Adaptive adjustment method for part machining coordinate system of numerical control horizontal machining center

Abstract

The application discloses a part machining coordinate system self-adaptive adjustment method of a numerical control horizontal machining center, which performs self-adaptive adjustment on a part machining coordinate system according to an actual position of a part, flexibly determines a part machining coordinate system center of an instant position, and eliminates the clamping system error, the machine tool coordinate precision and the measuring system error when machining a to-be-machined precision hole based on the part machining coordinate system after correction and adjustment, so that the machining qualified rate of the precision size of the part is greatly improved, and the machining precision is improved.

Description

Adaptive Adjustment Method of Part Machining Coordinate System for CNC Horizontal Machining Center Technical Field

[0001] This invention relates to the field of precision machining technology, and in particular, to a method for adaptive adjustment of the coordinate system of a part machining center in a CNC horizontal machining center. Background Technology

[0002] In the field of aero-engine manufacturing, to meet the precision assembly requirements of various components, the positional dimensions and accuracy of individual components are subject to very high standards. Taking a certain casing as an example, the runout requirement for the precision holes that mate with the assembled parts is 0.013, and the positional accuracy requirement for the locating holes is 0.05. However, during precision machining on a CNC horizontal machining center, the pass rate for machining these precision dimensions is low, and the machining quality is unstable. The main problems are as follows:

[0003] 1) Clamping system error

[0004] In batch production, after the CNC fixture wears out, the positioning accuracy of the positioning surface and positioning hole decreases, and the clamping position of the parts is prone to deviate, resulting in dimensional deviations.

[0005] 2) Machine tool coordinate accuracy and measurement system error

[0006] Due to the influence of its own center of gravity, the spindle of a CNC horizontal machining center will exhibit a downward wobbling phenomenon known as "spindle sag." This leads to backlash in the lead screw, repeatability deviations in each coordinate axis, and a decrease in machining accuracy after a certain period of use. These factors, along with errors in the machine tool's machining accuracy and measurement system, directly cause workpiece alignment deviations. These deviations are carried over into the actual coordinates of the workpiece during machining, resulting in deviations from technical requirements such as precision hole dimensions or positional accuracy.

[0007] Currently, the main method for addressing clamping system errors is the scheduled inspection and repair method. This involves periodically inspecting the fixture after a certain period of use. If severe wear is found on the fixture's locating surfaces and pins, or if related locating dimensions are out of tolerance, the fixture is sent for repair to ensure that the relevant dimensions and requirements are met. However, this method does not solve the problem of abnormal fixture wear during the scheduled inspection period. Moreover, the fixture inspection and repair period directly affects the production progress of parts. Furthermore, the fundamental problem of locating gaps in part clamping remains unresolved, and system errors are not eliminated.

[0008] For machine tool coordinate accuracy and measurement system errors, the main method currently used is the allowance correction method. This method focuses on the real-time adjustment of the program coordinates of the part's machining dimensions. Given a known slight misalignment or sag of the CNC machine tool spindle coordinates, instead of correcting the spindle coordinate offset, the machining allowance is allocated with tolerance, and then adjustments are made based on the real-time coordinates. This involves machining the part's precision dimensions in roughing and finishing steps. After roughing, sufficient finishing allowance is reserved (ensuring the tolerance for finishing is greater than the spindle misalignment during roughing). During the finishing step, the coordinates are adjusted to correct the dimensions to meet requirements. Specifically, after roughing, the part is measured in real-time, the measurement results are analyzed, and the direction and amount of the coordinate offset are recorded. Then, finishing is performed, and coordinate adjustments (program adjustments or machine tool compensation) are made based on the offset direction and amount to correct the part's dimensions and ensure the final precision dimensions are acceptable. However, this method is only suitable for precision machining of single-batch, single-piece parts. It is not suitable for machining and manufacturing multiple batches of multiple parts. When there are too many batches of parts, there are too many precision machining adjustments, unstable machining quality, and low machining efficiency. In addition, there is a risk that the machining allowance of the parts may be insufficient for error correction due to occasional excessive machine tool movement. Summary of the Invention

[0009] This invention provides an adaptive adjustment method for the coordinate system of a CNC horizontal machining center to solve the technical problems of poor machining accuracy and low pass rate in the finishing process of existing CNC horizontal machining centers.

[0010] According to one aspect of the present invention, an adaptive adjustment method for the coordinate system of a part machining center in a CNC horizontal machining center is provided, comprising the following:

[0011] The part is roughly positioned at the center of the machine's worktable. Based on the actual coordinates of the part in the X and Z directions of the machine tool's mechanical coordinate system, the on-machine coordinates of the machine tool's rotation center are offset and adjusted to obtain the on-machine coordinates of the zero point of the XZ axis in the part's machining coordinate system.

