High-precision milling combined machine tool and processing method thereof

Abstract

The application discloses a high-precision milling combined machine tool and a machining method thereof, and the machine tool comprises a machine base, a milling platform, a feeding driving mechanism, a gantry frame, a YZ two-dimensional driving mechanism, a milling mechanism, a thermal error detection and compensation mechanism and a cutter rotating shaft and milling cutter monitoring and analyzing mechanism. Through the thermal error detection and compensation mechanism, the feeding driving mechanism and the YZ two-dimensional driving mechanism can be thermally compensated, so that the error caused by thermal deformation to the milling machining can be reduced, and the machining precision of the workpiece is improved. Through the cutter rotating shaft and milling cutter monitoring and analyzing mechanism, the axis track of the cutter rotating shaft is monitored by adopting an image processing-based method, the damage state of the milling cutter can be obtained according to the monitoring result analysis, so that the milling cutter state can be monitored, the machining quality of the workpiece is ensured, and the loss caused by the damage of the workpiece or other components due to the abnormal milling cutter can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of combined machine tool equipment, in particular to a high-precision milling combined machine tool and a machining method thereof. BACKGROUND

[0002] Milling machine tool mainly refers to a machine tool for processing various surfaces of a workpiece with a milling cutter. Generally, the rotary motion of the milling cutter is the main motion, and the movement of the workpiece and the milling cutter is the feeding motion. It can process planes, grooves, and various curved surfaces, gears, etc., and is widely used in mechanical manufacturing and repair departments.

[0003] One of the main factors affecting the machining accuracy of the machine tool is thermal error. Measuring and then compensating for thermal error is an effective method to reduce thermal error. For example, patent CN113857936B discloses a machine tool column thermal compensation method and system based on visual detection, patent CN114310485B discloses a machine tool feed shaft thermal error prediction method, device and storage medium, and patent CN103567815B discloses a numerical control machine tool cutting thermal error testing and evaluation method based on milling small holes. However, the above-mentioned solutions have the defect of complex method, which limits their practical application.

[0004] On the other hand, for the milling machine tool, the milling cutter rotates under the drive of the rotating shaft. During high-speed rotation, the position of the shaft center of the rotating shaft is prone to change, which is manifested as radial runout, which will affect the machining accuracy of the milling cutter. However, the current milling machine tool usually cannot compensate for the shift of the shaft center of the rotating shaft. In addition, the milling cutter is prone to excessive wear, deformation, or even damage or cracking during work. In this case, if the work continues, the workpiece machining accuracy will be seriously affected, and even the workpiece or other components will be damaged. Therefore, it is necessary to monitor the state of the milling cutter. However, it is usually not possible to directly monitor the milling cutter because cooling liquid is usually applied to the milling cutter during machining, and debris is easily attached to the milling cutter. Patent CN114453630A discloses a method and device for controlling milling without sticking to the milling cutter, electronic equipment and storage medium. It uses an indirect method to detect the state of the milling cutter, but the method is complex, which limits its practical application.

[0005] Therefore, it is necessary to improve the existing technology to provide a more reliable solution. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a high-precision milling combined machine tool and a machining method thereof to solve the problems in the prior art.

[0007] To solve the above technical problems, the technical solution adopted by the present application is: a high-precision milling combined machine tool, comprising:

[0008] a machine base;

[0009] a milling platform, which is slidably arranged on the machine base along an X-axis direction, for carrying a workpiece to be processed;

[0010] a feed driving mechanism, which is used to drive the milling platform to move linearly along the X-axis direction;

[0011] a gantry frame, which is arranged astride the machine base;

[0012] a YZ two-dimensional driving mechanism, which is arranged on a cross beam of the gantry frame, for providing linear movement functions in Y-axis and Z-axis directions;

[0013] a milling mechanism, which is arranged on the YZ two-dimensional driving mechanism, and includes a tool spindle rotatably arranged on the YZ two-dimensional driving mechanism, a clamp connected to a bottom of the tool spindle, a milling cutter mounted on the clamp, and a rotation driving mechanism for driving the tool spindle to rotate around the Z-axis;

[0014] a thermal error detection and compensation mechanism, which acquires thermal error proportional coefficients of the feed driving mechanism in the X-axis direction, the YZ two-dimensional driving mechanism in the Y-axis and Z-axis directions, and the rotation driving mechanism in the Z-axis direction based on an image processing method, and accordingly performs thermal compensation;

[0015] and a tool spindle and milling cutter monitoring and analyzing mechanism, which monitors an axial track of the tool spindle based on an image processing method, and analyzes a damage state of the milling cutter according to a monitoring result.

[0016] Preferably, the feed driving mechanism is a lead screw motor driving mechanism, which includes an X lead screw and an X slide rail arranged on the machine base along the X-axis direction, an X lead screw nut cooperatively arranged on the X lead screw, an X slide block cooperatively arranged on the X slide rail, and an X motor for driving the X lead screw to rotate; the milling platform is arranged on the X slide block and connected with the X lead screw nut;

[0017] the YZ two-dimensional driving mechanism is a lead screw motor driving mechanism, which includes a Y lead screw and a Y slide rail arranged on the cross beam of the gantry frame along the Y-axis direction, a Y lead screw nut cooperatively arranged on the Y lead screw, a Y slide block cooperatively arranged on the Y slide rail, a Y motor for driving the Y lead screw to rotate, a Y mounting plate arranged on the Y slide block and connected with the Y lead screw nut, a Z lead screw and a Z slide rail arranged on the Y mounting plate along the Z-axis direction, a Z lead screw nut cooperatively arranged on the Z lead screw, a Z slide block cooperatively arranged on the Z slide rail, a Z motor for driving the Z lead screw to rotate, and a Z mounting plate arranged on the Z slide block and connected with the Z lead screw nut;

[0018] The milling mechanism is arranged on the Z mounting plate, the Z mounting plate is provided with a rotating shaft mounting block, the cutter rotating shaft is rotatably arranged on the rotating shaft mounting block, and the rotary driving mechanism is arranged on the rotating shaft mounting block and is in driving connection with the cutter rotating shaft.

[0019] Preferably, the ends of the X lead screw, the Y lead screw and the Z lead screw are provided with optical shaft parts, the shaft bodies of the optical shaft parts and the shaft body of the cutter rotating shaft are provided with thermal error detection patterns, and the thermal error detection pattern comprises two detection circles arranged on the circumferential surface of the shaft body in length direction and a filling area between the two detection circles, the filling area has a color different from that of the shaft body.

