Machine Tool Thermal Expansion Measurement via Speckle Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for addressing thermal deformation in machine tools are complex, costly, and fail to provide real-time calibration of absolute positioning coordinates, leading to reduced machining accuracy due to thermal expansion.
Innovation Solution
A measurement, calibration, and compensation system using speckle image sensors and low-thermal-variation positioning bases to directly measure thermal expansion and calibrate the machine tool's axes, ensuring precise thermal deformation compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional thermal deformation control technology is used (mounting temperature sensors, setting up three-dimensional measuring systems, constructing thermal deformation models), then thermal deformation can be measured and compensated, but the system complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts the thermal deformation measurement function from the complex multi-sensor system and implements it directly through the machine tool's existing control system using the machine tool center coordinate system. This eliminates the need for separate temperature sensors and three-dimensional measuring systems, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent makes the machine tool's control system perform multiple functions: it not only controls machining operations but also measures thermal deformation and performs compensation calculations. By utilizing the existing control system for thermal deformation measurement and compensation, the patent avoids adding separate measurement systems, thus reducing device complexity while maintaining measurement precision.
2Extent of automation
If CNC system-based thermal deformation control technology is implemented (using built-in software to calculate thermal deformation from temperature data), then real-time thermal compensation can be achieved, but positioning accuracy deteriorates over time due to limited sampling range and environmental temperature changes
Solution Approach 1:
The patent dynamically adjusts the thermal deformation measurement and compensation process by continuously monitoring the machine tool center coordinate system and updating compensation values in real-time based on current thermal conditions. This dynamic approach allows the system to adapt to environmental temperature changes and maintain positioning accuracy over time, resolving the contradiction between automation extent and manufacturing precision.
Solution Approach 2:
The patent implements a feedback mechanism where the measured thermal deformation of the machine tool center coordinate system is fed back to the control system for continuous compensation. This closed-loop feedback ensures that positioning accuracy is maintained despite environmental temperature changes and extended operation periods, resolving the contradiction between real-time compensation automation and manufacturing precision.
3Object-affected harmful factors
If thermo-friendly machine body and multi-passage zero-heat source cooling technology are adopted to reduce thermal deformation, then thermal deformation amount decreases, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent replaces complex mechanical thermal control systems (thermo-friendly machine body design and multi-passage cooling systems) with a measurement and compensation approach using the machine tool center coordinate system. Instead of mechanically preventing thermal deformation through complex structures, the patent measures the actual thermal deformation and compensates for it through coordinate system transformations, significantly reducing manufacturing complexity while effectively addressing thermal deformation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for real-time calibration of machine tool axes, enhancing machining accuracy by maintaining positioning accuracy within 1-5µm, thereby improving the quality of machining centers and multi-axis machine tools.
Implementation Method 1
A measurement, calibration and compensation system uses a simplified and low-cost way with good thermal deformation calibration accuracy to directly precisely measure the thermal expansion amounts at all axes of a machine tool
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A measurement, calibration and compensation system for machine tool includes a first positioning base; two first speckle image sensors for sensing speckle positions of an object holding unit at a first XY plane and a first XZ plane of the first positioning base before and after the machine tool is started for machining; a second positioning base; two second speckle image sensors for sensing speckle positions of a cutter holding unit at a second XY plane and a second YZ plane of the second positioning base before and after the machine tool is started for machining. Thus, the thermal expansion at all axes of the machine tool can be measured in a simplified and low-cost way, and the absolute positioning coordinates of all axes of the machine tool can be calibrated in real time to avoid reduced positioning accuracy due to the thermal expansion of the multi-axis machine tool.