阅读说明：本技术 一种双五轴镜像铣机床的精度自诊断方法 (Precision self-diagnosis method for double five-axis mirror milling machine tool ) 是由 宋维书 赵彤 张辉 叶佩青 米晶 于 2019-09-10 设计创作，主要内容包括：本发明公开了一种双五轴镜像铣机床的精度自诊断方法,该方法包含：采用基于三坐标测头和自诊断测试工装的自动零点检测,对工装进行位置检测以计算回零偏差,用于诊断机床几何精度；利用球杆仪,获得机床运动轮廓误差,以诊断机床空间轮廓精度；根据线激光轮廓仪对工装工艺位置的测试结果评估传感器精度状况,诊断镜像铣机床的测控传感器精度。本发明将根据生产需要提取双五轴镜像铣机床的状态特征,从机床几何精度、空间轮廓精度、测控传感器精度三个层面实现对机床精度的诊断,在保证评价精度的前提下提高诊断效率,完成机床周期性运行健康状态自评估。(the invention discloses a precision self-diagnosis method of a double five-axis mirror milling machine tool, which comprises the following steps: the automatic zero point detection based on the three-coordinate measuring head and the self-diagnosis test tool is adopted, and the position of the tool is detected to calculate the zero return deviation for diagnosing the geometric accuracy of the machine tool; utilizing a ball bar instrument to obtain the motion contour error of the machine tool so as to diagnose the space contour accuracy of the machine tool; and evaluating the accuracy condition of the sensor according to the test result of the line laser profiler on the process position of the tool, and diagnosing the accuracy of the measurement and control sensor of the mirror milling machine. According to the invention, the state characteristics of the double five-axis mirror milling machine tool are extracted according to production needs, the diagnosis of the machine tool precision is realized from three layers of the geometric precision, the spatial profile precision and the measurement and control sensor precision of the machine tool, the diagnosis efficiency is improved on the premise of ensuring the evaluation precision, and the self-evaluation of the health state of the periodic operation of the machine tool is completed.)

1. The precision self-diagnosis method of the double five-axis mirror milling machine tool is characterized by comprising the following steps of:

1) Judging whether the previous workpiece meets the set machining precision requirement, if not, executing the step 2), and carrying out geometric precision self-diagnosis on the double five-axis mirror image milling machine tool; if so, executing the step 4), and carrying out self-diagnosis on the spatial profile precision of the machine tool operation on the double five-axis mirror image milling machine tool;

2) Double five-axis mirror image milling machine tool geometric accuracy self-diagnosis

21) Design and installation geometric error diagnosis test fixture

Designing a geometric error diagnosis test tool based on a geometric precision mathematical model of a double five-axis mirror image milling machine tool, wherein the geometric error diagnosis test tool mainly comprises a first base plate and a first block body which is fixed on the first base plate and provided with five planes, and the geometric error diagnosis test tool is fixedly arranged on the double five-axis mirror image milling machine tool body through the first base plate; the five planes of the first block are defined according to the machine coordinate system XYZ as follows: a vertical plane parallel to the YZ plane is defined as a first plane, a horizontal plane parallel to the XZ plane is defined as a second plane, a vertical plane parallel to the XY plane is defined as a third plane, a 45 ° oblique plane having a normal vector of (0, 1, -1) is defined as a fourth plane, and a 45 ° oblique plane having a normal vector of (1, -1, 0) is defined as a fifth plane;

22) the geometric error diagnosis test tool is used for independently and repeatedly measuring the single points of the translational shafts on the milling side and the supporting side to obtain zero coordinates of the translational shafts, so that the repeated positioning precision of the translational shafts is detected; for three translational shafts on the milling side and the supporting side, respectively obtaining a zero point positioning error and a repeated positioning error of the corresponding side main shaft X, Y, Z direction by using a first plane, a second plane and a third plane of the geometric error diagnosis test tool;

23) The geometric error diagnosis test tool is used for independently and repeatedly measuring the single point of each rotating shaft on the milling side and the supporting side to obtain the zero point coordinates of each rotating shaft, so that the repeated positioning precision of each translation shaft is detected; for two rotating shafts on the milling side and the supporting side, respectively utilizing a fourth plane and a fifth plane of the geometric error diagnosis test tool to obtain a zero point positioning error and a repeated positioning error in the direction of the main shaft A, C on the corresponding side;

24) judging whether the X, Y, Z, A, C zero point error and the repeated positioning error of the milling side spindle and the support side spindle meet the set precision requirement, and if the set precision requirement is met, executing the step 4); if the set precision requirement is not met, executing the step 3);

3) Performing machine tool structure inspection and error compensation, then executing steps 22) to 23) until X, Y, Z, A, C zero point errors and repeated positioning errors of the milling side spindle and the supporting side spindle meet set accuracy requirements, and executing step 4);

4) Self-diagnosis of space profile precision of double five-axis mirror milling machine tool

The method comprises the following steps of setting a corresponding detection track based on a double five-axis synchronous motion model required by a mirror milling working principle, acquiring rod length change data under the set detection track by utilizing a rod instrument arranged on a main shaft and a working table of a double five-axis mirror milling machine tool, and obtaining a contour error of the machine tool in a motion state through calculation so as to diagnose the spatial contour accuracy of the machine tool, wherein the method specifically comprises the following steps:

41) the interpolation circular motion precision of the A axis and the C axis of the rotating shaft and the corresponding two translational axes is respectively detected

Mounting the fixed end of the ball rod instrument on a machine tool body, and mounting the movable end of the ball rod instrument on a milling side main shaft; setting a first detection track according to ISO230-1-2012 < Test code for chips-Part 1 > geometrical access of chips operating under no-load or quasi-static conditions; for a five-axis milling side, according to an AK1 mode in ISO230-1-2012 standard, precision detection is carried out on interpolation circular motion of each rotating shaft and two corresponding translational shafts by using a ball bar instrument according to a set first detection track, and a three-axis linkage error is calculated;

