Modelling and Prediction of Cutting Temperature in the Machining of H13 Hard Steel of Transient Heat Conduction

Cutting heat conduction undergoes three stages that include intensity transient-state, transient-state, and steady-states. Especially during machining with coated cutting tools, in the conduction process, cutting heat needs to pass through a few micron thick coatings and then flow into the tool body. This heat conduction presents typical non-Fourier heat conduction characteristics. This paper focuses on the cutting temperature in transient heat conduction with a coated tool. A new analytical model to characterize the thermal shock based on the non-Fourier heat conduction was proposed. The distribution of cutting temperature in mono-layer coated tools during the machining was then illustrated. The cutting temperature distribution predicted by the Fourier heat conduction model was employed to compare with that by non-Fourier heat conduction in order to reveal the non-Fourier heat conduction effect in transient heat conduction. The results show that the transient heat conduction analytical model is more suitable for the intensity transient-state and transient-state in the process of cutting heat conduction.

Experimental Study on Coupling Characteristics of Cutting Heat and Cutting Vibration Under Different Tool Wear States

The thermo-mechanical-vibration coupling characteristics of turning system has always been an important research topic in the field of machining, and the material, states and performance of cutting tools will directly affect this coupling characteristics. In this paper, a synchronous testing system for cutting temperature and cutting vibration is built to collect the cutting temperature and cutting vibration near the tip of three worn tools D1 (new blade), D2 (moderately worn blade) and D3 (severely worn blade). Based on the test data and the grey correlation theory, the coupling characteristics of cutting temperature rise and cutting vibration of tools in different wear states are analyzed. Based on the experimental data and least square method, (1) the regression model of cutting temperature rise about cutting vibration and cutting parameters (2) the regression model of cutting vibration about cutting temperature rise and cutting parameters have been established respectively. The undetermined parameters and correlation coefficients are obtained by MATLAB software programming. The research show that the coupling of cutting heat and cutting vibration of tools D1 and D2 is one-way coupling, that is, cutting vibration significantly affects cutting heat, but cutting heat has little effect on cutting vibration, while the coupling of cutting heat and cutting vibration of tool D3 is a bidirectional coupling.

Research on the Performance of Diamond-Like Carbon Coatings on Cutting Aluminum Alloy: Cutting Experiments and First-Principles Calculations

The purpose of this study is to investigate the cutting performance of amorphous carbon (a-C) coatings and hydrogenated amorphous carbon (a-C:H) coatings on machining 2A50 aluminum alloy. First-principles molecular dynamics simulation was applied to investigate the effect of hydrogen on the interaction between coatings and workpiece. The cross-section topography and internal structure of a-C and a-C:H films were characterized by field emission scanning electron microscopy and Raman spectroscopy. The surface roughness of the deposited films and processed workpiece were measured using a white light interferometer. The results show that the a-C-coated tool had the highest service life of 121 m and the best workpiece surface quality (Sq parameter of 0.23 μm) while the workpiece surface roughness Sq parameter was 0.35 and 0.52 μm when machined by the a-C:H-coated and the uncoated tool, respectively. Meanwhile, the build-up edge was observed on the a-C:H-coated tool and a layer of aluminum alloy was observed to have adhered to the surface of the uncoated tool at its stable stage. An interface model that examined the interactions between H-terminated diamond (111)/Al(111) surfaces revealed that H atoms would move laterally with the action of cutting heat (549 K) and increase the interaction between a-C:H and Al surfaces; therefore, Al was prone to adhere to the a-C:H-coated tool surface. The a-C coating shows better performance on cutting aluminum alloy than the a-C:H coating.

Research review on cutting temperature and cutting vibration of titanium alloy

The text should be set to 1 line spacing. The abstract should be centred across the page, indented 17 mm from the left and right page margins and justified. It should not normally exceed 200 words The titanium alloy called “strategic metal” is a typical refractory material that causes high temperature and vibration during cutting due to its high strength, low thermal conductivity and low elastic modulus. In the processing process, the tool wear is serious, and the accompanying cutting heat and cutting vibration are coupled to each other and change with time. Studying the temperature and vibration characteristics in the processing process is conducive to further understanding of cutting mechanism, better controlling temperature and vibration, improving cutting processing quality and reducing production cost. This paper reviews the current situation of cutting temperature and cutting vibration at home and abroad. Scholars focus on the influence of cutting factors on temperature and vibration, based on finite element simulation and mathematical modeling, and the research on temperature and vibration coupling of titanium alloy cutting should be further strengthened.

Effects of Cold Air Supply on Cutting Characteristics in Small Hole Drilling of PEEK

A polyetheretherketone (PEEK) is one of the thermoplastic resins. The material is superior in mechanical strength, heat resistance and chemical resistance. Therefore, it is suitable for industrial components such as automotive parts, machine parts, electrical and electronics parts. Particularly, it is used for an inspection socket of a connector and the semiconductor package in the field of electronic components. Consequently, a demand of the high efficiency machining in small drilling for the PEEK increases with a miniaturization and diversification of the industrial equipment. However, PEEK, which is a thermoplastic resin, has a problem that the hole accuracy is lowered due to the cutting heat. The objective of this study is to achieve high precision and high efficiency machining process for industrial components of the PEEK such as an inspection socket of a connector or the semiconductor package. In order to solve these problems, this study carries out cooling workpiece by cold air supply. This paper describes the investigation result of the effect of cold air cooling on hole accuracy and cutting state in the small hole machining of PEEK. As a result, it was found that cooling the workpiece is effective to suppressing the cutting heat and improve hole accuracy. Within the experimental conditions, the combination of non-step drilling and cooling enables high-precision drilling with approximately the same accuracy as step drilling.

