Workpiece position compensation method for multi-station five-axis machining based on on-machine measurement technology

Abstract

A multi-station five-axis machining workpiece position compensation method based on on-machine measurement technology includes the following steps: 1) establishing workpiece position deviation; 2) selecting a workpiece position deviation processing method; 3) selecting a specific workpiece position deviation to compensate for within the machining path; 4) setting active turntable angle limits; and 5) outputting a post-processing file, which is imported into the machine tool system software. The software automatically measures and compensates for workpiece position deviation based on the post-processing file. This invention provides an independent workpiece position deviation function, simplifies manual operation, supports the establishment of multiple workpiece position deviations for multi-station working conditions, and supports multiple measurement features and loop compensation to improve measurement accuracy. The output post-processing file can be run directly on the machine tool, improving measurement efficiency and safety.

Description

Technical Field

[0001] The present invention relates to the field of multi-station five-axis machining, and in particular to a multi-station five-axis machining workpiece position compensation method based on on-machine measurement technology. Background Art

[0002] Accurately determining and compensating for workpiece position deviations is a major headache for production technicians. This is particularly true in five-axis machining, particularly for workpieces with ambiguous datums, which can be costly, time-consuming, and wasteful. Existing solutions are gradually transitioning from a combination of precision jigs and manual table punching to on-machine measurement and compensation at the CNC machine. A representative example is the DMG DMU 50 five-axis machining center (powered by a Siemens 840D CNC system). By manually combining the CNC system's three functions—calibrate plane, calibrate edge, and calibrate edge—the system can achieve position compensation for workpieces with simple shapes, high incoming material accuracy, and minimal workpiece position deviation.

[0003] The traditional on-machine measurement and compensation methods for CNC machine tools support a limited range of measurement features and are subject to directional limitations. For workpieces with complex features or special directional requirements, the traditional method can only make a second-best choice and measure workpiece fixtures with simple features. This method uses the workpiece position deviation of the fixture instead of the workpiece position deviation, resulting in low-precision compensation for the workpiece. The traditional method can only establish one workpiece position deviation compensation at a time and is not suitable for multi-station processing. The traditional method lacks an independent workpiece position deviation compensation function and requires manual combination of multiple independent functions. Furthermore, each measurement point during measurement must be manually positioned to a safe position. Functions are dispersed, operations are prone to errors and difficult to check, and measurement efficiency is low. Summary of the Invention

[0004] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a workpiece position compensation method for multi-station five-axis machining based on on-machine measurement technology, which supports multiple measurement features and can be cyclically compensated to improve measurement accuracy. At the same time, it supports the establishment of multiple workpiece position deviations and can be applied to multi-station five-axis machining conditions. In addition, it can reduce manual operations and directly generate relevant measurement paths in the software to improve measurement operation efficiency.

[0005] In order to achieve the above object, the technical solution adopted by the present invention includes the following steps:

[0006] 1) Establish workpiece position deviation;

[0007] 2) Select the workpiece position deviation processing method;

[0008] 3) The machining path selects specific workpiece position deviation to compensate;

[0009] 4) Set the active turntable angle limit;

[0010] 5) Output the post-processing file and import it into the machine tool system software. The software will automatically measure and compensate the workpiece position deviation based on the post-processing file.

[0011] Furthermore, in step 1), six methods are provided for establishing workpiece position deviation, including custom, three-surface method, surface line point, one surface and two circles, rotational body, and one surface and one groove. The user selects one of the methods to establish the workpiece position deviation according to the specific working conditions.

[0012] Furthermore, in step 2), the user can select one of two workpiece position deviation processing methods: high-precision workpiece position deviation method and high-efficiency workpiece position deviation method. The high-precision workpiece position deviation processing method uses cyclic matching precision control, stopping the measurement of elements related to the workpiece position deviation when the number of measurement cycles or the measurement accuracy are reached. The high-efficiency workpiece position deviation processing method measures only the first reference element during the workpiece position deviation cyclic iteration process, and measures other elements only once.

[0013] Furthermore, step 1), step 2), and step 3) can simultaneously establish one or more workpiece position deviations, and the processing path can freely select any of the workpiece position deviations for compensation.

[0014] Furthermore, in step 4), the safety of the machine tool movement when the workpiece position deviation is compensated to the machine tool can be ensured by setting an active turntable angle limit.

