Priority: Quality Assurance

This is also confirmed by Dipl.-Ing. Volker Nötzel, managing director of the tool manufacturer Schumacher Precision Tools GmbH in Remscheid. For more than 100 years, Schumacher has been developing and producing tools for cutting internal threads for industrial applications at its Remscheid facility. The engineers in Remscheid have now fully digitized the design and manufacturing processes. Fully parameterized models are used for optimization purposes, including for FEM solid-body simulations. Through an express service, custom-designed tools can be manufactured as one-offs or in small batches using digital design within just about 48 hours. 

Fully Parametrized 

Schumacher Precision Tools GmbH, together with its sister company GAP Gesellschaft für angewandte Prozesslenkung GmbH, has been intensively engaged at a scientific level on data integration and digital control methods for more than 30 years. At the outset of the research, all areas relevant to production and operations were connected via information technology using a CIM strategy. As early as 20 years ago, the company was exploring deep learning approaches in the area of artificial intelligence (AI) and, in collaboration with RWTH Aachen University, was using neural networks for condition monitoring of CNC machining centers.

As a result of all these R&D activities, Schumacher now uses an in-house, modular engineering approach in product development. The modular system comprises the ToolDesign (TD) and ToolSimulation (TS) modules, which are used to construct cutting tools digitally through variant design and to simulate and test them in operation prior to production using FEM solid-body simulation. Accordingly, Schumacher Engineering works with fully parameterized tool models. Up to 180 parameters from the automated variant design describe each tool in 3D space—right down to the edge fillet.

The fully digitized tool kit developed by Schumacher and GAP provides an excellent foundation for close collaboration with E. ZOLLER GmbH & Co. KG. As Dr.-Ing. Bernd Schniering, owner and managing director of Schumacher and GAP, reports, it is particularly the personal contacts with Mr. Christoph Zoller that enable the development engineers of the participating companies to work together in a spirit of great trust. 

Bernd Schniering and Volker Nötzel consider ZOLLER’s expertise and competence in the highly precise measurement of all relevant tool parameters to be especially high. In particular, they emphasize that the specialists in Pleidelsheim record recommendations from measuring technology. “Within a short time, they optimize their measuring machines and software accordingly,” explains Bernd Schniering.

As emphasized, cutting tool manufacturers have needed tools with specifically rounded cutting edges for many years. At Schumacher in Remscheid, process planners therefore have equipment that corresponds to the manufacturing requirements—such as vibratory finishing machines. 

As a result, they have a certified quality assurance system that documents the cutting edge parameters. They use a »mμFocus« inspection unit from ZOLLER for this purpose. “After extensive comparisons of the currently available measurement methods and measuring machines, we were convinced that the »mμFocus« from ZOLLER corresponds to our requirements for reproducibility,” explains Volker Nötzel. It is compact and robust. This makes it suitable for measurements both during production and as part of final inspection. It operates non-contact using laser light and a measuring microscope. The measuring spot measures just 10 x 10 mm. Even the smallest contours and geometries can be captured with an accuracy of less than 1 μm. In addition, the »mμFocus« inspection unit easily handles complex geometries, such as cutting edges and thread flanks on cutting segments of highly twisted tap drills. 

Thanks to its large vertical working or adjustment range (Z-axis), the »mμFocus« allows for flexible and repeatable measurement of both very small and large tools. “This makes »the« »mμFocus« particularly well-suited for end-to-end quality assurance of threading tools. Thanks to the very short setup and adjustment times, our measuring technology technicians can, for example, fully measure all tools when manufacturing special tools in small batches. Roundings with design-specified dimensional ranges between 2 and 5 μm can be entered with reliable and repeatable measurement results. This allows us to ensure that the manufactured threading tools correspond exactly to the specifications,” reports Volker Nötzel. He is convinced that the optical measuring technology of the »mμFocus« inspection units has become indispensable for further optimizing threading tools.