[0020] The thermal error detection and compensation mechanism comprises four first CCD cameras arranged on the thermal error detection pattern side of the X lead screw, the Y lead screw, the Z lead screw and the cutter rotating shaft respectively, a thermal error analysis module connected with the four first CCD cameras, and a first control module connected with the thermal error analysis module, and the first control module is connected with the feeding driving mechanism, the YZ two-dimensional driving mechanism and the rotary driving mechanism.

[0021] The four first CCD cameras are used to respectively collect the planar images of the thermal error detection patterns at the corresponding positions, the thermal error analysis module compares and analyzes the collected planar images with the planar images corresponding to the thermal error detection patterns at the standard working temperature, so as to obtain the thermal error proportion coefficient, and the first control module performs thermal compensation on the feeding driving mechanism and the YZ two-dimensional driving mechanism according to the thermal error proportion coefficient.

[0022] Preferably, the working method of the thermal error detection and compensation mechanism comprises the following steps:

[0023] S1-1, collecting the planar image of the thermal error detection pattern by the first CCD camera;

[0024] S1-2, the thermal error analysis module obtains n line segments in the planar image which are parallel to the axis of the shaft body on which the planar image is located, as length line segments, calculates the average length of the n length line segments as the length of the planar image , obtains m line segments in the planar image which are perpendicular to the length line segments, as width line segments, and calculates the average length of the m width line segments as the width of the planar image .

[0025] S1-3, when , it is judged that the current planar image is valid, and the thermal error proportion coefficient K is calculated, ; otherwise, it is judged that the current planar image is invalid, and the collection of the planar image of the thermal error detection pattern by the first CCD camera is controlled again until the planar image is judged to be valid;

[0026] wherein ε k is a preset thermal error ratio threshold value; L b and D b respectively are length and width of the planar image corresponding to the thermal error detection pattern at the standard working temperature;

[0027] S1-4, the first control module controls the driving mechanism corresponding to the axis body where the current planar image is located according to the thermal error ratio coefficient K, so as to perform thermal compensation on the position along the axial direction of the axis body.

[0028] Preferably, the cutter shaft and the milling cutter monitoring and analyzing mechanism also compensate the radial position of the cutter shaft center according to the monitoring result of the cutter shaft center trajectory.

[0029] Preferably, a horizontal detection plate is connected to the Z mounting plate, and a detection hole is formed in the detection plate, the diameter of the detection hole is greater than the diameter of the cutter shaft, and the center of the detection hole coincides with the theoretical position of the axis center of the cutter shaft.

[0030] Preferably, the cutter shaft and the milling cutter monitoring and analyzing mechanism include a second CCD camera arranged above the detection plate, an image analysis and generation module connected with the second CCD camera, a cutter damage analysis module connected with the image analysis and generation module, and an axis center offset compensation module connected with the image analysis and generation module.

[0031] The axis center offset compensation module is connected with the feed driving mechanism and the YZ two-dimensional driving mechanism,

[0032] The image analysis and generation module is connected with the rotary driving mechanism, and the cutter damage analysis module is connected with the feed driving mechanism, the YZ two-dimensional driving mechanism, and the rotary driving mechanism.

[0033] The outer periphery of the outer detection circle on the detection plate is drawn with color one as X-axis and Y-axis, the X-axis and the Y-axis are perpendicular, the intersection point O0 of the extensions of the X-axis and the Y-axis coincides with the center of the detection hole, and the detection coordinate system XO0Y is established with the intersection point O0 as the origin and the X-axis and the Y-axis as the X-axis and the Y-axis, respectively.

[0034] The outer periphery of the cutter shaft is drawn with color two as an inner detection circle, the center of the cutter shaft is drawn with color three as a center dot, and the center O Z of the center dot coincides with the axis center of the cutter shaft.

[0035] Color 1 is different from the color of the detection plate, and Color 2 and Color 3 are both different from the color of the tool spindle body, so that the spindle detection pattern composed of the outer detection circle, X-axis, Y-axis, inner detection circle and center dot can be captured by the second CCD camera.

[0036] Preferably, the working method of the tool spindle and milling cutter monitoring and analysis mechanism includes the following steps:

[0037] S2-1. The second CCD camera acquires one image P of the rotation detection pattern every time Δt, and records the current time t. i The image of the acquired shaft detection pattern is P i Then at the previous time t i-1 The image of the acquired shaft detection pattern is P i-1 Δt=t i -t i-1 ;

[0038] S2-2, The image analysis and generation module will P i Obtain the center O after grayscale processing Z The position in the detection coordinate system XO0Y is denoted as O. Zi (X) i ,Y i ), then X i Y i These represent the offset positions of the tool spindle axis in the X and Y directions, respectively, i.e., O. Zi Indicates the radial position of the tool spindle axis; the axis offset compensation module is based on X. i Control the feed drive mechanism to achieve the desired result at the next time t. i+1 Perform position compensation in the X direction, based on the Y direction. i Control the YZ two-dimensional drive mechanism to achieve the desired effect at the next time t. i+1 Perform position compensation in the Y direction;

[0039] S2-3, The image analysis and generation module obtains P i The maximum value of the distance Δd between the outer and inner detection circles. max and minimum value Δd min When Δd max -Δd min >ε d If the machine detects abnormal radial deformation of the tool spindle, it issues an alarm and stops the milling mechanism for inspection; otherwise, it proceeds to the next step; where ε d The preset spacing threshold;

[0040] The method for obtaining the distance Δd between the outer and inner detection circles is as follows: passing through the center OZ Draw a straight line that intersects the inner and outer detection circles in sequence, and the distance between the two intersection points is taken as the spacing Δd;

[0041] S2-4, The image analysis and generation module obtains the current time t. i Center O Z Position O Zi The position O Zi This refers to the current axis position of the tool spindle, and the image analysis and generation module acquires the time t. i The center of the circle O at all previous moments Z The position is determined by replacing the Z-axis in the XYZ three-dimensional coordinate system with time t, establishing a tXY three-dimensional coordinate system, and assigning the center position O of the circle corresponding to each time t. Z By placing the coordinates in the tXY three-dimensional coordinate system, the axis trajectory S of the tool rotation axis at different times can be obtained. i Where, for any time t i The center position O of the circle at time Zi Represented as (t) i X i Y i ), t i Corresponding to the value on the t-axis, X i Y i These correspond to the values ​​on the X and Y axes, respectively.

[0042] S2-5, Tool breakage analysis module obtains the current time t. i The axis trajectory graph S below i Then, it determines whether the milling cutter is damaged. If it is damaged, it outputs the damage type judgment result. When the judgment result is that the tool is missing, broken, or deformed, it controls the milling mechanism to stop working and issues an alarm message.

[0043] The types of damage include: tool defects or breakage, tool wear, and tool deformation.

