Design method for variable-geometric parameter antifriction turning tool, and configuration

Abstract

The present invention belongs to the antifriction technical field of turning tools. Disclosed are a design method for a variable-geometric parameter antifriction turning tool, and a configuration. The method comprises: first analyzing the wear form and causes of a flank face of a turning tool during a turning process of a material which is difficult to machine; second, from among adjustable geometric parameters of the tool, preferentially selecting the rake angle, the clearance angle and the rounded edge radius of the turning tool as parameters to be designed; then, on the basis of software simulation, acquiring the rule of the parameters to be designed affecting the width of a flank wear land of the turning tool; and finally, adjusting the rake angle, the clearance angle and the rounded edge radius of the tool, so as to uniformly vary the parameters along the rounded edge of the tool and keep same constant at the straight edge of the tool, thereby finishing the design of the variable-geometric parameter turning tool. The present invention uses software simulation to evaluate the antifriction performance of tools of different configurations, thereby saving time and cost. In addition, the wear of the flank face at the tool nose of the designed variable-geometric parameter turning tool can be effectively reduced and further deterioration of the wear of a tool recess can be restrained, thereby satisfying differentiated antifriction requirements of different cutting positions of the turning tool.

Description

A design method and configuration of a variable geometry parameter wear-reducing turning tool Technical Field

[0001] The invention belongs to the technical field of turning tool wear reduction, and in particular relates to a design method and configuration of a turning tool with variable geometric parameters and wear reduction. Background Art

[0002] With the continuous improvement of equipment performance requirements in the fields of aerospace, defense and military, etc., lightweight, thin-walled and integrated components have been widely used, such as aviation structural parts, engine casings and integral blades. These high-performance components have small wall thickness but large outline dimensions, and the material removal rate is extremely high during machining, which makes tool wear a prominent problem. In addition, these components are mostly made of difficult-to-machine materials such as high-temperature alloys, high-strength steels, and titanium alloys. The friction between the tool-chip and tool-workpiece contact areas during cutting is severe, which further shortens the service life of the cutting tool and greatly restricts the forming accuracy, surface quality and processing efficiency of high-performance components.

[0003] Reasonable tool configuration design helps to weaken the tool's force and heat response, reduce friction in the cutting area, and thus increase the tool's service life. Invention patent CN105631072A discloses a method for designing a flat-bottomed milling cutter for rough machining of aluminum alloys. By optimizing the milling cutter's rake angle, back angle, helix angle, and blunt radius, the cutting force, cutting heat, and elastic strain during the cutting process are reduced. Invention patent CN103862073A discloses a turning method and a turning tool. By optimizing the turning tool's rake angle, back angle, main deflection angle, secondary deflection angle, and blade inclination angle, the tool's sharpness is increased, avoiding the phenomenon of chips sticking to the tool during target cutting. The paper “Patel K , Liu G , Shah SR , et al. Effect of Micro-Textured Tool Parameters on Forces, Stresses, Wear Rate and Variable Friction in Titanium Alloy Machining[J]. Journal of Manufacturing Science and Engineering, 2019, 142(2):1-31” designed a micro-textured turning tool for titanium alloy machining. By optimizing the geometric structure of the micro-texture, the cutting performance of the tool is improved, thereby reducing the wear rate of the turning tool. Invention patent CN101596607A discloses a TiZrN-coated tool and a preparation method thereof, wherein the tool surface is a TiZrN layer, and there are Ti and Zr / Ti transition layers between the TiZrN layer and the tool substrate. This multi-coating structure helps to reduce friction and inhibit tool wear.

