CN105643024B - A method of axially layered cutting of large-pitch threads, a tool wear test method, and a method for calculating mechanical and thermal loads - Google Patents

Abstract

An axial layered cutting method for turning large-pitch threads, a tool wear test method, and a method for calculating mechanical and thermal loads, aiming at eliminating the principle error existing in cutting large-pitch threads by radial layers. The technical points are: the cutting Methods The left and right thread surfaces of the large-pitch specimen were turned layer by layer with the test tool with left and right cutting edges in the axial direction, and the cutting method was used to test the wear of the large-pitch thread tool, and the wear pattern of the large-pitch thread tool was obtained. , revealing the influence of tool wear on the threading surface, and then using the tool flank wear and cutting edge blunt radius measurement data, the tool finite element analysis model was reconstructed, the tool temperature field and stress field were analyzed and calculated, and the tool was obtained Characteristics of mechanical and thermal load changes under wear conditions.

Description

A method of axially layered cutting of large-pitch threads and a method of testing tool wear And its calculation method of mechanical and thermal load

Technical field:

The present invention relates to a large-pitch thread turning method and its tool wear, mechanical and thermal load testing and calculation methods, in particular to a large-pitch thread axial layered turning method, an experiment and test method for turning large-pitch thread tool wear, and The construction and calculation method of the mechanical and thermal load analysis model of tool wear.

Background technique:

As a large-scale press adjustment component, the large-pitch screw controls the parallelism and perpendicularity between the upper mold and the lower mold in the press, which has an important impact on the static and dynamic accuracy of the press machine. The existing large-pitch thread turning mainly adopts the radial layered cutting method, which uses the tip of the tool for cutting, and controls the position accuracy of the tool tip to form the surface of the large-pitch thread, which has the advantages of easy CNC machining programming. However, this cutting method uses the principle of tool tip approximation, and there are principle errors in the formed thread surface, which makes it difficult to meet the high precision and high surface quality requirements of large pitch threads. The axial layered cutting uses the cutting edge of the tool for forming cutting, and there is no principle error in the thread surface formed by it. This method turns the existing multi-task cutting into a single-task cutting. Through the axial layered cutting, Guarantee thread size accuracy, tooth type accuracy and teaching surface quality respectively. Therefore, this cutting method eliminates the principle error of radial cutting, and is more suitable for cutting high-precision and large-pitch threads.

When the axial layered cutting method is used to finish the large pitch thread, if all the finishing allowance is removed by one cutting, the cutting force generated will be large, which will affect the quality of the machined surface and the machining accuracy; in order to improve the machining accuracy; When the sub-layered cutting method is used for finishing large-pitch threads, too many times of cutting will aggravate tool wear.

In the process of large-pitch thread cutting, there is an interactive relationship between mechanical and thermal loads and tool wear; the tool is in constant contact with the workpiece and chips, and there is high cutting temperature and pressure in the contact area. The mechanical and thermal loads on the tool are The main cause of its wear; at the same time, tool wear will cause changes in its mechanical and thermal loads; at present, the research on tool wear mainly focuses on the influence of mechanical and thermal loads on tool wear, ignoring the influence of tool wear on mechanical and thermal loads. The tool thermal load analysis model and boundary conditions used are the models and data in the initial cutting state of the tool, and the change characteristics of the thermal load with the increase of cutting stroke and the increase of tool wear cannot be obtained correctly, and the axial multiple layered turning with large pitch There are deficiencies in the experimental methods of thread tool wear and the calculation methods of mechanical and thermal loads.

Invention content:

In order to eliminate the principle error of radial layered cutting of large-pitch threads, the present invention designs an axial layered cutting method for turning large-pitch threads, and uses the method to test tool wear for turning large-pitch threads to obtain large-pitch turning The thread tool wear pattern reveals the influence of tool wear on the thread machining surface, and then uses the tool flank wear and cutting edge blunt radius measurement data to reconstruct the tool finite element analysis model to analyze and calculate the tool temperature field and stress field , to obtain the change characteristics of mechanical and thermal loads under the condition of tool wear.