[0012] The Y-axis coordinate value of the part machining coordinate system is compensated using an analogy compensation method.

[0013] Furthermore, the process of roughly positioning the part at the center of the machine's worktable, and adjusting the on-machine coordinates of the machine tool's rotation center based on the actual coordinates of the part in the X and Z directions of the machine tool's mechanical coordinate system to obtain the on-machine coordinates of the XZ axis zero point in the part's machining coordinate system is specifically as follows:

[0014] Use locating pins to roughly locate the parts, and then remove the locating pins after the positioning is complete.

[0015] Straighten the X-axis direction of the part;

[0016] Use a dial indicator to find the first on-machine coordinates of one of the locating holes on the part in the X and Z directions of the machine tool's mechanical coordinate system. After rotating the part 180° around the machine tool's rotation center, use the dial indicator again to find the second on-machine coordinates of the same locating hole in the X and Z directions of the machine tool's mechanical coordinate system.

[0017] Based on the first and second on-machine coordinates and the theoretical position of the positioning hole on the part, the on-machine coordinate adjustment value of the center of the part machining coordinate system relative to the machine tool rotation center is obtained. Then, combined with the on-machine coordinate of the machine tool rotation center, the on-machine coordinate of the zero point of the XZ axis in the part machining coordinate system is calculated.

[0018] Furthermore, when the machine tool's rotation center coincides with the machine tool's mechanical coordinate system center, the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool's rotation center is calculated using the following formula:

[0019]

[0020] Wherein, σX and σZ represent the on-machine coordinate adjustment values ​​of the center of the part machining coordinate system relative to the rotation center of the machine tool in the X and Z directions of the machine tool mechanical coordinate system, respectively; X and Z represent the theoretical coordinate values ​​of the positioning hole in the X and Z axes of the part machining coordinate system, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

[0021] Furthermore, when the machine tool's rotation center does not coincide with the machine tool's mechanical coordinate system center, the following formula is used to calculate the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool's rotation center:

[0022]

[0023] Wherein, σX and σZ represent the on-machine coordinate adjustment values ​​of the center of the part machining coordinate system relative to the rotation center of the machine tool in the X and Z directions of the machine tool mechanical coordinate system, respectively; X and Z represent the theoretical coordinate values ​​of the positioning hole in the X and Z axes of the part machining coordinate system, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

[0024] Furthermore, the following is included before calculating the on-machine coordinates of the XZ axis zero point in the part machining coordinate system:

[0025] Based on the first and second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool's mechanical coordinate system, the on-machine coordinates of the machine tool's rotation center are corrected and adjusted.

[0026] Furthermore, the on-machine coordinate correction value of the machine tool rotation center is calculated based on the following formula:

[0027]

[0028]

[0029] Where δX and δZ represent the correction values ​​of the X-axis and Z-axis coordinates of the machine tool rotation center, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

[0030] Furthermore, the process of straightening the part along the X-axis direction is specifically as follows:

[0031] Mount the dial indicator on the spindle of the CNC horizontal machining center, place the probe of the dial indicator vertically within the circumference of the first positioning hole, and continuously move the spindle along the Z-axis direction of the machine tool's mechanical coordinate system. Record the peak value of the dial indicator reading as the Z-axis coordinate of the first positioning hole.

[0032] Place the dial indicator probe vertically within the circumference of the second positioning hole, and continuously move the spindle along the Z-axis of the machine tool's mechanical coordinate system. Record the peak value of the dial indicator reading as the Z-axis coordinate of the second positioning hole.

[0033] The difference in Z-axis coordinates between the two positioning holes was calculated.

[0034] Continuously rotate the center of the worktable, repeating the above steps for each rotation angle, until the actual difference between the Z-axis coordinates of the two positioning holes is within the error range of the theoretical difference. Fix the rotation angle at this point and use the current spindle direction as the X-axis direction of the part machining coordinate system.

[0035] Furthermore, the process of using a dial indicator to find the in-machine coordinates of the positioning hole is as follows:

[0036] Mount the dial indicator on the spindle of the CNC horizontal machining center and place the probe of the dial indicator vertically within the circumference of the positioning hole;

[0037] The spindle is continuously moved along the Z-axis of the machine tool's mechanical coordinate system, and the dial reading is read. The peak value of the dial reading is used as the X-axis coordinate value of the positioning hole.

[0038] The spindle is continuously moved along the X-axis of the machine tool's mechanical coordinate system, and the dial reading is read. The peak value of the dial reading is used as the Z-axis coordinate value of the positioning hole.

