Machine tool thermal compensation system

Abstract

A machine tool thermal compensation system includes a thermal compensation monitoring device and a cloud computing device. The thermal compensation monitoring device receives and establishes or updates a thermal compensation database based on multiple workpiece temperature signals and corresponding machining error data. The cloud computing device provides a thermal compensation model and, based on the characteristics of these temperature signals and the machining error data, obtains thermal compensation values ​​to determine whether to modify the thermal compensation model or perform thermal compensation operations.

Description

Technical Field

[0001] The present disclosure relates to a thermal compensation system for machine tools, which can be connected and applied to machine tools located in different regions to perform thermal compensation operations. Background Art

[0002] In recent years, with the rapid development of machine tools, the demand for product precision has increased. However, the differences in production and sales areas of machine tool manufacturers can lead to a decrease in machine tool precision due to differences in ambient temperature and processing time. Thermal compensation technology can solve this problem, and therefore most machine tool manufacturers have made thermal compensation their main development trend.

[0003] Thermal compensation technology typically involves modeling before machine tools begin production. However, when machine tools are sold to locations with varying latitudes and longitudes, compensation accuracy can be distorted due to local climate variations. This means the same thermal compensation tool and values ​​may not be applicable to different regions. Therefore, developing a machine tool thermal compensation system to address these issues remains a pressing issue for the industry. Summary of the Invention

[0004] The present disclosure provides a machine tool thermal compensation system that can perform real-time online thermal compensation and continuously modify an established neural network thermal compensation model. This solves the problem of having to use specific instruments and equipment and hire dedicated personnel to conduct local modeling when selling machines to various regions.

[0005] One embodiment of the present disclosure provides a machine tool thermal compensation system suitable for connection to at least one machine tool for machining a workpiece. The machine tool thermal compensation system includes a thermal compensation monitoring device and a cloud computing device. The thermal compensation monitoring device receives and establishes or updates a thermal compensation database based on multiple temperature signals from the workpiece and corresponding machining error data at the same time. The cloud computing device provides a thermal compensation model and, based on the temperature signal characteristics and machining error data, generates a thermal compensation value to determine whether to modify the thermal compensation model or perform a thermal compensation operation.

[0006] To make the present disclosure more clearly understood, embodiments are given below with detailed descriptions in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 Schematic diagram of the thermal compensation system for machine tools disclosed herein.

[0008] Figure 2 This is a flowchart of the implementation of the thermal compensation system for machine tools disclosed herein. DETAILED DESCRIPTION

[0009] The following is a further description of the specific embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present disclosure and are not intended to limit the scope of protection of the present disclosure.

[0010] It should be noted that in the descriptions of the various embodiments, the terms "first" and "second" are used to describe different elements, and these elements are not limited by such designations. Furthermore, for ease of explanation and clarity, the thicknesses or dimensions of the various elements in the drawings are exaggerated, omitted, or schematically represented to facilitate understanding and reading by those skilled in the art. The dimensions of the various elements are not their actual dimensions and are not intended to limit the practicability of the present disclosure. Therefore, they have no substantive technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size, provided they do not affect the efficacy and objectives of the present disclosure, shall still fall within the scope of the technical content disclosed herein.

[0011] Figure 1 This is a schematic diagram of the thermal compensation system for machine tools disclosed herein. Figure 1 The thermal compensation system 100 of the machine tool of this embodiment is suitable for signal connection of machine tools and / or controllers in different regions, such as Figure 1 For example, a local or proximal machine tool 52 and multiple other local or distal machine tools 50 are shown, but the present disclosure is not limited thereto. The machine tool thermal compensation system 100 includes, for example, a thermal compensation monitoring device 120 and a cloud computing device 130, and is connected to a temperature sensing device 110 and a plurality of measuring devices (not shown). The temperature sensing device 110 may be installed next to the local machine tool 52 to measure the temperature signals of the workpiece at multiple different time points while the machine tool 52 is processing the workpiece. The temperature sensing device 110 is, for example, a temperature sensor, a thermal imager, or other sensor that can measure and record the temperature rise of the workpiece to sense the temperature value of the workpiece at certain or continuous time points. In addition, contact or non-contact measuring devices such as micrometers and displacement gauges are used to measure error data EA such as the machining accuracy and thermal deformation of the workpiece. These error data EA are transmitted to the thermal compensation monitoring device 120 along with the temperature signal.