[0044] Preferably, the tool breakage analysis module includes a feature extraction sub-module and a breakage discrimination sub-model based on a machine learning algorithm, wherein the breakage discrimination sub-model is constructed using the following method:

[0045] S3-1. Constructing the training dataset:

[0046] S3-1-1. Using the same batch of milling cutters to process the same batch of workpieces, after processing for the same amount of time, count the damage status of each milling cutter. The damage status includes: no damage, tool missing or broken, tool worn, and tool deformed. Among all the milling cutters counted, the number of milling cutters in each damage status is at least N; where N≥50.

[0047] S3-1-2, obtain the shaft center trajectory pattern of each milling cutter, and take the corresponding damage state of the milling cutter as the label of the shaft center trajectory pattern;

[0048] S3-1-3, the feature extraction submodule performs discriminant feature extraction on the shaft center trajectory pattern of each milling cutter, and the discriminant features include: phase and amplitude of the shaft center trajectory pattern, slope of each center position O Z on the shaft center trajectory pattern, and peak-to-peak distance; wherein the peak-to-peak distance is the straight-line distance between adjacent two peaks on the shaft center trajectory pattern;

[0049] S3-1-4, the shaft center trajectory pattern of one milling cutter, the corresponding label and the discriminant features are combined into one training data, and all the training data of the obtained milling cutters are combined to obtain a training data set;

[0050] S3-2, taking the shaft center trajectory pattern of the milling cutter and its discriminant features as input, and the corresponding damage state label as output, the training data set is used to train the CNN convolutional neural network, and the damage discriminant submodel is obtained after the training is completed;

[0051] When the tool damage analysis module works, the feature extraction submodule obtains the shaft center trajectory pattern S i at the current time t i , analyzes to obtain discriminant features, and then inputs the discriminant features and the shaft center trajectory pattern S i to the damage discriminant submodel, and obtains the judgment result of the damage state through the damage discriminant submodel;

[0052] The application also provides a machining method of the high-precision milling combined machine tool.

[0053] Step one, the feed drive mechanism works, and the workpiece to be machined on the milling platform is transported to the machining station;

[0054] Step two, the YZ two-dimensional drive mechanism works, moves the milling cutter on the milling mechanism above the position to be machined on the workpiece, and the rotary drive mechanism drives the milling cutter to rotate, and cooperates with the feed drive mechanism and the YZ two-dimensional drive mechanism to mill the workpiece;

[0055] Step three, during the whole machining process:

[0056] The thermal error detection and compensation mechanism analyzes the thermal error proportional coefficient of the X lead screw, the Y lead screw, the Z lead screw and the tool shaft, and performs thermal compensation accordingly;

[0057] The cutter rotating shaft and the milling cutter monitoring and analyzing mechanism monitor the axial track of the cutter rotating shaft, and compensate the radial position of the axial center of the cutter rotating shaft according to the monitoring result, judge whether the cutter rotating shaft has radial abnormal deformation, analyze the damage state of the milling cutter according to the monitoring result, and control the milling mechanism to stop working and send an alarm information when the cutter rotating shaft has radial abnormal deformation, the cutter is damaged or broken, or the cutter is deformed.

[0058] The present application has the following advantages:

[0059] The present application provides a high-precision milling combined machine tool and a machining method thereof. In the present application, the thermal error detection and compensation mechanism can obtain the thermal error proportion coefficient of the feed driving mechanism in the X-axis direction, the YZ two-dimensional driving mechanism in the Y-axis and Z-axis directions, and the rotary driving mechanism in the Z-axis direction based on image processing, so as to perform thermal compensation on the feed driving mechanism and the YZ two-dimensional driving mechanism, thereby reducing the error caused by thermal deformation in milling processing and improving the machining precision of the workpiece.

[0060] The cutter rotating shaft and the milling cutter monitoring and analyzing mechanism can monitor the axial track of the cutter rotating shaft based on image processing, analyze the damage state of the milling cutter according to the monitoring result, thereby realizing the monitoring of the milling cutter state, ensuring the machining quality of the workpiece, and reducing the loss caused by the damage of the workpiece or other components due to the abnormal milling cutter.

[0061] The cutter rotating shaft and the milling cutter monitoring and analyzing mechanism can also compensate the radial position of the axial center of the cutter rotating shaft according to the monitoring result, thereby reducing the machining error caused by the radial runout of the cutter rotating shaft and further improving the machining precision.

[0062] The present application realizes thermal error detection and compensation, milling cutter state monitoring, and compensation of the axial position of the cutter rotating shaft based on image processing, and has the advantages of simple equipment, low cost, high accuracy of the method, and good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 FIG. 1 is a structural schematic diagram of the high-precision milling combined machine tool in embodiment 1 of the present application (without a detection plate and a camera mounting plate);

[0064] Figure 2 FIG. 2 is a structural schematic diagram of the high-precision milling combined machine tool in embodiment 1 of the present application;

[0065] Figure 3 FIG. 3 is a structural schematic diagram of the Z-direction driving component of the YZ two-dimensional driving mechanism in embodiment 1 of the present application;

[0066] Figure 4 FIG. 4 is a structural schematic diagram of the high-precision milling combined machine tool in embodiment 2 of the present application; Figure 1A local enlarged view at the middle A;

[0067] Figure 5 A schematic view of a planar image corresponding to a thermal error detection pattern on the Z lead screw in embodiment 1 of the present application;

[0068] Figure 6 A schematic view of a principle structure of the thermal error detection and compensation mechanism in embodiment 1 of the present application;

[0069] Figure 7 A schematic view of a working flow of the thermal error detection and compensation mechanism in embodiment 1 of the present application;

[0070] Figure 8 A schematic view of a principle structure of the tool rotation axis and milling cutter monitoring and analyzing mechanism in embodiment 1 of the present application;

[0071] Figure 9 A schematic view of a rotation axis detection pattern in embodiment 1 of the present application;

[0072] Figure 10 A schematic view of a working flow of the tool rotation axis and milling cutter monitoring and analyzing mechanism in embodiment 1 of the present application;

[0073] Figure 11 A schematic view of a principle structure of the tool rotation axis and milling cutter monitoring and analyzing mechanism in embodiment 1 of the present application; Zi A schematic view of a position in a tXY three-dimensional coordinate system;

[0074] Figure 12 A schematic view of a working flow of the high-precision milling combined machine tool in embodiment 2 of the present application.