[0039] Furthermore, the process of compensating the Y-axis coordinate value of the part machining coordinate system using the analogy compensation method is specifically as follows:

[0040] Use a feeler gauge to check the clearance between the part and the fixture to ensure that they are firmly supported and attached in the Y-axis direction of the machine tool's mechanical coordinate system;

[0041] Install the dial indicator on the spindle and measure the in-machine Y-axis coordinate value of the fixture surface;

[0042] Locate the sub-precision analog hole on the part that is on the same machining surface as the precision hole to be machined, and use a dial indicator to measure the on-machine Y-axis coordinate value of the lowest point at the bottom of the sub-precision analog hole.

[0043] The spindle's Y-axis adjustment is calculated based on the on-machine Y-axis coordinates of the fixture surface, the on-machine Y-axis coordinates of the lowest point of the sub-precision analog hole, the actual radius of the sub-precision analog hole after machining, and the on-machine theoretical Y-axis coordinates of the sub-precision analog hole.

[0044] The Y-axis adjustment of the spindle is used to compensate for the on-machine Y-axis coordinate value of the precision hole to be machined. Further, the Y-axis adjustment of the spindle is calculated based on the following formula:

[0045] σY=Y-(R+Y2-Y1)

[0046] Where σY represents the Y-axis adjustment of the spindle, Y represents the theoretical Y-axis coordinate value of the sub-precision analog hole, R represents the actual radius value of the sub-precision analog hole after machining, Y1 represents the Y-axis coordinate value of the fixture surface, and Y2 represents the Y-axis coordinate value of the lowest point at the bottom of the sub-precision analog hole.

[0047] The present invention has the following effects:

[0048] The adaptive adjustment method for the part machining coordinate system of the CNC horizontal machining center of the present invention only requires rough positioning of the part at the center of the worktable of the horizontal machining center, and then offsetting the on-machine coordinates of the machine tool rotation center according to the measured on-machine X and Z axis coordinates of the part, so as to obtain the on-machine coordinates of the zero point of the XZ axis in the part machining coordinate system, thereby correcting and adjusting the X and Z axes of the part machining coordinate system. At the same time, an analogy compensation method is also used to compensate the Y axis coordinate value of the part machining coordinate system, thereby correcting and adjusting the XYZ axes of the part machining coordinate system simultaneously. In the method of this invention, the part machining coordinate system is adaptively adjusted according to the actual position of the part, and the center of the part machining coordinate system at the instantaneous position is flexibly determined. There is no need to physically align the part with the rotation center to align the part machining coordinate system. Furthermore, by correcting the error deviation of the part machining coordinate system, the part machining coordinate system can adaptively match any clamping position of the part. When machining the precision hole to be machined based on the corrected and adjusted part machining coordinate system, the clamping system error, machine tool coordinate accuracy, and measurement system error are eliminated, which greatly improves the machining qualification rate of the precision dimensions of the part and enhances the machining accuracy.

[0049] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0050] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0051] Figure 1 is a flowchart illustrating the adaptive adjustment method of the coordinate system for part machining in a CNC horizontal machining center according to a preferred embodiment of the present invention.

[0052] Figure 2 is a schematic diagram of the sub-process of step S1 in Figure 1.

[0053] Figure 3 is a schematic diagram of the sub-process of step S12 in Figure 2.

[0054] Figure 4 is a schematic diagram of the sub-process of step S13 in Figure 2.

[0055] Figure 5 is a schematic diagram of using a dial indicator to find the on-machine X-axis coordinate value of the positioning hole in a preferred embodiment of the present invention.

[0056] Figure 6 is a schematic diagram of using a dial indicator to find the in-machine Z-axis coordinate value of the positioning hole in a preferred embodiment of the present invention.

[0057] Figure 7 is a schematic diagram of the on-machine coordinate adjustment value of the center of the part machining coordinate system relative to the center of the machine tool rotation when the machine tool rotation center coincides with the center of the machine tool mechanical coordinate system in a preferred embodiment of the present invention.

[0058] Figure 8 is a schematic diagram of the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool rotation center when the machine tool rotation center does not coincide with the machine tool mechanical coordinate system center in a preferred embodiment of the present invention.

[0059] Figure 9 is a schematic diagram of correcting the on-machine coordinate calibration value of the machine tool rotation center in a preferred embodiment of the present invention.

[0060] Figure 10 is a schematic diagram of the sub-process of step S2 in Figure 1.

[0061] Figure 11 is a schematic diagram of the on-machine Y-axis coordinate value compensation using the analogy compensation method in a preferred embodiment of the present invention.

[0062] Figure 12 is a top view of the positioning of a certain casing in a preferred embodiment of the present invention.

