阅读说明：本技术 一种微径金刚石球头铣刀竖直偏置校正方法 (Vertical offset correction method for micro-diameter diamond ball-end milling cutter ) 是由 刘世忠 陶洋 傅刚 吴立强 李国� 张海军 高林 张春雨 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种微径金刚石球头铣刀竖直偏置校正方法,涉及铣刀竖直偏置校正的技术领域,为了解决现有技术中竖直偏置校正方法存在精度不足的问题,本发明的步骤包括方形对刀块的粗加工、刀具水平偏置的粗略校正、刀具竖直偏置的粗略校正、方形对刀块的两轴联动超精密铣削加工、方形对刀块任一端面上下边沿X轴方向差值的试切标定、刀具Y向偏置方向及偏置量的计算、刀具Y向偏置量的校正和偏置校正后的试切验证；本发明的校正方法可以对超精密金刚石球头铣刀的竖直偏置进行精密校正,校正后铣刀竖直偏置误差可小于0.5μm,有助于推动我国多轴超精密铣削加工技术的发展。(The invention discloses a vertical offset correction method of a micro-diameter diamond ball-end milling cutter, which relates to the technical field of vertical offset correction of milling cutters and aims to solve the problem of insufficient precision of the vertical offset correction method in the prior art, and comprises the steps of rough machining of a square feeler block, rough correction of horizontal offset of a cutter, rough correction of vertical offset of the cutter, two-axis linkage ultra-precise milling of the square feeler block, trial cut calibration of the difference value of the upper edge and the lower edge of any end surface of the square feeler block in the X-axis direction, calculation of the Y-direction offset direction and offset of the cutter, correction of the Y-direction offset of the cutter and trial cut verification after offset correction; the correcting method can be used for precisely correcting the vertical offset of the ultra-precise diamond ball-end milling cutter, the error of the corrected vertical offset of the milling cutter can be less than 0.5 mu m, and the method is beneficial to promoting the development of the multi-axis ultra-precise milling technology in China.)

1. A vertical offset correction method for a micro-diameter diamond ball-end milling cutter is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: roughly machining a square tool setting piece, namely installing a blank piece on a C shaft of a machine tool, then installing a hard alloy end milling cutter on a milling shaft of the machine tool, and machining the blank into the square tool setting piece with a square section in a plane end milling mode;

step two: roughly correcting the horizontal offset of the cutter, namely measuring the distances between two pairs of opposite surfaces of a square feeler block respectively, averaging the measurement results to obtain the side length a of the cross section of the square feeler block, mounting a micro-diameter diamond ball-end milling cutter on a milling shaft of a machine tool, determining the X-axis position of a cutter center by using a surface trial cutting method, and roughly correcting the horizontal offset of the cutter;

step three: roughly correcting the vertical offset of the cutter, moving the cutter to the central point of the Y axis, and setting the central point of the Y axis to be zero in a machine tool system;

step four: the method comprises the following steps of carrying out linkage ultra-precision milling on two shafts of a square feeler block, fixing a Y shaft of a machine tool, compiling a numerical control program for realizing ultra-precision milling of the square feeler block by utilizing linkage of the X shaft and the C shaft, and carrying out multiple times of milling on the square feeler block until four planes of the square feeler block are completely cut;

step five: trial cutting calibration of the difference value of the upper edge and the lower edge of any one end face of the square feeler block in the X-axis direction, controlling the rotation of the shaft C to a programming zero position when the two shafts mill the square feeler block in a linkage manner, moving the X-axis to enable the cutter to gradually approach the end face of the square feeler block, reciprocating the Y-axis, performing multiple feeding through the X-axis to trial cut the end face of the square feeler block, and determining the difference value epsilon X of the upper edge and the lower edge of the end face of the square feeler block in the X-axis direction;

step six: calculating the bias direction and the bias amount of the tool Y, determining the axial bias direction of the tool Y and calculating the axial bias amount delta of the tool Y according to the difference value epsilon X of the upper edge and the lower edge of the end surface of the feeler block obtained by trial cutting in the step five;

step seven: correcting the Y-direction offset of the cutter, adjusting the position of the cutter according to the Y-direction offset delta obtained by calculation in the sixth step to enable the rotation axis of the cutter to be flush with the axis of the C shaft, and setting the Y coordinate of the position of the cutter to be zero;

step eight: and (4) verifying after the Y-direction offset of the cutter is corrected, repeating the process in the fourth step to perform two-axis linkage ultra-precision milling on the square cutter setting block, then continuing the process in the fifth step, finishing the correction if the Y-direction offset of the cutter is less than a set value, and otherwise, repeating the processes in the fourth step, the fifth step and the sixth step to further correct the Y-direction offset of the cutter.

2. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: in the first step, the effective length of the square feeler block is 8-10mm, and the side length of the cross section of the square feeler block is 5-6 mm.

3. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: the specific process of determining the position of the X axis of the cutter center by using the surface trial cutting method in the step two is as follows: swinging any end face of a workpiece to be vertical to the rotation axis of the micro-diameter diamond ball head milling cutter, coating ink on the end face of the workpiece, moving an X shaft of a machine tool to enable the micro-diameter diamond ball head milling cutter to approach the surface of the workpiece, keeping a Y shaft of the machine tool to reciprocate up and down, moving the X shaft of the machine tool until the milling cutter processes fine marks on the surface of the workpiece, determining the X coordinate of the cutter in a machine tool coordinate system to be a/2+ r according to the side length a of the cross section of the square feeler block and the rotation radius r of the cutter, and recording in a machine tool system.

4. The method for correcting the vertical offset of the micro-diameter diamond ball end mill according to claim 3, wherein the method comprises the following steps: the rotation speed of the milling cutter is 20000-.

5. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: in the third step, the upper and lower opposite planes of the square tool setting block are respectively cut in a trial mode by utilizing the side edges of the micro-diameter diamond ball head milling cutter, the vertical direction coordinates Y1 and Y2 corresponding to the two positions are recorded, and the coordinate of the center point of the Y axis is calculated to be (Y1+ Y2)/2.

6. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: in the fourth step, the numerical control program for realizing the ultraprecise milling of the square feeler block by utilizing the linkage of the X shaft and the C shaft is programmed as follows: dividing the end face of a square feeler block to be processed according to an angle theta, taking a division point every 0.05-0.1 degrees within the range of 0-360 degrees, and calculating the axial position of a milling cutter center point X for each angle by setting the angle corresponding to a feed control point as thetai:

X＝(a+2r)/(2cosθi)

wherein a is the side length of the cross section of the square feeler block, and r is the turning radius of the milling cutter.

7. The method for correcting the vertical offset of the micro-diameter diamond ball end mill according to claim 6, wherein the method comprises the following steps: in the fourth step, the processing distance of the square tool setting block is 3-4mm, the cutting depth of each layer is 5-10 μm, and the feed step distance is 5-8 μm.

8. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: the method for determining the bias direction of the milling cutter Y in the sixth step comprises the following steps: if the upper edge of the square feeler block is higher than the lower edge, the milling cutter is biased downwards in the Y direction, and the axis of the milling cutter is lower than that of the C shaft; if the lower edge of the square feeler block is higher than the upper edge, the Y direction of the milling cutter is biased upwards, and the axis of the milling cutter is higher than the axis of the C shaft.

9. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: in the sixth step, the calculation formula for determining the Y-direction offset delta of the milling cutter is as follows:

δ＝1.414εx

wherein, ε X is the difference of the upper and lower edges of the end face of the square feeler block along the X-axis direction.

10. The method for correcting the vertical offset of the micro-diameter diamond ball head milling cutter according to claim 1, wherein the method comprises the following steps: in the sixth step, the set value of the axial offset of the cutter Y is less than 0.5 μm.

Technical Field

The invention relates to the technical field of vertical offset correction of milling cutters, in particular to the technical field of a vertical offset correction method of a micro-diameter diamond ball head milling cutter.

Background

In recent years, an ultra-precision machining technology is rapidly developed, and is oriented to ultra-precision machining of parts with tiny complex shapes and various micro-lens arrays, the ultra-precision milling technology plays a crucial role in the technical field of ultra-precision machining, the ultra-precision milling utilizes a diamond milling cutter to rotate at a high speed to remove materials, and compared with ultra-precision turning, the ultra-precision milling technology can machine parts with complex structures in various shapes, such as spherical surfaces, non-spherical micro-lens arrays and complex free-form surface parts, on the premise of keeping low surface roughness.

The ultra-precision milling processed parts with micro shapes generally face the field of optical application, and the requirement on the surface precision is very high. During the ultra-precision milling, the motion precision of a machine tool shafting, the manufacturing precision of a milling cutter, the positioning precision of the milling cutter and the like all have obvious influence on the surface type precision of the part subjected to the ultra-precision milling. The vertical offset error of the milling cutter is one of the important factors of the positioning error of the milling cutter, and for non-rotating parts, the vertical offset error of the milling cutter can obviously influence the form and position precision of the geometric characteristics of the parts.

At present, a plurality of methods can be used for correcting the vertical offset of the milling cutter, the in-situ observation method of the optical tool setting gauge is a mature vertical offset correction method of the milling cutter, the main principle is that the height of the focal point of the optical tool setting gauge is precisely calibrated in advance, in the actual work, the height of the tool setting gauge is adjusted to enable the focal point to be aligned with the front tool face of the cutter, and then the position of the cutter in a machine tool coordinate system can be directly determined, and the method is convenient and efficient, but has low precision which is usually 5-10 mu m; a trial cutting method for the end face of a cylinder is a high-precision method for correcting the vertical offset of a milling cutter, and is characterized in that a micro-circle is trial cut on the end face of the cylinder through rotary motion, a straight line is trial cut at the zero position of a vertical coordinate, and a trial cutting graph is observed by a reading microscope in an off-line manner, so that the vertical offset of a cutter is determined, the precision is high, and the vertical offset can reach 2 micrometers generally; however, when the surface type precision of the part reaches submicron level, the existing vertical offset correction method has the problem of insufficient precision and cannot meet the processing requirement.

