A tool setting device and a thermal error compensation method based on the tool setting device.

Abstract

This invention relates to the field of CNC machine tools, and particularly to a tool setter and a method for compensating for the thermal error of the tool setter. The tool setter includes a base and a telescopic rod. The telescopic rod is driven to extend and retract by a servo motor. A thermal sensor is installed on the telescopic rod, and a micro-displacement sensor is installed on the base. The servo motor obtains the thermal deformation amount ΔL of the base, and the micro-displacement sensor obtains the combined thermal deformation amount ΔS of the base and the telescopic rod. The thermal compensation amount of the tool setter is then calculated, and the thermal deformation amount is compensated into the tool measurement results by the CNC system. This eliminates the thermal error of the tool setter measurement, solves the problem of the tool setter's accuracy being sensitive to ambient temperature, and enables high-precision and stable tool setting operation of CNC machine tools under different operating ambient temperatures.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of numerical control machine tools, in particular to a tool setting instrument and a tool setting instrument thermal error compensation method. BACKGROUND

[0002] The automatic tool setting instrument is a core functional component of high-end numerical control machine tools, and its detection accuracy and accuracy stability are necessary requirements for its work.

[0003] The data measured by the tool setting instrument of the numerical control machine tool is used for tool compensation, and the measurement accuracy directly affects the machining accuracy of the machine tool. The movable tool setting instrument is currently divided into flat push type and rotary type structures. The tool setting instrument probe of the flat push type is installed at the end of a long rod, and the rod is extended for tool setting operation during measurement. When the temperature of the machine tool environment changes, the base part of the rod will be deformed due to temperature changes, which will change the spatial position of the tool setting instrument probe, and will directly affect the measurement accuracy of the tool setting instrument. SUMMARY

[0004] In order to solve the problem that the existing telescopic tool setting instrument cannot provide accurate measurement data due to telescopic deformation caused by changes in environmental temperature, the present application provides a tool setting instrument capable of detecting thermal deformation and a thermal compensation method based on the tool setting instrument.

[0005] A tool setting instrument, comprising a base and a telescopic rod slidingly arranged on the base, the base comprising a fixed reference end and a drift end capable of telescopic movement due to thermal deformation, a rack being arranged on the telescopic rod, a servo motor being arranged on the drift end for driving the rack to move and capable of calculating the moving distance, a stop block being arranged on the telescopic rod, limiting blocks being respectively arranged on the drift end and the reference end to limit the movement of the stop block therebetween, a tool setting sensor being arranged on the telescopic rod, the tool setting sensor being close to the reference end when the stop block abuts against the limiting block on the drift end, and a micro-displacement sensor being further arranged on the reference end for detecting the displacement change amount of the tool setting sensor when the stop block abuts against the limiting block on the drift end.

[0006] Further, a limiting device capable of limiting the upward tilting or swinging of the drift end is arranged on the drift end.

[0007] Further, a guide sliding member for reducing the friction of the movement of the drift end is arranged on the drift end.

[0008] A tool setting instrument thermal compensation method,

[0009] The thermal deformation amount ΔL between the two limiting blocks is obtained by driving the stop block to move between the two limiting blocks by the servo motor;

[0010] The displacement change amount ΔS of the tool setting sensor when the stop block abuts against the limiting block on the drift end is detected by the micro-displacement sensor.

[0011] The formula ΔC = ΔS - ΔL is used, where ΔC is the thermal compensation amount of the tool setter.

[0012] Furthermore, the thermal change between the two limiting blocks is ΔL = L2 - L1, where L2 is the distance parameter between the two limiting blocks obtained by the servo motor driving the stop block to move between the two limiting blocks in the initial state, and L1 is the distance parameter between the two limiting blocks obtained by the servo motor driving the stop block to move between the two limiting blocks after thermal deformation. ΔL provides real-time feedback on the thermal deformation between the reference end and the drift end, and ΔL has positive and negative values. The displacement change of the tool setting sensor is ΔS = S1 - S2, where S2 is the distance parameter of the tool setting sensor detected by the micro-displacement sensor when the stop block abuts against the drift end limiting block in the initial state, and S1 is the distance parameter of the tool setting sensor detected by the micro-displacement sensor when the stop block abuts against the drift end limiting block after thermal deformation. ΔS provides real-time feedback on the combined thermal deformation of the base and the telescopic rod, and ΔS has positive and negative values.

[0013] This invention relates to an automatic tool setter for CNC machine tools with a thermal error compensation structure. It adopts a dual detection structure of servo motor and micro displacement sensor, which can dynamically measure and acquire the thermal error deformation of the tool setter system in real time. The thermal deformation is compensated into the tool measurement results by the CNC system, eliminating the thermal error of the tool setter measurement, solving the problem of the sensitivity of the tool setter accuracy to the ambient temperature, and realizing high-precision and stable tool setting operation of CNC machine tools under different operating ambient temperatures. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the tool setting device of the present invention.

