阅读说明：本技术 一种测量切屑变形的方法 (Method for measuring chip deformation ) 是由 何利华 何琪 潘建峰 钱仁寅 袁选成 倪敬 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种测量切屑变形的方法。现有测量切屑变形的方法只测量了收缩系数,且测量误差大。本发明将金属切屑的变形转化为图案的变形,在金属材料表面绘制同心圆形图案,经过切削,测量切屑上图案的尺寸来计算收缩系数,又通过在图像上做辅助线的方法测量出切屑弯曲的曲率,从而达到能够表征切屑变形的效果。本发明能够系统测量切屑的纵收缩系数、横收缩系数和弯曲曲率,特别是提出了一种简易的测量切屑曲率半径的方法,曲率半径能直观地描述切屑的弯曲程度。(The invention discloses a method for measuring chip deformation. The existing method for measuring the chip deformation only measures the shrinkage coefficient and has large measurement error. The method converts the deformation of the metal chip into the deformation of the pattern, draws the concentric circular pattern on the surface of the metal material, measures the size of the pattern on the chip to calculate the shrinkage coefficient through cutting, and measures the curvature of the chip bending through a method of making an auxiliary line on the image, thereby achieving the effect of representing the chip deformation. The invention can systematically measure the longitudinal shrinkage coefficient, the transverse shrinkage coefficient and the bending curvature of the chip, and particularly provides a simple method for measuring the curvature radius of the chip, wherein the curvature radius can intuitively describe the bending degree of the chip.)

1. A method of measuring chip deformation, characterized by: the method comprises the following specific steps:

the method comprises the following steps: sequentially grinding and polishing the processing surface of the metal plate; selecting a plurality of pieces of abrasive paper with coarse particles to fine particles during grinding, and repeating the steps for multiple times; polishing is carried out for multiple times by using multiple polishing solutions with the abrasive grain sizes from large to small;

step two: marking a first concentric circle on the processing surface of the metal plate at a position which is L away from the edges of two adjacent edges by using a laser marking machine, and then marking a concentric circle every L along the vertical direction and the horizontal direction; wherein L is a value within a range of 1-2 cm, and the radiuses of the concentric circles are R₁、R₂And R₃Three circles of (a);

step three: placing the metal plate on a workbench of a planer and fixing the metal plate by using a clamp; then, adjusting the planer tool to the edge position of a first concentric circle on the machined surface of the metal plate, and setting a feeding amount t, wherein the t takes a value within the range of 1-2 mm; finally, the planer tool moves at a constant speed, and planing is carried out on the machined surface of the metal plate;

step four: collecting the cuttings, screening out the cuttings containing the complete concentric elliptical pattern, and executing the following steps on each piece of cuttings containing the complete concentric elliptical pattern: scanning and imaging the side surface of the chip by using an optical 3D surface profiler, taking a point A on a first layer of circular arc positioned in the chip curling in the obtained image, making a tangent line passing through the point A, then taking a point B on the tangent line, making a perpendicular line passing through the point B, intersecting the circular arc at a point C, measuring a linear distance r between the two points A, B and a linear distance h between the two points B, C, and then determining the curvature radius rho of the outer surface of the first layer of the chip curling as follows:

ρ＝r²/2h+h/2

finally, averaging the curvature radius of the outer surface of the first layer of all the curled chips containing the complete concentric elliptical patterns to be used as the final curvature radius of the metal plate chips;

step five: selecting a plurality of chips containing complete concentric elliptical patterns, and cutting each chip into a plurality of small sections by using a laser cutter, wherein each small section is ensured to contain a complete concentric elliptical pattern; then, the following steps are performed for each small chip containing a complete concentric elliptical pattern: scanning and imaging each small section of chip layer by using an optical 3D surface profiler, taking two points with the largest distance on the concentric elliptical pattern, drawing the major axis of the outermost ellipse through the two points, and finding out the midpoint of the two points, and marking the midpoint as the center of the concentric ellipse; then, a line segment perpendicular to the major axis of the outermost ellipse is made through the center of the concentric ellipse, the line segment intersects the outermost ellipse at two points, and the intersection point of the line segment and the two ellipses close to the inner part is taken to respectively calculate the length of the minor semi-axis of the three-layer ellipse; finally, averaging the semiaxis of the ellipse corresponding to the layer calculated on all the small sections of the cuttings containing the complete concentric elliptical pattern, and taking the average as the final semiaxis of the ellipse of the layer of the metal plate cuttings; the final minor semi-axes of the three layers of ellipses cut by the metal plate are respectively marked as r₁、r₂And r₃；