[0075] Explanation of reference numerals:

[0076] 1—machine base;

[0077] 2—milling platform;

[0078] 3—feed drive mechanism; 30—X lead screw; 31—X slide rail; 32—X slide block; 33—X motor;

[0079] 4—gantry frame; 40—cross beam;

[0080] 5—YZ two-dimensional drive mechanism; 510—Y lead screw; 511—Y slide rail; 512—Y slide block; 513—Y motor; 514—Y mounting plate; 520—Z lead screw; 521—Z slide rail; 522—Z lead screw nut; 523—Z slide block; 524—Z motor; 525—Z mounting plate; 526—detection plate; 527—detection hole;

[0081] 6—milling mechanism; 60—rotation axis mounting block; 61—tool rotation axis; 62—clamp; 63—rotary drive mechanism;

[0082] 70 - optical axis portion; 71 - thermal error detection pattern; 72 - detection circle; 73 - filled area;

[0083] 80 - first CCD camera;

[0084] 90 - second CCD camera; 91 - camera mounting plate. DETAILED DESCRIPTION

[0085] The application will be further described in conjunction with the embodiments below, so that those skilled in the art can implement the application according to the description.

[0086] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof. EMBODIMENT

[0087] REFERENCE Figures 1-4 The embodiment provides a high-precision milling combined machine tool, comprising:

[0088] a machine base 1;

[0089] a milling platform 2, which is slidably arranged on the machine base 1 along the X-axis direction, and is used to carry a workpiece to be processed;

[0090] a feed drive mechanism 3, which is used to drive the milling platform 2 to move linearly along the X-axis direction;

[0091] a gantry frame 4, which is arranged across the machine base 1;

[0092] a YZ two-dimensional drive mechanism 5, which is arranged on the cross beam 40 of the gantry frame 4, and is used to provide linear movement functions in the Y-axis direction and the Z-axis direction;

[0093] a milling mechanism 6, which is arranged on the YZ two-dimensional drive mechanism 5, and comprises a tool spindle 61 rotatably arranged on the YZ two-dimensional drive mechanism 5, a clamp 62 connected to the bottom of the tool spindle 61, a milling cutter (not shown in the figure) mounted on the clamp 62, and a rotary drive mechanism 63 used to drive the tool spindle 61 to rotate around the Z-axis;

[0094] a thermal error detection and compensation mechanism, which acquires thermal error proportional coefficients of the feed drive mechanism 3 in the X-axis direction, the YZ two-dimensional drive mechanism 5 in the Y-axis and Z-axis directions, and the rotary drive mechanism 63 in the Z-axis direction based on an image processing method, and performs thermal compensation accordingly;

[0095] a tool spindle 61 and milling cutter monitoring and analyzing mechanism, which monitors the axial track of the tool spindle 61 based on an image processing method, and analyzes the damage state of the milling cutter according to the monitoring result.

[0096] In this embodiment, the feeding driving mechanism 3 is a lead screw motor driving mechanism, which comprises an X lead screw 30 and an X slide rail 31 arranged on the machine base 1 along the X axis direction, an X lead screw nut (not shown in the figure) arranged on the X lead screw 30 in cooperation, an X slide block 32 arranged on the X slide rail 31 in cooperation, and an X motor 33 for driving the X lead screw 30 to rotate; the milling platform 2 is arranged on the X slide block 32 and connected with the X lead screw nut;

[0097] The YZ two-dimensional driving mechanism 5 is a lead screw motor driving mechanism, which comprises a Y lead screw 510 and a Y slide rail 511 arranged on the cross beam 40 of the gantry frame 4 along the Y axis direction, a Y lead screw nut (not shown in the figure) arranged on the Y lead screw 510 in cooperation, a Y slide block 512 arranged on the Y slide rail 511 in cooperation, a Y motor 513 for driving the Y lead screw 510 to rotate, a Y mounting plate 514 arranged on the Y slide block 512 and connected with the Y lead screw nut, a Z lead screw 520 and a Z slide rail 521 arranged on the Y mounting plate 514 along the Z axis direction, a Z lead screw nut 522 arranged on the Z lead screw 520 in cooperation, a Z slide block 523 arranged on the Z slide rail 521 in cooperation, a Z motor 524 for driving the Z lead screw 520 to rotate, and a Z mounting plate 525 arranged on the Z slide block 523 and connected with the Z lead screw nut 522;

[0098] The milling mechanism 6 is arranged on the Z mounting plate 525, the Z mounting plate 525 is provided with a rotating shaft mounting block 60, a cutter rotating shaft 61 is rotatably mounted on the rotating shaft mounting block 60, and a rotating driving mechanism 63 is arranged on the rotating shaft mounting block 60 and drivingly connected with the cutter rotating shaft 61.

[0099] Reference Figure 3 Taking the driving in the Z direction of the YZ two-dimensional driving mechanism 5 as an example, the working principle is as follows: the Z motor 524 drives the Z lead screw 520 to rotate, under the guidance and cooperation of the Z slide rail 521 and the Z slide block 523, the Z lead screw nut 522 drives the Z mounting plate 525 to move linearly along the Z axis direction, thereby providing the milling cutter with the movement function in the Z axis direction; the driving principles of the Y direction and the feeding driving mechanism 3 are the same, and are not described herein again; the rotating driving mechanism 63 is a rotating motor, which drives the cutter rotating shaft 61 to rotate, thereby providing the milling cutter with the rotation function around the Z axis; the feeding driving mechanism 3, the YZ two-dimensional driving mechanism 5, and the rotating driving mechanism 63 cooperate with each other to realize the milling machining.

[0100] In this embodiment, the end of the X lead screw 30, the Y lead screw 510 and the Z lead screw 520 is provided with an optical shaft part 70, the shaft body of the optical shaft part 70 and the shaft body of the tool rotating shaft 61 are provided with a thermal error detection pattern 71, the thermal error detection pattern 71 includes two detection circles 72 arranged on the circumferential surface of the shaft body along the length direction and a filling area 73 between the two detection circles 72, the color of the filling area 73 is different from the color of the shaft body, in this embodiment, the shaft body is gray black, the filling area 73 and the detection circle 72 are white; refer to Figure 4 and Figure 5 .

[0101] Refer to Figure 6 , the thermal error detection and compensation mechanism includes four first CCD cameras 80 arranged on the side of the thermal error detection pattern 71 of the X lead screw 30, the Y lead screw 510, the Z lead screw 520 and the tool rotating shaft 61, a thermal error analysis module connected with the four first CCD cameras 80, and a first control module connected with the thermal error analysis module, the first control module is connected with the feed driving mechanism 3, the YZ two-dimensional driving mechanism 5 and the rotating driving mechanism 63;

[0102] The four first CCD cameras 80 are used to respectively collect the planar image of the thermal error detection pattern 71 at the corresponding position, the thermal error analysis module compares and analyzes the collected planar image with the planar image corresponding to the thermal error detection pattern 71 at the standard working temperature, so as to obtain the thermal error proportion coefficient, and the first control module performs thermal compensation on the feed driving mechanism 3 and the YZ two-dimensional driving mechanism 5 according to the thermal error proportion coefficient.

