Home Abstracts of the presentations
Abstracts of the presentations
Wilfried Vancraen - Materialise - Belgium
Olli Nyrhilä, Martin Bullemer – EOS – Germany
Andy Christensen - Medical Modeling LLC - Colorado - USA
Dr. Ir. Peter Mercelis, Ir. Frederik Gelaude - Product Engineering, Machine Design and Automation (PMA) - KULeuven - Belgium
Prof. Deon de Beer - Central University of Technology - South Africa
Peter Ostiguy - De Puy Spine - Massachusetts - USA
Emanuele Magalini - Eurocoating - Italy
Paolo Gennaro, Maurizio Romeo - Protocast - Italy
Richard Bibb - PDR - UK
Dr. J. Poukens - University Hospital Maastricht, Ing. Paul Laeven, Ing. Maikel Beerens - Instrument Development Engineering & Evaluation (IDEE) - The Netherlands
Lieve Boeykens - Materialise - Belgium
Rapid Prototyping started as an experimental, promising but limited technology mainly used for early phase design communication in the industrial world. Throughout the years, technologies have developed and with it, their applications. Today’s technologies are being used increasingly for manufacturing applications. The usage of Rapid Technologies for (custom) implant manufacturing is being studied in many places, where several advantages of using the technologies are clear. However, there are many challenges to make this evolution truly happen. Challenges are to be found in materials, process, standards, regulations, logistics, design, … This forum will bring together experts in the field to present their experiences and stimulate discussions.
EOS was founded in 1989 and is today the world leading manufacturer of laser-sintering systems, the key technology for e-manufacturing™, the fast, flexible and cost-effective productions of parts, directly from electronic data.
Direct Metal Laser Sintering (DMLS) has been used for manufacturing prototypes, functional metal components and prototype tools for more than 10 years. During this period the technology has advanced to a level where direct production of complex metallic parts for various applications is everyday life and the medical market with its various challenges is one of the main targets. The shift from prototyping to production requires changes in the technology and also in organizations taking part in the shift.
This paper presents the latest status of the DMLS technology and materials development trends for different application areas using EOSINT M270 laser sintering machine. Commercially launched materials include presently biomedical materials like Titanium and Cobalt Chrome alloys, ultra high strength Maraging Steel alloy, Stainless Steels and other high-end engineering materials.
Additive fabrication of fully dense parts in biocompatible metals presents some exciting possibilities for direct production implantable medical devices. Production of near-net-shape implants using additive methods may allow for great benefit for custom and short run parts in terms of reduction of cost and time. While much hype has surrounded different layered fabrication techniques and their official “launches” of materials such as titanium and cobalt-chromium, sometimes too little work has been done in qualifying these materials for implant use. Factors to consider include the material properties, chemistry, microstructure, amount of internal porosity, tensile and fatigue strength. Depending on the application one may also need to consider surface finish, heat treating and other post processing steps and how they relate to producing a near-net shape. Factors such as process control, material batches and quality assurance become paramount when making parts for the medical industry, even more so with implantable devices. The main focus of this presentation will be on the presenter’s experience in qualifying titanium alloy, processed using the Electron Beam Melting process, for surgical implant applications.
Dr. Ir. Peter Mercelis, Ir. Frederik Gelaude - Product Engineering, Machine Design and Automation (PMA) - KULeuven - Belgium
Additive fabrication technologies offer great new opportunities for direct manufacturing of medical implants. Due to their inherent ability to produce complex shaped components, production of patient-specific prostheses is enabled. Although several clinical trials have already been performed by various researchers, large scale application of the technology has not yet been achieved. In order to promote the acceptance of the new technologies in the medical field, a lot of attention must be paid to the investigation of the resulting mechanical, physical and chemical properties. Moreover, process reliability and repeatability are at least equally important. A short overview of the work that has been performed at the division of Production Engineering, Automation and Machine Design (PMA) in this field will be presented.
Over the last few years, collaborations between the division of Production Engineering, Automation and Machine Design (PMA) and the divisions of Prosthetic Dentistry and Biomechanics and Engineering Design (BMGO) of K.U.Leuven resulted in the development of several new applications, some of which will be illustrated in the presentation. Next to implant supported dental prostheses, also clinical cases related to cranioplasty, hip joint replacement and mandible reconstruction will be presented.
The CUT’s Integrated Product Development research team serves a very diverse South African product development industry both as service bureau and research and development partner for just more than a decade now. Many innovative ideas have turned into products or unique services. One such an innovative product/service is the development of custom-designed implants.
Some of the research team’s work will be reviewed through case studies done with a Cape Town based orthopaedic company, together with some exploratory work done with surgeons in South Africa, covering bone replacement as well as soft tissue development. Both Virtual and Rapid Prototyping techniques have been applied to support a wide range of case studies. Further approaches to venture into Rapid Manufacturing will also be discussed.
Before the utilization of the metal prototyping machines we were making a number of plastic prototypes (over 6,000 last year) for our evaluations for project teams and our Designing Surgeons. This facility has been involved in Rapid Prototype technology for close to 15 years. The ability for RP technology to impact our business has been proven over and over at DePuy Spine. When there was a need to have a working metal prototype that could be used at a cadaver session we would manufacture the metal prototype. The average lead-time to make many of our prototype implants and instruments is 6 to 8 weeks and can be very costly. This did not guarantee that the item would work as intended when received, and often modifications were part of the process. Because of the extended delivery times it is a challenge to plan for surgeon team meeting and cadaver sessions.