42) Detecting five-axis linkage interpolation motion precision of fixed cutter point on milling side

keeping the installation position of the ball arm instrument unchanged; setting a second detection track according to the ISO230-1-2012 standard; performing precision detection on the five-axis linkage interpolation track of the fixed tool point by using a ball bar instrument according to an AK4 mode in the ISO230-1-2012 standard on the milling side five-axis according to a set second detection track, and calculating a five-axis linkage error;

43) Detecting the synchronous motion precision of the milling side main shaft and the supporting side main shaft along each translation axis

431) the fixed end of the ball arm instrument is arranged on the main shaft at the supporting side, and the installation position of the movable end of the ball arm instrument is kept unchanged;

432) setting step-by-step body Diagonal detection tracks for synchronous motion precision detection of a milling side and a supporting side on the basis of a body Diagonal measurement method in ISO 230-6-2002 Test code for machine tools-Part 6 (Determination of position acquisition on bodies and face dimensions) standard, and realizing synchronous precision error measurement in a full operation space range; dividing each body diagonal line into m sections equally, wherein each section moves along the X direction, then moves along the Y direction and finally moves along the Z direction;

433) enabling the milling side main shaft and the support side main shaft to sequentially and synchronously move along each body diagonal segment by segment according to the step body diagonal detection track set in the step 432), respectively recording the rod length change condition of the ball rod instrument in the moving process, and calculating X, Y, Z cutter point distance change quantity in each moving direction to be used as synchronous movement errors of the milling side main shaft and the support side main shaft;

44) If the measured linkage error is always within the allowable range in the steps 41), 42) and 43), the precision self-diagnosis of the dual five-axis mirror milling machine tool is finished; if any linkage error exceeds the allowable range and the step 2) is not executed in the diagnosis, executing the step 2); and if any linkage error exceeds the allowable range and the diagnosis is executed in the step 2), executing the step 3).

2. the accuracy self-diagnosis method according to claim 1, characterized by further comprising the steps of:

5) The precision self-diagnosis of the measurement and control sensor of the double five-axis mirror milling machine tool comprises a line laser profile instrument fixedly installed on a main shaft on the supporting side of the double five-axis mirror milling machine tool, and the specific implementation process is as follows:

51) precision diagnosis test tool for designing and installing line laser profiler

The line laser profilometer precision diagnosis testing tool is designed based on the working principle of a line laser profilometer, and comprises a second substrate, and a second block body and a third block body which are arranged on the second substrate, wherein the upper surfaces of the two block bodies are horizontal planes, and the line laser profilometer precision diagnosis testing tool is fixedly arranged on a main shaft at the supporting side of a double five-axis mirror image milling machine tool through the second substrate; grooves are formed in the second block body and the third block body at intervals, stepped surfaces are formed between the side surfaces of the block bodies and the upper surface of the second substrate respectively, and a circular hole is formed in the third block body; defining three characteristic planes on the line laser profilometer precision diagnosis testing tool, wherein the three characteristic planes are all parallel to each other and are all parallel to a YZ plane; the first characteristic plane is located at the plane of the second block body, the second characteristic plane is located at the step surface, and the third characteristic plane is located at the groove;

52) the main shaft at the side of the moving support is used for respectively placing the line laser profiler at a first characteristic plane and a second characteristic plane on the line laser profiler precision diagnosis test tool so as to measure the installation precision of an A axis and a C axis of the line laser profiler; if the installation accuracy is met, executing step 53), otherwise, correcting the corresponding installation error until the installation accuracy is met, and executing step 53);

53) The line laser profiler is respectively arranged at a first characteristic plane, a second characteristic plane and a third characteristic plane on the line laser profiler precision diagnosis test tool to measure the Z-axis, X-axis and Y-axis measurement precision of the line laser profiler; wherein the content of the first and second substances,

controlling the line laser profiler to move to a first characteristic plane and move along the Z direction, taking the distance from a read measuring head measured by the line laser profiler to the surface of a line laser profiler precision diagnosis test tool, namely the mean value of the Z-direction height as the measurement precision of the Z axis of the line laser profiler, and taking the error between the measured mean value of the Z-direction height and the actual depth of a groove in the line laser profiler precision diagnosis test tool as the self precision error of the line laser profiler in the Z direction;

Controlling the line laser profiler to move to a second characteristic plane and move along the X direction, so that the laser motion region identifies the critical positions of the upper surface and the lower surface of the step, and taking the error value of the measured X coordinate of the critical position and the actual coordinate position of the step surface region on the line laser profiler precision diagnosis test tool as the self precision error of the line laser profiler in the X direction;

controlling the line laser profiler to move to a third characteristic plane and move along the Y direction, and taking an error value between the groove width measured by the line laser profiler and the actual width of the groove as a self-precision error of the line laser profiler in the Y direction;

54) judging the self-precision error of each direction of the line laser profiler measured in the step 53), and if the self-precision of any direction of the line laser profiler exceeds the allowable range, correcting the line laser profiler; if the self-precision of each direction of the line laser profiler is within the allowable range, scanning a round hole on the line laser profiler precision diagnosis test tool, measuring the diameter of the round hole, comparing the diameter with the actual diameter, if the precision requirement is met, finishing the precision self-diagnosis of the double five-axis mirror image milling machine tool, and starting the machine tool to execute a machining program; if the requirements are not met, the distance between the line laser profiler and the line laser profiler precision diagnosis test tool is adjusted, the fact that the region to be tested of the line laser profiler precision diagnosis test tool is within the measurement working range of the line laser profiler is guaranteed, precision self-diagnosis of the double five-axis mirror milling machine tool is finished, and the machine tool starts to execute a machining program.