Step six: selecting a plurality of small sections of cutting scraps containing complete concentric elliptical patterns, measuring the thickness of each small section of cutting scraps by adopting a micrometer caliper, and taking the average value as the final thickness a of the metal plate cutting scraps;

step seven: calculating the transverse shrinkage coefficient K of the metal plate chip_a：

K_a＝a/t

Then, the longitudinal contraction coefficient K of three layers of ellipses on the metal plate cutting is calculated respectively_t1、K_t2And K_t3：

K_t1＝R₁/r₁

K_t2＝R₂/r₂

K_t3＝R₃/r₃

The average value of the three longitudinal contraction coefficients was defined as the longitudinal contraction coefficient K of the metal plate chip_t：

K_t＝(K_t1+K_t2+K_t3)/3。

2. A method of measuring chip deformation as claimed in claim 1, characterized in that: when the grinding and polishing processes are sequentially performed on the machined surface of the metal plate, the grinding and polishing processes are simultaneously performed on each of the adjacent surfaces of the machined surface.

3. A method of measuring chip deformation as claimed in claim 1, characterized in that: the granularity number of the sand paper is selected from 80-600 meshes.

4. A method of measuring chip deformation as claimed in claim 1, characterized in that: and polishing the processing surface of the metal plate by adopting polishing solutions with the abrasive grain diameters of 3 microns, 0.3 microns and 0.05 microns respectively.

5. A method of measuring chip deformation as claimed in claim 1, characterized in that: the total number of concentric circles punched on the processing surface of the metal plate is more than 20.

6. A method of measuring chip deformation as claimed in claim 1, characterized in that: r₁＝2mm、R₂4mm and R₃＝6mm。

Technical Field

The invention belongs to the technical field of metal cutting, and particularly relates to a method for measuring chip deformation.

Background

The metal deformation is the fundamental problem in the metal cutting process, the cutting force and the cutting heat are caused by the deformation, and the shrinkage coefficient of the metal is an important parameter for representing the metal deformation. There are two methods for measuring the coefficient of metal shrinkage at present. The first is a gravimetric method, in which the relationship between mass and chip area and chip length is derived, and the area and length are inversely proportional to each other, i.e., the coefficient of contraction can be expressed as an area ratio, depending on the fact that the volume of the chip before and after being cut is constant. Since the mass and size of the chips are small, the measurement requires a very high precision for the instrument, and therefore errors are unavoidable. The second method is simpler than the first method and uses direct measurement of the length before and after cutting to represent the shrinkage factor. However, both methods only measure the coefficient of contraction, and do not measure the curvature of the chip, and the second method only measures one longitudinal coefficient of contraction, which has large error and limited application range.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for measuring chip deformation, which can systematically measure the longitudinal shrinkage coefficient, the transverse shrinkage coefficient and the bending curvature of a chip, can more intuitively reflect the deformation of a metal machining chip and is easier to measure and calculate.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the invention relates to a method for measuring chip deformation, which comprises the following steps:

the method comprises the following steps: and sequentially grinding and polishing the processing surface of the metal plate. Selecting a plurality of pieces of abrasive paper with coarse particles to fine particles during grinding, and repeating the steps for multiple times; the polishing is repeated for a plurality of times by using a plurality of polishing solutions with the abrasive grain diameters from large to small.

Step two: distance between laser marking machine and processed surface of metal platePunching a first concentric circle at the position where the edges of two adjacent edges are L, and then punching a concentric circle every L along the vertical direction and the horizontal direction; wherein L is a value within a range of 1-2 cm, and the radiuses of the concentric circles are R₁、R₂And R₃Three circles of (a).

Step three: placing the metal plate on a workbench of a planer and fixing the metal plate by using a clamp; and then, adjusting the planer tool to the edge position of the first concentric circle on the processing surface of the metal plate, and setting the feeding amount t, wherein the t takes a value within the range of 1-2 mm. And finally, the planer tool moves at a constant speed, and planing the machined surface of the metal plate.

