Papers by Keyword: Cutting Edge Preparation

Abstract: The paper investigates the effects of cutting edge preparation on cutting force, cutting temperature and tool wear for hard turning. An optimized characterization approach is proposed and five kinds of cemented tools with different edge preparation are adopted in the simulations by DEFROM-2D^TM. The results show that both the forces and cutting temperature on the rake face climb up and then declines with the increasing of factor K (S_γ/S_α). While the temperature on flank face decrease with the increasing of the factor K. When the cutting conditions are identical, flank wear reduces while crater wear exacerbates before easing with the increasing of the factor K. The simulation results will provide valuable suggestions for optimization of cutting edge preparation for hard turning in order to obtain excellent machining quality and longer tool life.

Abstract: In order to increase tool life and workpiece surface quality, cutting processes with geometrically defined cutting edges demand inserts with a targeted prepared edge. For example, chamfers are largely used in many processes to provide edge strengthening without damaging the chip flow. In order to achieve a stable and reliable cutting process, small and uniform chamfers are necessary. In this context, the influence of grinding parameters on the edge quality and on the chamfer width deviations is investigated. It was found that larger abrasive grains increase edge chipping and that elastic deformation during chamfer grinding at insert corner radius is the main responsible for chamfer width deviation.

Abstract: In this paper, a new method for the preparation of cutting edges via grinding is presented. This method enables the manufacturing of the tool macro and micro geometry in one setup without reclamping, allowing improved flexibility, repeatability and accuracy at reduced processing times. This new method is path controlled using a special elastic bond for the grinding wheels. By using elastic bond, a rounded cutting edge instead of undesired chamfers can be achieved, as the bond nestles around the cutting edge and elastically deforms. The elastic bond is specified by the grain concentration and its basic hardness. Besides the specifications of the bond, the process kinematics highly influences the properties of the cutting edge. The kinematics is a combination of the tool path (machining strategy) and the grinding wheel geometry. The presented experiments include the examination of three different kinematics using three different grinding wheel geometries, FEPA 1A1, 1V1 and 4A2. For each kinematics, three different grain concentrations and three degrees of basic bond hardness were tested, resulting in a complete amount of 27 parameter combinations. The outer diameter cutting edges of cemented carbide milling tools (end mills) were prepared in a 5-axis tool grinding machine. The shape and quality of the achieved cutting edge rounding was qualitatively evaluated by means of scanning electron microscopy (SEM).

Abstract: The need for new cutting tool technologies is driven by the constantly increasing performance of machine tools and the rising market competition. Current research results show that an improved combination of the cutting edge macro- and microgeometry, together with an appropriate substrate and coating, leads to a significant enhancement of cutting tool performance. Furthermore, inappropriate cutting edge microgeometries cause, in addition to the higher production costs, a reduction of the tool life. Hence, it is essential to produce tailored cutting edge microgeometries with high precision and process reliability. This paper presents the influence of brushing process parameters on the size and the form of produced cutting edges of indexable inserts. This leads to a better understanding and higher quality of the cutting edge preparation process by means of abrasive brushes. Furthermore, the process reliability of 5-axes brushing is analyzed. An example of a tool life map presents the significantly enhanced tool performance through cutting edge preparation and its sensitivity towards varying the cutting edge microgeometry.

Abstract: The generation procedure of saw tooth chip when PCBN tools orthogonal cutting hard steel GCr15 is emulated by FEM software ABAQUS in this study. The model effectively overcomes serious element distortions and cell singularity in high strain domain caused by large material deformation. The effects of cutting edge preparation on cutting force, cutting temperature and residual stress are analyzed. Results of FEM show that cutting edge preparation has a great impact on cutting procedure. Under the same cutting condition, cutting force, temperature and residual stress of sharp edge, honed edge and chamfered edge increases in turn, and three kinds of cutting edge have the same change rule in residual stress. Chamfered edge has a good temperature distributing, and it is the best edge preparation in hard cutting.

Abstract: After the grinding process, the cutting edges of cemented carbide milling tools tend to chipping. Chipping has a strong influence on the tool performance. For this reason, the cutting edges are further prepared. Additionally, a cutting edge rounding has an impact on the wear behavior and the process stability. For the cutting edge preparation of milling tools, magnetic finishing is a promising process. This paper describes the process of magnetic finishing. The influencing parameters, i.e. the process time and the distance between the cutting tool and the magnetic disks, are investigated. Furthermore, the effect of magnetic finishing on the tool life is demonstrated using the example of a milling process with titanium.

Abstract: Austenitic stainless steels are extensively used in the areas with high corrosion. The high heat resistance and strength make them difficult-to-cut materials. The tool life in machining austenitic stainless steels is restricted by the high cutting force and temperature which induce the tool wear and edge chipped. To achieve tool edge strength and reduce the edge-related problems, tool edge preparation is applied by introducing the chamfered and honed edges. In the current paper, the effects of the cutting edge preparation in face milling of austenitic stainless steels were studied using statistical method. The output cutting parameters as cutting force, temperature were obtained by finite element analysis. The purpose for this research is to give guidance to the tool edge preparation for machining stainless steels.

Abstract: Machining hardened steels has become an important manufacturing process, particularly in the automotive and bearing industries. Hardened steel GCr15 with its harness between HRC50 and HRC65 is one kind of more difficult machining material. Abrasive processes such as grinding have typically been required to machine hardened steels, but advances in machine tools and a new cutting material of polycrystalline cubic boron nitride (PCBN) have allowed hard turning on modern lathes to seems to gain an ever increasing industrial acceptance as an economically and environmentally friendly alternative to many grinding applications. In this paper, based on large deformation theory and updated Lagrangian procedure, a coupled thermo-mechanical plane strain orthogonal precision cutting model with general finite element analysis software is developed to the influence of cutting edge preparation on the cutting of GCr15 with PCBN tool, such as cutting forces, shear angle, and cutting temperature. The three major designs of cutting edge preparation are used on most commercial cutting inserts: a) sharp edge, b) honed edge, and c) chamfer edge. The friction between the tool and the chip is assumed to follow a shear model and the local adaptive remeshing technique is used for the formation of chip. The calculated principle cutting forces are compared with published data and found to be in good agreement. The simulation results can be used as a practical tool both by researchers and toolmakers to design new tools with rational tool edge and to optimize the cutting process.