Papers by Keyword: Chip Shape

Abstract: Material cutting properties can be judged by turning temperature and chip shape. A new method that can measure turning temperature more accurately was discussed in this paper. Compared with the traditional method, results show that turning temperature can be accurately measured through a new method in turning process. Turning temperature become stable and will not jump after 20s later. In addition, the higher the hardness, the higher the energy is needed, leading to the higher turning temperature. The average turning temperature of the quenched specimen, normalized specimen and annealed specimen measured through the new method is 100°C,70°Cand 60°C, respectively. And the chip morphologies of quenched specimen, normalized specimen and annealed specimen are irregular band chips, spiral debris chips and C-shaped chips, respectively.

Abstract: This paper analyzed the large diameter Fresnel lens mold machining mechanism based on modal test methods .The design and mold machining principle of Fresnel lens were introduced . Explored the cutting speed and feed on chip formation process. The results show that: the material strength and plastic brittle have significant impact on chip morphology in the H62 brass mold processing, an improvement of material strength with the increase of strain rate and the evolution process of the chip can be divided into: ribbon cuttings, serrated chips, cell chips.

Abstract: The paper presents the results of research on the effect produced by modern cooling methods on the chip shapes and surface roughness when finish turning of ASTM A53 and AISI 1010 low carbon steels. Dry cutting, cooling by compressed air and the Minimum–Quantity–Cooling–Lubrication (MQCL) method were compared. The MQCL method is more effective for machining low carbon steel and ensures a usable chip shape and lesser surface roughness. Depending on the cutting conditions, the efficiency of the MQCL method is 10 to 30 % higher compared to dry machining. Examples of experimental investigations about reducing the use of cooling lubricant substances in turning process can be found in the open literature [1, 2].

Abstract: This paper describes the analysis of the chip formation mechanism in mold machining process of large diameter Fresnel lens based on the ABAQUS finite element simulation software and modal test methods. Combined with the material constitutive relation and material failure criteria etc, a two-dimensional orthogonal cutting model was established and the chip derived from the simulation was compared with the chip from modal test, with a consequent verification of the feasibility of simulation chip model. The simulation contributes to an investigation into the effects of the cutting speed on chip formation process. The results show that: the material strength and plastic brittle have significant impact on chip morphology in the H62 brass mold processing, and material strength will improve with the increase of strain rate, the evolution process of the chip of material plastic reduction can be divided into: ribbon cuttings, serrated chips, cell chips.

Abstract: Abstract. An orthogonal cutting is a symmetric cutting thus it can be modified as a two dimensional cutting. This paper uses quasi-steady molecular statics method to carry out simulation of two dimensional nanoscale cutting copper work piece by the diamond tools. For the two dimensional quasi-steady molecular statics nanoscale cutting model used by this paper, when the cutting tool moves on a copper work piece, displacement of atoms is caused due to the effects of potential on each other. After a small distance that each atom moves is directly solved by the calculated trajectory of each atom, the concept of force balance is used. The minimum energy method is employed to carry out the search, and obtain the new movement position for each atom. Based on the simulation results, this paper studies the chip formation shape and cutting forces in x direction and y direction.

Abstract: The three-dimensional explicit dynamic analysis of metal cutting process is done using the non- linear finite element software LS-DYNA. In the finite element model, 8- node 3D solid element based on one- point integration Lagrangian formulation is adopted, metal material is modeled with Johnson-Cook constitutive model, chip separation is simulated using the material failure criterion of Johnson and Cook proposed and combing the failure element deletion method, friction model of chip-tool contact interface is developed to simultaneously account for sticking and sliding situation. Through explicit analysis, rake angle, cutting depth, and cutting width on the shape of the chip influence are obtained.

Abstract: To select reasonable cutting parameters, improve the processing surface quality, and extend the tool life, this paper uses four solid carbide end milling tools to process TC4 titanium alloy, and analyses the influence of the difference cutting parameters and the geometric angles to chip shape. The experiment results indicate that the degree of serrated chip shape is increased by increasing the feed rate under the condition of certain spindle speed. But the degree of serrated chip shape may be decreased by the adoption of small axial and radial depth, or bigger rake angle and smaller helix angle. Select larger rake angle, cutting edge is sharp, the metal deformation of cutting layer is small, which can reduce the friction force when chip flowing through the tool rake face, so that the cutting force and cutting temperature decreases accordingly.The greater the helix angle is, the worse the chip removal conditions is, and the degree of serrated chip becomes larger, the blade is more sharp, easily crack, and the tool life decreases. So relatively small helix angle is better. The choice of angles is interrelated with each other, the selection of some angle separately cannot get the desired reasonable value.

Abstract: Cutting processes in machining involves the elastic and plastic formation where a layer of material is removed by a cutting tool to be removed from the workpiece in forms of various types of small chips. In this paper, a series of finite element simulations of 2D chip formation with various parameters are presented. Different types of chip shapes, such as continuous, discontinuous and serrated shape, are simulated under different conditions. A damage evolution technique based on fracture energy dissipation during material damage progression is used to demonstrate the influences on chip formation. It is concluded that the fracture energy in damage evolution is a crucial factor for the determination of chip shape. Further the influence of depth of cut and rake angle are considered in the simulations.

Abstract: The cutting tests were carried out on HT200, HT250 and HT300 cast iron. The effects of the strength, hardness, microstructure, chemical composition of cast iron on chip shape were studied. The results show the relationship of different strength, chip thickness and chip deformation of gray cast iron, in the similar cutting conditions.

Abstract: The present work aims at simulating three-dimensional milling operation of aluminum allo7451.Building a nose ring radius and edge radius tool model. Using finite element analysis software , conducted a three-dimensional simulation of milling process. Milling force, milling temperature, stress distribution and chip shape of milling process have been got. A milling force experiment was carried out under the same cutting conditions as the simulation, and a good agreement between the simulation result and the experimental result was achieved, and chip shape matched the practice well. The simulation shows that the three-dimensional finite element milling cutter model and the workpiece model can be used to correctly simulate precision milling process, optimizing the cutting parameters by analyzing variation of the cutting force, the temperature and equivalent stress.