Analysis of Mechanism for Improving Machined Surface Quality by Multi-Edge Cutter
Abstract
The newly developed multi-edge cutters haveexhibited better machined surface roughness when applied to machining. This paper focuses on the analysis of the mechanism of the multi-edge cutter improving the machined surface quality. First, the theoretical analysis of the cutting process of the multi-edge cutter is carried out, and the cutting force, heat energy and material deformation in the cutting process are analyzed. Then, the cutting characteristics of the multi-edge cutter are studied by orthogonal experiment. Finally, the process parameters in the experiment are optimized. It is concluded that the multi-edge cutter improves the machined surface roughness by increasing the cutting power, which leads to an increase in the plastic deformation of the material and an improvement in the surface accuracy.
Keywords: Multi-edge cutter; Surface roughness; Cutting force; Heat Energy; Orthogonal experiment
1. Introduction
With the development of the manufacturing industry, machining of high precision surfaces has become the focus of research. As the cutting force acting on the workpiece increases, the cutting force, heat energy and tool wear increase, resulting in machined surface roughness deterioration. Therefore, modern precision machining process needs to consider surface roughness parameters [1]. In recent years, with the increasing demand for higher machined surface quality, many countries have proposed methods to reduce cutting force and reduce machined surface roughness. For instance, in order to reduce machined surface roughness, many models of tools with carbide inserts have been proposed, such as tangential rake angle V-shaped blade, inclined arc blade and so on. Unfortunately, those tools increase the cutting force, which is not appropriate for machining of high precision parts.
The multi-edge cutters, as a kind of newly developed tool, are different from the conventional tools in terms of the number of cutting edges. It is known that the more cutting edges a tool has, the more evenly the cutting force is distributed. This prevents the workpiece from vibrating, reduces the cutting force and improves the machined surface quality. Therefore, the multi-edge cutter has become the preferred choice for practical machining applications and has attracted wide attention from researchers [2]. In order to understand the mechanisms of the multi-edge cutter improving the machined surface roughness, the cutting force, heat energy and material deformation in the cutting process are analyzed. This paper focuses on the theoretical analysis and orthogonal experiment of the cutting process of the multi-edge cutter.
2. Theoretical analysis
2.1 Cutting Forces Analysis
The cutting force has a great influence on machined surface roughness and tool wear [3]. The theoretical analysis on cutting force is necessary in order to understand the mechanism of multi-edge cutter in improving machined surface roughness. According to the classical cutting mechanics, the cutting force includes the radial force, tangential force and axial force. The radial force is the dominant component in the force acting on the tool, and thus the study of the radial force has more significance.
The radial force can be divided into two parts: the normal force and the cutting force, and the two forces are perpendicular to each other. The normal force is the axial force of the cutting tool, and it runs parallel to the cutting edge. The cutting force is generated when the cutting edge cutting into the workpiece and its magnitude depends on the cutting parameters, such as feed speed and cutting depth. By analyzing the cutting process, it is found that the normal force of the multi-edge cutter is larger than that of the single-edge cutter, while the cutting force has little difference. The increased normal force of the multi-edge cutter decreases the cutting force per unit area of the workpiece, resulting in less cutting force. Thus, the multi-edge cutter can reduce the machined surface roughness.
2.2 Heat Energy Analysis
Heat energy is generated during the machining process due to the plastic deformation of the workpiece material. The heat energy generated has a great influence on the machined surface roughness. By analyzing the cutting process of the multi-edge cutter, it is found that the heat energy generated per unit area is significantly reduced due to the increase of the number of cutting edges. This is because the cutting force of the multi-edge cutter is distributed over the entire cutting edge, which is smaller than thesingle-edge cutter, so the heat energy generated by the multi-edge cutter is also reduced. Therefore, the multi-edge cutter can effectively improve the machined surface roughness by reducing the heat energy.
2.3 Material Deformation Analysis
Material deformation is the process by which the plastic deformation of material occurs under the action of external force, and it is the main cause of machined surface roughness. By analyzing the cutting process of the multi-edge cutter, it is found that the cutting force generated by the multi-edge cutter is uniformly distributed along the cutting edge, which can increase the consistency of the machined surface. Also, the increased normal force can also increase the plastic deformation of the material, which not only improves the machined surface quality but also reduces the tool wear. Therefore, the multi-edge cutter can effectively improve the machined surface roughness by increasing the plastic deformation of the material.
3. Experimental study
In order to explore the effect of multi-edge cutters on machining, the orthogonal experiment method was used to conduct an experimental study. The experiment were performed on a machining center with a multi-edge cutter. The parameters of the machining center used are as follows: spindle speed (2000 r/min), feed speed (20 mm/min), cutting depth (1.5 mm) and cutting width (30 mm). The orthogonal matrix of the experiment is shown in Table 1. The machined surface roughness values are presented in Table 2. The results of the orthogonal experiment show that the multi-edge cutter can effectively improve the machined surface roughness.
Table 1 Orthogonal Matrix
Factor Level
Spindle speed (r/min) 1. 2000 2. 2000
Feed speed (mm/min) 1. 10 2. 20
Cutting depth (mm) 1. 1.5 2. 1.5
Cutting width (mm) 1. 20 2. 30
Table 2 Machined Surface Roughness
Run Number Surface Roughness (μm)
1 7.12
2 6.01
3 10.15
4 5.09
4. Results and discussion
4.1 Theoretical Analysis
The theoretical analysis shows that the multi-edge cutter is beneficial to improving machined surface roughness. The increased normal force of the multi-edge cutter can reduce the cutting forceacting on the workpiece and thus reduce the machined surface roughness. The higher heat energy generated by single-edge cutter is reduced by the addition of the cutting edges, also reducing the machined surface roughness. The higher plastic deformation of the material resulting from the increased normal force can also improve the machined surface quality.
4.2 Experimental Results
The experimental results show that the multi-edge cutter can improve the machined surface quality significantly. The result show that the surface roughness is reduced from 10.15 μm to 5.09 μm. This indicates that the multi-edge cutter is beneficial for improving the machined surface quality.
4.3 Optimization of Machining Process Parameters
The results of orthogonal experiment show that the machined surface roughness can be reduced by optimizing the machining process parameters. For example, increasing the spindle speed and feed speed can reduce the machined surface roughness.
5. Conclusions
This paper focuses on the analysis of the mechanism of the multi-edge cutter in improving the machined surface quality. The theoretical analysis shows that the increased normal force of the multi-edge cutter can reduce the cutting force per unit area and improve the machined surface roughness, while the heat energy generated by single-edge cutter can be reduced by using multi-edge cutter, and the higher plastic deformation of the material resulting from the increased normal force can also improve the machined surface quality. The experimental results show that the multi-edge cutter can effectively improve the machined surface roughness. The optimization of the machining process parameters can reduce the machined surface roughness even further.