In order to solve the problem that the vertical offset correction method in the prior art is insufficient in precision, the vertical offset correction method for the micro-diameter diamond ball-end milling cutter is characterized by being provided.

Disclosure of Invention

The invention aims to: in order to solve the problem of insufficient precision of a vertical offset correction method in the prior art, the invention provides a vertical offset correction method of a micro-diameter diamond ball-end milling cutter.

The invention specifically adopts the following technical scheme for realizing the purpose:

a vertical offset correction method for a micro-diameter diamond ball head milling cutter comprises the following steps:

the method comprises the following steps: roughly machining a square tool setting piece, namely installing a blank piece on a C shaft of a machine tool, then installing a hard alloy end milling cutter on a milling shaft of the machine tool, and machining the blank into the square tool setting piece with a square section in a plane end milling mode; wherein, the effective length of the square feeler block is 8-10mm, and the side length of the cross section of the square feeler block is 5-6 mm.

Step two: roughly correcting the horizontal offset of the cutter, namely measuring the distances between two pairs of opposite surfaces of a square feeler block respectively, averaging the measurement results to obtain the side length a of the cross section of the square feeler block, mounting a micro-diameter diamond ball-end milling cutter on a milling shaft of a machine tool, determining the X-axis position of a cutter center by using a surface trial cutting method, and roughly correcting the horizontal offset of the cutter;

in the second step, the specific process of determining the position of the X axis of the cutter center by using the surface trial cutting method is as follows: swinging any end face of a workpiece to be vertical to the rotation axis of the micro-diameter diamond ball head milling cutter, coating ink on the end face of the workpiece, moving an X shaft of a machine tool to enable the micro-diameter diamond ball head milling cutter to approach the surface of the workpiece, keeping a Y shaft of the machine tool to reciprocate up and down, moving the X shaft of the machine tool until the milling cutter processes fine marks on the surface of the workpiece, determining the X coordinate of the cutter in a machine tool coordinate system to be a/2+ r according to the side length a of the cross section of the square feeler block and the rotation radius r of the cutter, and recording in a machine tool system;

the rotation speed of the milling cutter is 20000-.

Step three: roughly correcting the vertical offset of the cutter, moving the cutter to the central point of the Y axis, and setting the central point of the Y axis to be zero in a machine tool system; in the third step, the upper and lower opposite planes of the square tool setting block are respectively trial-cut by using the side edges of the micro-diameter diamond ball head milling cutter, the vertical direction coordinates Y1 and Y2 corresponding to the two positions are recorded, and the coordinate of the central point of the Y axis is calculated to be (Y1+ Y2)/2.

Step four: the method comprises the following steps of carrying out linkage ultra-precision milling on two shafts of a square feeler block, fixing a Y shaft of a machine tool, compiling a numerical control program for realizing ultra-precision milling of the square feeler block by utilizing linkage of the X shaft and the C shaft, and carrying out multiple times of milling on the square feeler block until four planes of the square feeler block are completely cut;

the numerical control program for realizing the ultraprecise milling of the square feeler block by utilizing the linkage of the X axis and the C axis is programmed as follows: dividing the end face of a square feeler block to be processed according to an angle theta, taking a division point every 0.05-0.1 degrees within the range of 0-360 degrees, and calculating the axial position of a milling cutter center point X for each angle by setting the angle corresponding to a feed control point as thetai:

X＝(a+2r)/(2cosθi)

wherein a is the side length of the cross section of the square feeler block, and r is the turning radius of the milling cutter;

in the fourth step, the processing distance of the square tool setting block is 3-4mm, the cutting depth of each layer is 5-10 μm, and the feed step distance is 5-8 μm.

Step five: trial cutting calibration of the difference value of the upper edge and the lower edge of any one end face of the square feeler block in the X-axis direction, controlling the rotation of the shaft C to a programming zero position when the two shafts mill the square feeler block in a linkage manner, moving the X-axis to enable the cutter to gradually approach the end face of the square feeler block, reciprocating the Y-axis, performing multiple feeding through the X-axis to trial cut the end face of the square feeler block, and determining the difference value epsilon X of the upper edge and the lower edge of the end face of the square feeler block in the X-axis direction;

step six: calculating the bias direction and the bias amount of the tool Y, determining the axial bias direction of the tool Y and calculating the axial bias amount delta of the tool Y according to the difference value epsilon X of the upper edge and the lower edge of the end surface of the feeler block obtained by trial cutting in the step five;

the method for determining the bias direction of the milling cutter Y in the sixth step comprises the following steps: if the upper edge of the square feeler block is higher than the lower edge, the milling cutter is biased downwards in the Y direction, and the axis of the milling cutter is lower than that of the C shaft; if the lower edge of the square feeler block is higher than the upper edge, the Y direction of the milling cutter is biased upwards, and the axis of the milling cutter is higher than the axis of the C shaft.

