Machining accessories Complex manufacturing methods for medical technology
Source: press release
Many manufacturing companies are expanding their product portfolios and service offerings to attract a wider customer base. This gives production companies greater independence from sectors such as automotive or aerospace. Medical technology is an example of such market expansion, although it presents a wide range of challenges.
Metav 2022, International Exhibition of Metalworking Technologies, reflects the importance of the medical technology sector by giving it a dedicated space. From March 8 to 11, 2022, researchers and experts from the companies exhibiting in Düsseldorf will provide practical and theoretical information.
“The dynamic development of medical technology is unstoppable. The demands placed on manufacturers — and therefore on their suppliers — are constantly increasing. Products designed for use in the human body are becoming smaller, less invasive, more precise, safer and better tolerated,” says Markus Horn, Managing Director of Paul Horn in Tübingen. These are just some of the requirements that manufacturers of medical products face on a daily basis. As a toolmaker, Paul Horn is well qualified to meet these challenges and is constantly developing new tool solutions and manufacturing strategies for the medical technology industry: micro milling machines for the production of titanium spinal implants responsive to grooving tools for the aluminum pump housing of a heart-lung machine.
Horn continuously develops its know-how in the field of medical device technology. A good example here is swirl technology. High chip removal rates, long threads with high quality finishes, deep thread profiles, short metal chips, multi-start threads and low tool load levels are the main advantages of the whirling process. However, these are offset by various technical challenges. An important aspect is the materials used in the bone screws in the implants. The cutting edges of whirling plates are subjected to very high loads when machining titanium, stainless steel and other superalloys. Horn is constantly perfecting its technology to combat cutting edge wear at high chip removal rates and with short machining times. Markus Horn: “Medical technology will also play a central role for us at Metav 2022 in Düsseldorf. We will not only present whirling products, but also our solutions for manufacturing implants, instruments and medical devices.
Multi-axis 3D printing for cartilage implants
According to Professors Oliver Riedel and Alexander Verl, directors of the Institute for Control Technology for Machine Tools and Manufacturing Systems (ISW) at the University of Stuttgart, “Our job as engineers is to develop technologies who serve people. Medical technology plays a very special role here. Bio-printing, for example, is a new type of technology. Its goal is to produce biological tissue structures to replace the tissues of diseased patients. Research is ongoing at ISW on a 3D printing application to treat knee osteoarthritis using custom cartilage implants. Researchers take advantage of the fact that additive manufacturing can be used to produce complex components whose internal structures can be defined by graded material compositions.
A continuous process chain, from the MRI of the patient’s knee to the finished personalized implant, is being developed at the ISW (which is part of the WGP – German Academic Association for Production Technology – an association of leading academics in the industry). The scan data is used to generate replacement geometry for the defective section. This geometry can be used to calculate curved paths in space for the printing process. The NC program is then run on a 7-axis printing system. A specially developed printhead has been coupled to a CNC control system with feed with real-time capability. It compensates for the nonlinear tracking behavior of the extrusion printing process. The material consists of a methacrylate-modified gelatin solution, which is cured using UV LEDs. Cell cultures grown in a bioreactor are dissolved in the cartilaginous equivalent before being implanted. The biomaterials are developed at the Institute for Interfacial Process Engineering and Plasma Technology (IGVP) and the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) in Stuttgart. Metav 2022 dedicates separate spaces to the two fields of the future – medical and additive manufacturing.
Shrink fit and preset for greater productivity
Abutments, titanium adhesive bases as well as laboratory and implant screws are complex turned parts, many variants or which need to be produced in large quantities. This in turn means frequent retooling of lathes. Here, a tool management system consisting of shrink-fit collets and a shrink-fit and presetting device offers many advantages. This combination guarantees particularly high levels of precision, but also fast and safe tool presetting. “About eight minutes can be saved per tool when setting up the machine,” says Haimer based in Igenhausen, who supplies complete packages of suitable solutions. The European manufacturer of tool clamping technology offers shrink-fit collets which, unlike conventional ER collets, facilitate simple and fast tool changes and are characterized by their concentricity accuracy. They help to reduce vibration, which optimizes surface quality and tool life.
Haimer has a shrinking device whose horizontal design allows the handling of small tools in particular. The shrink-fit device is easy to operate via a 7″ touchscreen and intuitive software – and the i4.0 version is equipped for digital integration into the production system. Haimer recommends another product for tool presetting. Providing fully automatic tool measurement, it offers absolute operator independence and use with virtually no prior knowledge or experience. , or using a QR code and scanner.
Quick tightening is half the battle
In its production of complex surgical instruments, the company Anton Betzler from Tuttlingen exploits the efficiency offered by Schunk’s flexible and stationary modular system for clamping and configuration on 5-axis machining centers. The components of micro scissors and scalpels are first made on the machine and then finished manually with skilled craftsmanship. Here, Betzler combines a zero-point clamping system with two manual clamps from the Schunk range. These clamps are delivered complete with the corresponding clamping pallets. The clamping force in the vices can be adjusted as needed, thus preventing any deformation of thin forgings. The medium-sized family business has equipped all machines with two zero-point clamping modules each, thus ensuring fast assembly of each gripper. The entire gripper (including the pallet) is changed during the installation process. It’s easier and faster than changing the clamping jaws alone. This avoids bottlenecks and shortens delivery times.
However, even greater precision is possible: A newly developed small parts gripper with a quick jaw change system can be changed quickly and completely without the need for special tools. Accessibility makes it particularly suitable for 5-sided machining. Despite its compact dimensions, it offers high clamping forces up to a maximum of 16 kilonewtons. Combined with an extremely flat zero-point clamping system, this allows optimal use of machine space on small machine tools. “Our modular system offers users maximum flexibility and helps them reduce their installation times”, summarizes Markus Michelberger, sales manager for clamping technology at Schunk. “We are delighted to demonstrate our expertise at Metav 2022.”