Automated cutting edge optimization of punching and forming tools

A machine manufacturer was looking for an automated solution for optimizing the cutting edges of its punching and forming machines. A stream finishing system is used to achieve optimum cutting edge rounding and high gloss polish on the surfaces of a wide variety of tools.

Finding an automated solution for the punching and forming machines of renowned machine manufacturer Bihler that delivers consistently high-precision results was the challenge that the Otec team of experts set itself. By using the Otec systems, optimum cutting edge rounding and high-gloss polishing of the surfaces of a wide variety of tools made from carbide or hardened steel is achieved in just one work step. This ensures the longevity of tools and significantly reduces production costs.

In order to maintain a competitive advantage in the market, it is crucial for the tool industry to achieve optimum product quality and increased efficiency in the production of stamped and formed parts. Using the successful example of Otto Bihler Maschinenfabrik, this means an optimum cutting edge rounding of 10-20 μm as well as high-gloss polishing of the lateral surfaces with a surface roughness of up to Ra 0.02 μm for cutting punches and dies. With this high-performance quality, the carbide or hardened steel tools consistently achieve precise results and maximum tool life, even at high cycle rates. State-of-the-art 3D measuring technology from Keyence also ensures constant and reliable quality control and documentation.

A tailor-made machining process was developed at the Otec Finishing Center in order to fully meet the demanding surface requirements. The desired roughness parameters for the punching and forming tools were achieved using vibratory finishing technology in the so-called stream finishing (SF) process. With SF technology, the workpieces are clamped in a holder and lowered into the rotating container filled with grinding or polishing media. The granular and abrasive process agent flows around the workpieces and ensures even, homogeneous removal. By adjusting the processing parameters and the type of process agent used, both highly abrasive and fine polishing processes can be realized with just one machine.

Thanks to a special cycle operation of the system, this process is also suitable for a wide variety of tool geometries. The angle of the clamped tool is automatically changed again and again during the process, allowing a wide variety of surfaces to be achieved in a targeted manner. Thanks to the optimized processing of the tools in the stream finishing system, manual process steps (activities) are no longer necessary. The innovative solution is process-reliable and delivers consistent results without fluctuations.

The successful interplay of system size and equipment, process equipment and the appropriate process parameters was determined as a process using tools from the customer's series production and then tested in real-life use. Once the Otec SF-1 with cycle drive had been installed, the system was successfully commissioned at Bihler with the help of the Otec specialists. Ongoing support from process development and after-sales ensures a high level of process reliability and efficient use of the system in the long term.

The use of Otec stream finishing systems leads to effective resource and cost savings, while at the same time achieving the desired surface roughness parameters and surface properties. The extremely high demands of carbide tools for consistently high product quality and increased efficiency in production are reliably met and the service life of the parts is significantly increased, while at the same time reducing maintenance costs.

The special property of the slide-ground surface topography with its significant reduction in roughness peaks enables excellent tool performance. Smoothing and polishing the surfaces reduces friction and thus the thermal load. This significantly reduces tool wear and ideally prepares the surface for coating. (OM-12/23)