The axial layered cutting method for turning large-pitch thread of the present invention is to include the following steps in order to achieve the above-mentioned purpose:

1. Use the test tool with two cutting edges on the left and right to cut the left and right thread surfaces of the large pitch test piece in layers along the axial direction;

2. During turning, the radial cutting depth a _P is constant during each feeding process of the tool and is equal to the thread profile height H. The cutting layer area is only related to the feeding amount, and the relationship between the variables is shown in formula (1).

h>H=a _P , ε _r1 =ε _r1 ′, ε _r2 =ε _r2 ′, B>b, R ₁ =r ₁ , R ₂ =r ₂ (1)

Cutting layer thickness and cutting layer width when left edge cutting:

h _Dl =z _li ·sin k _γ ′ (2)

b _Dl =z _li /sin k _γ ′ (3)

The theoretical cutting layer area of each layered cutting is:

S _i ＝h _Dl ·b _Dl ＝z _li ·sin k _γ ′·(a _P /sin k _γ ′)=z _li ·a _P (4)

Similarly, when the right edge is cutting, the cutting layer area of each layered cutting is:

S _j = h _Dr b _Dr = z _rj sin k _γ ′ (a _P /sin k _γ ′) = z _rj a _P (5)

In the formula, H is the thread height, h is the cutter head height of the tool, B is the thread root width, b is the cutter head width; a _P is the radial depth of cut, z _li is the single machining allowance of the left edge, z _rj is the single machining allowance of the right edge, i is the cutting times of the left edge, j is the number of cutting of the right edge; h _Dl is the thickness of the cutting layer when turning the left edge of the tool, b _Dl is the width of the cutting layer when turning the left edge of the tool, h _Dr is the thickness of the cutting layer when turning the right edge of the tool, b _Dr is the width of the cutting layer when turning the right edge of the tool; S _i is the area of the cutting layer on the left cutting edge, S _j is the area of the cutting layer on the right cutting edge; ε _r1 , ε _r2 are the left and right flank angles of the thread, ε _r1 ' is the left edge angle of the tool, ε _r2 ' is the right edge angle of the tool; R ₁ and R ₂ are the tooth profile radii of the left and right sides of the specimen, respectively, r ₁ and r ₂ are the arc radii of the left and right tooth cusps of the tool.

The test method for tool wear of axial layered turning large-pitch thread tool of the present invention adopts the technical scheme to include the following steps:

One, in the process of turning large-pitch screw thread test pieces according to the cutting method described in claim 1, when the cutting strokes are 15072mm, 52752mm, 94200mm, 116808mm and 139400mm, the test tool is removed respectively, and the three-dimensional microscope with VHX-1000 ultra-depth of field is used. The system detects the wear morphology of the front and flank surfaces of the tool, and measures the cutting edge arc radius and flank wear of the test tool;

2. Take 5 identical cutting strokes along the length direction of the test tool, measure the flank wear width of the test tool under the 5 cutting strokes respectively, and obtain the change curve of the flank wear width of the test tool;

3. On the change curve of the flank wear width of the test tool, according to the difference between the cutting edge radius of the test tool and the change rate of the flank wear width, divide the test tool during the process of turning the large pitch thread specimen. Three stages of initial wear, normal wear and severe wear;

4. Measure the processed surface topography of the large-pitch thread specimen in the three stages in step 3, and use the tool wear pattern under the same cutting stroke and the corresponding processed surface topography of the large-pitch thread specimen to detect the test tool The difference in the influence of the increase of wear amount on the machined surface morphology of large pitch thread specimens.

Further, the large-pitch screw test piece is a trapezoidal right-handed external screw test piece with a pitch of 16 mm, an outer diameter of 120 mm, and a length of 160 mm, and its material is 35CrMo.

Further, the included angle of the left and right edges of the test tool is 26°, the relief angle of the top edge is 5°, the inclination angle and rake angle of the two cutting edges are both 0°, the relief angle is 5°, and the left edge The radius is 138.77mm, the radius of the left blade is 201.56mm, and its material is W18Cr4v.

Further, the test tool was turned on a CA6140 lathe with a rotating speed of 10 rpm and an axial machining allowance of 0.05 mm to turn a large pitch thread specimen.