Step four: collecting the cuttings, screening out the cuttings containing the complete concentric elliptical pattern, and executing the following steps on each piece of cuttings containing the complete concentric elliptical pattern: scanning and imaging the side surface of the chip by using an optical 3D surface profiler, taking a point A on a first layer of circular arc positioned in the chip curling in the obtained image, making a tangent line passing through the point A, then taking a point B on the tangent line, making a perpendicular line passing through the point B, intersecting the circular arc at a point C, measuring a linear distance r between the two points A, B and a linear distance h between the two points B, C, and then determining the curvature radius rho of the outer surface of the first layer of the chip curling as follows:

ρ＝r²/2h+h/2

finally, the radius of curvature of the outer surface of the first layer of all chip curls containing a complete concentric elliptical pattern is averaged as the final radius of curvature of the metal sheet chip.

Step five: selecting a plurality of chips containing complete concentric elliptical patterns, and cutting each chip into a plurality of small sections by using a laser cutter, wherein each small section is ensured to contain a complete concentric elliptical pattern. Then, the following steps are performed for each small chip containing a complete concentric elliptical pattern: scanning and imaging each small section of chip layer by using an optical 3D surface profiler, taking two points with the largest distance on the concentric elliptical pattern, drawing the major axis of the outermost ellipse through the two points, and finding out the midpoint of the two points, and marking the midpoint as the center of the concentric ellipse; then, a line segment perpendicular to the major axis of the outermost ellipse is made through the center of the concentric ellipse and intersects the outermost ellipse at two points, and the two points are takenThe length of the short half shaft of the three-layer ellipse is respectively calculated by the intersection point of the line segment and the two ellipses close to the inner part. Finally, averaging the semiaxis of the ellipse corresponding to the layer calculated on all the small sections of the cuttings containing the complete concentric elliptical pattern, and taking the average as the final semiaxis of the ellipse of the layer of the metal plate cuttings; the final minor semi-axes of the three layers of ellipses cut by the metal plate are respectively marked as r₁、r₂And r₃。

Step six: selecting a plurality of small sections of chips containing complete concentric elliptical patterns, measuring the thickness of each small section of chip by adopting a micrometer caliper, and taking the average value as the final thickness a of the metal plate chip.

Step seven: calculating the transverse shrinkage coefficient K of the metal plate chip_a：

K_a＝a/t

Then, the longitudinal contraction coefficient K of three layers of ellipses on the metal plate cutting is calculated respectively_t1、K_t2And K_t3：

K_t1＝R₁/r₁

K_t2＝R₂/r₂

K_t3＝R₃/r₃

The average value of the three longitudinal contraction coefficients was defined as the longitudinal contraction coefficient K of the metal plate chip_t：

K_t＝(K_t1+K_t2+K_t3)/3。

Preferably, when the grinding and polishing processes are sequentially performed on the processed surface of the metal plate, the grinding and polishing processes are also simultaneously performed on the respective adjacent surfaces of the processed surface.

Preferably, the grain size number of the sand paper is selected from 80-600 meshes.

Preferably, the processing surface of the metal plate is sequentially polished with polishing liquids having abrasive grain diameters of 3 μm, 0.3 μm, and 0.05 μm, respectively.

Preferably, the total number of concentric circles punched on the processing surface of the metal plate is more than 20.

Preferably, R₁＝2mm、R₂4mm and R₃＝6mm。

The invention has the following beneficial effects:

the invention can systematically measure the longitudinal shrinkage coefficient, the transverse shrinkage coefficient and the bending curvature of the chip, and particularly provides a simple method for measuring the curvature radius of the chip, wherein the curvature radius can intuitively describe the bending degree of the chip. Furthermore, the deformation of the metal cutting chips is converted into the deformation of the patterns, the concentric circular patterns are drawn on the surface of the metal material, and the concentric circular patterns are simple in structure and convenient to observe; the size of the pattern on the chip is measured through cutting to calculate the shrinkage coefficient, and the curvature of the chip bending is measured through a method of making an auxiliary line on the image, so that the effect of representing the chip deformation is achieved. Therefore, the invention can reflect the deformation of the metal processing chip more intuitively and is easier to measure and calculate.

Drawings

Fig. 1 is a pattern printed on a metal surface before shaving.

Fig. 2 shows the pattern printed on the metal surface after deformation on the chip.

FIG. 3 is a schematic illustration of the planing of a metal surface to form chips.

Fig. 4 is a schematic view of the measurement of the curvature of the chip.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The method for measuring the chip deformation has wide application range, and the chip deformation of free-cutting metal materials such as metal aluminum, copper, steel and the like can be measured by the method. The shape of the metal material below is selected from a rectangular plate.