[0103] Refer to Figure 7 , in this embodiment, the working method of the thermal error detection and compensation mechanism includes the following steps (the thermal error detection pattern on the Z lead screw 520 is taken as an example for illustration):

[0104] S1-1, the planar image of the thermal error detection pattern 71 collected by the first CCD camera 80 (on the Z lead screw 520);

[0105] S1-2, the thermal error analysis module acquires n line segments in the planar image which are parallel to the axis of the shaft body as length line segments, calculates the average length of the n length line segments as the length of the planar image , acquires m line segments in the planar image which are perpendicular to the length line segments as width line segments, and calculates the average length of the m width line segments as the width of the planar image ;

[0106] The values of n and m can be set according to requirements, for example, in this embodiment, n=50 and m=30;

[0107] S1-3, when When the ratio is within the range, it is determined that the current planar image is valid, and the thermal error proportion coefficient K is calculated, ; since the material of the Z lead screw 520 is uniform, the thermal deformation in the length direction and the width direction should be the same or substantially the same, so the ratio of the length L to the width D of the planar image corresponding to the thermal error detection pattern 71 at the standard working temperature (25℃) should remain substantially unchanged, i.e., substantially the same as the ratio at the standard working temperature. If the ratio changes too much, it indicates that the collected image has a problem and needs to be collected again.

[0108] Otherwise, it is determined that the current planar image is invalid, and the control re-collects the planar image of the thermal error detection pattern 71 through the first CCD camera 80 until the planar image is determined to be valid.

[0109] wherein ε k is a pre-set thermal error ratio threshold value, which is selected according to the actual situation; L b and D b are the length and the width of the planar image corresponding to the thermal error detection pattern 71 at the standard working temperature (25℃), respectively; referring to Figure 5 , which is a schematic diagram of the planar image corresponding to the thermal error detection pattern 71 on the Z lead screw 520 at 25℃. The obtained image is a two-dimensional planar image.

[0110] S1-4, the first control module controls the driving mechanism corresponding to the axis body on which the current planar image is located according to the thermal error proportion coefficient K, so as to perform thermal compensation on the position in the axial direction of the axis body. Specifically, in the embodiment, the first control module controls the Z motor 524 according to the thermal error proportion coefficient K, so as to perform thermal compensation on the position of the Z lead screw 520 in the Z direction, thereby reducing the error caused by the thermal deformation in the axial direction. The method and principle are the same for other lead screws and the tool spindle 61, and will not be described in detail.

[0111] Since the axial dimension and the radial dimension of the Z lead screw 520, the X lead screw 30 and the Y lead screw 510 are very different, the thermal error in the radial direction can be ignored compared with the axial direction. For the tool spindle 61, the position change of the tool spindle 61 in the radial direction directly connected with the milling cutter cannot be ignored, and all subsequent compensations are performed through the axis offset compensation module.

[0112] In the embodiment, the tool spindle 61 and the milling cutter monitoring and analyzing mechanism also compensate the radial position of the axis of the tool spindle 61 according to the monitoring result of the axis trajectory of the tool spindle 61.

[0113] In the embodiment, the Z mounting plate 525 is connected with a horizontally arranged detection plate 526, the detection plate 526 is provided with a detection hole 527, the diameter of the detection hole 527 is greater than the diameter of the tool spindle 61, and the center of the detection hole 527 coincides with the theoretical position of the axis of the tool spindle 61.​

[0114] Reference Figure 8 The tool spindle 61 and milling cutter monitoring and analysis mechanism includes a second CCD camera 90 set above the detection plate 526, an image analysis and generation module connected to the second CCD camera 90, a tool breakage analysis module connected to the image analysis and generation module, and an axis offset compensation module connected to the image analysis and generation module.

[0115] The second CCD camera 90 is connected to the Z mounting plate 525 via the camera mounting plate 91;

[0116] The axis offset compensation module is connected to both the feed drive mechanism 3 and the YZ two-dimensional drive mechanism 5.

[0117] The image analysis and generation module is connected to the rotary drive mechanism 63, and the tool breakage analysis module is connected to the feed drive mechanism 3, the YZ two-dimensional drive mechanism 5, and the rotary drive mechanism 63.

[0118] Reference Figure 9 On the outer periphery of the outer detection circle on the detection plate 526, the X-axis and Y-axis are drawn with color one. The X-axis and Y-axis are perpendicular. The intersection point O0 of the extension lines of the X-axis and Y-axis coincides with the center of the detection hole 527. With the intersection point O0 as the origin, the X-axis and Y-axis are used as the X-axis and Y-axis respectively to establish the detection coordinate system XO0Y.

[0119] The outer periphery of the tool spindle 61 is drawn with an inner detection circle in color two, and the center of the tool spindle 61 is drawn with a center dot in color three, with the center of the center dot being O. Z Coincides with the axis of the tool spindle 61;

[0120] Color 1 is different from the color of the detection plate 526, and colors 2 and 3 are both different from the color of the tool shaft 61 body, so that the shaft detection pattern composed of the outer detection circle, X-axis, Y-axis, inner detection circle and center dot can be captured by the second CCD camera 90. In this embodiment, the tool shaft 61 and the detection plate 526 are both gray-black, and colors 1, 2 and 3 are all white, which can facilitate differentiation.

[0121] Reference Figure 10 The working method of the tool spindle 61 and the milling cutter monitoring and analysis mechanism includes the following steps:

[0122] S2-1. The second CCD camera 90 acquires one image P of the rotating axis detection pattern every time Δt, and records the current time t. i The image of the acquired shaft detection pattern is P i Then at the previous time t i-1 The image of the acquired shaft detection pattern is P i-1 Δt=ti -t i-1 .

[0123] S2-2, Image Analysis and Generation Module will P i Obtain the center O after grayscale processing Z The position in the detection coordinate system XO0Y is denoted as O. Zi (X) i ,Y i ), then X i Y i These represent the offset positions of the tool spindle 61's axis in the X and Y directions, respectively, i.e., O. Zi Indicates the radial position of the tool spindle 61 axis; the axis offset compensation module is based on X. i Control the feed drive mechanism 3 to achieve the following at the next time t i+1 Perform position compensation in the X direction, based on the Y direction. i Control the YZ two-dimensional drive mechanism 5 to achieve the following at the next time t i+1 Position compensation is performed in the Y direction.

