Optimum coating of mini and micro tools

With mini and micro tools, the coating error tolerances are very small and the coating thicknesses are minimal. A specialist ensures the necessary process reliability when coating precision tools.

Miniaturization is setting trends - from dental implants to electronic components and movements to micro ball bearings. The demand for ever smaller components leads to ever smaller precision tools and ever tighter tolerances. As a consequence, the coating must also be able to measure up to these developments. What counts here is not only that the coatings combine minimal coating thicknesses with outstanding properties, but also that work processes and handling are adapted to the tools, which are only a few millimetres or even tenths of a millimetre thick. Tool manufacturers can find this comprehensive know-how from the coating experts at CemeCon.

When tolerances in the micrometer range have to be adhered to, there are high demands on process reliability, tool life and precision. Ultra-thin and smooth HiPIMS and diamond coatings ensure that micro-tools achieve the required performance in everyday machining. And anyone who has their tools coated in one of the CemeCon coating centers can be sure that their mini and micro tools are in good hands.

This is made possible by a passion for perfection and attention to detail, which is reflected in the sophisticated work plans. Quality is the sum of many building blocks, and so every work step is documented. "We have developed coordinated workflows, processes and devices for handling the delicate micro-tools to enable employees to work reliably. Examples include special holders for the micro-tools during charging or the specially developed cleaning system for evaporating cooling channels. No system available on the market had convinced us. That is why CemeCon Production Engineering built a system that is perfectly suited to micro-tools. To avoid direct contact with fingers, our colleagues also use tweezers and wear gloves during handling," says Manfred Weigand, Product Manager Round Tools at CemeCon, explaining some of the adaptations made in CemeCon Production especially for micro tools.

Absolute cleanliness is particularly important when coating micro-tools. Even the smallest particles on the tools affect the coating and therefore the quality. This is why CemeCon places a special focus on cleaning: this applies not only to the tools, but also to cladding, charging material and, quite simply, the entire production process. Particularly gentle cleaning of the micro-tools during pre-treatment ensures an excellent coating result. CemeCon's diamond coating department also has another special feature: tools are processed in a clean room, protected from external influences.

Why is CemeCon so good at coating micro-tools? CemeCon has over 35 years of experience in the coating of cutting tools and has specialized exclusively in this field. This means that all procedures and processes are tailored to precision tools - whether HiPIMS or diamond coatings. This comprehensive expertise in dealing with tools makes it easier to adapt the processes to the "Minis". "We also started coating small tools very early on - when micro tools were still rather exotic. Sputtering is our technology of choice and - just like HiPIMS as its further development - is perfect for coating miniature tools. The traditional arc process is out of the question here. We have been able to gain experience in this field over many years," adds Manfred Weigand.

HiPIMS is perfect for micro tools, says Ramesh Agarwalla, Director at CTC Praezision Tools, India, and an expert in micro tools for PCB manufacturing and micro cutting tools for dental and medical technology. "Especially with micro tools, flaws in the coating - so-called droplets - are fatal, as they have a much more extreme effect in these tiny dimensions than with larger tools. Consequently, uncompromising smoothness is an absolute requirement. This makes the HiPIMS process - in which no droplets can occur due to the process - the key to our success!"

The ultra-thin HiPIMS coatings reproduce complex tool geometries one-to-one. Christoph Schiffers, Product Manager Technology at CemeCon: "If you want to apply coatings to the filigree geometry of a micro-tool in an adhesive and process-safe manner, you need adapted residual stresses. This is the only way to homogeneously coat fine cutting edge geometries. With our HiPIMS technology, the residual stresses can be controlled and significantly reduced - perfect for sharp cutting edges on micro-tools."

The high-precision multilayer CCDia coatings are ideal for high-end micro-tools, for example for the production of highly complex graphite electrodes or dental implants. Production using the hot filament process ensures thin layers with a homogeneous layer thickness distribution within tight tolerances - even with complex, delicate geometries. "To ensure that the high accuracy of the tools is also guaranteed after coating, we coat precision tools to the desired final dimensions on request - and this can be reproduced at any time, including documentation," adds Manfred Weigand. (OM-9/24)