The calculation method of the present invention for carrying out axial layered turning large-pitch thread tool wear thermal load adopts the technical scheme as follows: according to the obtained test tool front and flank wear data and the circular arc after cutting edge and tool tip wear Radius, using Deform software to calculate the cutting temperature and cutting force of the test tool under different tool wear states, using the calculated cutting temperature and cutting force as the boundary conditions for stress field analysis, using Ansys software to calculate the maximum value of the test tool under different wear states stress.

Further, the wear depth of the test tool is calculated by formula (5):

ω＝∫apve ^-b/T dt (6)

In the formula, p is the normal pressure, v is the sliding speed of the chip relative to the test tool, the chip is relative to the tool, T is the temperature of the contact area between the test tool and the chip, a and d are the test coefficients, and the default a and d values are taken for the material;

Further, using Deform software to obtain the thermal-mechanical coupling field at different wear stages of the tool, draw a vertical line d ₂ ' perpendicular to the left cutting edge of the test tool at the position with the highest temperature of the thermal-mechanical coupling field, and the distance from the vertical foot to the tool tip is d ₁ ', use the tool tip, d ₁ ' and d ₂ ' to describe the position of the highest temperature of the test tool, extract the exact position of the highest temperature of the test tool and the highest temperature of the contact area between the test tool and the chip, and extract the temperature of the rake face of the test tool at this position The curve of the temperature in the contact area with the test tool and the chip changes with time, extract the maximum temperature of the tool at each wear stage, and obtain the change curve of the temperature of the test tool with the wear width of the flank.

The beneficial effects of the present invention are: the method for axially layered cutting of large-pitch threads proposed by the present invention is to use the cutting edge of a tool for forming cutting, and there is no principle error in the formed thread surface. Some multi-task cutting is decomposed into single-task cutting. Through axial layered cutting, the thread size accuracy, tooth shape accuracy and teaching surface quality are respectively guaranteed. Therefore, this cutting method eliminates the principle error of radial cutting. It is more suitable for the cutting of high-precision and large-pitch threads; the tool wear experiment and the calculation method of the mechanical and thermal loads provided by the present invention reveal the mechanical and thermal loads of the cutting edge and flank structure changes in the cutting process after tool wear The impact of the distribution can calculate the tool wear from the initial wear stage to the middle and late wear stage, the tool stress and the temperature growth rate of the contact area between the tool and the chip reveal the middle and late wear stage of the tool; the mechanical and thermal load calculation of the tool wear proposed by the present invention Method, using the tool wear data obtained in the experiment of turning large-pitch thread, such as the wear length, width and depth of the front and rear flanks of the tool, and the radius of the arc after the cutting edge and tool tip are worn, the finite element analysis model of the tool is corrected, and the obtained turning large The analysis and calculation results of the pitch thread stress field and temperature field can accurately locate the part where the maximum stress and the highest temperature occur during the tool wear process, which provides a basis for the design of the tool cutting edge structure and efficient cutting process design.

Description of drawings:

Figure 1 is a schematic diagram of the contact relationship between the tool and the specimen in axial layered cutting;

Fig. 2 is the side view of Fig. 1;

Figure 3 is a schematic diagram of the left widening of the test tool;

Figure 4 is a schematic diagram of the right widening of the test tool;

Figure 5 is a schematic diagram of the thread development of the test piece;

Figure 6 is a graph showing the variation of the flank wear width of the test tool with the cutting stroke;

Figure 7 is a schematic diagram of the contact with the large-pitch thread specimen before the test tool wears;

Fig. 8 is a schematic diagram of the contact with the large-pitch thread specimen after the test tool is worn;

Fig. 9 is a model diagram of the corrected tool;

Figure 10 is a finite element model diagram of the test tool;

Fig. 11 is a curve diagram of the maximum stress of the cutter followed by the change curve of the wear width of the cutter face;

Fig. 12 is a schematic diagram of extracting the highest temperature position;

Fig. 13 is a curve diagram of the change of the tool face wear width after the test tool temperature.

detailed description:

Referring to Fig. 1 to Fig. 5, the axial layered cutting method for turning large-pitch threads uses a tool with left and right cutting edges to axially turn the left and right thread surfaces of large-pitch thread specimens in layers, in the figure: n is The rotational speed of the workpiece, _{v f} is the axial feed speed of the tool, v _c is the main movement speed, and the _Cartesian coordinate system perpendicular to each other is formed between them; , γ ₀ is the auxiliary relief angle of the tool, α ₀ is the rake angle of the tool, Φ is the helix angle of the test piece, ε _r1 , ε _r2 are the left and right flank angles of the thread respectively, ε _r1 ' is the left edge side of the tool angle, ε _r2 ' is the right edge side angle of the tool; d is the outer diameter of the specimen, d ₁ is the minor diameter of the specimen, d ₂ is the middle diameter of the specimen, d _w is the diameter of the specimen during cutting, H is Thread height, h is the height of the cutter head of the tool, B is the width of the thread bottom, b is the width of the cutter head; a _p is the radial depth of cut, z _li is the single machining allowance of the left blade, z _rj is the single machining allowance of the right blade Secondary machining allowance (where i=1,2...n, j=1,2...m), h _Dl is the thickness of the cutting layer when turning the left edge of the tool, b _Dl is the width of the cutting layer when turning the left edge of the tool, h _Dr is the thickness of the cutting layer when turning the right edge of the tool, b _Dr is the width of the cutting layer when turning the right edge of the tool; P is the pitch of the specimen, R ₁ and R ₂ are the tooth profile radii of the left and right sides of the specimen, r ₁ , r ₂ is the arc radius of the left and right tooth cusps of the tool; P _s is the cutting plane, P _r is the base surface, A _γ is the rake face of the tool, and A _α is the flank face of the tool.

When turning a large-pitch threaded specimen, the depth of cut _ap remains constant during each feeding process of the tool and is equal to the thread profile height H. The area of the cutting layer is only related to the feeding amount, and the relationship between the variables is shown in the following formula .

h>H=a _P , ε _r1 =ε _r1 ′, ε _r2 =ε _r2 ′, B>b, R ₁ =r ₁ , R ₂ =r ₂ (1)

Cutting layer thickness and cutting layer width when left edge cutting:

h _Dl =z _li ·sin k _γ ′ (2)

b _Dl =z _li /sin k _γ ′ (3)

The theoretical cutting layer area of each layered cutting is:

S _i ＝h _Dl ·b _Dl ＝z _li ·sin k _γ ′·(a _P /sin k _γ ′)=z _li ·a _P (4)

Similarly, when the right edge is cutting, the cutting layer area of each layered cutting is:

S _j = h _Dr b _Dr = z _rj sin k _γ ′ (a _P /sin k _γ ′) = z _rj a _P (5)

In this method, the cutting edge of the tool participates in cutting during the entire machining process, and is mainly used in the semi-finishing and finishing processes of large-pitch threads. The cutting layer area S _i , S _j of the cutting edge is related to the single machining allowance z _li , z _rj of the left and right cutting edges and the radial depth of cut a _P , which is much larger than that of the radial cutting method. Therefore, the tool is subjected to a relatively large load during the cutting process, which directly affects the thread machining accuracy and machined surface quality.

Test method for tool wear in turning large-pitch threads;

According to the above cutting method, using a test tool with a symmetrical structure of left and right cutting edges, on a CA6140 lathe with a rotational speed of 10rpm and an axial machining allowance of 0.05mm, the experiment of tool wear in turning large-pitch thread is carried out. The material of the large-pitch thread test piece used is For quenching and tempering 35CrMo, the material of the test tool used is W18Cr4v, and the geometric angle of the tool is shown in Table 1;

Table 1 Tool geometry angle

In the experiment, the cutter head was removed when the cutting strokes were 15072mm, 52752mm, 94200mm, 116808mm and 139400mm respectively, and the VHX-1000 ultra-depth three-dimensional microscope system was used to detect the wear morphology of the front and flank surfaces of the tool, and measure the arc of the cutting edge Radius and flank wear.

The cutting edge and flank wear test results of the test tool:

The test tool feeds 4 times. When the cutting stroke is 15.072m, when the radius of the blunt circle of the cutting edge and the distance between the right flank and the tool tip are 3.6-5.4mm, the wear form of the tool flank is abrasive wear, and the radius of the blunt circle of the cutting edge is 30.82μm, and the tool flank wear width is 94.57μm. At this stage of the tool, the flank wear width and cutting edge arc change rapidly. The reason is that the flank of the newly sharpened tool has roughness and unevenness, and the cutting edge is sharp. The flank and the large pitch thread The contact area of the machined surface of the specimen is small and the compressive stress is large. At the same time, the cutting edge structure, tool assembly and clamping and tool contact relationship of the tool in the initial cutting stage are in an unstable state, which also has a greater impact on tool wear.

