Bio: W. König is an academic researcher. The author has contributed to research in topics: Shearing (manufacturing) & Drilling. The author has an hindex of 1, co-authored 1 publications receiving 50 citations.
01 Jan 1968
TL;DR: In this article, it has been shown that different reactions take part in the tool wear when steel is machined with carbide cutting tools within the whole range of cutting speed. But the effect of different types of wear can be distinguished in the wear curves with increasing load.
Abstract: SUMMARY Basic research on the wear behaviour of tools has shown that different reactions take part in the tool wear when steel is machined with carbide cutting tools. Changes in the mechanism of wear can clearly be distinguished in the “wear–cutting speed” curves with increasing load. Dependent on the chosen cutting conditions, as for example, cutting speed, feed or the combination of work- and tool-material, considerably different kinds of wear will occur, which determine finally the tool-life of carbide cutting tools within the whole range of cutting speed. At low and medium cutting speeds increased wear of the clearance face is caused by frequent shearing of welded material between work- and tool-material by the formation of built-up edges. In these cases tool-life depends on the wear at the clearance face. When steel is machined under extreme cutting conditions, plastic deformation may occur resulting in a rapid breakdown of the cutting-tool. Within the range of high cutting speeds, diffusion reactions between chip and tool material effect an increased crater wear, which determines frequently tool-life of carbide cutting tools. Additionally an oxidation of the carbide tools at high cutting temperatures results in an outbreak of the side cutting edge. Recent investigations on the influence of non-metallic inclusion on machinability have shown that during machining special killed carbon steel the formation of sulfide and oxide layers can be observed in the contact zones of cutting tools. These layers prevent crater wear and decrease flank wear considerably in a wide range of cutting speed and improve substantially the machinability of ordinary plain carbon steel.
TL;DR: In this paper, an analytical method is presented which enables the crater and flank wear of tungsten carbide tools to be predicted for a wide variety of tool shapes and cutting conditions in practical turning operations based on orthogonal cutting data from machining and two wear characteristic constants.
TL;DR: A review of the various techniques and methods of monitoring tool wear particularly in turning operations can be found in this paper, where the authors present a single-minded approach which is capable of detecting and diagnosing tool wear and failure relating to particular classes of faults.
Abstract: Although a wide variety of tool failure sensing techniques have been developed over the years, few of them have been used in industries successfully. This paper provides a review of the numerous techniques and methods of monitoring tool wear particularly in turning operations. By and large, these techniques appear to be “single-minded” in that they are capable of detecting and diagnosing tool wear and failure relating to particular classes of faults. A universal approach which can detect the very many failure modes in tool condition monitoring has still not been devised.
TL;DR: In this paper, the wear mechanisms of cutting tools made of tungsten-carbide (WC), PCBN and PCD were investigated using the tool life and temperature results available in the literature.
Abstract: The wear mechanisms of cutting tools made of tungsten-carbide (WC), PCBN and PCD were investigated using the tool life and temperature results available in the literature. For tool/work combinations WC/steel and PCBN/hardened-steel, under practical conditions, tool wear was found to be greatly influenced by the temperature. It was concluded that the most likely dominant tool wear mechanism for WC is diffusion and that for PCBN is chemical wear. For PCD, more experimental results and hence further research is required to determine the dominant wear mechanism.
TL;DR: In this paper, the authors present a survey of tool wear in hard turning of superhard materials such as polycrystalline cubic boron nitride (known as CBN).
Abstract: Direct machining steel parts at a hardened state, known as hard turning, offers a number of potential benefits over traditional grinding in some applications. In addition, hard turning has several unique process characteristics, e.g., segmented chip formation and microstructural alterations at the machined surfaces, fundamentally different from conventional turning. Hard turning is, therefore, of a great interest to both the manufacturing industry and research community. Development of superhard materials such as polycrystalline cubic boron nitride (known as CBN) has been a key to enabling hard turning technology. A significant pool of CBN tool wear studies has been surveyed, in an attempt to achieve better processing and tooling applications, and discussed from the tool wear pattern and mechanism perspectives. Although various tool wear mechanisms, or a combination of several, coexist and dominate in CBN turning of hardened steels, it has been suggested that abrasion, adhesion (possibly complicated by tribochemical interactions), and diffusion may primarily govern the CBN tool wear in hard turning. Further, wear rate modeling including one approach developed in a recent study, on both crater and flank wear, is discussed as well. In conclusion, a summary of the CBN tool wear survey and the future work are outlined.
TL;DR: In this article, the authors present a methodology to analyze the CBN tool flank wear rate as a function of tool/workpiece material properties, cutting parameters and process arrangement in three-dimensional finish hard turning.
Abstract: Cubic Boron Nitride (CBN) cutters are widely used in finish turning of hardened parts. Their wear mechanisms and associated wear rates are important issues to be understood in view of the high cost of CBN cutters and because of the tool change down-time cost which impacts the economic justification of CBN precision hard turning. The objective of this study is to present a methodology to analytically model the CBN tool flank wear rate as a function of tool/workpiece material properties, cutting parameters and process arrangement in three-dimensional finish hard turning. The proposed model is calibrated with experimental data of finish turning of hardened 52100 bearing steel with a CBN insert, and further validated over practical hard turning conditions. It is shown that adhesion is the main wear mechanism over common cutting conditions, which agrees with documented observations, however, chemical diffusion can gain dominance over extended periods of machining time under aggressive cutting conditions.