Technical Field

The invention relates to the field of machinery and numerical control machines, in particular to a precision self-diagnosis method of a double five-axis mirror milling machine.

background

The double five-axis mirror milling machine tool is used for realizing the functions of milling the thickness, milling the inner and outer contours, drilling and milling holes of the curved surface metal skin parts and realizing the high-speed, high-precision and pollution-free mechanical milling processing of the large curved surface skin parts.

In a dual five-axis mirror milling machine, in addition to the spindle tool on the machining side of the skin, there are also scratch-free bearing heads on the other side, as shown in fig. 1. In the machining process, the tool swing head and the supporting swing head can move together along the surface of the skin, the directions are in curved mirror symmetry, so that the whole machining process is guaranteed to be point-to-point normal supporting and milling all the time, the workpiece can have enough rigidity in the machining process, the problem of vibration caused by machining of a large flat thin-wall part on a common five-axis machine tool is avoided, and high-precision control of machining of the thin-wall part is achieved. Because the tool swing head and the supporting swing head move synchronously and the machining function of a complex curved surface needs to be realized, both the two swing heads have five-axis movement functions, and the mirror milling machine tool adopts a double five-axis structure. One side of the tool swing head is called a milling side and mainly plays a role in milling, and one side of the tool swing head which is supported is called a supporting side and mainly plays a role in supporting a skin and preventing flutter.

the existing precision detection method is directed at five-axis machining centers or large gantry machine tools, and is single five-axis detection, and means for detecting evaluation indexes such as motion synchronization precision and the like of the double five-axis structure are lacked. In addition, the probability and mathematical statistics are used as a mathematical basis, a large sample with probability repeatability is used for determining the failure distribution of the same batch of equipment, and the accuracy evaluation for a certain single machine tool is lacked.

Meanwhile, the skin deforms after being clamped on a double five-axis mirror image milling machine tool, so that a line laser profiler is required to be used for profile scanning before machining, and the existing patent lacks on-site detection precision diagnosis and calibration of the line laser profiler.

Disclosure of Invention

The invention aims to provide a precision self-diagnosis method of a double five-axis mirror milling machine tool, which is used for extracting the state characteristics of the double five-axis mirror milling machine tool according to production requirements, realizing the diagnosis of the machine tool precision from three layers of the geometric precision, the spatial profile precision and the measurement and control sensor precision of the machine tool, improving the diagnosis efficiency on the premise of ensuring the evaluation precision and finishing the self-evaluation of the health state of the periodic operation of the machine tool.

in order to achieve the above object, the present invention provides a precision self-diagnosis method for a dual five-axis mirror milling machine, which comprises the following steps:

1) judging whether the previous workpiece meets the set machining precision requirement, if not, executing the step 2), and carrying out geometric precision self-diagnosis on the double five-axis mirror image milling machine tool; if so, executing the step 4), and carrying out self-diagnosis on the spatial profile precision of the machine tool operation on the double five-axis mirror image milling machine tool;

2) Double five-axis mirror image milling machine tool geometric accuracy self-diagnosis

21) Design and installation geometric error diagnosis test fixture

designing a geometric error diagnosis test tool based on a geometric precision mathematical model of a double five-axis mirror image milling machine tool, wherein the geometric error diagnosis test tool mainly comprises a first base plate and a first block body which is fixed on the first base plate and provided with five planes, and the geometric error diagnosis test tool is fixedly arranged on the double five-axis mirror image milling machine tool body through the first base plate; the five planes of the first block are defined according to the machine coordinate system XYZ as follows: a vertical plane parallel to the YZ plane is defined as a first plane, a horizontal plane parallel to the XZ plane is defined as a second plane, a vertical plane parallel to the XY plane is defined as a third plane, a 45 ° oblique plane having a normal vector of (0, 1, -1) is defined as a fourth plane, and a 45 ° oblique plane having a normal vector of (1, -1, 0) is defined as a fifth plane;

22) the geometric error diagnosis test tool is used for independently and repeatedly measuring the single points of the translational shafts on the milling side and the supporting side to obtain zero coordinates of the translational shafts, so that the repeated positioning precision of the translational shafts is detected; for three translational shafts on the milling side and the supporting side, respectively obtaining a zero point positioning error and a repeated positioning error of the corresponding side main shaft X, Y, Z direction by using a first plane, a second plane and a third plane of the geometric error diagnosis test tool;

23) the geometric error diagnosis test tool is used for independently and repeatedly measuring the single point of each rotating shaft on the milling side and the supporting side to obtain the zero point coordinates of each rotating shaft, so that the repeated positioning precision of each translation shaft is detected; for two rotating shafts on the milling side and the supporting side, respectively utilizing a fourth plane and a fifth plane of the geometric error diagnosis test tool to obtain a zero point positioning error and a repeated positioning error in the direction of the main shaft A, C on the corresponding side;

24) judging whether the X, Y, Z, A, C zero point error and the repeated positioning error of the milling side spindle and the support side spindle meet the set precision requirement, and if the set precision requirement is met, executing the step 4); if the set precision requirement is not met, executing the step 3);

3) performing machine tool structure inspection and error compensation, then executing steps 22) to 23) until X, Y, Z, A, C zero point errors and repeated positioning errors of the milling side spindle and the supporting side spindle meet set accuracy requirements, and executing step 4);

4) Self-diagnosis of space profile precision of double five-axis mirror milling machine tool

The method comprises the following steps of setting a corresponding detection track based on a double five-axis synchronous motion model required by a mirror milling working principle, acquiring rod length change data under the set detection track by utilizing a rod instrument arranged on a main shaft and a working table of a double five-axis mirror milling machine tool, and obtaining a contour error of the machine tool in a motion state through calculation so as to diagnose the spatial contour accuracy of the machine tool, wherein the method specifically comprises the following steps:

41) the interpolation circular motion precision of the A axis and the C axis of the rotating shaft and the corresponding two translational axes is respectively detected

mounting the fixed end of the ball rod instrument on a machine tool body, and mounting the movable end of the ball rod instrument on a milling side main shaft; setting a first detection track according to ISO230-1-2012 < Test code for chips-Part 1 > geometrical access of chips operating under no-load or quasi-static conditions; for a five-axis milling side, according to an AK1 mode in ISO230-1-2012 standard, precision detection is carried out on interpolation circular motion of each rotating shaft and two corresponding translational shafts by using a ball bar instrument according to a set first detection track, and a three-axis linkage error is calculated;

42) detecting five-axis linkage interpolation motion precision of fixed cutter point on milling side

Keeping the installation position of the ball arm instrument unchanged; setting a second detection track according to the ISO230-1-2012 standard; performing precision detection on the five-axis linkage interpolation track of the fixed tool point by using a ball bar instrument according to an AK4 mode in the ISO230-1-2012 standard on the milling side five-axis according to a set second detection track, and calculating a five-axis linkage error;

43) detecting the synchronous motion precision of the milling side main shaft and the supporting side main shaft along each translation axis

431) The fixed end of the ball arm instrument is arranged on the main shaft at the supporting side, and the installation position of the movable end of the ball arm instrument is kept unchanged;

432) setting step-by-step body Diagonal detection tracks for synchronous motion precision detection of a milling side and a supporting side on the basis of a body Diagonal measurement method in ISO 230-6-2002 Test code for machine tools-Part 6 (Determination of position acquisition on bodies and face dimensions) standard, and realizing synchronous precision error measurement in a full operation space range; dividing each body diagonal line into m sections equally, wherein each section moves along the X direction, then moves along the Y direction and finally moves along the Z direction;

433) enabling the milling side main shaft and the support side main shaft to sequentially and synchronously move along each body diagonal segment by segment according to the step body diagonal detection track set in the step 432), respectively recording the rod length change condition of the ball rod instrument in the moving process, and calculating X, Y, Z cutter point distance change quantity in each moving direction to be used as synchronous movement errors of the milling side main shaft and the support side main shaft;

44) If the measured linkage error is always within the allowable range in the steps 41), 42) and 43), the precision self-diagnosis of the dual five-axis mirror milling machine tool is finished; if any linkage error exceeds the allowable range and the step 2) is not executed in the diagnosis, executing the step 2); and if any linkage error exceeds the allowable range and the diagnosis is executed in the step 2), executing the step 3).

further, the method comprises the following steps:

5) the precision self-diagnosis of the measurement and control sensor of the double five-axis mirror milling machine tool comprises a line laser profile instrument fixedly installed on a main shaft on the supporting side of the double five-axis mirror milling machine tool, and the specific implementation process is as follows:

51) Precision diagnosis test tool for designing and installing line laser profiler

The line laser profilometer precision diagnosis testing tool is designed based on the working principle of a line laser profilometer, and comprises a second substrate, and a second block body and a third block body which are arranged on the second substrate, wherein the upper surfaces of the two block bodies are horizontal planes, and the line laser profilometer precision diagnosis testing tool is fixedly arranged on a main shaft at the supporting side of a double five-axis mirror image milling machine tool through the second substrate; grooves are formed in the second block body and the third block body at intervals, stepped surfaces are formed between the side surfaces of the block bodies and the upper surface of the second substrate respectively, and a circular hole is formed in the third block body; defining three characteristic planes on the line laser profilometer precision diagnosis testing tool, wherein the three characteristic planes are all parallel to each other and are all parallel to a YZ plane; the first characteristic plane is located at the plane of the second block body, the second characteristic plane is located at the step surface, and the third characteristic plane is located at the groove;

52) the main shaft at the side of the moving support is used for respectively placing the line laser profiler at a first characteristic plane and a second characteristic plane on the line laser profiler precision diagnosis test tool so as to measure the installation precision of an A axis and a C axis of the line laser profiler; if the installation accuracy is met, executing step 53), otherwise, correcting the corresponding installation error until the installation accuracy is met, and executing step 53);

53) The line laser profiler is respectively arranged at a first characteristic plane, a second characteristic plane and a third characteristic plane on the line laser profiler precision diagnosis test tool to measure the Z-axis, X-axis and Y-axis measurement precision of the line laser profiler; wherein the content of the first and second substances,

Controlling the line laser profiler to move to a first characteristic plane and move along the Z direction, taking the distance from a read measuring head measured by the line laser profiler to the surface of a line laser profiler precision diagnosis test tool, namely the mean value of the Z-direction height as the measurement precision of the Z axis of the line laser profiler, and taking the error between the measured mean value of the Z-direction height and the actual depth of a groove in the line laser profiler precision diagnosis test tool as the self precision error of the line laser profiler in the Z direction;

controlling the line laser profiler to move to a second characteristic plane and move along the X direction, so that the laser motion region identifies the critical positions of the upper surface and the lower surface of the step, and taking the error value of the measured X coordinate of the critical position and the actual coordinate position of the step surface region on the line laser profiler precision diagnosis test tool as the self precision error of the line laser profiler in the X direction;

Controlling the line laser profiler to move to a third characteristic plane and move along the Y direction, and taking an error value between the groove width measured by the line laser profiler and the actual width of the groove as a self-precision error of the line laser profiler in the Y direction;

54) judging the self-precision error of each direction of the line laser profiler measured in the step 53), and if the self-precision of any direction of the line laser profiler exceeds the allowable range, correcting the line laser profiler; if the self-precision of each direction of the line laser profiler is within the allowable range, scanning a round hole on the line laser profiler precision diagnosis test tool, measuring the diameter of the round hole, comparing the diameter with the actual diameter, if the precision requirement is met, finishing the precision self-diagnosis of the double five-axis mirror image milling machine tool, and starting the machine tool to execute a machining program; if the requirements are not met, the distance between the line laser profiler and the line laser profiler precision diagnosis test tool is adjusted, the fact that the region to be tested of the line laser profiler precision diagnosis test tool is within the measurement working range of the line laser profiler is guaranteed, precision self-diagnosis of the double five-axis mirror milling machine tool is finished, and the machine tool starts to execute a machining program.