A method for measuring chip deformation specifically comprises the following steps:

the method comprises the following steps: in order to facilitate marking on the metal plate and clearly observe the morphological characteristics of the chips, the processing surface of the metal plate is sequentially ground and polished. During grinding, selecting a plurality of sand papers with the grains from coarse grains to fine grains (the grain size of the sand paper is selected from 80-600 meshes), and repeating for multiple times; the polishing is repeated several times by using several polishing solutions with the abrasive grain sizes from large to small (in this example, polishing solutions with abrasive grain sizes of 3 μm, 0.3 μm and 0.05 μm are used).

Step two: marking a first concentric circle on the processing surface of the metal plate at a position which is L away from the edges of two adjacent edges by using a laser marking machine, and then marking a concentric circle every L along the vertical direction and the horizontal direction; wherein the total number of the concentric circles is more than 20, and L is a value within a range of 1-2 cm. As shown in FIG. 1, the concentric circles have radii R₁、R₂And R₃Three circles of (a).

Step three: placing the metal plate on a workbench of a planer and fixing the metal plate by using a clamp; then, the planer tool is adjusted to the edge position of the first concentric circle punched on the processing surface of the metal plate, and the feeding amount (the depth of cutting into the processing surface) t is set, as shown in fig. 3, wherein t takes a value within the range of 1-2 mm. And finally, the planer tool moves at a constant speed to plane the processing surface of the metal plate.

Step four: collecting cuttings, and screening out the cuttings containing complete concentric elliptical patterns (complete deformation patterns of concentric circles); then, the following steps are performed for each chip containing a complete concentric elliptical pattern: scanning and imaging the side surface of the chip by using an optical 3D surface profiler (as the chip planed by a planer tool on the planer is in a curved shape with sawtooth inner surface, each side surface of the curved layer is approximate to a regular circular arc), as shown in FIG. 4, taking a point A on the circular arc of the first layer with the curved chip in the obtained image, making a tangent line passing through the point A, then taking a point B on the tangent line, making a perpendicular line passing through the point B, intersecting the circular arc at a point C, then measuring a linear distance r between the two points A, B and a linear distance h between the two points B, C, and then determining the curvature radius rho of the outer surface of the first layer with the curved chip as follows:

ρ＝r²/2h+h/2

finally, the radius of curvature of the outer surface of the first layer of all chip curls containing a complete concentric elliptical pattern is averaged as the final radius of curvature of the metal sheet chip.

Step five: selecting multiple chips containing complete concentric elliptical patterns, cutting each chip into several small segments by laser cutter, and avoiding mechanical deformation of chips during cuttingEach segment contains a complete concentric oval pattern. Then, the following steps are performed for each small chip containing a complete concentric elliptical pattern: scanning and imaging each small section of chip layer by using an optical 3D surface profiler, taking two points with the largest distance on the concentric elliptical pattern, drawing the major axis of the outermost ellipse through the two points, and finding out the midpoint of the two points, and marking the midpoint as the center of the concentric ellipse; then, a line segment perpendicular to the major axis of the outermost ellipse is made through the center of the concentric ellipse, the line segment intersects with the outermost ellipse at two points, and the length of the minor semi-axis of the three-layer ellipse is calculated by taking the intersection point of the line segment and the two ellipses close to the inner ellipse. And finally, averaging the semiaxis of the ellipse of the corresponding layer calculated on all the small sections of the chips containing the complete concentric elliptical pattern to serve as the final semiaxis of the metal plate chips on the ellipse of the layer, and respectively recording the final semiaxis of the ellipse of the three layers of the metal plate chips as r₁、r₂And r₃As shown in fig. 2.

Step six: a plurality of small sections of the chips containing complete concentric elliptical patterns are selected, the thickness of each small section of the chip is measured by a micrometer screw, and the average value is taken as the final thickness a of the metal plate chip, as shown in FIG. 3.

Step seven: calculating the transverse shrinkage coefficient K of the metal plate chip_a：

K_a＝a/t

Then, the longitudinal contraction coefficient K of three layers of ellipses on the metal plate cutting is calculated respectively_t1、K_t2And K_t3：

K_t1＝R₁/r₁

K_t2＝R₂/r₂

K_t3＝R₃/r₃

The average value of the three longitudinal contraction coefficients was defined as the longitudinal contraction coefficient K of the metal plate chip_t：

K_t＝(K_t1+K_t2+K_t3)/3。

Preferably, when the grinding and polishing processes are sequentially performed on the processed surface of the metal plate, the grinding and polishing processes are also simultaneously performed on the respective adjacent surfaces of the processed surface.

Preferably, R₁＝2mm、R₂4mm and R₃＝6mm。