[0063] Figure 13 is a schematic diagram of the horizontal machining plane of a certain casing in the A direction according to a preferred embodiment of the present invention. Detailed Implementation

[0064] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0065] As can be understood, as shown in Figure 1, a preferred embodiment of the present invention provides a method for adaptive adjustment of the coordinate system of a part machining center in a CNC horizontal machining center, including the following:

[0066] Step S1: Roughly position the part at the center of the machine's worktable. Based on the actual coordinates of the part in the X and Z directions of the machine tool's mechanical coordinate system, offset and adjust the on-machine coordinates of the machine tool's rotation center to obtain the on-machine coordinates of the zero point of the XZ axis in the part's machining coordinate system.

[0067] Step S2: Compensate the Y-axis coordinate value of the part machining coordinate system using the analogy compensation method.

[0068] It is understood that the adaptive adjustment method of the part machining coordinate system of the CNC horizontal machining center in this embodiment only requires coarsely positioning the part at the center of the worktable of the horizontal machining center, and then offsetting the on-machine coordinates of the machine tool rotation center according to the measured on-machine X and Z axis coordinates of the part. This yields the on-machine coordinates of the zero point of the X and Z axes in the part machining coordinate system, thereby correcting and adjusting the X and Z axes of the part machining coordinate system. At the same time, an analogy compensation method is also used to compensate the Y axis coordinate value of the part machining coordinate system, thereby correcting and adjusting each axis of the XYZ axis of the part machining coordinate system simultaneously. In the method of this invention, the part machining coordinate system is adaptively adjusted according to the actual position of the part, and the center of the part machining coordinate system at the instantaneous position is flexibly determined. There is no need to physically align the part with the rotation center to align the part machining coordinate system. Furthermore, by correcting the error deviation of the part machining coordinate system, the part machining coordinate system can adaptively match any clamping position of the part. When machining the precision hole to be machined based on the corrected and adjusted part machining coordinate system, the clamping system error, machine tool coordinate accuracy, and measurement system error are eliminated, which greatly improves the machining qualification rate of the precision dimensions of the part and enhances the machining accuracy.

[0069] As can be understood, as shown in Figure 2, in step S1, the process of roughly positioning the part at the center of the machine's worktable, and adjusting the on-machine coordinates of the machine tool's rotation center based on the actual coordinates of the part in the X and Z directions of the machine tool's mechanical coordinate system to obtain the on-machine coordinates of the zero point of the XZ axis in the part's machining coordinate system is as follows:

[0070] Step S11: Use the locating pin to perform coarse positioning of the part, and remove the locating pin after positioning is completed;

[0071] Step S12: Straighten the X-axis direction of the part;

[0072] Step S13: Use a dial indicator to find the first on-machine coordinates of one of the positioning holes on the part in the X and Z directions of the machine tool's mechanical coordinate system. After rotating the part 180° around the machine tool's rotation center, use the dial indicator again to find the second on-machine coordinates of the same positioning hole in the X and Z directions of the machine tool's mechanical coordinate system.

[0073] Step S14: Based on the first and second on-machine coordinates and the theoretical position of the positioning hole on the part, calculate the on-machine coordinate adjustment value of the center of the part machining coordinate system relative to the machine tool rotation center, and then combine it with the on-machine coordinate of the machine tool rotation center to calculate the on-machine coordinate of the zero point of the XZ axis in the part machining coordinate system.

[0074] Specifically, the part is first roughly positioned at the center of the machine's worktable using a locating pin, and then the locating pin is removed after rough positioning. Next, the X-axis of the part is straightened, i.e., the X-axis of the part is aligned. As shown in Figure 3, the process of straightening the X-axis of the part is as follows:

[0075] Step S121: Mount the dial indicator on the spindle of the CNC horizontal machining center, place the probe of the dial indicator vertically within the circumference of the first positioning hole, and continuously move the spindle along the Z-axis direction of the machine tool's mechanical coordinate system. Record the peak value of the dial indicator reading as the Z-axis coordinate of the first positioning hole.

[0076] Step S122: Place the dial indicator probe vertically within the circumference of the second positioning hole, and continuously move the spindle along the Z-axis direction of the machine tool's mechanical coordinate system. Record the peak value of the dial indicator reading as the Z-axis coordinate of the second positioning hole.

[0077] Step S123: Calculate the Z-axis coordinate difference between the two positioning holes;

[0078] Step S124: Continuously rotate the center of the worktable. Repeat the above steps for each rotation angle until the actual difference between the Z-axis coordinates of the two positioning holes is within the error range of the theoretical difference. Fix the rotation angle at this time and take the current spindle direction as the X-axis direction of the part machining coordinate system.

