CN106017377A - Calibration method for measuring probe for online measurement in processing machine tool - Google Patents

Abstract

A method for calibrating a measuring probe for on-line measurement in a processing machine tool, which is used for calibrating the on-line measuring probe of a machining machine tool, is characterized in that it includes the following steps: 1. On an element that can fix a standard measuring rod after the machine tool is calibrated Install a standard measuring rod as a reference for calibration; 2. Use the measuring probe to touch any position of the standard measuring rod multiple times, and record the coordinate data of the measuring probe when touching; 3. Process the measured data recorded in step 2, and get A semicircle profile; Fourth, the center position coordinates are calculated from the fitted semicircle profile, and the center coordinates are geometrically processed with the center and radius of the standard measuring rod and the radius of the measuring probe to obtain the coordinates of the center of the measuring probe. The calibration method has the advantages of simple design structure and installation process, space saving and low cost.

Description

Calibration method of measuring probe for on-line measurement in processing machine tool

technical field

The invention belongs to the field of mechanical processing, in particular to a calibration method for a measuring probe of a processing machine tool.

Background technique

Machining is the basic operation of advanced manufacturing technology and the most basic and active link in the advanced manufacturing system. Its basic goal is to ensure the quality of products under the conditions of low cost and high productivity. Machining online measurement technology can measure the workpiece on site, give real-time feedback on the quality of assembly and processing, and to a certain extent, perform real-time compensation for tool wear and temperature rise online to improve processing accuracy and quality. Especially under the conditions of multi-variety and small-batch production, it is of great significance to study advanced on-line measurement technology, because on-line measurement is an important part of processing and measurement integration technology and an important means to ensure quality and improve productivity.

Existing measurement systems generally use a standard sphere as a calibration object to calibrate the three-coordinate probe that needs to be calibrated. However, in online measurement, due to the limitation of machine tools, not all machine tools have enough degrees of freedom and space to install three-coordinate probes and standard balls. The online measurement and calibration method of installing a three-coordinate probe and a standard ball has many restrictions and high costs. Therefore, most of the machine tools produced in China do not include an online measurement system, which greatly restricts the improvement of the accuracy and quality of my country's processing and manufacturing.

Contents of the invention

In order to solve the above problems, the present invention proposes a method for calibrating measuring probes for on-line measurement in processing machine tools. The method does not need to use costly three-coordinate probes and standard balls, and can adapt to on-line measurement of most domestically produced machine tools.

A method for calibrating a measuring probe for online measurement in a processing machine tool, which is used for calibrating an online measuring probe for a machining machine tool, is characterized in that it includes the following steps:

Step 1, install a standard measuring rod on the component that can fix the standard measuring rod after the machine tool is calibrated as a calibration reference;

Step 2, use the measuring probe to touch any position of the standard measuring rod multiple times, and record the coordinate data of the measuring probe when touching;

Step 3, process the measurement data recorded in step 2 to obtain a semicircle profile by fitting;

Step 4: Calculate the coordinates of the center of the circle from the fitted semicircle profile, and perform geometric processing on the coordinates of the center of the circle with the center and radius of the standard measuring rod and the radius of the measuring probe to obtain the coordinates of the center of the measuring probe.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention may also have such a feature: wherein, the standard measuring rod is installed on the thimble.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention may also have the feature that the measuring probe is installed on the rotatable machine tool spindle and can move along with the machine tool spindle.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention may also have such a feature: wherein, the measuring probe is rotatably installed on the main shaft of the machine tool.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention may also have the feature that the measuring probe is a contact probe.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention may also have such a feature: wherein, the measuring probe is connected with the control part of the processing machine tool, and when the measuring probe is subjected to a certain pressure, the processing machine tool stops the current operation and simultaneously The coordinates at this time are recorded in the control unit.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention may also have such a feature: wherein, in step 2, the measuring probe touches different positions at different angles of the standard gauge rod.

The method for calibrating the measuring probe for on-line measurement in the processing machine tool provided by the present invention can also have such a feature: wherein, in step 3, any one of Matlab, Mathmatica, Maple and OriginLab software is used to complete the fitting.