[0015] The components are: 1. Base; 1-1 Reference end; 1-2 Drift end; 2. Telescopic rod; 3. Rack; 4. Servo motor; 5. Stop block; 6. Limit block; 7. Tool setting sensor; 8. Micro displacement sensor; 9. Limiting device; 10. Guide slide. Detailed Implementation

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0017] like Figure 1 The tool setter shown is a telescopic tool setter, including a base 1, a telescopic rod 2 slidably mounted on the base 1, a tool setter sensor 7 mounted at one end of the telescopic rod 2, a servo motor 4 mounted on the base 1 to drive the telescopic rod 2 to move, and a rack 3 mounted on the telescopic rod 2 to cooperate with the servo motor 4. The servo motor 4 drives the rack, thereby moving the telescopic rod on the base 1 to achieve the extension and retraction of the telescopic rod 2. The base 1 is connected to the machine tool to install the entire tool setter into the machine tool. After the telescopic rod 2 drives the tool setter sensor to extend, the tool on the machine tool spindle collides with the tool setter to determine the zero point position and tool size.

[0018] The base 1 includes a reference end 1-1 fixed on the machine tool as the reference of the tool setting gauge and a drift end 1-2 capable of changing the distance with the reference end 1-1 due to temperature change. The servo motor 4 is arranged at the drift end 1-2. To avoid the drift end 1-2 from being upturned or swinging, a limiting device 9 is arranged at the drift end 1-2 to provide downward pressure to the drift end 1-2. However, the limiting device 9 does not form a block to the thermal deformation of the drift end 1-2. In this embodiment, a compression spring is used to limit the upturn of the drift end 1-2. A strip-shaped hole is arranged at the drift end 1-2 for the bolt of the compression spring to pass through. Thus, the compression spring provides downward pressure to the drift end 1-2 to prevent the drift end 1-2 from being upturned. The strip-shaped hole cooperates with the bolt to avoid the bolt from blocking the thermal deformation of the drift end 1-2. To avoid the friction between the drift end 1-2 and the machine tool being too large when thermal deformation occurs, a guide sliding member 10 (such as a ball or a roller) is arranged at the contact surface of the drift end 1-2 and the machine tool.

[0019] The limiting blocks 6 are arranged at the drift end 1-2 and the reference end 1-1 respectively. The stop block 5 is arranged on the rack 3 in this embodiment. The stop block 5 is arranged between the two limiting blocks 6. When the servo motor 4 drives the telescopic rod 2 to move, the stop block 5 is blocked by the limiting blocks 6. The moving range of the stop block 5 is only between the two limiting blocks 6. Thus, the reference Figure 1 When the stop block 5 abuts against the limiting block 6 of the drift end 1-2, the telescopic rod 2 is in the retracted state. When the stop block 5 abuts against the limiting block 6 of the reference end 1-1, the telescopic rod 2 is in the extended state. At this time, the tool setting operation is performed. Thus, the tool setting sensor 7 is arranged at the extended end of the telescopic rod 2. When the stop block 5 abuts against the limiting block 6 of the drift end 1-2, the tool setting sensor 7 is close to the reference end 1-1. Since the telescopic rod 2 itself also undergoes thermal deformation due to temperature change, the micro displacement sensor 8 is arranged at the reference end 1-1 to detect the displacement change amount of the tool setting sensor 7. When the displacement change amount of the tool setting sensor 7 is detected, the stop block 5 needs to abut against the limiting block 6 of the drift end 1-2, i.e. the telescopic rod 2 is in the retracted state to make the tool setting sensor 7 close to the reference end 1-1 for detection.

[0020] Based on the above structure, the method for specifically calculating the thermal compensation amount of the tool setting gauge is as follows:

[0021] Since the drift end 1-2 undergoes thermal deformation relative to the reference end 1-1, the distance between the two limiting blocks 6 changes, which further affects the extension length of the telescopic rod 2. Meanwhile, the telescopic rod 2 itself also undergoes thermal deformation, which causes the distance between the tool setting sensor 7 and the reference end 1-1 to change. Thus, the overall thermal deformation amount of the base 1 and the telescopic rod 2 needs to be considered to determine the thermal compensation amount.

[0022] The thermal deformation amount of the base 1 is obtained by the servo motor 4. In the initial state (i.e. the normal temperature state after assembly without thermal deformation), the servo motor 4 drives the telescopic rod 2 to move, and the distance that the stop block 5 moves between the two limiting blocks 6 is the distance parameter between the two limiting blocks in the non-thermal deformation state (denoted as L2). After thermal deformation occurs, when the servo motor 4 drives the telescopic rod to move, the distance that the stop block 5 moves between the two limiting blocks 6 changes. The distance at this time is the distance parameter between the two limiting blocks after thermal deformation (denoted as L1). By taking the difference, the thermal deformation amount ΔL between the two limiting blocks 6 can be obtained, i.e. ΔL = L2 - L1. It can be seen that ΔL has positive and negative values. When the distance between the two limiting blocks increases, ΔL is negative, and vice versa.