The test tool feeds 21 times, and when the cutting stroke is 94.22m, when the blunt circle radius of the cutting edge and the right flank are 3.6-5.4mm away from the tool tip, the flank wear of the tool at this stage is normal abrasive wear. The radius of the blunt circle of the blade is 52.13 μm, and the wear width of the tool flank is 175.63 μm. Compared with the initial wear, the front and rear flank wear increases the radius of the blunt circle of the cutting edge, and the flank wear rate slows down. The reason is that the rough surface of the cutting edge and the front and back face of the tool has been ground, the cutting force and cutting heat change are basically stable, and the change range is small, and the wear amount of the flank face increases approximately proportionally with the prolongation of cutting time.

When the cutting stroke of the test tool reaches 139.4m, when the distance between the radius of the blunt circle of the cutting edge and the right flank is 3.6-5.4mm from the tool tip, the radius of the blunt circle of the cutting edge is 69.37μm, the wear width of the flank is 212.07μm, and the tool cuts The edge is damaged, and the flank is bonded wear. Compared with the tool wear when the cutting stroke is 94.22m, the tool wear rate is significantly increased.

The experimental results of the effect of increased tool wear on the machined surface morphology of large-pitch thread specimens:

In the experiment of turning large-pitch threads, five sections of the same cutting stroke were selected to measure the flank wear width VB values of 94.58 μm, 163.2 μm, 175.6 μm, 190.3 μm and 240.7 μm, and the flank wear width variation curves were obtained as shown in Fig. As shown in Figure 6, it can be seen from Figure 6 that the test tool has experienced three stages of initial wear, normal wear and severe wear during the process of turning large-pitch threads. In these three stages, the tool edge radius and flank wear width The rate of change is significantly different. With the intensification of tool wear, the surface morphology of the threaded surface has changed significantly. Tool wear has a significant impact on the quality of the machined surface. In order to obtain a threaded surface that meets the requirements, the tool wear during the cutting process must be considered .

Calculation method of force and heat load for tool wear:

The contact relationship between the test tool and the large-pitch thread specimen before and after tool wear is shown in Figure 7 and Figure 8. It can be seen from Figure 7 and Figure 8 that the geometric structure of the cutting edge of the worn tool has changed, which will directly affect its The force and heat load distribution in the cutting process, for this reason, using the tool wear data obtained in the turning large-pitch thread experiment, such as the tool wear length, width, depth, cutting edge and radius of the arc after the tool tip is worn, corrected The tool model shown in Figure 9, using the measured data of the tool wear experiment, uses Deform and Ansys to calculate the stress field and temperature field of different wear states of the turning large-pitch thread tool, and its boundary conditions are shown in Table 2;

Table 2 Boundary conditions

Stress field calculation method and results of tool wear:

Ansys is more accurate in calculating the stress and strain fields of the mechanical structure, while Deform is more accurate in calculating the thermal-mechanical coupling field in the cutting process. Therefore, Deform and Ansys software are used for the collaborative calculation of the stress field under the tool wear state, and the tool after-effect obtained by the experiment is used. The amount of tool face wear, the radius of the cutting edge blunt circle, and the cutting temperature and cutting force calculated by the Deform solution are used as the boundary conditions for the finite element analysis of Ansys software to calculate the tool stress field. The finite element model of the tool is shown in Figure 10. The main distribution of the tool's maximum stress On the cutting edge of the tool and the area adjacent to the cutting edge and the front and rear rake faces of the tool, as the wear width of the tool flank and the radius of the blunt circle of the cutting edge gradually increase, the maximum stress on the tool gradually increases, and The range gradually expands and extends along the cutting edge to the front and rear flanks of the tool, thus obtaining the characteristic curve of the maximum stress of the tool changing with the flank wear width as shown in Figure 11.