[0124] S2-3, Image Analysis and Generation Module Obtains P i The maximum value of the distance Δd between the outer and inner detection circles. max and minimum value Δd min When Δd max -Δd min >ε d If the machine detects abnormal radial deformation of the tool spindle 61, it issues an alarm and stops the milling mechanism 6 for inspection; otherwise, it proceeds to the next step; where ε d The preset spacing threshold can be selected based on the actual situation.

[0125] The method for obtaining the distance Δd between the outer and inner detection circles is as follows: passing through the center O Z Draw a straight line that intersects the inner and outer detection circles in sequence, and the distance between the two intersection points is taken as the spacing Δd;

[0126] The tool spindle 61 is in direct contact with the milling cutter. During machining, the milling cutter generates a large amount of heat, which is transferred to the tool spindle 61, causing its temperature to rise and resulting in thermal deformation. Axial thermal errors can be well compensated for using the methods described above. Under normal radial thermal deformation conditions, the tool spindle will experience uniform thermal expansion in the radial direction, resulting in a uniform increase in diameter at all positions. Therefore, the axis of the tool spindle 61 remains essentially unchanged, and its impact on machining can be ignored. When Δd max -Δd min >ε dIf the radial deformation is significantly uneven, the change in the axis of the tool spindle 61 cannot be ignored and will have a significant impact on the machining process. At this time, it is necessary to stop the machine for inspection to avoid workpiece defects or damage to the milling cutter and workpiece.

[0127] S2-4, Image Analysis and Generation Module obtains the current time t i Center O Z Position O Zi The position O Zi This refers to the current axis position of the tool spindle 61, obtained by the image analysis and generation module at time t. i The center of the circle O at all previous moments Z The position is determined by replacing the Z-axis in the XYZ three-dimensional coordinate system with time t, establishing a tXY three-dimensional coordinate system, and assigning the center position O of the circle corresponding to each time t. Z By placing the coordinates in the tXY three-dimensional coordinate system, the axis trajectory S of the tool axis 61 at different times can be obtained. i ; where, for any time t i The center position O of the circle at time Zi Represented as (t) i X i Y i ), t i Corresponding to the value on the t-axis, X i Y i These correspond to the values ​​on the X and Y axes, respectively.

[0128] Reference Figure 11 This indicates O Zi Position in the tXY three-dimensional coordinate system; via the axis trajectory graph S i It can display the specific position change of the axis center in the XY plane at different times, that is, the radial position change of the axis center, so as to know the radial runout of the tool axis 61; further, by controlling the feed drive mechanism 3 and the YZ two-dimensional drive mechanism 5 through the axis offset compensation module, the position offset in the X and Y directions caused by the radial runout of the tool axis 61 can be compensated, thereby further reducing the machining error.

[0129] S2-5, Tool breakage analysis module obtains the current time t. i The axis trajectory graph S below i Then, it determines whether the milling cutter is damaged. If it is damaged, it outputs the damage type judgment result. When the judgment result is that the tool is missing, broken, or deformed, it controls the milling mechanism 6 to stop working and issues an alarm message.

[0130] The types of damage include: tool defects or breakage, tool wear, and tool deformation.

[0131] In this embodiment, the tool breakage analysis module includes a feature extraction submodule and a breakage discrimination submodule based on a machine learning algorithm. The breakage discrimination submodule is constructed by the following method:

[0132] S3-1, constructing a training data set:

[0133] S3-1-1, using the same batch of milling cutters to process the same batch of workpieces, and after processing the same time, the breakage state of each milling cutter is counted, including: no breakage, tool damage or collapse, tool wear, and tool deformation. The number of milling cutters of each breakage state in all the milling cutters includes at least N; wherein N≥50; in this embodiment, the number of no breakage is 200, and the number of tool damage or collapse, tool wear, and tool deformation is 120 in turn;

[0134] S3-1-2, obtaining the axis trajectory graph of each milling cutter, and taking the breakage state corresponding to the milling cutter as the label of the axis trajectory graph;

[0135] S3-1-3, the feature extraction submodule extracts the following discriminant features from the axis trajectory graph of each milling cutter, including: phase and amplitude of the axis trajectory graph, slope of each center position O Z on the axis trajectory graph, and peak-to-peak distance; wherein the peak-to-peak distance is the straight line distance between two adjacent peaks on the axis trajectory graph;

[0136] S3-1-4, combining the axis trajectory graph of one milling cutter, the corresponding label and the discriminant features into one training data, and combining the training data of all the milling cutters to obtain the training data set;

[0137] S3-2, taking the axis trajectory graph of the milling cutter and its discriminant features as input, and the corresponding breakage state label as output, training the CNN convolutional neural network using the training data set, and obtaining the breakage discrimination submodule after training;

[0138] When the tool breakage analysis module works, the feature extraction submodule obtains the axis trajectory graph S i at the current time t i , analyzes the discriminant features, and then inputs the discriminant features and the axis trajectory graph S i into the breakage discrimination submodule to obtain the judgment result of the breakage state through the breakage discrimination submodule.

[0139] In a theoretical case, the axial position of the tool rotating shaft 61 is constant, so the axial locus graph is a straight line, but in the actual machining process, the end milling cutter of the tool rotating shaft 61 processes the workpiece, the change of the milling cutter state will cause the change of the axial position, which can finally be reflected on the axial locus graph; for example, the continuous wear of the milling cutter during the machining process will cause a smooth change in the phase of the graph and affect the size of the peak value; when the milling cutter is damaged or broken, the phase will change suddenly; when the tool is deformed, the phase and waveform will change, and the peak-to-peak distance will also change. Although there is a close relationship between different milling cutter state factors and the changes in the axial locus graph, it is difficult to directly describe the specific relationship through a formula, and the CNN convolutional neural network with strong learning ability for graph analysis is used to learn the above relationship, which can more accurately predict the milling cutter state according to the change of the axial locus graph, so as to realize the monitoring of the milling cutter state, ensure the machining quality of the workpiece, and also reduce the loss caused by the damage to the workpiece or other components due to the abnormal milling cutter.

[0140] In an application test example, the judgment results of the tool breakage analysis module on the milling cutter state in a period of time are counted, and the accuracy of the judgment is calculated, and the specific results are shown in Table 1 as follows:

[0141] Table 1

[0142]

[0143] From the results in Table 1, it can be seen that the tool breakage analysis module has high accuracy.