[0023] The composite thermal deformation amount, when the block 5 abuts against the limit block 6 of the drift end 1-2 in the initial state without thermal deformation, the micro displacement sensor 8 records the distance parameter S2 of the tool setting sensor 7, when the block 5 abuts against the limit block 6 of the drift end 1-2 after thermal deformation, the micro displacement sensor 8 records the distance parameter S1 of the tool setting sensor 7, the displacement change amount (the composite thermal deformation amount, that is, the thermal deformation of the base and the thermal deformation of the telescopic rod) ΔS of the tool setting sensor 7 can be obtained by the difference, it can be seen that ΔS has positive and negative values, when the tool setting sensor is close to the micro displacement sensor, ΔS is negative, and vice versa. The formula for finally calculating the thermal compensation amount of the tool setting instrument is ΔC=ΔS-ΔL, it can be seen that ΔC also has positive and negative values, when ΔC is positive, it is the thermal elongation amount of the telescopic arm of the tool setting instrument relative to the reference end, when it is negative, it is the thermal contraction amount relative to the reference end, and the thermal error compensation is carried out by using the data. Further explanation of the calculation formula: since the position of the reference end is unchanged, only the thermal deformation amount between the block 5 and the tool setting sensor 7 needs to be obtained to obtain the thermal error compensation amount of the whole tool setting instrument, however, this deformation amount cannot be directly measured, unless an equipment can accurately measure the distance change between the block 5 and the tool setting sensor 7, therefore, the method adopts the composite solution method to calculate the thermal compensation amount, it can be seen that when the block abuts against the limit block 6 of the drift end, due to the position change of the limit block 6 of the drift end 1-2 under the influence of the thermal deformation of the base 1, the position of the tool setting sensor 7 changes, at the same time, the thermal deformation of the telescopic rod 2 also causes the position of the tool setting sensor 7 to change, at this time, the distance change of the tool setting sensor 7 on the side of the micro displacement sensor 8 is the composite data of the displacement change amount of the limit block 6 of the drift end 1-2 and the distance change between the block 5 and the tool setting sensor 7, when the drift end 1-2 moves away from the reference end 1-1, the tool setting sensor 7 should be close to the micro displacement sensor 8, and considering that the telescopic rod 2 also has thermal deformation, when the distance between the tool setting sensor 7 and the block 5 increases, it will also drive the tool setting sensor 7 to move away from the micro displacement sensor 8, therefore, the change amount ΔS measured by the micro displacement sensor 8 is the distance change amount between the block and the tool setting sensor (that is, the thermal compensation amount ΔC to be solved) minus the distance change amount of the limit block of the drift end (that is, the thermal deformation amount ΔL between the two limit blocks), so that the formula for the tool setting instrument thermal compensation amount is ΔC=ΔS-ΔL.

Claims

1. A method for thermal compensation of a tool setting gauge, the tool setting gauge comprising a base (1) and a telescopic rod (2) slidingly arranged on the base (1), characterized in that: The base (1) includes a fixed reference end (1-1) and a drift end (1-2) capable of telescopic movement with thermal deformation, a rack (3) is arranged on the telescopic rod (2), a servo motor (4) capable of driving the rack (3) to move and calculating the moving distance is arranged on the drift end (1-2), a stop block (5) is arranged on the telescopic rod (2), limiting blocks (6) are arranged on the drift end (1-2) and the reference end (1-1) respectively to limit the movement of the stop block (5) between them, a tool sensor (7) is arranged on the telescopic rod (2), and the tool sensor (7) is close to the reference end (1-1) when the stop block (5) abuts against the limiting block (6) on the drift end (1-2), and a micro-displacement sensor (8) is further arranged on the reference end (1-1) to detect the displacement change amount of the tool sensor (7) when the stop block (5) abuts against the limiting block (6) on the drift end (1-2). The thermal compensation method comprises: The thermal deformation amount ΔL between the two limiting blocks is obtained by driving the stop block to move between the two limiting blocks by the servo motor, the displacement change amount ΔS of the tool sensor when the stop block abuts against the limiting block on the drift end is detected by the micro-displacement sensor, the thermal compensation amount ΔC of the tool sensor is obtained by the formula ΔC=ΔS-ΔL, the thermal change amount ΔL between the two limiting blocks is L2-L1, wherein L2 is the distance parameter between the two limiting blocks obtained by driving the stop block to move between the two limiting blocks by the servo motor in the initial state, L1 is the distance parameter between the two limiting blocks obtained by driving the stop block to move between the two limiting blocks by the servo motor after thermal deformation, ΔL is the thermal deformation amount of the reference end and the drift end, ΔL has positive and negative values, the displacement change amount ΔS of the tool sensor is S1-S2, wherein S2 is the distance parameter of the tool sensor detected by the micro-displacement sensor when the stop block abuts against the limiting block on the drift end in the initial state, S1 is the distance parameter of the tool sensor detected by the micro-displacement sensor when the stop block abuts against the limiting block on the drift end after thermal deformation, ΔS is the combined change amount of the thermal deformation of the base and the telescopic rod, ΔS has positive and negative values.

2. The method of claim 1, wherein: The limiting device (9) capable of limiting the upward or swinging movement of the drift end (1-2) is arranged on the drift end (1-2).

3. The method of claim 1, wherein: The guide slide (10) capable of reducing the friction of the movement of the drift end (1-2) is arranged on the drift end (1-2).

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