The researchers from the Department of Mechanical Engineering, Faculty of Mechanical Engineering, the Brno University of Technology came up with an original way of solving the age-old problem of cutting tool manufacturers. Their technology will help with the so-called deburring of the cutting edges, i.e. the finishing treatment of the cutting edges in the production of tools intended for machining various materials. The result of their work is an effective way to replace the original lengthy and problematic deburring process with new technology.
"Sharpening from the cutting edge has been bothering toolmakers since time immemorial. On the one hand, they impair the cutting geometry of the cutting edges, which are excessively rounded by their curvature, so that the tool is not as sharp as it could be. On the other hand, it prevents effective coating of the cutting edges with hard and abrasion-resistant coatings; even worse, the coated particle then easily breaks off, which can cause further damage to the tool, which in layman's terms breaks a tooth,” Miroslav Píška from the Institute of Manufacturing Technology, FME BUT, who worked with his team on the invention, explained.
The Czech company GSP High Tech Saws, which manufactures saw blades, knives and circular saws, came up with the initiative. Until now, the deburring of the cutting edges was carried out using automatic brushes, which were to remove the sharpening. It was not easy: the operation is laborious, the brushes have to be changed regularly and sometimes the new sharpening is devalued by this processing. "The new cutting edge then becomes inoperable and the process often leads to a tool crash. The tool will be destroyed practically by itself,“ Miroslav Píška pointed out. "Having a guaranteed and efficient finishing operation is a condition for the stability of production and maintaining the high quality of production," Vít Gilík, the CEO of GSP High Tech Saws, added.
The researchers decided to solve the age-old problem of cutting tool manufacturers effectively. They designed the technology of reverse trailing abrading, where the tools are clamped on a special holder and then are being abraded in an abrasive, i.e. a kind of rough mixture, which removes unwanted sharp edges and at the same time smooths them evenly. As part of the development of the technology, the researchers proposed an optimal procedure for how quickly and in what way it is necessary to grind tools in an abrasive mixture. That the technology really works is proven by both measurements and detailed images of the tested cutting edges, which are even sharper and smoother for the layman. "It is not an easy task, in addition to the chosen abrasive effect, the grinding phases of the cutting edges must be correctly calculated so that all cutting edges are ground in a similar way and to the same extent," the co-author Katrin Bučková from the Institute of Manufacturing Technology, FME BUT, explained.
"Our approach has several advantages. First, you can machine a large number of tools at once. Also, all teeth are processed at the same time, i.e. up to several hundred teeth, in just a few minutes. The result is a deburring cutting tool that has an almost ideally rounded cutting edge with a smooth surface. And above all, cutting tools deburred with this technology have better cutting properties and last longer,” Píška evaluated.
Astra Motor, s.r.o. Brno also cooperated with BUT in the development of the invention. "This technology is advantageous for circular saws and similar rotary tools with a large number of teeth, but it can also be applied to other tools, which is a competitive advantage," the CEO of Astra Motor, s.r.o. Brno Jan Keprda, who has been professionally engaged in the production of cutting tools for a long time, concluded.
The research team has already registered its invention for patenting.
References: PÍŠKA, M.; BUČKOVÁ, K; GILIK, V; KEPRDA, J.: Powerful technology of deburring circular saws and cutters by reverse abrading. PV 2019-774.