[0144] Referring to Figure 12 , the embodiment provides a machining method of the high-precision milling combined machine tool of embodiment 1, comprising the following steps:

[0145] Step one, the feed drive mechanism 3 works, and the workpiece to be machined on the milling platform 2 is transported to the machining station;

[0146] Step two, the YZ two-dimensional drive mechanism 5 works, so that the milling cutter on the milling mechanism 6 moves above the position to be machined on the workpiece, the rotary drive mechanism 63 drives the milling cutter to rotate, and the workpiece is machined by cooperating with the feed drive mechanism 3 and the YZ two-dimensional drive mechanism 5;

[0147] Step three, during the whole machining process:

[0148] The thermal error detection and compensation mechanism analyzes the thermal error proportion coefficient of the X lead screw 30, the Y lead screw 510, the Z lead screw 520 and the tool rotating shaft 61, and performs thermal compensation accordingly;

[0149] The tool rotation shaft 61 and the milling cutter monitoring and analyzing mechanism monitor the axial track of the tool rotation shaft 61, compensate the radial position of the axial center of the tool rotation shaft 61 according to the monitoring result, judge whether the tool rotation shaft 61 has radial abnormal deformation, analyze the damage state of the milling cutter according to the monitoring result, and control the milling mechanism 6 to stop working and send an alarm information when the tool rotation shaft 61 has radial abnormal deformation, the tool is damaged or broken, or the tool is deformed.

[0150] Although the embodiments of the present application have been disclosed as above, they are not limited to the application listed in the specification and the embodiments, and can be applied to various fields suitable for the present application, and additional modifications can be easily made by those skilled in the art, and thus the present application is not limited to specific details, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A high-precision milling combination machine tool, characterized by comprising: The machine base, the milling platform, the feed drive mechanism, the gantry, the YZ two-dimensional drive mechanism, the milling mechanism, the thermal error detection and compensation mechanism, and the tool spindle and milling cutter monitoring and analysis mechanism are provided. The YZ two-dimensional drive mechanism is a lead screw motor drive mechanism, which includes a Y lead screw and a Y sliding rail arranged along the Y axis direction on the cross beam of the gantry, a Y lead screw nut arranged in cooperation with the Y lead screw, a Y sliding block arranged in cooperation with the Y sliding rail, a Y motor for driving the Y lead screw to rotate, a Y mounting plate arranged on the Y sliding block and connected with the Y lead screw nut, a Z lead screw and a Z sliding rail arranged along the Z axis direction on the Y mounting plate, a Z lead screw nut arranged in cooperation with the Z lead screw, a Z sliding block arranged in cooperation with the Z sliding rail, a Z motor for driving the Z lead screw to rotate, and a Z mounting plate arranged on the Z sliding block and connected with the Z lead screw nut. The Z mounting plate is connected with a horizontally arranged detection plate, the detection plate is provided with a detection hole, the diameter of the detection hole is greater than the diameter of the tool spindle, and the center of the detection hole coincides with the theoretical position of the axis of the tool spindle. The tool spindle and milling cutter monitoring and analysis mechanism includes a second CCD camera arranged above the detection plate, an image analysis and generation module connected with the second CCD camera, a tool damage analysis module connected with the image analysis and generation module, and an axis offset supplement module connected with the image analysis and generation module. The axis offset supplement module is connected with the feed drive mechanism and the YZ two-dimensional drive mechanism. The image analysis and generation module is connected with the rotation drive mechanism, and the tool damage analysis module is connected with the feed drive mechanism, the YZ two-dimensional drive mechanism, and the rotation drive mechanism. The outer periphery of the outer detection circle on the detection plate is drawn with color X axis and Y axis, the X axis and the Y axis are perpendicular, the intersection point O0 of the extensions of the X axis and the Y axis coincides with the center of the detection hole, the intersection point O0 is taken as the origin, the X axis and the Y axis are taken as the X axis and the Y axis respectively, and a detection coordinate system XO0Y is established. ​ ​ ​ ​ ​ ​ ​ ​ The outer peripheral contour of the tool spindle is drawn with an inner detection circle in color two, the center of the tool spindle is drawn with a center dot in color three, and the center of the center dot O Z coincides with the axis of the tool spindle; Color one is different from the color of the detection plate, and color two and color three are different from the color of the tool shaft body, so that the shaft detection pattern composed of the outer detection circle, the X-axis, the Y-axis, the inner detection circle and the center circle point can be collected by the second CCD camera; The working method of the tool shaft and the milling cutter monitoring and analyzing mechanism comprises the following steps: S2-1, the second CCD camera collects an image P of the rotating shaft detection pattern every interval Δt, and the current time is recorded as t i The collected image of the rotating shaft detection pattern is P i The previous time t i-1 The collected image of the rotating shaft detection pattern is P i-1 , Δt=t i -t i-1 ; S2-2, The image analysis and generation module will P i Obtain the center O after grayscale processing Z The position in the detection coordinate system XO0Y is denoted as O. Zi (X) i ,Y i ), then X i Y i These represent the offset positions of the tool spindle axis in the X and Y directions, respectively, i.e., O. Zi Indicates the radial position of the tool spindle axis; the axis offset compensation module is based on X. i Control the feed drive mechanism to achieve the desired result at the next time t. i+1 Perform position compensation in the X direction, based on the Y direction. i Control the YZ two-dimensional drive mechanism to achieve the desired effect at the next time t. i+1 Perform position compensation in the Y direction; S2-3, the image analysis and generation module acquires P i the maximum value Δd of the interval Δd between the middle detection circle and the inner detection circle max and the minimum value Δd min When Δd max -Δd min > ε d , it is judged that the tool rotation shaft has radial abnormal deformation, an alarm information is sent and the milling mechanism is controlled to stop working for shutdown inspection; otherwise, the next step is entered; wherein, ε d is a pre-set interval threshold value; The method for obtaining the interval Δd between the outer detection circle and the inner detection circle is as follows: drawing a straight line through the center O of the circle, and sequentially intersecting the straight line with the inner detection circle and the outer detection circle, and the distance between the two intersection points is the interval Δd. Z The method for obtaining the interval Δd between the outer detection circle and the inner detection circle is as follows: drawing a straight line through the center O of the circle, and sequentially intersecting the straight line with the inner detection circle and the outer S2-4, the image analysis and generation module acquires the current time t i The center of the circle O Z Zi The position O Zi is the current tool shaft position, the image analysis and generation module acquires the time t i The position of the center of the circle O Z at all previous times, replace the Z axis in the XYZ three-dimensional coordinate system with the time t to establish the tXY three-dimensional coordinate system, place the center position O Z of the circle corresponding to each time t in the tXY three-dimensional coordinate system, thereby obtaining the shaft center trajectory graph S i of the tool shaft at different times; wherein the center position O i of the circle at any time t Zi is represented as (t i , X i , Y i ), t i corresponds to the value of the t axis, X i and Y i correspond to the values of the X and Y axes respectively;​ S2-5, the tool breakage analysis module acquires the current time t i under the axis trajectory pattern S i Then, it is judged whether the milling cutter has a breakage state. When the milling cutter has a breakage state, a judgment result of the breakage type is output. When the judgment result is tool breakage or tool collapse or tool deformation, the milling mechanism is controlled to stop working, and an alarm information is sent out. The damage types include tool defect or collapse, tool wear, and tool deformation. The tool damage analysis module comprises a feature extraction submodule and a damage discrimination submodule based on a machine learning algorithm. S3-1, a training data set is constructed: S3-1-1, the same batch of milling cutters is used to process the same batch of workpieces, and after processing for the same time, the damage state of each milling cutter is counted, including no damage, tool defect or collapse, tool wear, and tool deformation. In all the milling cutters counted, the number of milling cutters of each damage state includes at least N milling cutters; wherein N≥50; S3-1-2, the shaft center trajectory pattern of each milling cutter is obtained, and the damage state corresponding to the milling cutter is taken as the label of the shaft center trajectory pattern; S3-1-3, the feature extraction submodule performs the following discriminative feature extraction on the axis trajectory pattern of each milling cutter: the discriminative features include the phase and amplitude of the axis trajectory pattern, and the position O of the center of each circle on the axis trajectory pattern. Z The slope and peak-to-peak distance; where the peak-to-peak distance is the straight-line distance between two adjacent peaks on the axis-centered trajectory graph; S3-1-4, the shaft center trajectory pattern of one milling cutter, the corresponding label and the discrimination features are combined into one training data, and all the training data of the milling cutters obtained are combined to obtain the training data set; S3-2, the shaft center trajectory pattern of the milling cutter and its discrimination features are taken as the input, and the corresponding damage state label is taken as the output. The CNN convolutional neural network is trained using the training data set, and the damage discrimination submodule is obtained after the training is completed. The tool breakage analysis module works, the feature extraction submodule obtains the shaft center trajectory graph S i at the current time t i , analyzes the obtained discriminant features, and then inputs the discriminant features and the shaft center trajectory graph S i into the breakage discrimination submodule to obtain a judgment result of the breakage state through the breakage discrimination submodule.

