A detection and calculation method for the rotation accuracy of B and C axes of a five-axis machining center

Abstract

The present invention provides a simple method for B and C axis calibration accuracy, which calibrates the B and C axes respectively through standard tooling and ring gauges, calculates the zero compensation values ​​of the B and C axes through coordinate parameters, and corrects the errors of the rotation accuracy of the B and C axes of the machining center through the zero compensation values. The detection and calculation method for the rotation accuracy of the B and C axes of the five-axis machining center provided by the present invention is simple and practical, low in cost, and low in expense. Relevant technicians and operators can directly complete the calibration work, the technology is relatively mature, the method is simple and easy to operate, the equipment accuracy calibration risk and the product quality risk can be identified and improved through experimental verification, the risk is controllable, the production cost can be greatly saved, and the machine tool can be effectively and timely corrected to avoid the time loss caused by waiting for the equipment manufacturer to perform detection and calibration, so that the product production can be delivered on time.

Description

Technical Field

[0001] The invention relates to the technical field of precision calibration of machining machine tools, and in particular to a detection and calculation method for the rotation precision of B and C axes of a five-axis machining center. Background Art

[0002] The five-axis machining center is a high-tech, high-precision machining center specially used for machining complex curved surfaces. This machining center system has a significant impact on a country's aviation, aerospace, military, scientific research, precision instruments, high-precision medical equipment and other industries. The five-axis linkage CNC machining center system is the only means to solve the processing of impellers, blades, marine propellers, heavy generator rotors, turbine rotors, large diesel engine crankshafts, etc.

[0003] Since the cutting force, clamping force, frictional heat, ambient temperature changes, vibration and other factors in actual work will affect the accuracy, and thus affect the accuracy of the workpiece being processed, it is necessary to detect and calibrate the accuracy of the machining center to ensure the quality of the workpiece.

[0004] Usually, the calibration and inspection of the rotation accuracy of the B and C axes of a five-axis machining center is completed through "modular inspection + calculation". The purchase cost of the modular calculation software and related inspection tools is relatively expensive (about 200,000 yuan), and the equipment manufacturer needs to send experts to the site for calibration and inspection. Due to the timing and time constraints of the technical service personnel sent by the equipment manufacturer, the waiting time is uncertain, which often cannot meet the needs of parts processing and affects product delivery. Summary of the invention

[0005] In view of the high cost of calibration and inspection of the rotation accuracy of the B and C axes of the current five-axis machining center, and the poor timeliness of calibration and inspection only relying on the technical service personnel of the equipment manufacturer, the present invention provides a simple and practical detection and calculation method for the rotation accuracy of the B and C axes of the five-axis machining center, which can directly complete the calibration work by relying on relevant technicians and operators.

[0006] The technical solution adopted by the present invention to solve the related problems is: a detection and calculation method for the rotation accuracy of the B and C axes of a five-axis machining center, comprising the following steps:

[0007] S1. Preparation for calibration operation, including: checking and adjusting the level of the machine tool worktable, checking and adjusting the verticality of the machine tool spindle and the worktable, preparing a standard ring gauge, the inner diameter of the standard ring gauge is 20-50, and the roundness is ≤0.002; preparing a calibration fixture, the calibration fixture adopts a square shape, measuring and calibrating the spindle probe length L and the probe diameter.

[0008] S2, calibrating the machine tool B axis, including the following steps:

[0009] S2-1. Fix the calibration fixture on the machine tool workbench.

[0010] S2-2. Turn the spindle vertically to the worktable, move the probe to one of the corner points A on the surface of the calibration tooling, and record the machine tool coordinates X1, Y1, and Z1 at this time.

[0011] S2-3. The spindle rotates 90°, that is, the spindle is parallel to the worktable. The probe finds the same corner point A on the tooling surface and records the machine coordinates X2, Y2, and Z2 at this time.

[0012] S2-4. Calculate the zero position compensation value of the B axis

[0013] Substitute the two recorded coordinate parameters into the calculation formula

[0014] △Z+L+△X=X1+X2

[0015] △Z+L-△X=Z2-Z1

[0016] Get △X and △Z.

[0017] S2-5. Input the specific values ​​of △X and △Z into the zero position parameter of the machine tool B axis to replace the original B axis zero position parameter value, so as to correct the rotation accuracy error of the machine tool B axis.

[0018] S3. Calibrate the C axis of the machine tool

[0019] S3-1. Fix the inspection ring gauge on the machine tool workbench.

[0020] S3-2. Turn the spindle vertically to the worktable, and use the probe to find the coordinates X3, Y3, and Z3 of the center of the inner diameter of the ring gauge.

[0021] S3-3. The workbench rotates 180°, and the probe finds the coordinate values ​​X4, Y4, and Z4 of the center of the inner diameter of the ring gauge, ensuring that the coordinate height Z remains consistent, where Z3=Z4.