[0004] The existing technical solution takes the entire turning tool cutting edge as a design subject, and improves the wear resistance of each point on the cutting edge indiscriminately through methods such as tool angle optimization, micro-texture customization, and tool coating preparation. However, the turning tool cutting edge is usually composed of two parts: an arc edge and a straight edge, and the cutting thickness corresponding to each point on the arc edge is significantly different. This means that the force and heat loads on each point on it are different, so the back face wear of the turning tool also presents a typical non-uniform distribution pattern. The current constant parameter tool design method and tool configuration will not be able to meet the differentiated wear reduction needs of each point on the turning tool cutting edge. Technical issues

[0005] In view of the shortcomings of the existing technology, the present invention provides a design method and configuration of a variable geometric parameter wear-reducing turning tool to solve the problem of differentiated wear of existing turning tools at different cutting positions. Technical Solutions

[0006] The technical solution of the present invention:

[0007] A tool design method for reducing turning tool wear, the specific steps are as follows:

[0008] Step 1: Analyze the wear morphology of the tool flank. First, divide the tool cutting edge into two parts: the arc edge and the straight edge. Discrete the cutting edges separately and introduce orthogonal planes at each discrete point to describe the tool geometry and cutting state information. Analysis shows that the cutting thickness increases gradually along the arc edge from the tool vertex and remains constant at the straight edge. This non-uniform cutting contact state induces differentially distributed mechanical and thermal loads along the cutting edge, which in turn leads to non-uniform wear bands on the back face of the turning tool. In the tool tip wear zone, the excessively small cutting thickness prevents the material to be removed from forming chips upward along the tool separation point. Instead, it moves downward under the action of plowing and is eventually squeezed onto the workpiece surface, which intensifies the friction between the tool and the workpiece. The poor heat dissipation conditions at the tool tip further worsen the wear problem here. In the groove wear zone, due to the hardened layer on the machined surface, stress gradients, and chip scratches, narrow V-shaped grooves are prone to appear near the contact point between the cutting edge and the workpiece surface and gradually widen and deepen. It can be seen that increasing the tool sharpness helps reduce tool tip wear, while reducing the tool sharpness helps inhibit the occurrence of groove wear. The wear bandwidths of the above two areas jointly restrict the service life of turning tools for difficult-to-machine materials, but the configuration requirements for wear-reducing tools are contradictory.

[0009] Step 2: Select the geometric parameters of the turning tool to be designed; a cutting simulation model for describing the turning state is established based on finite element analysis software, and the tool arc radius, blade width, blunt radius, rake angle, clearance angle, groove type and groove depth are selected as the parameter set. The maximum bandwidth of the rear tool face wear is used as the main evaluation index, while taking into account the manufacturing difficulty and cost of the tool. Finally, the tool rake angle, tool clearance angle and tool blunt radius are selected from the above parameter set as the three geometric parameters to be designed for the wear-reducing tool;

[0010] Step 3: Simulate the wear resistance of turning tools with different configurations; Based on the established turning simulation model, explore the law of the wear bandwidth of the tool flank as a function of the geometric parameters to be designed; The simulation results show that as the tool rake angle increases, the mechanical and thermal response value of the cutting contact area decreases, and the wear bandwidth of the flank also decreases; As the tool rake angle increases, the contact length between the tool flank and the workpiece decreases, and the wear bandwidth of the flank also decreases; As the tool blunt radius increases, the thickness of the material to be removed that moves downward due to the plowing action gradually increases, which intensifies the friction between the tool and the workpiece, and the wear bandwidth of the flank also increases;

[0011] Step 4: Configuration design of the variable geometric parameter turning tool; in response to the non-uniformly distributed wear band on the back face of the tool, combined with the wear simulation results of turning tools with different configurations, the geometric parameters of the tool to be designed are adjusted so that it changes continuously along the turning tool cutting edge, which not only increases the tool sharpness at the tool tip arc, but also increases the tool strength in the groove wear area.

[0012] Specifically, a wear-reducing tool for turning difficult-to-machine materials, the turning tool blade has an overall diamond structure, including a main cutting edge, a secondary cutting edge and a tip arc edge connecting the two cutting edges; the symmetry axis of the main cutting edge and the secondary cutting edge divides the tip arc edge into two symmetrical parts, and the intersection of the symmetry axis and the tip arc edge is defined as the tool vertex, and the designed wear-reducing tool has the smallest blunt circle radius and the largest front angle and back angle at this point; then the tool's geometric parameters to be designed change evenly along the tip arc edges on both sides, wherein the blunt circle radius gradually increases, and the front angle and back angle gradually decrease; at the main and secondary straight edges, the blunt circle radius, front angle and back angle of the designed tool remain unchanged; in addition, the tool geometric parameters of the main cutting edge and the secondary cutting edge are symmetrical, the tool vertex divides the tip arc edge into two sections, and the tool geometric parameters of the two sections of the arc edge are also symmetrical.