In the sixth step, the calculation formula for determining the Y-direction offset delta of the milling cutter is as follows:

δ＝1.414εx

wherein, ε X is the difference value of the upper and lower edges of the end surface of the square feeler block along the X-axis direction;

in the sixth step, the set value of the axial offset of the cutter Y is less than 0.5 μm.

Step seven: correcting the Y-direction offset of the cutter, adjusting the position of the cutter according to the Y-direction offset delta obtained by calculation in the sixth step to enable the rotation axis of the cutter to be flush with the axis of the C shaft, and setting the Y coordinate of the position of the cutter to be zero;

step eight: and (4) verifying after the Y-direction offset of the cutter is corrected, repeating the process in the fourth step to perform two-axis linkage ultra-precision milling on the square cutter setting block, then continuing the process in the fifth step, finishing the correction if the Y-direction offset of the cutter is less than a set value, and otherwise, repeating the processes in the fourth step, the fifth step and the sixth step to further correct the Y-direction offset of the cutter.

The invention has the following beneficial effects:

(1) according to the invention, the vertical offset of the diamond ball end mill is precisely corrected by an up-down trial cutting method, and the amplification of the vertical offset error of the milling cutter is realized by utilizing the recognition of the cutting trace of the ball end mill, so that the recognition precision of the vertical offset error of the milling cutter is obviously improved.

(2) The method has simple operation and low cost, can correct the vertical offset error of the milling cutter to be less than 0.5 mu m, and meets the requirement of processing high-precision complex curved surface parts.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic diagram of a three-dimensional structure of a square feeler block for rough machining and milling of an ultra-precise five-axis machine tool in the invention;

FIG. 3 is a schematic diagram of a programming method for milling a machining plane by using X-axis and C-axis two-axis linkage according to the present invention;

FIG. 4 is a schematic view of a three-dimensional structure of the ultra-precision square feeler block of the present invention using X-axis and C-axis linkage;

FIG. 5 is a schematic view of the back surface of the square feeler block of the present invention for trial cutting and machining up and down;

FIG. 6 is a schematic plan view of the invention after machining in a different Y-offset direction;

reference numerals: 1 square feeler block, 2 milling shafts and 3 micro-diameter diamond ball-end milling cutters.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

Example 1

As shown in fig. 1-2 and 4, the present embodiment provides a method for correcting vertical offset of a micro-diameter diamond ball end mill, including the following steps:

the method comprises the following steps: roughly machining a square tool setting piece, namely installing a cylindrical nonferrous metal blank on a C shaft of an ultra-precise five-shaft machine tool, then installing a hard alloy end milling cutter on a milling shaft of the machine tool, and machining the blank into the square tool setting piece with a square section in a plane end milling mode; wherein, the effective length of square feeler block is 8mm, and square feeler block's cross-section length of side is 5 mm.

Step two: roughly correcting the horizontal offset of the cutter, namely measuring the distance between two pairs of opposite surfaces of a square feeler block by using a micrometer screw, averaging the measurement results to obtain the side length a of the section of the square feeler block, mounting a micro-diameter diamond ball head milling cutter on a milling shaft of a machine tool, determining the X-axis position of a cutter center by using a surface trial cutting method, and roughly correcting the horizontal offset of the cutter;

in the second step, the specific process of determining the position of the X axis of the cutter center by using the surface trial cutting method is as follows: swinging any end face of a workpiece to be vertical to the rotation axis of the micro-diameter diamond ball end mill, coating ink on the end face by using a marking pen, rotating the micro-diameter diamond ball end mill at a high speed of 20000r/min, moving an X shaft by using a hand wheel to enable the micro-diameter diamond ball end mill to be close to the surface of a square feeler block, keeping the Y shaft to reciprocate up and down when the micro-diameter diamond ball end mill is in contact with the surface of the square feeler block, moving the X shaft by using the hand wheel in single feeding of 0.2 mu m until the micro-diameter diamond ball end mill processes a weak fine mark on the surface of the square feeler block, determining an X coordinate a/2+ r of the cutter under a machine tool coordinate system at the moment according to the side length a of the cross section of the square feeler block and the rotation radius r of the cutter, and recording the X coordinate a/2+ r in the machine tool system.

Step three: roughly correcting the vertical offset of the cutter, respectively trial-cutting upper and lower opposite planes of a square tool setting block by using a side edge of a micro-diameter diamond ball head milling cutter, recording vertical direction coordinates Y1 and Y2 corresponding to two positions, calculating to obtain a central point Y coordinate of (Y1+ Y2)/2, moving the cutter to the position, and setting the position Y coordinate to be zero in a machine tool system.