[0022] S3-4. Calculate the C-axis zero position compensation value

[0023] Substitute the two recorded coordinate parameters into the calculation formula

[0024] X=(X3+X4) / 2

[0025] Y=(Y3+Y4) / 2

[0026] Get X, Y.

[0027] S3-5. Input the specific values ​​of X and Y into the C-axis zero position parameters of the machine tool to replace the original C-axis zero position parameters, and the rotation accuracy error of the C-axis of the machine tool can be corrected.

[0028] Beneficial effects of the present invention:

[0029] The detection and calculation method for the rotation accuracy of the B and C axes of the five-axis machining center provided by the present invention is simple and practical, low-cost, and low-expense. Relevant technicians and operators can directly complete the verification work. The technology is relatively mature, the method is simple and easy to operate, and the equipment accuracy verification risks and product quality risks can be identified and improved through experimental verification. The risks are controllable, which can greatly save production costs and can effectively and timely calibrate the machine tool to avoid time loss caused by waiting for equipment manufacturers to perform detection and calibration, so that product production can be delivered on time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a side view diagram of B-axis verification when the spindle is vertical.

[0031] Figure 2 It is a side view diagram of B-axis calibration when the spindle is rotated 90° to be horizontal.

[0032] Figure 3 This is a schematic diagram of C-axis calibration inspection.

[0033] Figure 4 This is a schematic diagram of the operating table with the ring gauge fixed when it is rotated 180°.

[0034] Numbers in the figure: spindle 1, probe 2, calibration fixture 3, workbench 4, corner point A5, ring gauge 6. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0036] Example 1: In order to meet the precision requirements of processed products, it is necessary to perform precision calibration on the five-axis machining center from time to time. Only when it is determined that the equipment precision meets the relevant requirements can the processing and production of parts be carried out.

[0037] At present, the calibration and detection of the rotation accuracy of the B and C axes of the five-axis machining center is completed through "modular detection + calculation". The purchase cost of the modular calculation software and related detection tools is relatively expensive, and the equipment manufacturer needs to send experts to the site for calibration and detection. Due to the availability or time restrictions of the technical service personnel sent by the equipment manufacturer, the waiting time is uncertain and cannot meet the needs of part processing, affecting the equipment accuracy calibration confirmation time, and thus affecting the product delivery time.

[0038] In order to reduce costs and meet the needs of equipment precision calibration, the present invention provides a simple method for calibrating the accuracy of B and C axes. The method calibrates the B and C axes respectively through standard tooling and ring gauges, calculates the 0-bit compensation values ​​of the B and C axes through coordinate parameters, and corrects the errors in the rotation accuracy of the B and C axes of the machining center through the 0-bit compensation values.

[0039] The specific calibration process includes the following steps:

[0040] Step 1: Make preliminary preparations for the calibration work. Use a level to adjust the machining center machine tool to keep the machine tool worktable in a horizontal state. After adjusting the machine tool worktable level, check and adjust the machining center spindle to keep it vertical to the worktable surface.

[0041] Prepare standard calibration fixtures and standard ring gauges in advance, and use them as the basis for calibration of the machining center. Move the B-axis and C-axis so that the probe of the machining center points to the same position of the standard calibration workpiece. Change the directions of the B-axis and C-axis to obtain different coordinate systems for the B-axis and C-axis. Use the coordinate system to match the calculation formula to obtain the compensation values ​​for the B-axis and C-axis. Input the compensation values ​​into the machining center to calibrate the rotation accuracy of the B-axis and C-axis to eliminate the machining center error.

[0042] Calibrate the spindle probe length L and probe diameter to eliminate the influence of probe length and width during the calculation process.

[0043] Step 2: Use the standard calibration tool to calibrate the B axis, which includes the following steps:

[0044] Fix the calibration fixture on the workbench of the machining center. The calibration fixture is square and has multiple corner points.

[0045] While ensuring that the spindle is perpendicular to the workbench, move the probe to a corner point A on the surface of the calibration tooling, and record the coordinates X1, Y1, and Z1 displayed by the machining center at this time;

[0046] Control the spindle to 90°, even if the spindle is parallel to the worktable, move the probe to find the same corner point A on the tooling surface, and record the coordinates X2, Y2, and Z2 displayed by the machining center at this time;

[0047] Use the formula to calculate the B-axis zero compensation value, and substitute the corresponding parameters of the two coordinates recorded above into the calculation formula

[0048] △Z+L+△X=X1+X2

[0049] △Z+L-△X=Z2-Z1

[0050] Calculate △X and △Z, input the specific values ​​of △X and △Z into the machine tool B-axis zero position parameter, replace the original B-axis zero position parameter value, and the machine tool B-axis rotation accuracy error can be corrected.