2. The high-precision milling combination machine according to claim 1, characterized in that, The feeding drive mechanism is a lead screw motor drive mechanism, which includes an X lead screw and an X slide rail arranged on the machine base along the X axis direction, an X lead screw nut arranged on the X lead screw, an X slide arranged on the X slide rail, and an X motor for driving the X lead screw to rotate. The milling platform is arranged on the X slide and connected with the X lead screw nut. The milling mechanism is arranged on the Z mounting plate, and the shaft mounting block is arranged on the Z mounting plate. The tool shaft is rotatably mounted on the shaft mounting block. The rotary drive mechanism is arranged on the shaft mounting block and is drivingly connected with the tool shaft.

3. The high-precision milling combination machine according to claim 2, characterized in that, The ends of the X lead screw, the Y lead screw and the Z lead screw are provided with optical shaft parts. The shaft bodies of the optical shaft parts and the tool shaft are provided with thermal error detection patterns. The thermal error detection pattern includes two detection circles arranged on the circumferential surface of the shaft body along the length direction and a filling area between the two detection circles. The color of the filling area is different from the color of the shaft body. The thermal error detection and compensation mechanism comprises four first CCD cameras arranged on the thermal error detection pattern side of the X lead screw, the Y lead screw, the Z lead screw and the tool shaft, a thermal error analysis module connected with the four first CCD cameras, and a first control module connected with the thermal error analysis module. The first control module is connected with the feeding drive mechanism, the YZ two-dimensional drive mechanism and the rotary drive mechanism. Four first CCD cameras are used to collect planar images of thermal error detection patterns at corresponding positions, the thermal error analysis module compares the collected planar images with planar images corresponding to thermal error detection patterns at standard working temperature, thereby obtaining a thermal error proportionality coefficient, and the first control module performs thermal compensation on the feed driving mechanism and the YZ two-dimensional driving mechanism according to the thermal error proportionality coefficient.

4. The high-precision milling combination machine according to claim 3, characterized in that, The working method of the thermal error detection and compensation mechanism comprises the following steps: S1-1, collecting a planar image of a thermal error detection pattern by a first CCD camera; S1-2, the thermal error analysis module acquires n line segments in the planar image that are parallel to the axis of the axis body in which the planar image is located, as length line segments, and calculates the average length of the n length line segments as the length of the planar image ; acquires m line segments in the planar image that are perpendicular to the length line segments, as width line segments, and calculates the average length of the m width line segments as the width of the planar image ; S1-3, when the current planar image is valid, and a thermal error proportionality coefficient K is calculated, otherwise, the current planar image is invalid, and the control reacquires the planar image of the thermal error detection pattern through the first CCD camera until the planar image is judged as valid. wherein ε k is a pre-set thermal error ratio threshold; L b and D b are the length and width, respectively, of the planar image corresponding to the thermal error detection pattern at the standard operating temperature. S1-4, the first control module controls the driving mechanism corresponding to the axis body on which the current planar image is located according to the thermal error proportionality coefficient K, so as to perform thermal compensation on the position along the axial direction of the axis body.

5. The high-precision milling combination machine according to claim 3, characterized in that, The cutter shaft and milling cutter monitoring and analysis mechanism also compensates the radial position of the cutter shaft axis according to the monitoring result of the axis trajectory of the cutter shaft.

6. A method of machining a high-precision milling combination machine tool as claimed in any one of claims 1-5, characterized in that, Comprise the following steps: Step one, the feed driving mechanism works, and the workpiece to be machined on the milling platform is transported to the machining station; Step two, the YZ two-dimensional driving mechanism works, the milling cutter on the milling mechanism moves above the position to be machined on the workpiece, the rotary driving mechanism drives the milling cutter to rotate, and the feed driving mechanism and the YZ two-dimensional driving mechanism cooperate to mill the workpiece; Step three, during the whole machining process: The thermal error detection and compensation mechanism analyzes the thermal error proportionality coefficient of the X lead screw, the Y lead screw, the Z lead screw and the cutter shaft, and performs thermal compensation accordingly; The cutter shaft and milling cutter monitoring and analysis mechanism monitors the axis trajectory of the cutter shaft, compensates the radial position of the cutter shaft axis according to the monitoring result, judges whether the cutter shaft has radial abnormal deformation, analyzes the damage state of the milling cutter according to the monitoring result, and controls the milling mechanism to stop working and send an alarm information when the cutter shaft has radial abnormal deformation, the cutter is damaged or broken, or the cutter is deformed.

Images