[0079] It is understandable that before performing coordinate calculations, the X-axis of the part should be straightened first, i.e., the part should be aligned. This facilitates the subsequent calculation of the part's coordinate adjustment values, because the known values ​​of the part's machining coordinate system are often given fixed values ​​on a certain axis. If the X-axis is not straightened, the known values ​​in the direction where it is not straightened need to be calculated using trigonometric functions. At the same time, it helps to place the part in a position close to the center of the worktable, avoiding local overtravel or interference caused by the part being too large.

[0080] Then, select one of the locating holes on the part, and use a dial indicator to find the first on-machine coordinate values ​​of the locating hole in the X and Z directions of the machine tool's mechanical coordinate system. Next, rotate the part 180° around the machine tool's rotation center, and again use the dial indicator to find the first on-machine coordinate values ​​of the locating hole in the X and Z directions of the machine tool's mechanical coordinate system. As shown in Figure 4, the specific process of finding the on-machine coordinates of the locating hole using a dial indicator is as follows:

[0081] Step S131: Mount the dial indicator on the spindle of the CNC horizontal machining center and place the probe of the dial indicator vertically within the circumference of the positioning hole;

[0082] Step S132: Continuously move the spindle along the Z-axis of the machine tool's mechanical coordinate system and read the dial reading. Use the peak value of the dial reading as the X-axis coordinate value of the positioning hole.

[0083] Step S133: Continuously move the spindle along the X-axis of the machine tool's mechanical coordinate system and read the dial reading. Use the peak value of the dial reading as the Z-axis coordinate value of the positioning hole.

[0084] Specifically, first, install the dial indicator on the spindle and visually adjust the probe so that it is perpendicular to the circumference of the positioning hole. Then, continuously move the spindle along the Z-axis of the machine tool's coordinate system and read the dial indicator readings. The peak value (only one) of the dial indicator reading is taken as the X-axis coordinate value X1 of the positioning hole, as shown in Figure 5. Next, continuously move the spindle along the X-axis of the machine tool's coordinate system and read the dial indicator readings. The peak value (only one) of the dial indicator reading is taken as the Z-axis coordinate value Z1 of the positioning hole, as shown in Figure 6. Thus, the first on-machine coordinates (X1, Z1) of the positioning hole in the X and Z directions of the machine tool's coordinate system can be obtained. Similarly, after the part rotates 180°, the same measurement method can be used to obtain the first on-machine coordinates (X2, Z2) of the positioning hole in the X and Z directions of the machine tool's coordinate system. Additionally, when using a dial indicator to locate the positioning hole, it is important to ensure that the orientation of the dial indicator remains consistent before and after rotation.

[0085] Next, based on the first and second on-machine coordinates and the theoretical position of the positioning hole on the part, the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool rotation center is calculated. Specifically, when the machine tool rotation center coincides with the machine tool mechanical coordinate system center, as shown in Figure 7, the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool rotation center is calculated using the following formula:

[0086]

[0087] When the machine tool's rotation center does not coincide with the machine tool's mechanical coordinate system center, as shown in Figure 8, the following formula is used to calculate the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool's rotation center:

[0088]

[0089] Wherein, σX and σZ represent the on-machine coordinate adjustment values ​​of the center of the part machining coordinate system relative to the rotation center of the machine tool in the X and Z directions of the machine tool mechanical coordinate system, respectively. X and Z represent the theoretical coordinate values ​​of the positioning hole in the X and Z axes of the part machining coordinate system, respectively. These values ​​are given according to the specific part machining requirements and are known values. X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system, and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

[0090] Then, by combining the on-machine coordinates of the machine tool's rotation center, the on-machine coordinates of the XZ axis zero point in the part machining coordinate system are calculated. The specific calculation formula is: X o =X s +σX,Z o =Z s +σZ, where X o and Z o These represent the on-machine coordinate values ​​of the X and Z axis zero points in the part machining coordinate system in the X and Z directions of the machine tool mechanical coordinate system, respectively. s and Z s These represent the on-machine coordinates of the machine tool's rotation center in the X and Z directions of the machine tool's mechanical coordinate system, respectively.

[0091] It is understandable that before machining, the part is roughly positioned on the center of the worktable of the horizontal machining center using locating pins. At this time, the center of the part's machining coordinate system and the machine tool's rotation center are not coaxial before alignment. Even if the part's center is aligned using physical alignment methods, due to factors such as machine tool lead screw backlash, measurement system errors, or decreased accuracy due to equipment aging, there will still be a significant deviation between the part's machining coordinate system and the machine tool's rotation center. This deviation reflects the deviation of the theoretical center of the machining coordinate system. In this invention, however, before machining, the on-machine coordinate adjustment value of the part's machining coordinate system center in the machine tool's mechanical coordinate system can be calculated using the symmetrical mean method based on the part's actual position in the machine tool's mechanical coordinate system. Then, the on-machine coordinates of the part's machining coordinate system center are adjusted according to this adjustment value, thus determining the on-machine coordinates of the XZ axis zero point of the part's machining coordinate system that adaptively matches the actual position. Furthermore, there is no need to align the part's center, making it well-suited for situations where it is impossible to align the part's center when machining irregularly shaped or large parts on a CNC horizontal machining center.