Invention function and effect

According to the calibration method of the measuring probe for on-line measurement in the processing machine tool provided by the present invention, because the measuring probe is installed on the main shaft of the machine tool, the main shaft is directly used for measurement and calibration, and the rotation operation can be performed, so the design structure and installation process are simple, The advantages of saving space and low cost; in addition, the standard measuring stick is used as the calibration reference object and installed on the existing fixture of the machine tool, so there is no need to add additional calibration reference objects; and because the position of the measurement point is arbitrary, the online measurement The design of the calibration procedure is relatively simple.

Description of drawings

Fig. 1 is the overall schematic diagram of the calibration of the gear grinding machine during the calibration work of the calibration method of the measuring probe of on-line measurement in the processing machine tool of the present invention;

Figure 2 is a schematic diagram of the position of the measuring probe when it is working and in a shutdown state;

Fig. 3 is a schematic diagram of the position of the measuring probe in the measurement and calibration state; and

Fig. 4 is a schematic diagram of the position of each component when the measuring probe is calibrated;

Fig. 5 is a schematic diagram of the measuring position of the measuring probe.

detailed description

In order to make the technical means, creative features, goals and effects of the present invention easy to understand, the following embodiments will specifically illustrate the principles, steps, and effects of the calibration method of the measuring probe for on-line measurement in the processing machine tool of the present invention in conjunction with the accompanying drawings.

Example

Fig. 1 is an overall schematic diagram of the calibration of the gear grinding machine tool during the calibration work of the calibration method of the measuring probe for on-line measurement in the processing machine tool of the present invention.

As shown in Figure 1, the gear grinding machine tool includes a base 1, a guide rail 2, a guide rail 3, a column 4, a grinding wheel 5, a grinding wheel spindle motor 6, a measuring probe 7, a diamond wheel 8, thimbles 9a and 9b, a workpiece spindle motor 10, and a standard gauge Rod 11, guide rail 12 and the control part not shown in the figure.

Among them, due to the existence of the rotating shaft in the guide rail 2, the guide rail 3 and the column 4, the machine tool spindle has three degrees of freedom, which are the Y axis moving back and forth, the X axis moving left and right, and the B axis of rotation, and the workpiece fixing device is a For the thimbles 9a and 9b, the right thimble 9b can move left and right through the guide rail 12 for clamping, and at the same time, due to the workpiece spindle motor 10, it can rotate around the A axis. The position and action of each axis are connected to each other through the sensors on each axis, the transmission motor and the console for information interaction and action control. A standard measuring stick 11 is installed between the thimbles 9a and 9b after the machine tool is calibrated as a calibration reference.

Fig. 2 is a schematic diagram of the position of the measuring probe in working and stopping states.

Fig. 3 is a schematic diagram of the position of the measuring probe in the measurement and calibration state.

Fig. 4 is a schematic diagram of the positions of various components when the measuring probe is calibrated.

As shown in Figure 2, the measuring probe 7 is installed on the side of the transmission motor on the main shaft of the gear grinding machine tool. This state is in a contracted state. The measuring probe is in this position when processing and stopping; when measuring and calibrating, the measuring probe will rotate 90°, as shown in Figure 3 and 4.

As shown in Fig. 2, when the measuring probe 7 is in the extended state, the calibration work can be carried out.

First, the standard measuring rod 11 is installed on the fixture thimble 9a and 9b of the machine tool and fixed;

Second, through the forward movement of the Y axis of the machine tool column 4, the measuring probe 7 is touched to the standard gauge rod 11, and the coordinate values of each axis of the machine tool (coordinate values of X, Y, A, B axes) are recorded when touching ); This completes the first touch. After the touch is completed, move back along the Y axis, and withdraw the measuring probe 7 .

On the basis of the last measurement, rotate the B axis at a certain angle, and then perform a second touch. Similarly, record the coordinate values of each axis of the machine tool when touching. Next, it is the repetition of the above operation. Multiple points can be touched to maintain high calibration accuracy.

Third, since the size of the machine tool, the diameter of the standard measuring rod, the length of the probe, the diameter of the probe and other parameter conditions are known, the position of the measuring probe 7 can be obtained after obtaining the coordinate values of each axis of the machine tool.

The 4th, according to the position of measuring probe when a plurality of touches, rely on Matlab, Mathmatica, Maple and OriginLab program function to be able to fit out the circle center position coordinates of virtual measuring stick, what used in the present embodiment is Matlab.