[0012] In this embodiment, the thermal compensation monitoring device 120 is, for example, a computer, which may be located near or installed beside the machine tools 50, 52. Figure 1The device shown and described below is configured at the proximal end as an example. It is signal-connected to the temperature sensing device 110 and the measuring device, and includes a signal processing unit 121, a storage unit, and a communication unit (not shown) to receive and extract features of multiple temperature signals, and to establish a thermal compensation database 122 based on the corresponding error data received. In addition to recording temperature features and error data, this database 122 also records identification data of the machine tool 52 in the local area, such as the machine model, location, and other data.

[0013] The cloud computing device 130 is, for example, a computer located at a remote location and includes a processing unit, a storage unit, and a communication unit (not shown). It is signal-connected to the thermal compensation monitoring device 120, or may be combined with the thermal compensation monitoring device 120 into a single computer device located at a local location. The cloud computing device 130 receives temperature characteristics and error data EA, and references all data in the thermal compensation database 122 to establish, apply, or modify the thermal compensation model MA and generate a thermal compensation value. This thermal compensation value is then transmitted back to the thermal compensation monitoring device 120 and then, via the controller 52A, to the machine tool 52 for calibration. Machine tools 50 located in other locations can also receive the same thermal compensation value, provided that the model, machining operation, and ambient temperature conditions meet. The communication unit described above may be a two-way communication unit, either wired or wireless.

[0014] Under this architecture, the machine tool thermal compensation system 100 can instantly perform thermal compensation operations on similar machine tools in all regions based on on-site processing conditions in a single region, and can continuously modify the established thermal compensation model MA to solve the problem of having to use specific instruments and equipment and hire dedicated personnel for on-site calibration when machines are sold to various regions.

[0015] In one embodiment, the thermal compensation monitoring device 120 further includes a user interface 124 to display various information and provide the user with instructions to receive and process temperature signals and error data, initiate the creation or update of the thermal compensation database 122, and initiate a communication connection with the cloud computing device 130.

[0016] For example, the thermal compensation implementation process of the machine tool thermal compensation system 100 of the present disclosure is as follows: Figure 2As shown, in step S11, a temperature signal is received. The temperature sensing device 110 receives temperature signals of a workpiece at multiple different time points during machining by the machine tool 52. Next, in step S12, temperature features are extracted. The signal processing unit 121 receives the temperature signal and uses signal processing methods to reduce noise and extract temperature features from the temperature signal. In step S13, error data is measured. The error data EA of the workpiece machining dimensions measured by the measuring device at different time points is used. For example, the first cut (time point 0) of the modeling workpiece is used as the measurement reference. The error data EA is calculated by subtracting the error data from the second cut and subsequent cuts at other time points. By continuously extracting temperature features at different time points during the machining process and measuring the error data EA at the corresponding time points, the thermal compensation database 122 is established or updated, as shown in step S14.

[0017] Next, in step S15, a thermal compensation model is established, applied, or modified. The cloud computing device 130 uses the temperature characteristics at different time points as input values ​​and the error data corresponding to each different time point as output values. For example, a neural network-like algorithm is used to establish the thermal compensation model MA. That is, the present disclosure uses machine learning calculations to establish the thermal compensation model MA, but is not limited to this.

[0018] In one embodiment, the thermal compensation model MA of the present disclosure is established as follows:

[0019] y=f k (∑ i＝1 X i W i +b) (1);

[0020] In mathematical formula (1), Xi represents the temperature signal of the workpiece during machining, y represents the measurement error, fk represents the transfer function or recursive function, Wi represents a vector, and b represents the offset value, which is a constant. Given fk, Wi, and b, the value of y obtained by inputting Xi is the thermal compensation value.

[0021] In one embodiment, step S15 further includes modifying the thermal compensation model MA via cloud computing. The cloud computing device 130 calculates a corresponding thermal compensation value based on the temperature signal characteristics of the thermal compensation model MA and compares the calculated thermal compensation value with the machining accuracy of the modeling workpiece during the first cut. This calibrates or modifies the established thermal compensation model MA to the latest thermal compensation model MA.

[0022] Therefore, the present disclosure establishes a thermal compensation model MA based on the correlation between the length of time and the thermal elongation or machining accuracy of the modeling workpiece, and uses a neural network to perform corrections, thereby continuously updating the thermal compensation model MA to produce more accurate thermal compensation values.

[0023] In the embodiment, the thermal compensation model MA can also be modified by using the mathematical formula (1) by cloud computing combined with workpiece error measurement for modeling, thereby increasing the data volume of the thermal compensation model MA to continuously improve the machining accuracy.