Step four: the method comprises the following steps of carrying out linkage ultra-precision milling on two shafts of a square feeler block, fixing a Y shaft of a machine tool, compiling a numerical control program for realizing ultra-precision milling of the square feeler block by only utilizing linkage of the X shaft and the C shaft, setting a processing distance to be 3mm, setting the cutting depth of each layer to be 5 mu m, setting the feed step distance to be 5 mu m, and carrying out milling processing on the square feeler block for multiple times until four planes of the square feeler block are completely cut;

as shown in fig. 3, the numerical control program for realizing the ultra-precise milling of the square feeler block by using the X-axis and C-axis linkage is programmed as follows: dividing the end face of a square feeler block to be processed according to an angle theta, taking a division point every 0.05 degrees within the range of 0-360 degrees, and calculating the axial position of a milling cutter center point X for each angle by setting the angle corresponding to a feed control point to be thetai:

X＝(a+2r)/(2cosθi)

wherein a is the side length of the cross section of the square feeler block, and r is the turning radius of the milling cutter;

the semi-circle in fig. 3 represents a milling cutter, and the corresponding coordinate of the center point X of the milling cutter is from X by taking the change of the C-axis angle theta from 0 DEG to 45 DEG as an example_sChange to x_dAccording to the coordinate relation between the C axis and the X axis, the X axis feed coordinate corresponding to one circle of rotation of the C axis can be calculated for each position in the Z axis direction, so that the square tool setting block can be machined only by linkage of the X axis and the C axis on the premise of fixing the Y axis, and the program can be compiled by most conventional mainstream programming software.

Step five: trial cutting calibration of the difference value of the upper edge and the lower edge of any one end face of the square feeler block in the X-axis direction, controlling the C-axis to rotate to a programmed zero position when the two axes are linked to mill the square feeler block, moving the X-axis to enable the cutter to gradually approach the end face of the square feeler block, setting the single feeding amount in the X direction to be 0.2 mu m, reciprocating the Y-axis, and performing multiple feeding through the X-axis to trial cut the end face of the square feeler block, wherein the surface cut mark of the end face of the square feeler block is shown in figure 5, as can be seen from figure 5, the upper edge of the square feeler block is firstly cut, and the corresponding X coordinate is X at the moment₁Cutting the lower edge of the feeler block, wherein the coordinate corresponding to X is X₂Accordingly, the difference value epsilon X of the upper edge and the lower edge of the end surface of the square feeler block in the X-axis direction can be determined;

step six: calculating the bias direction and the bias amount of the tool Y, determining the axial bias direction of the tool Y and calculating the axial bias amount delta of the tool Y according to the difference value epsilon X of the upper edge and the lower edge of the end surface of the feeler block obtained by trial cutting in the step five;

the method for determining the Y-direction offset direction of the milling cutter comprises the following steps: if the upper edge of the square feeler block is higher than the lower edge, the milling cutter is biased downwards in the Y direction, and the axis of the milling cutter is lower than that of the C shaft; if the lower edge of the square feeler block is higher than the upper edge, the Y direction of the milling cutter is biased upwards, and the axis of the milling cutter is higher than the axis of the C shaft; for example, when the milling cutter is biased downward in the Y direction and has a size of 5 μm, the shape of the machined square table end surface with a side length of 6mm is shown as the solid curve in fig. 6, and the upper edge is higher than the lower edge, so that when the square table end surface is trial cut, if the upper edge of the square block is cut first and the lower edge is cut later, the axis of the cutter is lower than the axis of the C-axis; when the milling cutter Y is biased upwards and has the size of 5 mu m, the shape of the square table end face obtained by processing is shown as a dotted curve in fig. 6, and the lower edge is higher than the upper edge, so that when the square table end face is trial cut, if the lower edge of the square block is cut firstly and the upper edge is cut later, the cutter axis is higher than the C-axis.

In the sixth step, the calculation formula for determining the Y-direction offset delta of the milling cutter is as follows:

δ＝1.414εx

wherein, ε X is the difference value of the upper and lower edges of the end surface of the square feeler block along the X-axis direction;

step seven: correcting the Y-direction offset of the cutter, adjusting the position of the cutter according to the Y-direction offset delta obtained by calculation in the sixth step to enable the rotation axis of the cutter to be flush with the axis of the C shaft, and setting the Y coordinate of the position of the cutter to be zero;

step eight: and (4) verifying after the Y-direction offset of the cutter is corrected, repeating the process in the fourth step to perform two-axis linkage ultra-precision milling on the square cutter setting block, then continuing the process in the fifth step, finishing the correction if the Y-direction offset of the cutter is less than 0.5 mu m, and otherwise, repeating the processes in the fourth step, the fifth step and the sixth step to further correct the Y-direction offset of the cutter.

Example 2

As shown in fig. 1-2 and 4, the present embodiment provides a method for correcting vertical offset of a micro-diameter diamond ball end mill, including the following steps:

the method comprises the following steps: roughly machining a square tool setting piece, namely installing a cylindrical nonferrous metal blank on a C shaft of an ultra-precise five-shaft machine tool, then installing a hard alloy end milling cutter on a milling shaft of the machine tool, and machining the blank into the square tool setting piece with a square section in a plane end milling mode; wherein, the effective length of square feeler block is 10mm, and square feeler block's cross-section length of side is 6 mm.

