Thinking loops in the system

Precision comes from interaction

When it comes to tight shape tolerances and high-precision surfaces, grinding is a key technology in modern manufacturing. The decisive factor for stable and economical processes is not just the process, but also the precise interaction of machine, tool, process knowledge and measurement technology - especially for demanding workpieces such as brake disks. These react extremely sensitively to mechanical and thermal loads. Excessive process forces quickly lead to distortion and thus to deviations in axial run-out and parallelism. The aim of modern grinding processes is therefore to ensure that material removal is as gentle as possible and at the same time reproducible.

One approach that has proven its worth here is the consistent consideration of the entire process chain. Coating and grinding are designed as an integrated process, while machines, grinding tools and cutting materials are precisely matched to each other. At the same time, Nagel Technologies GmbH from Nürtingen assumes responsibility for the entire machining process. "Grinding today is no longer just about stock removal, but about the controlled interaction of all process components," explains Andreas Schmohl, Managing Director of Elgan Diamant-
KG and Head of the Superfinishing business unit at Nagel Technologies. "Our aim is to keep the process forces as low as possible in order to avoid deformation and achieve maximum precision."

Technically, the approach is based on double surface grinding, in which both sides of the brake disc are machined simultaneously. The even load distribution reduces local force peaks and enables stable processes with high quality over the entire service life of the self-sharpening grinding segments. Practical experience illustrates the range of this technology: around 40,000 coated brake discs in around 300 variants have already been processed for customers in the pre-series and prototype area. Both car and truck brake discs can be produced on one machine - as well as coated cast brake discs and ceramic variants where only the cutting medium is changed. Grinding is thus increasingly becoming an integrated key technology in which the precise interaction of tool, machine and measuring technology determines quality and cost-effectiveness. "At GrindingHub 2026, we will be happy to go into even more detail here in a direct exchange," says Schmohl.

Measuring instead of reworking: Precision directly in the grinding machine

In modern grinding machines, measuring technology plays a decisive role when it comes to ensuring workpiece quality. Renishaw's touch probe solutions enable geometric feedback for the quality control loop. "Our touch probes record the position, orientation and condition of the workpieces. Determining the actual material allowance avoids unproductive 'air cuts'. The final inspection can also be carried out directly in the machine's work area," reports Dr. Jan Linnenbürger, Business Development Manager EMEA at Renishaw, based in Pliezhausen, Germany. "This allows users to achieve a high level of process capability - even with fluctuating process parameters. Integrating geometric measurement into the grinding machine significantly increases process reliability and efficiency."

A special feature of Renishaw technology is its exceptional accuracy in 3D measurements: "Renishaw is known for achieving a repeatability of less than 0.25 micrometres," emphasizes Linnenbürger. Thanks to their robust and particularly compact design, the touch probes meet the high requirements that prevail in a grinding machine. Especially where space in the machine room is limited, the company offers motorized measuring arms to reach all measuring points. The portfolio also includes high-precision encapsulated displacement encoders that are specially tailored to the needs of grinding machines. Francesco Palumbo, Sales Encoder at Renishaw, is convinced: "With our solution, we get the last micrometers of accuracy and ensure optimal grinding patterns."

Optimized CBN (rotor) grinding wheels - tools for special requirements

Following a development phase lasting several years, new and specified CBN roughing and finishing grinding wheels for rotor machining are now available for the first time. The tools were developed specifically for machining cast iron rotors and complement the established CBN line from the Kapp Niles Group in Coburg. In the roughing process, the newly used grain achieves a significant reduction in heat due to optimized coolant supply and larger chip spaces. In industrial applications, it was also possible to multiply the metal removal rate Q'w and therefore - in combination with the lower heat input - reduce the grinding time by up to 30 percent. By increasing the process parameters, it is possible to machine high oversize situations (e.g. pre-cast rotors with 2-4 mm profile oversize) economically. Pre-machining of the rotor profiles is no longer necessary and the milling process can be saved.

An optimized CBN grain is used for finishing, which is used specifically for machining castings. The result is a significant increase in tool life with the usual - consistently high - component quality. The optimized CBN grinding wheels can be used individually or combined as a performance package and noticeably increase the potential of the RX machines in the series production of cast rotors. Existing tools can be updated; the solutions have been tried and tested in industry and are ready for the store floor.

With the additional CBN tool series, Kapp Niles is strengthening its position in rotor series production and creating the basis for innovative and even more customer-specific solutions, thus providing new impetus. "The feedback from our customers shows that we have struck a chord with the optimized CBN tools and can support our customers' production in a needs-based and efficient manner," says Andreas Paatz, Head of Service/Tools/Digitization.

Redefining reliability in tools

Numerous international exhibitors are also represented in Stuttgart. Many suppliers will be focusing on the topics of tools, grinding and holistic processes. Ceratizit, based in Luxembourg, for example, will be presenting its 'Rods & Preforms' business unit and the entire 'Private Label' division, focusing on its portfolio for tool manufacturers. "At GrindingHub, we will be showcasing our fully integrated value chain, true to the motto 'Reliability Redefined': from powder to the finished semi-finished product. Especially in times when availability is paramount, we are ensuring our customers the highest level of supply and premium quality at the same time," announces Michael Knittl, Head of Sales and PM at Ceratizit.

This year, these include additions to the ultra-fine portfolio, for example for solid carbide (solid carbide) milling, as well as new versions of milling blanks for micro-machining with up to seven cooling channels. "This optimizes the milling performance thanks to targeted cooling in the engagement zone and increases the tool life, of course with full stability of the shank and the finished ground tool," adds Knittl. In addition, the company has already had carbide substrates in its range for some time, whose recycled tungsten carbide powder has the highest material cycle in its category: 99 percent of the powder is recycled using advanced metallurgical technologies and 100 percent renewable energy. Michael Knittl comments: "And in this category, too, we are constantly working on new ways to expand the range of applications for these substrates!"

Holistic approaches for efficient grinding

High-precision grinding in today's production processes is often achieved through the coordinated interaction of all components involved in the process. This is particularly true for demanding components. Modern approaches include integrated process chains including high-precision measurement technology directly in the machine in order to minimize process forces and increase quality and efficiency. New developments such as optimized CBN grinding wheels also increase productivity, reduce thermal loads and significantly shorten processing times. Overall, grinding is developing into a holistic key technology in which integrated systems and innovative tools are decisive for precision, efficiency and process reliability - all of which can be experienced in one place at GrindingHub (May 5 to 8) in Stuttgart.

Dag Heidecker, trade journalist