[0013] Furthermore, the rake angle of the tool to be designed ranges from 3° to 15°.

[0014] Furthermore, the tool clearance angle to be designed ranges from 3° to 15°.

[0015] Furthermore, the radius of the blunt circle of the tool to be designed varies in the range of 10 μm to 30 μm.

[0016] Furthermore, the included angle between the main cutting edge and the secondary cutting edge of the variable geometry parameter wear-reducing turning tool insert is 55°.

[0017] Furthermore, the arc radius of the tool tip arc edge ranges from 0.1 mm to 0.4 mm. Beneficial effects

[0018] This invention proposes a tool design method for reducing tool wear during the turning process of difficult-to-machine materials, and accordingly designs a wear-reducing turning tool configuration with variable geometric parameters. The invention uses software simulation to understand how the wear bandwidth of the back tool face changes with the tool's geometric parameters, eliminating the need for extensive trial cutting experiments to determine the wear-reducing performance of tools with different configurations, saving time and cost. The designed variable-geometry turning tool can effectively reduce tool tip wear and curb further deterioration of groove wear, meeting the differentiated wear-reducing requirements of the turning tool at different cutting positions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 (a) is a partial schematic diagram of the tool tip structure during the turning process;

[0020] Figure 1(b) is a schematic diagram of the cutting layer parameters of the rake face of the turning tool during the turning process;

[0021] Figure 1(c) is a schematic diagram of the wear area of ​​the tool flank during turning;

[0022] Figure 1 (d) is a schematic diagram of the discrete positions of the turning tool cutting edge;

[0023] Figure 1(e) is a schematic diagram of two-dimensional tool cutting at different discrete positions.

[0024] Figure 2 is a line graph showing the change in tool flank wear width versus tool rake angle.

[0025] Figure 3 is a line graph showing the change in tool back angle as the wear width of the tool back surface changes.

[0026] Figure 4 is a line graph showing the change in tool flank wear width versus tool blunt radius.

[0027] Figure 5 (a) is a partial enlarged view of the designed tool tip structure;

[0028] Figure 5(b) is a schematic diagram of the tool geometric parameters at the designed tool cross section;

[0029] Figure 5 (c) is a schematic diagram of the designed tool and the tool geometry parameters;

[0030] Figure 5 (d) is a schematic diagram of the designed tool and the tool geometry parameters;

[0031] Figure 5(e) is a schematic diagram of the designed tool and the tool geometric parameters at the cross section.

[0032] Figure 6 (a) is a line graph showing the rake angle of the designed tool changing with the actual lead angle;

[0033] Figure 6(b) is a line graph showing the change of the clearance angle of the designed tool with the actual main deflection angle;

[0034] Figure 6 (c) is a line graph showing the change of the blunt circle radius of the designed tool with the actual main deflection angle. Modes for Carrying Out the Invention

[0035] The present invention will be further described below with reference to the accompanying drawings and in conjunction with specific embodiments:

[0036] A tool design method for reducing turning tool wear, the specific steps are as follows:

[0037] Step 1: Analysis of the wear morphology of the flank of the turning tool. As shown in Figure 1, in the turning process of rotating parts, the feed direction of the tool remains parallel to the rotation axis of the part. The turning tool cutting edge is divided into arc edge and straight edge, and the above cutting edges are discretized. At each discrete point, an orthogonal plane Si (i=1,2,3…,9) is introduced to describe the tool geometric parameter information and cutting state information at the discrete position. The angle between the contour tangent of the turning tool cutting edge and the tool feed direction is defined as the actual main deflection angle, which is used to locate the orthogonal plane Si. In this example, the actual main deflection angles corresponding to planes S1, S3 and S8 are 0°, 40° and 62.5°, respectively. When the tool feed rate is f=0.1mm / r, the cutting thicknesses corresponding to the above discrete positions are T1=0.027 mm, T3=0.08 mm and T8=0.089 mm, respectively. The cutting thickness gradually increases from the tool vertex along the arc edge and remains constant at the straight edge. This non-uniform cutting contact state induces differentially distributed mechanical and thermal loads along the cutting edge, which in turn causes the flank wear zone of the turning tool to be non-uniform. Therefore, the flank wear zone of the tool is divided into the tool tip wear zone RC, the uniform wear zone RB and the groove wear zone RN. The wear bandwidths of the three wear zones are represented by VC, VB and VN respectively. In the tool tip wear zone RC, the excessively small cutting thickness causes the material to be removed to be unable to form chips upward along the tool separation point, but to move downward under the plowing action and eventually squeezed on the workpiece surface, which aggravates the tool-workpiece gap. Friction, and poor heat dissipation conditions at the tool tip further exacerbate the tool wear problem here; in the groove wear area RN, due to the hardened layer on the machined surface, stress gradients, and chip scratches, narrow V-shaped grooves are likely to appear near the contact point between the cutting edge and the workpiece surface, and gradually widen and deepen; thus, increasing tool sharpness helps reduce wear at the tool tip, while reducing tool sharpness helps suppress groove wear. The above two wear areas jointly restrict the service life of turning tools for difficult-to-machine materials, but the configuration requirements for wear-reducing tools are contradictory;

[0038] Step 2: Select the geometric parameters of the turning tool to be designed. A cutting simulation model for describing the turning state is established based on the finite element analysis software AdvantEdge. The tool arc radius, blade width, blunt radius, rake angle, clearance angle, groove type, and groove depth are selected as the parameter set. The maximum bandwidth of the rear tool face wear is used as the main evaluation indicator. While taking into account the manufacturing difficulty and cost of the tool, the tool rake angle, tool clearance angle, and tool blunt radius are finally selected from the above parameter set as the three geometric parameters to be designed for the wear-reducing tool.

[0039] Step 3, wear resistance simulation of turning tools with different configurations; the established turning simulation model is used to explore the law of tool flank wear changing with the geometric parameters to be designed; as shown in Figure 2, the range of the selected tool rake angle is [3°, 15°]. The simulation results show that as the tool rake angle increases, the mechanical and thermal response value of the cutting contact area decreases, and the wear bandwidth of the flank also decreases accordingly; as shown in Figure 3, the range of the selected tool rake angle is [3°, 15°]. The simulation results show that as the tool rake angle increases, the contact length between the tool flank and the workpiece decreases, so the wear bandwidth of the flank also decreases; as shown in Figure 4, the range of the selected tool blunt circle radius is [10 um, 30 um]. The simulation results show that as the tool blunt circle radius increases, the thickness of the material to be removed that moves downward due to the plowing action gradually increases, which intensifies the friction between the tool and the workpiece, so the wear bandwidth of the flank will also increase;

[0040] Step 4: Configuration design of the variable geometric parameter turning tool; in response to the non-uniformly distributed wear band on the back face of the tool, combined with the wear simulation results of turning tools with different configurations, the geometric parameters of the tool to be designed are adjusted so that it changes continuously along the turning tool cutting edge, which not only increases the tool sharpness at the tool tip arc, but also increases the tool strength in the groove wear area.