Our interest, in this new technology was stimulated with the advent of metal machines companies, which were beginning to develop in medical materials. Samples were made in CoCr with good success. With this success we investigated the potential of DePuy purchasing this type of equipment. During our investigation eos presented to us their Direct Metal Laser Sintering (DMLS) machine that had the capability to produce 17-4 stainless steel. A fair number of our instrumentation is made from 17-4 SS. We reviewed the benefits of having this technology with our executives and received strong support to move ahead. We purchased a machine late last year and had it operational in February of this year. With insightful training and excellent run time on the machine, we have produced over 2,000 parts on over 50 builds. The machine runs close to 24/7. We have made instruments, implants, sales samples and test fixture. An early success was on an instrument that was in development. The engineer was looking to get some metal samples. The quote to manufacture was for $5,000 with a 6 to 10 week delivery time. We built the team a working prototype in a little over a week at a fraction of the cost. We proceeded to build the team two more iterations in less time than the earliest delivery time set by the vendor. The engineer and the team had the ability to make effective modification so that when it was time to go to production there was complete confidence from the team that they had a robust design. These instrument samples became an important part in getting feed back for surgeon in a very timely manner and was utilized effectively at cadaver sessions. From that early success there has been no turning back. Part of our success is to have individuals that are talented in the removal and clean up of the parts after they have been built. With our gained experience on what is conducive for successful builds we have combined building the samples on the DMLS machine to be followed up with some post machining. We have been able to go from “Model to Metal”. We have reduced the need to have fully detailed drawings for development as we did in the past with our earlier prototypes.
Where do we go from here? We are optimistic that eos in the near future will have developed a heat treatable stainless steel material. With this development it will open a number of new avenues. This technology spawns a new foundation on how we design our components. In the past we “Designed for Manufacturability”. Now we can “Design for Functionality”. Geometric constrains have been reduced.
The Rapid Manufacturing (RM) technology based on direct metal powder melting offers the possibility to examine new options for external structures that are intended to be used in contact with the bone tissue. The technology permits to design and realize actual geometries in complete freedom and overcoming limitations of conventional machining. Moreover the possibility to work with metal and metal alloys, suitable for implant application, permits to obtain not only functional prototypes but components potentially “ready to use”.
In recent times Eurocoating has collected results by using both laser (EOS) and e-beam (Arcam) techniques. Components with macroscopic geometry, surface topography and specific intrinsic surface texture were obtained. The two equipments are very different for driving physic principles however essential common points do exist in both manufacturing methods.
Orthopaedics devices such as acetabular cups and knee femoral components were realized in few working hours in pure cpTi, Ti-6Al4V and CoCr alloys. Components were designed with geometries not allowed if done otherwise.
Surface topographies obtained were characterized by very fine structures with thin walls (average thickness 0,2-1mm). Surface may be done with numbers of narrow holes (Range of 0,2-0,5mm). Undercuts in the same range of dimensions may be created when and where the implant lock by bone ingrowth is desired.
Texture is characterized by an intrinsic surface roughness that is very similar to some conventional titanium plasma spray coatings, well known for very good osseointegration potential both in short and long term clinical application. The presence of an intrinsic surface roughness can potentially guarantee an effective bone cell adhesion, spreading and proliferation.
Anyway differences between the two machines exist. In particular EBM seems to be more effective in manufacturing massive components and dimensional huge reticular structures. Laser technology is, at the moment, more accurate in detail reproduction allowing manufacturing of fine net structures.
Production of orthopaedics implants in Titanium alloy and Cobalt alloy.
The presentation will focus on the production of acetabular cups and stems in Ti6Al4V with EBM machine, acetabular cups and knees in CoCrM7 with EOS machine and knees in CoCrm7 with EBM machine. The 2 production technologies will be compared by the point of view of quality and cost.
Since 1998 PDR has been involved in the medical applications of product design and development technologies. Since then we have explored the application of scanning, CAD and Rapid Manufacturing to a range of medical devices and prostheses. Our experience has led to an understanding of many of the issues and obstacles that are faced in fully exploiting the latest technologies whilst meeting the strictest quality assurance and clinical standards. This presentation will discuss these issues and how they relate to the direct production of artificial implants.
Dr. J. Poukens - University Hospital Maastricht, Ing. Paul Laeven, Ing. Maikel Beerens - Instrument Development Engineering & Evaluation (IDEE) - The Netherlands
CAD-CAM and rapid prototyping and manufacturing is getting more and more attention in the medical sector, especially in cranio-maxillofacial surgery where defects of the face (f.i. absence of nose, ear or eye) have a very large psycho-social impact. European funded projects such as PHIDIAS, CUSTOMFIT and CUSTOM-IMD promote the use of these technologies. Reconstruction of complex defects in the face, bony tissue as well soft tissue, is challenging and requires custom made treatment modalities. We will highlight the use of these new techniques in the reconstruction of skull defects with CNC milled or rapid manufactured titanium implants. The raw data, which were used for processing, were acquired by CT scan. After conversion with Mimics, the stl-data could be processed with the 3-matic software.
Introduction of CAD-CAM and rapid manufacturing in medicine means a real breakthrough in medicine by introducing treatment modalities to complex cases, which could not be treated before, and by reducing operation time and patient discomfort.
Creating an implant through rapid manufacturing would open a lot of possibilities regarding the complexity of the case, for integration of growth factors, etc. However this dream opens a box full of questions. Creating an implant is a process where a lot of disciplines come together, each with their own problems to solve. All disciplines need to be brought together to combine the different viewpoints on this implant. If we look on a wider scale, how can we go into automation? And last but not least, how can we offer this super implant in a safe and controlled way to the patient?