Compared with the prior art, the invention has the characteristics and beneficial effects that:

the method adopts automatic zero point detection based on a three-coordinate measuring head and a self-diagnosis test tool, and carries out position detection on the tool to calculate zero return deviation for diagnosing the geometric accuracy of the machine tool; utilizing a ball bar instrument to obtain the motion contour error of the machine tool so as to diagnose the space contour accuracy of the machine tool; and evaluating the accuracy condition of the sensor according to the test result of the line laser profiler on the process position of the tool, and diagnosing the accuracy of the measurement and control sensor of the mirror milling machine.

(1) according to the invention, the state characteristics of the double five-axis mirror milling machine tool are extracted according to production needs, and the comprehensive precision detection of the double five-axis machine tool is realized from the self-diagnosis of three layers of geometric precision, spatial profile precision and measurement and control sensor precision, so that the diagnosis of the current state of the machine tool is realized.

(2) The invention designs a geometric error diagnosis test tool based on a machine tool geometric precision mathematical model and a line laser contourgraph precision diagnosis test tool based on a line laser measurement principle, ensures the measurement precision by establishing a correct calculation model, simplifies the traditional measurement process and saves the installation time because of using a fixed test tool, can realize the improvement of the machine tool geometric precision and the sensor precision diagnosis efficiency under the condition of ensuring that the measurement precision meets the requirement, and provides a foundation for the guarantee of the machine tool precision stability and the continuous production of skins.

drawings

Fig. 1 shows the working principle of a conventional double five-axis mirror milling machine.

Fig. 2 is a flow chart of the precision self-diagnosis method for the dual five-axis mirror milling machine tool according to the invention.

fig. 3 is a schematic structural diagram of a geometric error diagnosis test fixture designed by the present invention.

FIG. 4 is a schematic diagram of the full working space and the body diagonal thereof according to the present invention.

FIG. 5 is a schematic diagram of a step volume diagonal detection trajectory employed by the present invention.

Fig. 6 is a schematic structural diagram of a line laser profiler precision diagnosis test tool designed by the invention.

fig. 7 is a partially enlarged schematic view of fig. 6.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

the precision self-diagnosis method of the double five-axis mirror milling machine tool comprises self-diagnosis of two layers of geometric precision and space profile precision, the working flow of the method is shown in figure 2, and the method specifically comprises the following steps:

1) Judging whether the previous workpiece meets the set machining precision requirement, if not, executing the step 2), and carrying out geometric precision self-diagnosis on the double five-axis mirror image milling machine tool; if so, executing the step 4), and carrying out self-diagnosis on the spatial profile precision of the machine tool operation on the double five-axis mirror image milling machine tool;

2) double five-axis mirror image milling machine tool geometric accuracy self-diagnosis

the geometric precision mathematical model based on the double five-axis mirror milling machine tool is used for constructing a geometric error diagnosis test tool, automatic zero point detection based on a three-coordinate measuring head and the geometric error diagnosis test tool is adopted, position detection is carried out on the geometric error diagnosis test tool to calculate zero return deviation of each direction of a machine tool spindle, the geometric precision of the double five-axis mirror milling machine tool is diagnosed, whether the machine tool has zero point drift and other phenomena is judged, and quantitative expression of a moving reference of a machine tool cutter is obtained. The specific implementation process is as follows:

21) designing and installing a geometric error diagnosis test tool;

As shown in fig. 3, the geometric error diagnosis testing tool 10 mainly includes a substrate 2 and a block 1 fixed on the substrate 2 and having five planes, and the geometric error diagnosis testing tool 10 is fixedly mounted on a dual five-axis mirror milling machine body through a bolt hole on the substrate 2 and a matched bolt. The five planes of the block 1 are defined according to the machine coordinate system XYZ as follows: a vertical plane parallel to the YZ plane is defined as a first plane 11, a horizontal plane parallel to the XZ plane is defined as a second plane 12, a vertical plane parallel to the XY plane is defined as a third plane 13, a 45 ° oblique plane having a normal vector of (0, 1, -1) is defined as a fourth plane 14, and a 45 ° oblique plane having a normal vector of (1, -1, 0) is defined as a fifth plane 15.

22) and the geometric error diagnosis test tool is used for independently and repeatedly measuring the translation shafts on the milling side and the supporting side in a single point manner to obtain zero coordinates of the translation shafts, so that the repeated positioning precision of the translation shafts is detected. Due to the complex coupling relation of five-axis geometric errors of the double five-axis mirror milling machine tool, single-axis motion is adopted to avoid coupling influence among all axis errors.

