Dimensional accuracy is the number one issue in the manufacture and use of dental tools, as Oerlikon Balzers reports. The Lohmar-based company ibb Zerspanungstechnik manufactures CAD/CAM micro-tools with micrometer precision and applies them, including the cutting edge and coating, to the various machining processes and materials such as cobalt-chrome (CoCr), titanium, zirconium oxide or glass ceramics.
AlTiSiN coating applied using an advanced PVD process
Because customers need to produce dentures quickly and stably, ibb decided to speed up the production process by increasing the infeed rate while maintaining the same tool life as far as possible. The geometry, carbide substrate, cutting edge preparation and coating of the speed milling cutter designed as a result were adapted to the roughing process. The newly introduced AlTiSiN coating Baliq Tisinos Pro from Oerlikon Balzers was the ideal surface protection.
This PVD coating was specially developed for hardened steels, stainless steels or high-temperature alloys. It reduces tool stress and significantly improves wear resistance during hard machining of steels up to a hardness of 70 HRC, as Oerlikon Balzers reports. Customers benefit from longer tool life and high production quality.
This coating is produced on the basis of the S3p process (Scalable Pulsed Power Plasma). This technology combines the advantages of the arc evaporation (arc) and magnetron sputtering processes and, according to Oerlikon Balzers, pushes the performance limits of conventional HiPIMS coatings. The advantages of S3p are longer high-current pulses and a high current density, which result in strong ionization of the coating. The coatings developed on this basis have an exceptionally smooth and defect-free surface without droplets. Their modified microstructure and high-precision layer thickness distribution ensure highly stable and evenly protected cutting edges. According to the coating specialist, this is crucial for greater precision and performance, especially in micro-machining. The high-performance coating is extremely wear-resistant and designed for hard machining up to HRC 70. It also withstands the high temperatures in cobalt-chrome machining and prevents built-up edges despite the material's high tendency to stick.
Roughing time halved with the new coating
In ibb's research and development laboratory, a speed milling cutter coated with Baliq Tisinos Pro (diameter 2 mm, edge radius 0.3 mm) was tested on a test machine when roughing cobalt-chrome blanks with special test specimens to measure dimensional accuracy. The results were compared with previous test results. In comparison with milling cutters with a competitive coating, a clear picture emerged: With an unchanged milling strategy, an almost doubled tool life can be achieved, as stated in the press release from Oerlikon Balzers. Alternatively, a doubled infeed depth was achievable with almost the same tool life in relation to the chip volume, which roughly halves the roughing time.