[0092] Optionally, in step S14, before calculating the on-machine coordinates of the XZ axis zero point in the part machining coordinate system, the following is also included:

[0093] Based on the first and second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool's mechanical coordinate system, the on-machine coordinates of the machine tool's rotation center are corrected and adjusted.

[0094] Specifically, as shown in Figure 9, when the actual coordinates of the machine tool's rotation center deviate from the theoretical coordinates, i.e., when the on-machine coordinate calibration value of the machine tool's rotation center deviates, the on-machine coordinates of the machine tool's rotation center can be corrected and adjusted based on the first and second on-machine coordinates of the positioning holes in the X and Z directions of the machine tool's mechanical coordinate system. Taking the X-axis as an example, based on the rotation relationship, we can obtain: X1 - δX = X2 + δX, therefore, δX = (X1 + X2) / 2; similarly, based on the rotation relationship of the Z-axis, we can obtain: δZ = (Z1 + Z2) / 2. Therefore, the corrected value of the on-machine coordinates of the machine tool's rotation center is calculated based on the following formula:

[0095]

[0096]

[0097] Where δX and δZ represent the correction values ​​of the X-axis and Z-axis coordinates of the machine tool rotation center, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

[0098] It is understood that the present invention can also correct and adjust the on-machine coordinates of the machine tool rotation center based on the first and second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system, thereby eliminating the on-machine coordinate deviation of the machine tool rotation center and ensuring the accuracy of the on-machine coordinate conversion of the zero point of the XZ axis of the part machining coordinate system.

[0099] As can be understood, as shown in Figure 10, in step S2, the process of compensating the Y-axis coordinate value of the part machining coordinate system using the analogy compensation method specifically involves:

[0100] Step S21: Use a feeler gauge to check the clearance between the part and the fixture to ensure that they are firmly supported in the Y-axis direction of the machine tool's mechanical coordinate system;

[0101] Step S22: Install the dial indicator on the spindle and measure the on-machine Y-axis coordinate value of the fixture surface;

[0102] Step S23: Locate the sub-precision analog hole on the part that is on the same machining surface as the precision hole to be machined, and use a dial indicator to measure the on-machine Y-axis coordinate value of the lowest point of the sub-precision analog hole.

[0103] Step S24: Calculate the spindle's Y-axis adjustment amount based on the on-machine Y-axis coordinate value of the fixture surface, the on-machine Y-axis coordinate value of the lowest point of the sub-precision analog hole, the actual radius value of the sub-precision analog hole after machining, and the on-machine theoretical Y-axis coordinate value of the sub-precision analog hole;

[0104] Step S25: Compensate the on-machine Y-axis coordinate value of the precision hole to be machined based on the spindle's Y-axis adjustment amount.

[0105] Specifically, as shown in Figure 11, first, a feeler gauge is used to check the clearance between the part and the fixture to ensure that they are firmly supported and attached in the Y-axis direction of the machine tool's mechanical coordinate system. Then, a dial indicator is placed on the spindle to measure and record the pressure gauge reading on the fixture surface, thereby obtaining the on-machine Y-axis coordinate value Y1 of the fixture surface. Next, a sub-precision analog hole is found on the part located on the same machining surface as the precision hole to be machined, and the on-machine Y-axis coordinate value Y2 of the lowest point of the sub-precision analog hole is measured using a dial indicator. Then, based on the on-machine Y-axis coordinate value Y1 of the fixture surface, the on-machine Y-axis coordinate value Y2 of the lowest point of the sub-precision analog hole, the actual radius value R of the sub-precision analog hole after machining, and the on-machine theoretical Y-axis coordinate value Y of the sub-precision analog hole, the Y-axis adjustment amount of the spindle is calculated. The specific calculation formula is as follows:

[0106] σY=Y-(R+Y2-Y1)

[0107] Where σY represents the Y-axis adjustment of the spindle, Y represents the theoretical Y-axis coordinate value of the sub-precision analog hole, R represents the actual radius value of the sub-precision analog hole after machining, Y1 represents the Y-axis coordinate value of the fixture surface, and Y2 represents the Y-axis coordinate value of the lowest point at the bottom of the sub-precision analog hole.