Calculation method and results of temperature field of tool wear:

According to the experimental results of tool wear and the calculation method of its force and heat load, the Usui model suitable for metal cutting is used to calculate the temperature field of the tool for turning large-pitch threads. The formula for calculating the tool wear depth is:

ω＝∫apve ^-b/T dt (6)

In the formula, p is the normal pressure; v is the slip velocity (the chip is relative to the tool); T is the temperature of the tool-chip contact area; a and b are the test coefficients, and the default values of a and b are taken for the material.

Using Deform software to calculate the thermal coupling field, extract the temperature of the test tool and the temperature of the contact area between the test tool and chips, as shown in Figure 12, calculate the exact position of the highest temperature of the test tool, as can be seen from Figure 12, the highest overtemperature position, Make a vertical line d ₂ ' perpendicular to the left cutting edge, and the distance from the foot to the tip of the tool is d ₁ '. Use the tip of the tool, d ₁ ' and d ₂ ' to describe the position of the highest temperature of the tool, as shown in Table 3:

Table 3 The highest temperature position of the tool

The temperature of the contact area between the test tool and the chip is higher than the temperature of the test tool itself. The temperature of the test tool and the temperature of the contact area between the test tool and the chip are gradually increasing since the test tool cuts into the large-pitch thread specimen, and it reaches a stable state after cutting for a period of time. Extract the maximum temperature of the test tool in each wear stage, and obtain the change curve of the tool temperature and then the wear width of the tool face as shown in Figure 13. From Figure 13, it can be seen that the temperature of the test tool and the contact between the test tool and the chip from the initial wear stage to the middle and late wear stage. The temperature of the zone increased by 12.3% and 15.7%, 14.1% and 17.3%, 45.2% and 53.9%, respectively, compared with the temperature of the previous wear stage. In the middle and late wear stages of the test tool, under the combined action of thermal load, the cutting load exceeded the test tool Yield strength and sticking welding effect, the test tool is bonded, damaged and worn, and further causes the thermal load of the test tool to increase, which increases the wear process of the test tool, until the test tool is scrapped, and the surface quality of the large-pitch thread test piece is serious. decline.

Claims (8)

1. a kind of turning steep-pitch thread axial stratification cutting process, it is characterised in that comprise the following steps：

First, using the left and right flank of the big pitch test specimen of layering turning vertically of the experiment cutter with the cutting edge of left and right two；

2nd, radial cutting depth a during each feed of cutter during turning_PIt is constant and equal to form of thread height H, cutting lay Area is only relevant with the depth of cut, shown in its relationship between variables such as formula (1),

H ＞ H=a_P, ε_r1=ε_r1', ε_r2=ε_r2', B ＞ b, R₁=r₁, R₂=r₂ (1)

Cutting layer thickness and cutting lay width during left sword cutting：

h_Dl=z_li-sink_γ′ (2)

b_Dl=z_li/sink_γ′ (3)

Its each time layered cutting desired cut aspect product be：

S_i=h_Dl·b_Dl=z_li·sink_γ′·(a_P/sink_γ')=z_li·a_P (4)

During right sword cutting, the cutting lay area of layered cutting is each time：

S_j=h_Dr·b_Dr=z_rj·sink_γ′·(a_P/sink_γ')=z_rj·a_P (5)

In formula, H is height of thread, and h is the cutter head height of cutter, and B is ridge bottom width, and b is cutter head width；a_PFor radial direction cutting-in, z_liFor left sword single process surplus, z_rjFor right sword single process surplus, i is that left sword cuts number of times, and j is that right sword cuts number of times；h_Dl Cutting layer thickness, b when being cut for the left knife car of cutter_DlCutting lay width, h when being cut for the left knife car of cutter_DrCut for the right knife car of cutter When cutting layer thickness, b_DrCutting lay width when being cut for the right knife car of cutter；S_iFor left cutting edge cutting lay area, S_jFor right cut Cut sword cutting lay area；ε_r1、ε_r2The respectively left and right flank angle of screw thread, ε_r1' be cutter left sword side angle, ε_r2' it is cutter Right sword side angle；R₁、R₂Respectively the tooth form radius of test specimen left and right side, r₁、r₂For the left and right cusp arc radius of cutter, κ_r＇ is Cutter auxiliary angle.