The specific implementation process is as follows:

221) For three translational axes on the milling side:

a) Enabling the milling side spindle to move only along the X axis of the machine tool coordinate system until a three-coordinate measuring head of the double five-axis mirror milling machine tool contacts with a first plane 11 of the geometric error diagnosis testing tool 10, obtaining and recording coordinate data delta xi of a contact point of the three-coordinate measuring head and the first plane 11, and then enabling the milling side spindle to return along an original path to finish single measurement; the above operation is repeated N (in this embodiment, N is 6) times, and a milling-side spindle X zero-point positioning error Δ X and a repeated positioning error δ X are obtained, and the calculation formulas are respectively as follows:

δx＝Δx-Δx

wherein, Δ xi is coordinate data of a contact point of the three-coordinate measuring head and the first plane 11 recorded in the ith measurement; and delta xmax and delta xmin are respectively the maximum value and the minimum value in the coordinate data of the contact point of the three-coordinate measuring head and the first plane 11 in the N times of measurement.

b) enabling the milling side spindle to move only along the Y axis of the machine tool coordinate system until a three-coordinate measuring head of the double five-axis mirror milling machine tool is contacted with the second plane 12 of the geometric error diagnosis testing tool 10, acquiring and recording coordinate data delta yi of a contact point of the three-coordinate measuring head and the second plane 12, and then enabling the milling side spindle to return along an original path to finish single measurement; the above operation is repeated N (N is 6 in this embodiment) times, and a milling-side spindle Y-direction zero point positioning error and a repeated positioning error are obtained.

c) Enabling the milling side spindle to move only along the Z axis of the machine tool coordinate system until a three-coordinate measuring head of the double five-axis mirror milling machine tool is contacted with a third plane 13 of the geometric error diagnosis test tool 10, acquiring and recording coordinate data delta zi of a contact point of the three-coordinate measuring head and the third plane 13, and then enabling the milling side spindle to return along an original path to finish single measurement; the above operation is repeated N (N is 6 in this embodiment) times, and a milling-side spindle Z-direction zero point positioning error and a repeated positioning error are obtained.

222) And for the three translational shafts on the supporting side, obtaining X, Y, Z zero-point positioning errors and repeated positioning errors of the main shaft on the supporting side according to the operation of the step 221), namely enabling the main shaft on the supporting side to move along X, Y, Z shafts in sequence, and detecting X, Y, Z shaft zero-point positioning errors and repeated positioning errors of the main shaft on the supporting side by using the first plane 11, the second plane 12 and the third plane 13 of the geometric error diagnosis test tool 10 respectively.

23) and the geometric error diagnosis test tool is used for independently and repeatedly measuring the single point of each rotating shaft on the milling side and the supporting side so as to obtain the zero point coordinates of each rotating shaft, so that the detection of the repeated positioning precision of each rotating shaft is realized.

231) For two rotational axes of the milling side:

a) Enabling the milling side spindle to move only around an axis A of a machine tool coordinate system until a three-coordinate measuring head of the double five-axis mirror milling machine tool contacts with a fourth plane 14 of the geometric error diagnosis test tool 10, obtaining coordinate data (x1, y1, z1) of a contact point of the three-coordinate measuring head and the fourth plane 14, then enabling the milling side spindle to retreat to a position A (0) along an original path, recording the coordinate data (x2, y2, z2) of a tool point in a numerical control system at the moment, calculating a single zero point positioning error of the axis A through the following formula, and completing single measurement of the axis A:

The above operation is repeated N (N is 6 in this embodiment) times, and a milling-side spindle a zero-point positioning error and a repeated positioning error are obtained.

b) Enabling the milling side spindle to move only around the C axis of the machine tool coordinate system until a three-coordinate measuring head of the double five-axis mirror milling machine tool contacts with a fifth plane 15 of the geometric error diagnosis test tool 10, obtaining coordinate data (x3, y3, z3) of a contact point of the three-coordinate measuring head and the fifth plane 15, then enabling the milling side spindle to retreat to the position where C is 0 along the original path, recording the coordinate data (x4, y4, z4) of a tool tip point in the numerical control system at the moment, calculating a single zero point positioning error of the C axis through the following formula, and completing single measurement of the C axis:

The above operation is repeated N (N is 6 in this embodiment) times, and a zero point positioning error and a repeated positioning error of the milling-side spindle C are obtained.

232) For the two rotating shafts on the supporting side, the zero point positioning error and the repeated positioning error of the rotating shaft A, C on the supporting side are obtained according to the operation of the step 231), that is, the main shaft on the supporting side is made to move around the shaft A, C in sequence, and the zero point positioning error and the repeated positioning error of the shaft A, C of the main shaft on the supporting side are detected by the fourth plane 14 and the fifth plane 15 of the geometric error diagnosis test tool 10 respectively.

24) judging whether the X, Y, Z, A, C zero point error and the repeated positioning error of the milling side spindle and the support side spindle meet the set precision requirement, and if the set precision requirement is met, executing the step 4); if the set precision requirement is not met, executing the step 3);

3) performing machine tool structure inspection and error compensation, then performing steps 22) -23) until X, Y, Z, A, C zero point errors and repeated positioning errors of the milling-side spindle and the supporting-side spindle meet set accuracy requirements, and performing step 4).

4) Self-diagnosis of the spatial profile precision of the double five-axis mirror milling machine tool: setting a corresponding detection track based on a double five-axis synchronous motion model required by a mirror milling working principle, acquiring rod length change data under the set detection track by utilizing a rod instrument arranged on a main shaft and a working table of a double five-axis mirror milling machine tool, and obtaining a contour error of the machine tool in a motion state through calculation so as to diagnose the spatial contour accuracy of the machine tool.