[0108] Finally, the on-machine Y-axis coordinate value of the precision hole to be machined is compensated based on the spindle's Y-axis adjustment, i.e., Y... η =Y + σY, where Y η This represents the compensated Y-axis coordinate value of the precision hole to be machined in the part's machining coordinate system, where Y represents the Y-axis coordinate value of the precision hole to be machined before compensation. In practical applications, there are two ways to compensate the Y-axis coordinate of the precision hole to be machined: 1) inputting the Y-axis compensation value σY on-machine, and 2) updating the theoretical Y-axis value in the machining program to Y. η .

[0109] It is understandable that the spindle may experience "sag" when machining precision holes on a CNC horizontal machine. Therefore, this invention selects a sub-precision hole with less stringent dimensional and technical requirements as an analog hole. After machining the hole, its actual Y-axis height value (i.e., the on-machine Y-axis coordinate value) is measured and compared with the theoretical height value. The difference is considered as the spindle's instantaneous adjustment amount. An analog compensation method is used to apply the spindle's instantaneous sag to the precision hole to be machined, and the on-machine Y-axis coordinate value of the precision hole to be machined is adjusted accordingly to ensure that the machining is qualified.

[0110] It is understood that the present invention compensates and adjusts the XZ-axis coordinates and Y-axis coordinates of the part machining coordinate system by using the symmetrical mean method and the analogy compensation method respectively, so as to ensure the machining accuracy and machining pass rate of precision holes.

[0111] It is understandable that, in order to prove the feasibility of this method, the inventors of this application performed actual CNC horizontal machining on a certain casing using this method. As shown in Figure 12, this casing is a typical irregular structure casing, and its precision technical requirements are mainly reflected in the mounting surfaces and their precision positioning holes. The zero point of the part machining coordinate system is determined by the relative position of two positioning holes. In the vertical plane A view, the dimensions and technical requirements of each mounting surface and precision hole are relatively high, as shown in Figure 13. This invention first uses the symmetrical mean value method to align the G54 coordinate system by rotating through positioning hole D1, and then verifies it through positioning hole D2. Then, the analogy compensation method is applied, using φK as the analog hole for coordinate calculation to determine the Y-axis compensation value σY. The Y-axis machining coordinate is adjusted by inputting the Y-axis compensation value into the machine to ensure that the Y-axis height dimensions of the precision compensation holes φK1, φK2, φK3, and φK4 are finally qualified.

[0112] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0113] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0114] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart illustrations and / or one or more block diagrams.

[0115] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0116] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0117] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0118] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for adaptive adjustment of the coordinate system for part machining in a CNC horizontal machining center, characterized in that, The process includes the following: Roughly positioning the part at the center of the machine's worktable; adjusting the on-machine coordinates of the machine tool's rotation center based on the actual coordinates of the part in the X and Z directions of the machine tool's mechanical coordinate system to obtain the on-machine coordinates of the XZ axis zero point in the part's machining coordinate system; compensating the Y-axis coordinate value of the part's machining coordinate system using an analogy compensation method; specifically, the process of roughly positioning the part at the center of the machine's worktable and adjusting the on-machine coordinates of the machine tool's rotation center based on the actual coordinates of the part in the X and Z directions of the machine tool's mechanical coordinate system to obtain the on-machine coordinates of the XZ axis zero point in the part's machining coordinate system involves: using a locating pin to roughly position the part, and then removing the locating pin after positioning; straightening the part along the X-axis; using a dial indicator to find the first on-machine coordinates of one of the locating holes on the part in the X and Z directions of the machine tool's mechanical coordinate system; rotating the part 180° around the machine tool's rotation center, and then using the dial indicator to find the second on-machine coordinates of the same locating hole in the X and Z directions of the machine tool's mechanical coordinate system; based on the first and second on-machine coordinates and the... The theoretical position of the locating hole on the part is calculated to obtain the on-machine coordinate adjustment value of the center of the part's machining coordinate system relative to the machine tool's rotation center. Then, combined with the on-machine coordinate of the machine tool's rotation center, the on-machine coordinate of the zero point of the XZ axis in the part's machining coordinate system is calculated. The process of compensating the Y-axis coordinate value of the part's machining coordinate system using the analogy compensation method specifically involves: using a feeler gauge to check the clearance between the part and the fixture to ensure tight support in the Y-axis direction of the machine tool's mechanical coordinate system; installing a dial indicator on the spindle and measuring the on-machine Y-axis coordinate value of the fixture surface; and then... Identify the sub-precision analog hole on the workpiece that is on the same machining surface as the precision hole to be machined. Measure the on-machine Y-axis coordinate of the lowest point of the sub-precision analog hole using a dial indicator. Calculate the spindle's Y-axis adjustment based on the on-machine Y-axis coordinate of the fixture surface, the on-machine Y-axis coordinate of the lowest point of the sub-precision analog hole, the actual radius of the machined sub-precision analog hole, and the theoretical on-machine Y-axis coordinate of the sub-precision analog hole. Compensate for the on-machine Y-axis coordinate of the precision hole to be machined based on the spindle's Y-axis adjustment. Calculate the spindle's Y-axis adjustment using the following formula: Where σY represents the Y-axis adjustment of the spindle, Y represents the theoretical Y-axis coordinate value of the sub-precision analog hole, R represents the actual radius value of the sub-precision analog hole after machining, Y1 represents the Y-axis coordinate value of the fixture surface, and Y2 represents the Y-axis coordinate value of the lowest point at the bottom of the sub-precision analog hole.