[0041] The described wear-reducing tool for turning difficult-to-machine materials, FIG5 shows the geometric parameters of the tool at different discrete positions; wherein, the turning tool blade is a diamond structure as a whole, comprising a main cutting edge, a secondary cutting edge and a tip arc edge connecting the two cutting edges, wherein the angle between the main cutting edge and the secondary cutting edge is preferably 55°, and the tip arc radius is preferably 0.2 mm; the symmetry axis of the main cutting edge and the secondary cutting edge divides the tip arc edge into two symmetrical parts, and the intersection of the symmetry axis and the tip arc edge is defined as the tool vertex, and the designed wear-reducing tool has the smallest blunt circle radius at this point, which is 10 um, and the largest front angle and back angle, both of which are 15°; then, the geometric parameters of the tool are adjusted so that it changes evenly along the arc edge, wherein the blunt circle radius gradually increases, and the front angle and back angle gradually decrease. At the intersection of the main and secondary cutting edges of the arc edge, the blunt circle radius of the tool is 20 um, the rake angle and relief angle are both 9°. Figure 6 is a schematic diagram of the continuous change of the rake angle, relief angle and blunt circle radius of the turning tool with the actual main deflection angle; in addition, the tool geometric parameters of the main cutting edge and the secondary cutting edge are symmetrical. The tool vertex divides the tool tip arc edge into two sections, and the tool geometric parameters of the two sections of the arc edge are also symmetrical.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A design method for a variable geometry parameter wear-reducing turning tool, characterized in that: Here are the steps: Step 1: Wear morphology analysis of the back face of the turning tool; The straight edge and arc edge of the turning tool are discretized respectively, and the corresponding tool geometric parameters at each discrete point are described by orthogonal plane. Under the condition of given cutting amount, the cutting state of the tool at each discrete point is mastered. Then, the wear cause is analyzed based on the actual wear morphology of the back face of the turning tool, and the main wear area that affects the service life of the tool is determined. Based on this, the preliminary demand for the wear-reducing turning tool configuration is proposed. Step 2: Select the geometric parameters of the turning tool to be designed; Based on the finite element analysis software, a cutting simulation model for describing the turning state is established. The tool arc radius, blade width, blunt radius, rake angle, clearance angle, groove type and groove depth are selected as the parameter set. The maximum bandwidth of the rear tool face wear is used as the main evaluation index. At the same time, the manufacturing difficulty and cost of the tool are taken into consideration. Finally, the tool rake angle, tool clearance angle and tool blunt radius are selected from the above parameter set as the three geometric parameters to be designed for the wear-reducing tool. Step 3: Wear resistance simulation of turning tools with different configurations; Based on the established turning simulation model, the influence of tool rake angle, tool clearance angle and tool blunt radius on the flank wear bandwidth is determined respectively. Step 4: Configuration design of variable geometry parameter turning tool; In view of the non-uniformly distributed wear band on the tool flank, combined with the wear simulation results of turning tools with different configurations, the tool's geometric parameters to be designed are adjusted to make them change continuously along the turning tool cutting edge, which not only increases the tool sharpness at the tool tip arc, but also increases the tool strength in the groove wear area.

2. A variable geometry parameter wear-reducing turning tool for turning difficult-to-machine materials, characterized in that: The variable geometry parameter wear-reducing turning tool blade is a diamond structure, including a main cutting edge, a secondary cutting edge and a tool tip arc edge connecting the two cutting edges; the symmetry axis of the main cutting edge and the secondary cutting edge divides the tool tip arc edge into two symmetrical parts, and the intersection of the symmetry axis and the tool tip arc edge is defined as the tool vertex; the designed wear-reducing turning tool has the smallest blunt circle radius at this point, and the largest front angle and back angle; the geometric parameters to be designed of the wear-reducing turning tool change evenly along the tool tip arc edges on both sides, wherein the blunt circle radius gradually increases, and the front angle and back angle gradually decrease; at the main cutting edge and the secondary cutting edge, the blunt circle radius, front angle and back angle of the designed tool remain unchanged; in addition, the tool geometric parameters of the main cutting edge and the secondary cutting edge are symmetrical, the tool vertex divides the tool tip arc edge into two sections, and the tool geometric parameters of the two sections of the arc edge are also symmetrical.

3. The variable geometry parameter wear-reducing turning tool according to claim 2, characterized in that: The range of tool rake angle to be designed is 3°~15°.

4. The variable geometry parameter wear-reducing turning tool according to claim 2, characterized in that: The tool back angle to be designed ranges from 3° to 15°.

5. The variable geometry parameter wear-reducing turning tool according to claim 2, characterized in that: The radius of the blunt circle of the tool to be designed varies in the range of 10μm-30μm.

6. The variable geometry parameter wear-reducing turning tool according to claim 2, characterized in that: The angle between the main cutting edge and the secondary cutting edge of the variable geometry parameter wear-reducing turning tool insert is 55°.

7. The variable geometry parameter wear-reducing turning tool according to claim 2, characterized in that: The arc radius of the tool tip arc edge ranges from 0.1 mm to 0.4 mm.

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