[0015] Compared with the existing technology, the beneficial effects of the present invention are: supporting multiple types of measurement features, solving the problem that complex features and features with special directional requirements cannot be directly measured, and expanding the measurement range; supporting the establishment of multiple workpiece position deviations for compensating for different workstations in the workpiece, and expanding the compensation range; the workpiece position deviation establishment method is simple and complete, with centralized functions, low manual participation, and automatic output of the running program, which improves the stability of the running results and reduces the error rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Flowchart of the workpiece position compensation method for multi-station five-axis machining of the present invention;

[0017] Figure 2 The present invention generates a schematic diagram of workpiece position deviation;

[0018] Figure 3 Schematic diagram of the custom method of the present invention;

[0019] Figure 4 Schematic diagram of the three-surface method of the present invention;

[0020] Figure 5 Schematic diagram of the surface line point method of the present invention;

[0021] Figure 6 Schematic diagram of the one-side-two-circles method of the present invention;

[0022] Figure 7 Schematic diagram of the rotary body method of the present invention;

[0023] Figure 8 Schematic diagram of the one-side-one-slot method of the present invention;

[0024] Figure 9 Schematic diagram of high-precision processing of the present invention;

[0025] Figure 10 Schematic diagram of high-efficiency processing of the present invention;

[0026] Figure 11 Schematic diagram of workpiece position deviation compensation for machining path selection in the present invention;

[0027] Figure 12 Schematic diagram of setting active turntable angle limitation in the present invention. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below with reference to the accompanying drawings. Figure 1 .

[0029] 1. See Figure 2 , establish the workpiece position deviation

[0030] The methods of establishing workpiece position deviation include custom, three-surface method, surface line point, one surface and two circles, rotational body, and one surface and one groove.

[0031] 1) See Figure 3 The custom method is the basis of other methods. It is flexible to use and can be used in complex working conditions.

[0032] 2) See Figure 4 , the three-plane method is applied to working conditions where the datum is three planes.

[0033] 3) See Figure 5 , surface line point is applied to the working conditions where the datum is surface, line or point.

[0034] 4) See Figure 6 The one-plane-two-circles method is applied to the working condition where the datum is a plane and two circles.

[0035] 5) See Figure 7 , the body of revolution method is applied to the working condition where the workpiece geometry is a body of revolution.

[0036] 6) See Figure 8The one-face-one-groove method is applied to working conditions where the base is a face and groove type geometry.

[0037] 2. Select the workpiece position deviation processing method

[0038] 1) See Figure 9 , high-precision processing method

[0039] Cyclic precision control stops measuring elements related to workpiece position deviation when the number of measurement cycles or the measurement accuracy is reached. In high-precision mode, all elements are measured repeatedly during the iterative process of workpiece position deviation. This means that if the number of cycles is N, all elements are measured the same number of times (≤ N). This high-precision processing method is suitable for applications requiring high precision.

[0040] 2) See Figure 10 , high efficiency processing method

[0041] High-efficiency mode measures only the first reference element during the iterative process of workpiece position deviation, and all other elements are measured only once. For a given number of iterations, the first reference element is iterated N times, while all other elements are measured only once. High-efficiency processing is suitable for applications with small workpiece position rotation deviations and high efficiency requirements.

[0042] 3. The machining path selects specific workpiece position deviation for compensation.

[0043] See also Figure 11 , the processing path can select the corresponding workpiece position deviation for compensation processing.

[0044] 4. Set the active turntable angle limit

[0045] See also Figure 12 , fill in the active turntable angle limit. When the active turntable angle exceeds this limit each time the workpiece position deviation is calculated, the machine tool will issue an alarm to ensure the safety of the measurement operation.

[0046] 5. Output the post-processing file and import it into the machine tool system software. The software will automatically measure and compensate the workpiece position deviation based on the post-processing file without manual intervention.

Claims

1. A multi-station five-axis machining workpiece position compensation method based on on-machine measurement technology is characterized by: The following steps are involved: 1) Establish workpiece position deviation, including custom, three-surface method, surface line point, one surface two circles, rotational body, one surface one groove; 2) Select the workpiece position deviation processing method, which includes two methods. The high-precision workpiece position deviation processing method is: cyclic matching accuracy control, when the measurement cycle number or measurement accuracy is reached, the measurement of the workpiece position deviation related elements is stopped; the high-efficiency workpiece position deviation processing method is: in the high-efficiency mode, during the workpiece position deviation cyclic iteration process, only the first reference element is measured cyclically, and other elements are measured only once; 3) The machining path selects a specific workpiece position deviation for compensation. Steps 1), 2), and 3) can simultaneously establish one or more workpiece position deviations. The machining path can freely select any of the workpiece position deviations for compensation. 4) Set the active turntable angle limit; 5) Output the post-processing file and import it into the machine tool system software. The software will automatically measure and compensate the workpiece position deviation based on the post-processing file.

2. The method for compensating workpiece position in multi-station five-axis machining based on on-machine measurement technology according to claim 1, characterized in that: The step 4) uses a method of limiting the rotation angle of the active axis to ensure the safety of the machine tool movement when the workpiece position deviation is compensated to the machine tool.

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