Step two: roughly correcting the horizontal offset of the cutter, namely measuring the distance between two pairs of opposite surfaces of a square feeler block by using a micrometer screw, averaging the measurement results to obtain the side length a of the section of the square feeler block, mounting a micro-diameter diamond ball head milling cutter on a milling shaft of a machine tool, determining the X-axis position of a cutter center by using a surface trial cutting method, and roughly correcting the horizontal offset of the cutter;

in the second step, the specific process of determining the position of the X axis of the cutter center by using the surface trial cutting method is as follows: swinging any end face of a workpiece to be vertical to the rotation axis of the micro-diameter diamond ball end mill, coating ink on the end face by using a marking pen, rotating the micro-diameter diamond ball end mill at a high speed of 30000r/min, moving an X shaft by using a hand wheel to enable the micro-diameter diamond ball end mill to be close to the surface of a square feeler block, keeping the Y shaft to reciprocate up and down when the micro-diameter diamond ball end mill is in contact with the surface of the square feeler block, moving the X shaft by using the hand wheel in single feeding of 0.2 mu m until the micro-diameter diamond ball end mill processes a weak fine mark on the surface of the square feeler block, determining an X coordinate a/2+ r of the cutter under a machine tool coordinate system at the moment according to the side length a of the cross section of the square feeler block and the rotation radius r of the cutter, and recording the X coordinate a/2+ r in the machine tool system.

Step three: roughly correcting the vertical offset of the cutter, respectively trial-cutting upper and lower opposite planes of a square tool setting block by using a side edge of a micro-diameter diamond ball head milling cutter, recording vertical direction coordinates Y1 and Y2 corresponding to two positions, calculating to obtain a central point Y coordinate of (Y1+ Y2)/2, moving the cutter to the position, and setting the position Y coordinate to be zero in a machine tool system.

Step four: the method comprises the following steps of carrying out linkage ultra-precision milling on two shafts of a square feeler block, fixing a Y shaft of a machine tool, compiling a numerical control program for realizing the ultra-precision milling of the square feeler block by only utilizing the linkage of the two shafts of the X shaft and the C shaft, setting a processing distance to be 4mm, setting the cutting depth of each layer to be 10 mu m, setting the feed step distance to be 8 mu m, and carrying out multiple times of milling on the square feeler block until four planes of the square feeler block are completely cut;

as shown in fig. 3, the numerical control program for realizing the ultra-precise milling of the square feeler block by using the X-axis and C-axis linkage is programmed as follows: dividing the end face of a square feeler block to be processed according to an angle theta, taking a division point every 0.1 degree within the range of 0-360 degrees, and calculating the axial position of a milling cutter center point X for each angle by setting the angle corresponding to a feed control point to be thetai:

X＝(a+2r)/(2cosθi)

wherein a is the side length of the cross section of the square feeler block, and r is the turning radius of the milling cutter;

the semi-circle in fig. 3 represents a milling cutter, and the corresponding coordinate of the center point X of the milling cutter is from X by taking the change of the C-axis angle theta from 0 DEG to 45 DEG as an example_sChange to x_dAccording to the coordinate relation between the C axis and the X axis, the X axis feed coordinate corresponding to one circle of rotation of the C axis can be calculated for each position in the Z axis direction, so that the square tool setting block can be machined only by linkage of the X axis and the C axis on the premise of fixing the Y axis, and the program can be compiled by most conventional mainstream programming software.

Step five: trial cutting calibration of the difference value of the upper edge and the lower edge of any one end face of the square feeler block in the X-axis direction, controlling the C-axis to rotate to a programmed zero position when the two axes are linked to mill the square feeler block, moving the X-axis to enable the cutter to gradually approach the end face of the square feeler block, setting the single feeding amount in the X direction to be 0.2 mu m, reciprocating the Y-axis, and performing multiple feeding through the X-axis to trial cut the end face of the square feeler block, wherein the surface cut mark of the end face of the square feeler block is shown in figure 5, as can be seen from figure 5, the upper edge of the square feeler block is firstly cut, and the corresponding X coordinate is X at the moment₁Cutting the lower edge of the feeler block, wherein the coordinate corresponding to X is X₂Accordingly, the difference value epsilon X of the upper edge and the lower edge of the end surface of the square feeler block in the X-axis direction can be determined;

step six: calculating the bias direction and the bias amount of the tool Y, determining the axial bias direction of the tool Y and calculating the axial bias amount delta of the tool Y according to the difference value epsilon X of the upper edge and the lower edge of the end surface of the feeler block obtained by trial cutting in the step five;

the method for determining the Y-direction offset direction of the milling cutter comprises the following steps: if the upper edge of the square feeler block is higher than the lower edge, the milling cutter is biased downwards in the Y direction, and the axis of the milling cutter is lower than that of the C shaft; if the lower edge of the square feeler block is higher than the upper edge, the Y direction of the milling cutter is biased upwards, and the axis of the milling cutter is higher than the axis of the C shaft; for example, when the milling cutter is biased downward in the Y direction and has a size of 5 μm, the shape of the machined square table end surface with a side length of 6mm is shown as the solid curve in fig. 6, and the upper edge is higher than the lower edge, so that when the square table end surface is trial cut, if the upper edge of the square block is cut first and the lower edge is cut later, the axis of the cutter is lower than the axis of the C-axis; when the milling cutter Y is biased upwards and has the size of 5 mu m, the shape of the square table end face obtained by processing is shown as a dotted curve in fig. 6, and the lower edge is higher than the upper edge, so that when the square table end face is trial cut, if the lower edge of the square block is cut firstly and the upper edge is cut later, the cutter axis is higher than the C-axis.