[0051] Step 3: Use the standard ring gauge to calibrate the C axis, including the following steps:

[0052] Fix the prepared standard calibration ring gauge on the workbench of the machining center. The position can be arbitrary and as close to the center of the workbench as possible. The ring gauge uses a standard ring gauge with a diameter of 20mm to 50mm and a roundness of ≤0.002mm.

[0053] Re-adjust the spindle to be perpendicular to the worktable, control the probe to find the coordinates of the inner diameter center point of the ring gauge, and record the coordinates X3, Y3, and Z3 of the machining center at this time;

[0054] While the workbench is kept horizontal, rotate the workbench 180° and control the probe to find the coordinate values ​​X4, Y4, and Z4 of the center point of the inner diameter of the ring gauge again. In this process, the coordinate height Z must be kept consistent, that is, Z1=Z2.

[0055] Substitute the coordinate parameters recorded above into the corresponding calculation formula

[0056] X=(X3+X4) / 2

[0057] Y=(Y3+Y4) / 2

[0058] Thus, the zero position compensation value of the C axis is obtained;

[0059] The obtained C-axis zero position compensation values ​​X and Y are input into the C-axis zero position parameters of the machine tool to replace the original C-axis zero position parameters, so as to correct the rotation accuracy error of the C-axis of the machine tool.

[0060] The five-axis machining center calibrated by this method was compared with the calibrated values ​​of B and C axis rotation accuracy determined by "modular computing software and related detection tools", and the two errors were controlled within 0.08%.

[0061] The detection and calculation method for the rotation accuracy of the B and C axes of the five-axis machining center provided by the present invention is simple and practical, low-cost, and low-expense. Relevant technicians and operators can directly complete the verification work. The technology is relatively mature, the method is simple and easy to operate, and the equipment accuracy verification risks and product quality risks can be identified and improved through experimental verification. The risks are controllable, which can greatly save production costs and can effectively and timely calibrate the machine tool to avoid time loss caused by waiting for equipment manufacturers to perform detection and calibration, so that product production can be delivered on time.

[0062] The above describes the basic principle, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention to be protected.

Claims

1. A detection and calculation method for the rotation accuracy of the B and C axes of a five-axis machining center, characterized in that: The following steps are included: S1. Preparation for calibration operation includes the following steps: S1-1. Check and adjust the level of the machine tool worktable (4); S1-2, checking and adjusting the verticality of the machine tool spindle (1) and the worktable (4); S1-3. Prepare the standard ring gauge (6); S1-4, prepare the inspection tool (3); S1-5, calibrate the length L of the spindle probe (2) and the diameter of the probe (2); S2, calibrating the machine tool B axis, including the following steps: S2-1, fixing the calibration tool (3) on the machine tool workbench (4); S2-2, the spindle (1) is perpendicular to the worktable (4), and the probe (2) is moved to one of the corner points A (5) on the surface of the calibration tool (3), and the machine tool coordinates X1, Y1, and Z1 at this time are recorded; S2-3, the spindle (1) rotates 90°, that is, the spindle (1) is parallel to the worktable (4), and the probe (2) finds the same corner point A (5) on the tooling surface, and records the machine tool coordinates X2, Y2, and Z2 at this time; S2-4. Calculate the zero position compensation value of the B axis Substitute the two recorded coordinate parameters into the calculation formula △Z+L+△X=X1+X2 △Z+L-△X=Z2-Z1 Get △X, △Z; S2-5, input the specific values ​​of △X and △Z into the zero position parameter of the machine tool B axis, replace the original B axis zero position parameter value, and then correct the rotation accuracy error of the machine tool B axis; S3. Calibrate the C axis of the machine tool S3-1. Fix the standard inspection ring gauge (6) on the machine tool workbench (4); S3-2, the spindle (1) is vertical to the worktable (4), and the probe (2) finds the coordinate values ​​X3, Y3, and Z3 of the inner diameter center of the ring gauge (6); S3-3, the workbench (4) rotates 180°, and the probe (2) finds the coordinate values ​​X4, Y4, and Z4 of the inner diameter center of the ring gauge (6), ensuring that the coordinate height Z remains consistent, where Z3=Z4; S3-4. Calculate the C-axis zero position compensation value Substitute the two recorded coordinate parameters into the calculation formula X=(X3+X4) / 2 Y=(Y3+Y4) / 2 Get X, Y; S3-5. Input the specific values ​​of X and Y into the C-axis zero position parameters of the machine tool to replace the original C-axis zero position parameters, and the rotation accuracy error of the C-axis of the machine tool can be corrected.

2. The detection and calculation method for the rotation accuracy of the B and C axes of a five-axis machining center according to claim 1 is characterized in that: The calibration fixture (3) adopts a square calibration fixture, and the standard ring gauge (6) adopts a ring gauge with an inner diameter of 20 mm to 50 mm and a roundness of ≤0.002 mm.

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