in the bundle provides simple digitization of production processes. With TULIP, users can quickly, intuitively create apps without programming knowledge. An existing AM app simplifies powder base material tracking. The software also enables tracking powder loading, consumables, and print jobs.

Rethinking old processes

Production of individually adapted hip cups shows that while AM is already widely used in medical manufacturing, there’s still more room for advancements. Sutor agrees, concluding, “We will keep putting many proven processes to the test and continue optimizing them with the help of our powder bed machines.”

DMG MORI USA
https://us.dmgmori.com

About the author: Elizabeth Engler Modic is editor of TMD. She can be reached at 216.393.0264 or emodic@gie.net.