For circle fitting, in theory, the points measured by the machine tool should be located on the outer circle of the standard gauge rod, but since the contact measurement is used, the measurement probe part needs to have a certain amount of deformation during the measurement process. The trigger signal will be generated, so that the actual measurement position deviates from the theoretical position, resulting in a certain error in the measurement.

Figure 5 is a schematic diagram of the measuring position of the measuring probe

The schematic diagram of the change relationship of the measurement position and the position deviation of the measurement is shown in Figure 5. Since the touch probe needs to generate a trigger signal through the deformation of the measuring rod, when the probe gradually moves to the bottom, a large deviation value.

Taking this machine tool as an example, as shown in Figure 5, the length of the measuring probe L is about 80mm, the diameter of the standard measuring rod is 30mm, Δθ=0.0035°, based on the vertical direction, when θ is 90°, the measuring probe produces The amount of slip is 10 times that when θ is 0°. It can be seen that with the increase of the length of the measuring probe and the weakening of the trigger sensitivity of the probe, the resulting slip will further increase. On the premise of ensuring the accuracy, in order to obtain more measurement data, according to the measurement data and relevant experience, the value range of θ should not be greater than 40°～50°.

Effects and beneficial effects of the embodiment

According to the calibration method of the measuring probe for online measurement in the processing machine tool provided in this embodiment, because the measuring probe is installed on the main shaft of the machine tool, the main shaft is directly used for measurement and calibration, and can be rotated, so the design structure and installation process are simple. , space-saving, and low-cost advantages; in addition, a standard gauge rod is used as a calibration reference object and installed on the existing fixture of the machine tool, so there is no need to add additional calibration reference objects; and because the measurement point position is arbitrary, online measurement The design of the calibration procedure is relatively simple.

Furthermore, since the standard measuring rod is installed on the thimble, the standard measuring rod is clamped and fixed by the clamping and fixing mechanism of the processing machine tool, which saves the cost of designing and installing the clamping structure, and is more conducive to the promotion of the calibration method.

Furthermore, since the measuring probe is a contact probe, compared with the non-contact probe measurement, it can adapt to the pollution of oil in the machine tool and ensure the measurement accuracy. At the same time, the technology is mature and the purchase cost is low, which is more suitable for most domestically produced machine tools. The measurement system is adopted to meet their requirements of low cost and good effect.

In addition, using existing commercial processing software Matlab, Mathmatica, Maple and OriginLab, it is easy to implement and saves the trouble of developing processing software by yourself.

Claims (8)

1. a method for calibrating the measuring probe of on-line measurement in a processing machine tool, for calibrating the on-line measuring probe of a machining machine tool, it is characterized in that, comprising the following steps: Step 1, installing the standard measuring rod on the element that can fix the standard measuring rod after the machine tool is calibrated as a calibration reference; Step 2, using the measuring probe to touch any position of the standard measuring rod multiple times, and recording the coordinate data of the measuring probe when touching; Step 3, process the measurement data recorded in step 2 to obtain a semicircle profile by fitting; Step 4, calculate the position coordinates of the center of the circle from the semicircle profile obtained by fitting, and carry out geometric processing with the center of circle and the radius of the standard measuring rod and the radius of the measuring probe to obtain the center of the measuring probe coordinate. 2. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 1, is characterized in that: Wherein, the standard measuring rod is installed on the thimble. 3. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 1, it is characterized in that: Wherein, the measuring probe is installed on a rotatable machine tool spindle and can move along with the machine tool spindle. 4. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 3, it is characterized in that: Wherein, the measuring probe is rotatably installed on the machine tool spindle. 5. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 1, is characterized in that: Wherein, the measuring probe is a contact probe. 6. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 1, it is characterized in that: Wherein, the measuring probe is connected to the control part of the processing machine tool, and when the measuring probe is subjected to a certain pressure, the processing machine tool stops the current operation and records the coordinates at this time in the control part. 7. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 1, it is characterized in that: Wherein, the measurement probe in step 2 touches different positions of different angles of the standard gauge rod, in order to reduce the error caused by the deformation of the standard gauge rod, it should be reduced as much as possible under the condition of meeting the measurement requirements. The length of the standard measuring stick. 8. the calibration method of the measuring probe of on-line measurement in the processing machine tool according to claim 1, it is characterized in that: Wherein, in step 3, any one of Matlab, Mathmatica, Maple and OriginLab software is used to complete the fitting.