41) The interpolation circular motion precision of the A axis and the C axis of the rotating shaft and the corresponding two translational axes is respectively detected

Mounting the fixed end of the ball rod instrument on a machine tool body, and mounting the movable end of the ball rod instrument on a milling side main shaft; setting a first detection track according to ISO230-1-2012 < Test code for chips-Part 1 > geometrical access of chips operating under no-load or quasi-static conditions; for a milling side five-axis, according to an AK1 mode in ISO230-1-2012 standard, precision detection is carried out on interpolation circular motion of each rotating axis (an axis A and an axis C) and two corresponding translational axes by using a ball bar instrument according to a set first detection track, and a three-axis linkage error is calculated;

42) detecting five-axis linkage interpolation motion precision of fixed cutter point on milling side

Keeping the installation position of the ball arm instrument unchanged; setting a second detection track according to the ISO230-1-2012 standard; performing precision detection on the five-axis linkage interpolation track of the fixed tool point by using a ball bar instrument according to an AK4 mode in the ISO230-1-2012 standard on the milling side five-axis according to a set second detection track, and calculating a five-axis linkage error;

43) detecting the synchronous motion precision of the milling side main shaft and the supporting side main shaft along each translation axis

for a double five-axis mirror milling machine tool, when the double five axes are in linkage, the distance between the tool nose points of the milling side main shaft and the supporting side main shaft along each translational axis (X, Y, Z) is theoretically one skin thickness. The double five-axis mirror milling machine tool aims at processing the skin, and the distance error of the tool nose point of the double five-axis mirror milling machine tool can directly influence the thickness of the milled skin, so that the synchronous motion precision is an important index for detection and evaluation. The specific implementation process is as follows:

431) the fixed end of the ball rod instrument is arranged on the main shaft at the supporting side by utilizing the magnetic suction seat, namely the fixed end of the ball rod instrument moves synchronously along with the main shaft at the supporting side, and the installation position of the moving end of the ball rod instrument is kept unchanged;

432) setting step-by-step body Diagonal detection tracks for synchronous motion precision detection of a milling side and a supporting side on the basis of a body Diagonal measurement method in ISO 230-6-2002 Test code for machine tools-Part 6 standard of Determination of position acquisition on body and face dimensions (dimensional displacement tests), and realizing synchronous precision error measurement in a full operation space range, specifically: referring to fig. 4, the whole operation space of the machine tool is a cube abcdefgh, the body diagonal line from point a to point g is ppp, the body diagonal line from point d to point f is npp, the body diagonal line from point b to point h is pnp, and the body diagonal line from point e to point c is ppn, which are vectors; wherein p represents that the component direction of each body diagonal on X, Y, Z coordinate axis is the same as each coordinate axis positive direction, and n represents that the component direction of each body diagonal on X, Y, Z coordinate axis is opposite to each coordinate axis positive direction; referring to fig. 5, in order to ensure the measurement efficiency and the principle of repeated measurement at the same time, each body diagonal is equally divided into m segments (only the segmentation of the body diagonal ppp is illustrated in fig. 5, and the other body diagonals are the same and not illustrated; in this embodiment, m is 3, the body diagonal ppp is equally divided into three segments, P0P1, P1P2 and P2 Pm), and each segment moves along the X direction (e.g., P0 to P0X in fig. 5, Δ X is the component of the body diagonal of the current segment along the X axis), then moves along the Y direction (e.g., P0X to P0Y in fig. 5, Δ Y is the component of the body diagonal of the current segment along the Y axis), and finally moves along the Z direction (e.g., P0Y to P1 in fig. 5, Δ Z is the component of the body diagonal of the current segment along the Z axis);

433) And (3) enabling the milling side main shaft and the support side main shaft to synchronously move along each body diagonal segment in sequence according to the step body diagonal detection track set in the step 432), respectively recording the rod length change condition of the ball rod instrument in the moving process, and calculating X, Y, Z the distance change amount of the tool nose point in each moving direction to be used as the synchronous movement error of the milling side main shaft and the support side main shaft.

The step body diagonal measurement method has the advantages that full coverage of respective measuring ranges of all the axes can be achieved, and the ergodicity of the full operation space is reflected.

44) If the measured linkage error is always within the allowable range in the steps 41), 42) and 43), the diagnosis is finished; if any linkage error exceeds the allowable range and the step 2) is not executed in the diagnosis, executing the step 2); and if any linkage error exceeds the allowable range and the diagnosis is executed in the step 2), executing the step 3).

since the milling side is the machining side, the spatial accuracy thereof has a direct influence on the final machining accuracy. While the support side is mainly used for surface support, particularly high machining accuracy is not required compared to point cutting, which is concerned with enabling follow-up support and ensuring that the cutting region can be supported in the normal direction. Therefore, the spatial accuracy of the supporting side is not measured independently in the step, and the measurement efficiency can be improved while the measurement accuracy is ensured.

Further, the method also comprises the following steps after the step 4) is finished:

5) the precision self-diagnosis of the measurement and control sensor of the double five-axis mirror milling machine tool is as follows:

The measurement and control sensor comprises a line laser profiler which is used for scanning the profile of a blank to be processed and providing data for subsequent processing track planning, and is fixedly installed on a main shaft at the supporting side of the double five-axis mirror image milling machine tool, and the installation and measurement precision of the measurement and control sensor cannot neglect the machining precision of the machine tool, so that the invention self-diagnoses the precision of the third layer of the double five-axis mirror image milling machine tool through the installation precision and the detection precision of the line laser profiler.