In the sixth step, the calculation formula for determining the Y-direction offset delta of the milling cutter is as follows:

δ＝1.414εx

wherein, ε X is the difference value of the upper and lower edges of the end surface of the square feeler block along the X-axis direction;

step seven: correcting the Y-direction offset of the cutter, adjusting the position of the cutter according to the Y-direction offset delta obtained by calculation in the sixth step to enable the rotation axis of the cutter to be flush with the axis of the C shaft, and setting the Y coordinate of the position of the cutter to be zero;

step eight: and (4) verifying after the Y-direction offset of the cutter is corrected, repeating the process in the fourth step to perform two-axis linkage ultra-precision milling on the square cutter setting block, then continuing the process in the fifth step, finishing the correction if the Y-direction offset of the cutter is less than 0.5 mu m, and otherwise, repeating the processes in the fourth step, the fifth step and the sixth step to further correct the Y-direction offset of the cutter.

Example 3

As shown in fig. 1-2 and 4, the present embodiment provides a method for correcting vertical offset of a micro-diameter diamond ball end mill, including the following steps:

the method comprises the following steps: roughly machining a square tool setting piece, namely installing a cylindrical nonferrous metal blank on a C shaft of an ultra-precise five-shaft machine tool, then installing a hard alloy end milling cutter on a milling shaft of the machine tool, and machining a pure aluminum blank into the square tool setting piece with a square section in a plane end milling mode; wherein, the effective length of square feeler block is 9mm, and the cross-section side length of square feeler block is 5.5 mm.

Step two: roughly correcting the horizontal offset of the cutter, namely measuring the distance between two pairs of opposite surfaces of a square feeler block by using a micrometer screw, averaging the measurement results to obtain the side length a of the section of the square feeler block, mounting a micro-diameter diamond ball head milling cutter on a milling shaft of a machine tool, determining the X-axis position of a cutter center by using a surface trial cutting method, and roughly correcting the horizontal offset of the cutter;

in the second step, the specific process of determining the position of the X axis of the cutter center by using the surface trial cutting method is as follows: swinging any end face of a workpiece to be vertical to the rotation axis of the micro-diameter diamond ball end mill, coating ink on the end face by using a marking pen, rotating the micro-diameter diamond ball end mill at a high speed of 25000r/min, moving an X shaft by using a hand wheel to enable the micro-diameter diamond ball end mill to be close to the surface of a square feeler block, keeping the Y shaft to reciprocate up and down when the micro-diameter diamond ball end mill is in contact with the surface of the square feeler block, moving the X shaft by using the hand wheel in single feeding of 0.2 mu m until the micro-diameter diamond ball end mill processes a weak fine mark on the surface of the square feeler block, determining an X coordinate a/2+ r of the cutter under a machine tool coordinate system at the moment according to the side length a of the cross section of the square feeler block and the rotation radius r of the cutter, and recording the X coordinate a/2+ r in the machine tool system.

Step three: roughly correcting the vertical offset of the cutter, respectively trial-cutting upper and lower opposite planes of a square tool setting block by using a side edge of a micro-diameter diamond ball head milling cutter, recording vertical direction coordinates Y1 and Y2 corresponding to two positions, calculating to obtain a central point Y coordinate of (Y1+ Y2)/2, moving the cutter to the position, and setting the position Y coordinate to be zero in a machine tool system.

Step four: the method comprises the following steps of carrying out double-shaft linkage ultra-precision milling on a square feeler block, fixing a Y shaft of a machine tool, compiling a numerical control program for realizing the ultra-precision milling of the square feeler block by only utilizing double-shaft linkage of an X shaft and a C shaft, setting a processing distance to be 3.5mm, setting the cutting depth of each layer to be 7.5 mu m, setting a feed step distance to be 6.5 mu m, and carrying out multiple times of milling on the square feeler block until four planes of the square feeler block are completely cut;

as shown in fig. 3, the numerical control program for realizing the ultra-precise milling of the square feeler block by using the X-axis and C-axis linkage is programmed as follows: dividing the end face of a square feeler block to be processed according to an angle theta, taking a dividing point every 0.075 DEG within the range of 0-360 DEG, and calculating the axial position of a milling cutter center point X for each angle by setting the angle corresponding to a feed control point to be theta i:

X＝(a+2r)/(2cosθi)

wherein a is the side length of the cross section of the square feeler block, and r is the turning radius of the milling cutter;

the semi-circle in fig. 3 represents a milling cutter, and the corresponding coordinate of the center point X of the milling cutter is from X by taking the change of the C-axis angle theta from 0 DEG to 45 DEG as an example_sChange to x_dAccording to the coordinate relation between the C axis and the X axis, the X axis feed coordinate corresponding to one circle of rotation of the C axis can be calculated for each position in the Z axis direction, so that the square tool setting block can be machined only by linkage of the X axis and the C axis on the premise of fixing the Y axis, and the program can be compiled by most conventional mainstream programming software.

