Papers by Keyword: Coated Tool

Abstract: Mar-M247 is widely used in industry for its excellent mechanical properties at high temperatures, but it has the shortcoming of difficulty manufactured. In order to obtain the cutting characteristics of Mar-M247, firstly, an end milling experiment was set up accordingly, where three types of cutting tools coated respectively by TiN, TiCN and TiAlN were employed. Then the parameters of cutting speed and feed rate were defined as the tool cutting variables. Finally, based on different cutting variables, the performance of tool wear, tool life, and workpiece surface roughness were analyzed and discussed. The results indicate when the tool coated by TiAlN, cutting speed of range 1600 ~ 3200 rpm and feed rate of range 0.06 ~ 0.08 mm / tooth are chosen together, the integrated states manufactured of the tool and the workpiece would be best, the method of this research can provide some references for studying others Nickel-based superalloys.

Abstract: Recently, cutting has replaced grinding in the finish processing of hardened steel. However, tool damage is a major problem in high-efficiency operations that use high-speed cutting and high feed rate conditions instead of the present cutting conditions. Therefore, the examination of a new cutting technique that can realize high-efficiency cutting is desired. In this study, the effects and efficiency of driven rotary cutting are investigated in the finish turning of carburized hardened steel. Based on the results, flaking occurs at the cutting edge at a short cutting length of 0.2 km using single-point turning. On the other hand, even if the cutting length amounts to 1.5 km, the tool wear width without flaking is small in the case of a driven rotary tool. Additionally, the tool wear is uniformly distributed along the circumference of the cutting edge. Furthermore, based on an examination of high-efficiency processing by increasing the feed rate, it is clarified that a feed rate of 0.3 mm/rev is the optimum condition from the viewpoint of wear resistance and surface roughness. Additionally, even if the cutting length amounts to 5.0 km for this condition, the flank wear width is as small as 0.04 mm, and the tool wear progresses gradually.

Abstract: The wear resistance of coated tool can be predicted widely by experiments and theoretical analysis. In the paper, an unique method is adopted to analyze influence of high speed on key stresses of the coated tool .First, through the cutting process simulation with different high cutting speeds, contact stress, shear stress and temperature distribution of the surface of the coated tool can be obtained when the cutting process is steady. Then the stresses and temperature are applied to the coated tool to analyze the key stresses in the tool. The result shows the potential failure of coated tool can be predicted by Finite element analysis correctly. Crack between coating and substrate may occur at the same position with different cutting speeds.

Abstract: Hardened steel P20 at 50 HRC is milled at high speed by TiN coated and TiAlN coated solid carbide straight end mills, and the cutting forces and tool wear are measured. The result shows that TiAlN coated tool is more suitable for cutting hardened steel at high speed. Then the hardened steel is milled under different cutting parameters. It is indicated that the effect of cutting speed on cutting forces is small, but the effect of cutting speed on machine vibration should be considered. Increase feed per tooth or radial depth of cut will increase the cutting forces.

Abstract: MoS2/Zr composite coatings were deposited onto M2 high speed steel tools by medium-frequency magnetron sputtered coupled with multi-arc ion plated techniques. The thickness, micro-hardness and coating-substrate adhesion strength of the coatings were studied. Surface morphologies of the as-deposited coatings as well as wear surface features after dry machining tests were investigated. The experimental results indicated that deposition of PVD MoS2/Zr composite coatings onto M2 HSS tools shows higher hardness compared to the pure MoS2 coatings, and exhibits significant enhancement in cutting performance. The wear mechanism of the MoS2/Zr coated tools is mainly delamination of the coating owing to the elevated cutting temperature and friction force.

Abstract: Tools coated with TiBON films of varying boron concentrations were made, and the influence of boron concentration on tool wear was investigated. The TiBON coating film acts as a lubricant at high temperature. Tools coated with such films were applied to the machining of difficult-to-cut materials (Ti-6Al-4V and Inconel 718), where　the cutting temperature increases rapidly and heavy adhesion occurs. In the experiment, turning and interrupted cutting were performed. In cutting of Ti-6Al-4V, the tool coated with a film of high boron concentration showed long tool life. In turning of Inconel 718, the tool coated with a film of a boron concentration of 15% showed the longest tool life-about four times longer than that of a tool coated with TiAlN.

Abstract: Conventional coating tools have a high affinity for ductile materials, like aluminum alloy, so cutting chips tend to adhere to cutting edge and work material surface. Therefore, chipping is caused, and surface texture is degraded. In order to solve these problems, recently, DLC (Diamond-Like-Carbon) has been applied to coating material. In this research, it is curried out cutting of Aluminum alloy by the use of DLC coating tool, and examined influence of DLC coating conditions on cutting characteristics. So far we have been concerned with the effect of type of hydrocarbon gas (acethylene:C2H2, methane:CH4) on cutting. As a result, it is revealed that cohesion of chips decreases, and surface roughness of work material improves in the case of acethylene-DLC. On the other hand, internal stress is produced by deference in hardness between tool surface and DLC film, and which is considered cause of film peeling [1]. Therefore, we examined interlayer between DLC film and tool surface in order to relax of internal stress. As a result, it was cleared that Titanium interlayer excels in adhesion.

Abstract: Different materials coated on milling tools (tungsten carbide) such as TiCN, TiAlN, TiN and DLC are integrated in this study for the analysis of cutting performance such as tool wear, surface roughness and noise induced in high-speed machining of mold steels such as NAK80 and SKD61 under different combinations of cutting conditions. The study attempts to find out the advantages and adaptabilities in various coating materials being suitable for which cutting circumferences with specific performance request. High-speed milling experiments of NAK80 and SKD61 mold steels with four materials coating tools were carried out in the laboratory. The tool wear was measured through the toolmaker’s microscope and the roughness of the machined surface was measured by the roughness measuring instruments after each surface layer was removed from the workpiece in the experiment. Besides, the noise-mediator was used to detect cutting noise during each surface layer workpiece removing of high-speed milling process, and the curl chips removed from the workpiece were also collected for the result verifications. Good surface quality and small amount of tool wear can be achieved under the cutting conditions of high-speed revolutions, small feed rate and small depth of cut for four materials coating tools. From the observations of the annealing temperature from the removed chips and the analysis of the cutting noise levels, TiAlN material coating tool has the better tool life and it is suitable for rougher high-speed machining, while DLC material coating tool only has a good surface roughness in shallow cut and hence it is not suitable for high-speed machining of mold steel with excellent cutting performance request.

Abstract: MQL (Minimum Quantity Lubrication) technology was applied to finish-turning of a nickel base superalloy, Inconel 718, with a PVD coated carbide tool with a super lattice coating of TiN/AlN. Cutting lubricant used for MQL was a biodegradable synthesis ester, which was supplied to the cutting point with compressed air from the both sides of flank and rake faces of the tool. At a cutting speed of 1.0 m/s and an air supply pressure of 0.4 MPa, MQL cutting showed longer tool life and better surface finish than both the dry cutting and wet cutting. When increasing the pressure of the air supply from 0.40 MPa to 0.60 MPa, however, the corner wear, the most predominant wear in all the cutting conditions in this study, increased. When the cutting speed was increased to 1.5 m/s, the tool life in MQL decreased drastically. These results suggested that when finishing Inconel 718, the special care must be taken for choosing the pressure of air supply and cutting speed. The obtained results provided a useful understanding of the complicated influence of MQL on the cutting performance of Inconel 718.