Absolutely reliable: unmanned production of precision components for medical technology

Micro milling tool with HiPIMS InoxaCon® coating ensures a dependable manufacturing process

Together with CemeCon, tool manufacturer HPTec has developed the RQR 350 milling cutter with a diameter of only 3 millimeters and InoxaCon® coating. This “miracle tool” for micro-machining in medical technology guarantees uncompromising machining quality and exceptionally long tool life. This makes it ideal for a stable, precisely reproducible manufacturing process that can be safely automated overnight.

A steady hand is not everything: since surgical instruments are used directly in the human body, the requirements for their surface quality, burr-free finish, and dimensional accuracy are particularly critical. This is a matter of course that has also driven Bacher Medizintechnik GmbH for decades as a manufacturer of instruments for endoscopy and minimally invasive surgery. At the same time, cost-effectiveness is required in component manufacturing: when machining so-called jaw parts—functional instrument gripping heads for grasping or separating tissue—the Baden-Württemberg-based company therefore relies on manufacturing processes that run automatically for many hours.

Even in unmanned production, continuous in-process control is naturally carried out throughout the entire process. An integrated 3D measuring probe system and supplementary laser measurement continuously monitor the relevant geometries, thus ensuring that the required quality is maintained at all times, even during automated night shifts.

Another important aspect is the performance of the machining tool: “In medical technology, there is no room for fluctuating quality,” explains Mate Bekavac, Head of CNC Production at Bacher Medizintechnik. “Especially with batches that run unmanned overnight, i.e., without the possibility of direct intervention, I have to be able to rely 100% on the tool working fail-safe right down to the last jaw. Additionally, I need to be sure that there is no scrap.”

The challenge: roughing with diameters up to three millimeters

The requirements profile for the partner HPTec was thus clearly defined—the tool manufacturer was to develop a roughing tool with a long tool life and persistently high sharpness for consistently stable and high-quality machining. A particular technical challenge was that only a very small tool diameter of no more than 3 millimeters was permitted. The required high-performance machining tool still had to absorb high forces and remove large amounts of material in a short time.

HPTec’s first step toward a solution was to optimize the tool geometry: within a short time, the developers succeeded in achieving a balanced ratio of core diameter, chip space, and cutting geometry, ensuring stability and efficient chip removal. The design is complemented by special roughing and finishing teeth. These produce short chips and, with the appropriate coating, achieve an extremely uniform surface finish even during the roughing process.

Optimal tool coating complements optimal tool geometry

A key performance factor of the new RQR 350 milling cutter is the HiPIMS coating from CemeCon. During the joint development phase, the coating specialist and tool manufacturer HPTec designed a coating that gives the cutting edge outstanding sharpness and long-lasting performance. The basis for this is the very hard and temperature-stable InoxaCon® coating material based on TiAlSiN. Thanks to CemeCon’s many years of experience with HiPIMS, the coating could be adapted to support the long-term stability of the tool, thereby significantly increasing its tool life.

“With the innovative micro milling cutter, we are already achieving excellent surface quality during roughing with a low allowance of maximum 0.05 millimeters, which allows us to carry out the subsequent finishing process with a very small engagement width,” says Bekavac. “This significantly diminishes the cutting forces and thus the load on the finishing tool, reduces burr formation, and has a positive effect on the entire process.”

Julian Reck, Key Account Manager at HPTec GmbH, adds: “Especially in micro and fine machining, it is crucial that the coating does not ‘round off’ the cutting edge. CemeCon has specified the HiPIMS coating for us in such a way that exactly that is achieved: high hardness, excellent adhesion, and a coating thickness and homogeneity that optimally complements the carbide substrate and tool geometry.” As a result, the tool life is many times longer than that of the competing tools previously used—while maintaining consistently high machining quality throughout the entire service life.

For Bacher Medizintechnik, the decisive advantage lies not only in this extended tool life, but above all in 100% reliable processes. Wear-related quality deterioration during unmanned production would result in unnoticed rejects—and thus high costs. “The new tool gives us the assurance that the jaw parts still have exactly the required quality even after many hours of automated production,” says Bekavac.

Technical excellence and collaborative development open up new perspectives

The project clearly shows how close cooperation between users, tool manufacturers and coating specialists leads to measurable success. For HPTec, the tool developed in collaboration with CemeCon is also another important step into a strategic growth market. The company’s many years of experience in the manufacturing of high-precision tools for the printed circuit board and dental industries—including as an OEM—could be seamlessly transferred to the demanding field of medical technology. The expertise gained—from precision engineering and reliable process stability to strict quality requirements—provided an ideal basis for developing innovative, robust solutions tailored precisely to the application in medical technology.

“For us, projects like this are more than just product development,” emphasizes HPTec Sales and Marketing Manager Wolfgang Würtz. “They show how we can tap into new markets and expand our technological expertise in a targeted manner together with strong partners.”

The combination of optimized tool geometry, high-performance HiPIMS coating and close user integration makes this flagship project a good blueprint for further applications—even beyond medical technology: wherever precision, process reliability and cost-effectiveness must come together.