Step five: trial cutting calibration of the difference value of the upper edge and the lower edge of any one end face of the square feeler block in the X-axis direction, controlling the C-axis to rotate to a programmed zero position when the two axes are linked to mill the square feeler block, moving the X-axis to enable the cutter to gradually approach the end face of the square feeler block, setting the single feeding amount in the X direction to be 0.2 mu m, reciprocating the Y-axis, and performing multiple feeding through the X-axis to trial cut the end face of the square feeler block, wherein the surface cut mark of the end face of the square feeler block is shown in figure 5, as can be seen from figure 5, the upper edge of the square feeler block is firstly cut, and the corresponding X coordinate is X at the moment₁Cutting the lower edge of the feeler block, wherein the coordinate corresponding to X is X₂Therefore, the upper and lower edges of the end surface of the square feeler block can be determinedThe difference in the X-axis direction is ε X;

step six: calculating the bias direction and the bias amount of the tool Y, determining the axial bias direction of the tool Y and calculating the axial bias amount delta of the tool Y according to the difference value epsilon X of the upper edge and the lower edge of the end surface of the feeler block obtained by trial cutting in the step five;

the method for determining the Y-direction offset direction of the milling cutter comprises the following steps: if the upper edge of the square feeler block is higher than the lower edge, the milling cutter is biased downwards in the Y direction, and the axis of the milling cutter is lower than that of the C shaft; if the lower edge of the square feeler block is higher than the upper edge, the Y direction of the milling cutter is biased upwards, and the axis of the milling cutter is higher than the axis of the C shaft; for example, when the milling cutter is biased downward in the Y direction and has a size of 5 μm, the shape of the end surface of a square table with a side length of 6mm obtained by processing is shown as the solid curve in fig. 6, the abscissa is an x-direction coordinate, the ordinate is a Y-direction coordinate, two curves are planar actual contour diagrams with errors, the middle vertical line is an ideal contour, the unit of numerical value is mm, and the upper edge is higher than the lower edge, so that when the end surface of the square table is trial cut, if the upper edge of a square block is cut first and the lower edge is cut later, the axis of the cutter is lower than the axis of the C-axis; when the milling cutter Y is biased upwards and has the size of 5 mu m, the shape of the square table end face obtained by processing is shown as a dotted curve in fig. 6, and the lower edge is higher than the upper edge, so that when the square table end face is trial cut, if the lower edge of the square block is cut firstly and the upper edge is cut later, the cutter axis is higher than the C-axis.

In the sixth step, the calculation formula for determining the Y-direction offset delta of the milling cutter is as follows:

δ＝1.414εx

wherein, ε X is the difference value of the upper and lower edges of the end surface of the square feeler block along the X-axis direction;

step seven: correcting the Y-direction offset of the cutter, adjusting the position of the cutter according to the Y-direction offset delta obtained by calculation in the sixth step to enable the rotation axis of the cutter to be flush with the axis of the C shaft, and setting the Y coordinate of the position of the cutter to be zero;

step eight: and (4) verifying after the Y-direction offset of the cutter is corrected, repeating the process in the fourth step to perform two-axis linkage ultra-precision milling on the square cutter setting block, then continuing the process in the fifth step, finishing the correction if the Y-direction offset of the cutter is less than 0.5 mu m, and otherwise, repeating the processes in the fourth step, the fifth step and the sixth step to further correct the Y-direction offset of the cutter.

The cutter mentioned in the application refers to a micro-diameter diamond ball end milling cutter, and through the embodiment, the invention is mainly realized by adopting a trial cutting method, utilizing a unique C-axis and X-axis two-axis linkage machining plane, and realizing the precise identification of the vertical offset error of the milling cutter through up-down trial cutting, thereby realizing the precise correction of the vertical offset of the diamond ball end milling cutter. Rough machining of a square feeler block, rough correction of horizontal offset of a cutter, rough correction of vertical offset of the cutter, two-axis linkage ultra-precise milling of the square feeler block, trial cutting calibration of difference values of the upper edge and the lower edge of any end surface of the square feeler block in the X-axis direction, calculation of the Y-direction offset direction and offset of the cutter, correction of the Y-direction offset of the cutter and trial cutting verification after offset correction; the correcting method can be used for precisely correcting the vertical offset of the ultra-precise diamond ball-end milling cutter, the error of the corrected vertical offset of the milling cutter can be less than 0.5 mu m, and the method is beneficial to promoting the development of the multi-axis ultra-precise milling technology in China.