The method comprises the steps of designing a line laser profiler precision diagnosis test tool based on the working principle of the line laser profiler, diagnosing the installation precision and the detection precision of the line laser profiler by using the test tool, evaluating the precision condition of the line laser profiler during on-site measurement, diagnosing the precision of a measurement and control sensor of a mirror milling machine tool, and ensuring the accuracy of blank shape information required by process planning before the machine tool is processed. The specific implementation process is as follows:

51) precision diagnosis test tool for designing and installing line laser profiler

In order to more efficiently and accurately acquire the installation precision and the measurement precision of the line laser profiler, the line laser profiler precision diagnosis testing tool 20 shown in fig. 6 is designed based on the working principle of the line laser profiler and is fixedly installed on a machine tool body, so that the installation precision and the self measurement precision of the line laser profiler can be diagnosed. The line laser profilometer precision diagnosis testing tool 20 comprises a base plate 3 and two blocks 4 and 5 arranged on the base plate 3 at intervals, wherein the upper surfaces of the two blocks are horizontal planes, and the line laser profilometer precision diagnosis testing tool 20 is fixedly arranged on a main shaft at the supporting side of a double five-axis mirror image milling machine tool through a bolt hole on the base plate 3 and a matched bolt. A groove 6 is formed between two adjacent blocks, a step surface 7 (as shown by reference numeral 7 in fig. 6) is formed between the side surface of each block and the upper surface of the substrate 3, and a circular hole 51 is formed on the block 5. Taking three positions in the line laser profilometer precision diagnosis testing tool 20 as shown in fig. 7 as three characteristic planes, wherein the three characteristic planes are parallel to each other and are parallel to a YZ plane under the guarantee of high precision of the line laser profilometer precision diagnosis testing tool; wherein, the first characteristic plane 41 is located at the plane of the block 4, the second characteristic plane 42 is located at the stepped surface 7, and the third characteristic plane 43 is located at the groove 6 (the positions of the three characteristic planes in the figure are only used as an illustration and are not limited to the three positions shown in the figure);

52) The main shaft at the side of the moving support is used for respectively placing the line laser profiler at a first characteristic plane and a second characteristic plane on the line laser profiler precision diagnosis test tool so as to measure the installation precision of an A axis and a C axis of the line laser profiler; if the installation accuracy is met, executing step 53), otherwise, correcting the corresponding installation error until the installation accuracy is met, and executing step 53); the method comprises the following specific steps:

521) and moving the support side main shaft to enable the line laser profiler to move to a first characteristic plane position and move along the Z direction, reading distance data from a measuring head measured by the line laser profiler to the surface of the line laser profiler precision diagnosis test tool, calculating the slope of each contour line by using a plurality of contour lines measured by the line laser profiler, and calculating a plane inclination angle through the average value of all the contour line slopes to serve as a diagnosis result of the rotation angle of the A axis. If the error of the diagnosis result exceeds the allowable range, the A-axis installation angle of the line laser profiler is corrected and then the line laser profiler is scanned again until the measured height value is basically unchanged.

522) And (3) moving the side main shaft to support the line laser profiler to a second characteristic plane position, moving the line laser profiler along the Y direction, if a single-side step appears in the profile scanned by the line laser profiler, indicating that the laser has a deflection angle along the C axis and does not meet the installation precision of the line laser profiler, firstly adjusting the specific angle of the C axis by operating a hand wheel of a numerical control machine until no obvious step exists, setting the C axis angle corresponding to the measurement coordinate system to be 0, and then executing the step 53). If the profile scanned by the laser does not have obvious single-side steps, indicating that the installation position of the line laser profiler along the C axis meets the precision requirement, executing step 53).

53) The method comprises the following steps of moving a support side main shaft, respectively arranging a line laser profiler at a first characteristic plane, a second characteristic plane and a third characteristic plane on a line laser profiler precision diagnosis test tool so as to measure the Z-axis, X-axis and Y-axis measurement precision of the line laser profiler, and specifically comprises the following steps:

531) And moving the support side main shaft to enable the line laser profiler to move to the first characteristic plane position and move along the Z direction, and reading distance data from a measuring head measured by the line laser profiler to the surface of the line laser profiler precision diagnosis testing tool, namely obtaining the Z-direction height. Since the mounting accuracy is already ensured at this time, the Z-direction height should theoretically be a constant value. But this step takes the average of the height as the measurement accuracy of the Z-axis, taking into account the incompleteness of the diagnosis and random errors of the measurement of step 52). And taking the error between the measured Z-direction height average value and the actual depth of the groove 6 in the line laser profiler precision diagnosis test tool 20 as the Z-direction self error of the line laser profiler. And changing the distance between the measuring head and the first characteristic plane for multiple times to obtain deviation values at different heights until the height exceeds the measuring range of the line laser profilometer.

532) And moving the support side spindle to move the line laser profiler to a second characteristic plane position, and moving the line laser profiler along the X direction, so that the laser movement area can identify the critical positions (such as the side surface of the block body 4) of the upper surface and the lower surface of the step, the measured X coordinate of the critical position is compared with the actual coordinate position of the step area on the test tool, and the error value is the self precision error of the line laser profiler in the X direction.

533) and moving the support side spindle to move the line laser profiler to a third characteristic plane position, and moving the line laser profiler along the Y direction. The groove width of the test tool is 60mm, the movement speed ensures that 600 coordinate points can be collected, and the distance between each point and each other is ensured to be within 0.1 mm. And comparing the measured groove width with the actual groove width of 60mm, wherein the error value is the self-precision error of the line laser profile instrument in the Y direction.

54) Judging the self-precision error of each direction of the line laser profiler measured in the steps 531) to 533), and if the self-precision of any direction of the line laser profiler exceeds the allowable range, correcting the line laser profiler so as to facilitate the compensation in the subsequent data processing; if the self-precision of each direction of the line laser profiler is within the allowable range, scanning the circular hole 51, measuring the diameter of the circular hole, comparing the diameter with the actual diameter, and if the precision requirement is met, finishing the self-diagnosis of the precision of the dual five-axis mirror image milling machine tool and starting the machine tool to execute the machining program. If the requirements are not met, the distance between the line laser profiler and the line laser profiler precision diagnosis test tool is adjusted, the fact that the region to be tested of the line laser profiler precision diagnosis test tool is within the measurement working range of the line laser profiler is guaranteed, precision self-diagnosis of the double five-axis mirror milling machine tool is finished, and the machine tool starts to execute a machining program.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.