Chip Breaking During Automated Processing by Cutting Hard-to-Work Steels by Integrated Use of Chip Breaking Tools and High-Temperature Embrittlement

Purpose of research is to increase productivity when cutting hard-to-work steels by integrated use of chip breaking tool geometry and cutting modes, which reduce the viscous properties of the chips and the processed material. The article discusses the problems of mechanical processing of parts of oil production equipment at enterprises in Western Siberia. It is presented the main condition for ensuring chip crushing and revealed the problem of low efficiency of existing methods in modern industry, to one degree or another guiding, curling and chip-cutting method.Methods. Simulation modeling, calculation of chip direction and crushing were performed; effective methods for solving the problem of chip crushing during the machining of parts made of materials with corrosion-resistant, heat-resistant properties were identified; laboratory, persistent tests of the complex method were carried out.Results of studying the mechanism of chip formation during processing by cutting heat-resistant and corrosionresistant alloys are given here. To solve the problem, we have formulated two tasks that were solved using information taken from the theory of material resistance, tensile diagrams when testing samples of corrosionresistant, heat-resistant materials with high operational properties. A chip breaking exchangeable insert with a variable rake angle is designed and presented. The results and analysis of laboratory test data, in which a plate with chip breaking geometry of the front surface is used, are presented, the operating conditions of effective chip breaking are shown. The conclusions on the solution of the first problem are formulated, it is shown that the determining factor in chip breaking is the physical and mechanical characteristics of the processed material, which vary with different cutting conditions.Conclusion. The work shows that chip removal from the cutting zone prevents it from entering the cutting edge area, reducing impact loads on it and improving the quality of machining. It is possible to form stress concentrators in the chips, leading to chip self-destruction even when processing viscous heat-resistant alloys. The hypothesis is used that the temperature conditions for the maximum workability of heat-resistant and corrosion-resistant steels and alloys correspond to the conditions of high-temperature embrittlement, with the help of which it is possible to create conditions for effective chip crushing and conditions for maximum workability when cutting heat-resistant steels and alloys.

Study on Milling Temperature of Titanium Alloy with Micro-Textured Ball End Milling Cutter under Radius of Blunt Edge

A high temperature is produced in the process of precision milling of titanium alloy, and the cutting temperature can be effectively reduced by placing a micro-texture on the tool surface. In order to study the milling temperature of micro-textured ball-end milling cutter in milling titanium alloy under the combined action of a blunt radius with different edges and a micro-texture with different parameters, a new method based on micro-element theory and the generation and transmission of cutting heat has been established. At the same time, the influence of different radii of blunt edges on the milling temperature is simulated by the finite element method and experimentally verified to explore the influence of different radii of a blunt edge and micro-texture parameters on the milling temperature. Taking the milling temperature as the evaluation index, the optimum parameters of micro-circular pit texture are as follows: the diameter of micro-circular pit is 40 micron, pit spacing is 225 micron, distance from cutting edge is 100 microns, and radius of the blunt edge is 60 microns.

Performance of stone-plastic composites with different mix ratios during orthogonal cutting

The present study aimed to increase understanding of the machinability of stone-plastic materials with different mix ratios subjected to diamond planing. To that end, orthogonal cutting was carried out. Different stone-plastic materials were machined by diamond cutting tools to produce chips. Based on the results, four conclusions are drawn: (1) Among stone-plastic materials with decreasing polyvinyl chloride content ratio, the maximum cutting forces and fluctuation of dynamic forces show decreasing trends, and cutting stability increases. (2) The temperature of chips is slightly higher than that of tool edges; the cutting heat generated during machining is mainly absorbed by the chips of removed material and, to a lesser extent, stored in the tool edge. The type of stone-plastic material has a great effect on the changes in the temperatures of chip and tool edge. (3) With a decrease in polyvinyl chloride content, the chip shapes evolve from crack, to arc, and eventually to elemental chips. (4) The cutting quality of the machined surface improves with a decrease in the polyvinyl chloride content ratio of the stone-plastic materials.

Experimental Study on a “Snake-Type” Vibration Cutting Method for Cutting Force and Cutting Heat Reductions

Cutting is the foundation of manufacturing in industry. The main cutting objects include metals, ceramics, glasses, compositions, and even biological materials such as tissues and bones. The special properties of each material such as hardness, ductility, brittleness, and heat conductivity lead to either a large cutting force or a high cutting temperature. Both of these factors result in poor machinability due to rapid tool wear or break or unsatisfactory surface integrity of the material finishing surface using the conventional cutting (CC, conventional cutting) types. In nature, snakes have their own way of reducing heat accumulation on their body when moving on the hot desert surface. They move forward along an “S”-type path, so that the bottom of their body separates from the desert intermittently. In this way, the separation interval both reduces the cutting heat accumulations and effectively achieves cooling by allowing the air to go through. In addition, the acceleration of Odontomachus monticola’s two mandibles when striking a target can reach 71,730 g m/s2 within 180 ms, which can easily break the target surface by the transient huge impact. Therefore, based on a snake’s motion on the desert surface and Odontomachus monticola’s striking on the target surface, respectively, an ultrasonic-frequency intermittent cutting method, also called “snake-type” vibration cutting (SVC, snake-type vibration cutting), was proposed in this study. First, its bionic kinematics were analyzed, then the SVC system’s design was introduced. Finally, cutting experiments were conducted on a common and typical difficult-to-cut material, namely titanium alloys. Cutting force, cutting temperature, and the surface integrity of the material finishing surface were measured, respectively. The results demonstrated that, compared to conventional cutting methods, SVC achieved a maximum of 50% and 30% reductions of cutting force and cutting temperature, respectively. Moreover, the surface integrity was improved both in surface roughness and residual stress state.