2. The adaptive adjustment method for the coordinate system of a CNC horizontal machining center as described in claim 1, characterized in that, When the machine tool's rotation center coincides with the machine tool's mechanical coordinate system center, the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool's rotation center is calculated using the following formula: Where σX and σZ represent the on-machine coordinate adjustment values ​​of the center of the part machining coordinate system relative to the rotation center of the machine tool in the X and Z directions of the machine tool mechanical coordinate system, respectively; X and Z represent the theoretical coordinate values ​​of the positioning hole in the X and Z axes of the part machining coordinate system, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

3. The adaptive adjustment method for the coordinate system of a CNC horizontal machining center as described in claim 1, characterized in that, When the machine tool's rotation center does not coincide with the machine tool's mechanical coordinate system center, the following formula is used to calculate the on-machine coordinate adjustment value of the part machining coordinate system center relative to the machine tool's rotation center: Where σX and σZ represent the on-machine coordinate adjustment values ​​of the center of the part machining coordinate system relative to the rotation center of the machine tool in the X and Z directions of the machine tool mechanical coordinate system, respectively; X and Z represent the theoretical coordinate values ​​of the positioning hole in the X and Z axes of the part machining coordinate system, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

4. The adaptive adjustment method for the coordinate system of a part machining center as described in claim 1, characterized in that, Before calculating the on-machine coordinates of the XZ axis zero point in the part machining coordinate system, the following steps are also included: based on the first and second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system, the on-machine coordinates of the machine tool rotation center are corrected and adjusted.

5. The adaptive adjustment method for the coordinate system of a CNC horizontal machining center as described in claim 4, characterized in that, The on-machine coordinate correction value of the machine tool rotation center is calculated based on the following formula: Where δX and δZ represent the correction values ​​of the X-axis and Z-axis coordinates of the machine tool rotation center, respectively; X1 and Z1 represent the first on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system; and X2 and Z2 represent the second on-machine coordinates of the positioning hole in the X and Z directions of the machine tool mechanical coordinate system.

6. The adaptive adjustment method for the coordinate system of a part machining center as described in claim 1, characterized in that, The process of straightening the X-axis direction of the part is as follows: A dial indicator is mounted on the spindle of a CNC horizontal machining center. The probe of the dial indicator is vertically positioned within the circumference of the first positioning hole, and the spindle is continuously moved along the Z-axis direction of the machine tool's coordinate system. The peak value of the dial indicator reading is recorded as the Z-axis coordinate of the first positioning hole. The probe of the dial indicator is vertically positioned within the circumference of the second positioning hole, and the spindle is continuously moved along the Z-axis direction of the machine tool's coordinate system. The peak value of the dial indicator reading is recorded as the Z-axis coordinate of the second positioning hole. The difference between the Z-axis coordinates of the two positioning holes is calculated. The center of the worktable is continuously rotated, and the above steps are repeated for each rotation angle until the actual difference between the Z-axis coordinates of the two positioning holes is within the error range of the theoretical difference. The rotation angle is then fixed, and the current spindle direction is taken as the X-axis direction of the part machining coordinate system.

7. The adaptive adjustment method for the coordinate system of a part machining center as described in claim 1, characterized in that, The process of finding the on-machine coordinates of the positioning hole using a dial indicator is as follows: Mount the dial indicator on the spindle of the CNC horizontal machining center, and place the probe of the dial indicator vertically within the circumference of the positioning hole; continuously move the spindle along the Z-axis of the machine tool's mechanical coordinate system and read the dial indicator reading, taking the peak value of the dial indicator reading as the X-axis coordinate value of the positioning hole; continuously move the spindle along the X-axis of the machine tool's mechanical coordinate system and read the dial indicator reading, taking the peak value of the dial indicator reading as the Z-axis coordinate value of the positioning hole.

Images