[0024] Next, in step S16, the thermal compensation value is calculated. After the cloud computing device 130 receives the temperature signal characteristics and error data of the modeling workpiece at different time points and compares them with the data in the thermal compensation database 122, it calculates the corresponding thermal compensation value based on the thermal compensation model MA. Then, in step S17, it is determined whether this thermal compensation value exceeds a predetermined threshold. If it is determined to be true, it indicates that the error is too large and it is necessary to return to step 15 to correct the model and recalculate. Conversely, if it is determined to be false, it indicates that the thermal compensation value does not exceed the threshold at this time and the subsequent thermal compensation operation can be carried out normally, as shown in step S18. Figure 1 As shown, in one embodiment, a threshold value can be set to the minimum control accuracy of each machine tool controller, such as 1 micron (μm). If the thermal compensation value calculated by the thermal compensation model MA does not exceed the threshold value, the cloud computing device 130 can automatically perform the calculation and then transmit the thermal compensation value to the machine tools 52, 50 in each region via the local controller 52A or the remote controller 50 for calibration, thereby stably and continuously monitoring the machining accuracy of the workpiece. If the machine tools 50 in other regions may already have CNC controllers or PLC systems, the thermal compensation value can be directly transmitted to the machine tools for compensation.

[0025] In summary, the disclosed machine tool thermal compensation system can perform thermal compensation in real time based on on-site machining conditions in various regions and continuously revise completed thermal compensation models, thereby resolving the inconvenience of having to use specific instruments and equipment and hire dedicated personnel to perform on-site thermal modeling when selling machines to various regions.

[0026] Furthermore, the present disclosure establishes a thermal compensation model based on the correlation between time and the thermal elongation or machining accuracy of the modeled workpiece, and uses a neural network to perform corrections, thereby continuously updating the thermal compensation model to produce more accurate thermal compensation values.

[0027] Furthermore, when the thermal compensation value calculated by the thermal compensation model does not exceed a predetermined threshold, a cloud computing device can automatically perform calculations and thermal compensation operations to stably monitor the machining accuracy of machine tools in various regions, thus meeting the requirements for an invention patent.

[0028] Although some embodiments of the present disclosure have been disclosed as above, they are not intended to limit the present disclosure. Anyone with ordinary knowledge in the technical field may make slight changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the appended claims.

[0029] [Explanation of symbols]

[0030] 50: Machine tools / controllers

[0031] 52: Machine tools

[0032] 52A: Controller

[0033] 100: Machine tool thermal compensation system

[0034] 110: Temperature sensing device

[0035] 120: Thermal compensation monitoring device

[0036] 121: Signal processing unit

[0037] 122: Thermal Compensation Database

[0038] 124: User Interface

[0039] 130: Cloud computing device

[0040] EA: Error data

[0041] MA: Thermal Compensation Model

[0042] S11~S18: steps.

Claims

1. A machine tool thermal compensation system, suitable for use in a machine tool for machining a workpiece, the machine tool thermal compensation system comprising: A thermal compensation monitoring device is used to receive temperature signals of the workpiece at different time points, extract corresponding temperature features, and then establish or update a thermal compensation database based on the corresponding error data of the workpiece; as well as The cloud computing device provides a thermal compensation model and calculates a thermal compensation value based on the temperature characteristics and the corresponding multiple error data. The cloud computing device then determines whether to modify the thermal compensation model or perform a thermal compensation operation based on the thermal compensation value and a predetermined threshold, wherein the threshold is the minimum control accuracy of the controller of the machine tool. 2 . The machine tool thermal compensation system according to claim 1 , wherein the plurality of temperature signals are measured by a temperature sensing device. 3 . The machine tool thermal compensation system according to claim 1 , wherein if the thermal compensation value is greater than the threshold, the thermal compensation model is modified; otherwise, the thermal compensation operation is performed. 4 . The machine tool thermal compensation system according to claim 1 , wherein the thermal compensation operation is transmitting the thermal compensation value to the machine tool. 5 . The machine tool thermal compensation system according to claim 1 , wherein the plurality of error data are measured by a measuring device. 6 . The machine tool thermal compensation system according to claim 1 , wherein the thermal compensation database further records identification data of the machine tool. 7 . The machine tool thermal compensation system according to claim 1 , wherein the cloud computing device establishes the thermal compensation model using a neural network-like algorithm based on the plurality of temperature characteristics and the corresponding plurality of error data. 8 . The machine tool thermal compensation system according to claim 7 , wherein the cloud computing device modifies the thermal compensation model using the neural network algorithm. 9 . The machine tool thermal compensation system according to claim 1 , wherein the cloud computing device is connected to the thermal compensation monitoring device via a communication unit signal. 10 . The machine tool thermal compensation system according to claim 9 , wherein the cloud computing device is connected to a plurality of other machine tools via the communication unit signal.

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