2. a kind of cutting process according to claim 1 carries out the test of axial stratification turning steep-pitch thread tool wear Method, it is characterised in that comprise the following steps：

First, during the cutting process turning steep-pitch thread test specimen as described in claim 1, it is in cutting stroke respectively Experiment cutter is removed when 15072mm, 52752mm, 94200mm, 116808mm and 139400mm, the super depth of field three of VHX-1000 is utilized The microscopic system detection forward and backward knife face wear morphology of cutter is tieed up, and measures the cutting edge arc radius and rear knife face mill of experiment cutter Damage amount；

2nd, 5 sections of identical cutting strokes are taken along along experiment tool length direction, measures test cutter under 5 sections of cutting strokes respectively Wear of the tool flank width, obtain experiment cutter wear of the tool flank width change curve；

3rd, on the change curve of the wear of the tool flank width of experiment cutter, by the radius of edge and knife face thereafter of experiment cutter The difference of abrasion width rate of change, marks off the mill at initial stage undergone during experiment cutter turning steep-pitch thread test specimen Damage, normal wear and sharp wear three phases；

4th, in measuring process three in three phases steep-pitch thread test specimen machined surface pattern, utilize identical cutting stroke Under tool wear form and corresponding steep-pitch thread test specimen machined surface pattern, detect to test tool abrasion Increase on difference present on the machined surface pattern influence of steep-pitch thread test specimen.

3. a kind of method of testing for carrying out axial stratification turning steep-pitch thread tool wear according to claim 2, its It is characterised by：The steep-pitch thread test specimen is that pitch is that 16mm, external diameter are 120mm, length for 160mm the outer spiral shell of trapezoidal dextrorotation Bar test specimen, its material is 35CrMo.

4. a kind of method of testing for carrying out axial stratification turning steep-pitch thread tool wear according to claim 2, its It is characterised by：The left and right sword angle of the experiment cutter is 26 °, top relief angle is 5 °, two cutting edges cutting edge inclination and anterior angle Be 0 °, relief angle be 5 °, left sword radius of edge be that 138.77mm, left sword radius of edge are 201.56mm, its material is W18Cr4v。

5. a kind of method of testing for carrying out axial stratification turning steep-pitch thread tool wear according to claim 2, its It is characterised by：The experiment cutter is on CA6140 lathes with rotating speed 10rpm, axial direction allowance 0.05mm to steep-pitch thread Test specimen carries out turning.

Carried 6. a kind of method of testing according to claim 2 carries out axial stratification turning steep-pitch thread tool wear heating power The computational methods of lotus, it is characterised in that：The forward and backward knife face wear data of the experiment cutter obtained by step one in claim 2 And the arc radius after cutting edge and corner wear, calculated using Deform softwares under the different tool wear forms of experiment cutter Cutting temperature and cutting force, the boundary condition of analysis on Stress Field is used as with cutting force using the cutting temperature that calculates, is used Ansys softwares calculate the maximum stress under the different state of wear of experiment cutter, and obtain power thermal force increases and knife with cutting stroke Has the variation characteristic that wear extent increases.

7. a kind of calculating side of axial stratification turning steep-pitch thread tool wear heating power load according to claim 6 Method, it is characterised in that：The wearing depth of experiment cutter is calculated by formula (6)：

ω=∫ apve^-b/Tdt (6)

P is that normal pressure, v are that sliding velocity chip of the chip relative to experiment cutter is experiment cutter relative to cutter, T in formula It is test coefficient with chip contact area temperature, a, d, material takes a of acquiescence, d values；

8. a kind of calculating side of axial stratification turning steep-pitch thread tool wear heating power load according to claim 6 Method, it is characterised in that：The Thermal-mechanical Coupling of the different wear stages of cutter is obtained using Deform softwares, in Thermal-mechanical Coupling temperature Highest position is the vertical line d of the left cutting edge perpendicular to experiment cutter₂', the distance of intersection point to point of a knife is d₁', using point of a knife, d₁' and d₂' experiment cutter maximum temperature position is depicted, extract experiment cutter most temperature and experiment cutter and chip contact area The accurate location of maximum temperature, extracts and cutter rake face temperature and experiment cutter and chip contact area temperature is tested at the position The curve changed over time, extracts cutter each wear stage maximum temperature, obtains experiment tool temperature with its wear of the tool flank Change width curve.