Machine Tool Thermal Displacement Correction via Single Sensor

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Solution Overview

Problem

Current machine tools face challenges in accurately correcting thermal displacement due to varying environmental temperatures, as existing solutions either fail to consider external temperature variations or require expert knowledge to adjust correction coefficients, limiting versatility and accuracy.

Innovation Solution

The machine tool incorporates a system with temperature sensors to estimate environmental temperature system thermal displacement, allowing for dynamic correction magnification adjustments, enabling workers to easily correct thermal displacement across different environments without requiring extensive technical knowledge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a thermal displacement correction system uses multiple temperature sensors and complex calculation formulas with multiple coefficients to accurately correct thermal displacement, then the manufacturing precision is improved, but the device complexity increases and requires expert knowledge for adjustment

Engineering Contradiction:
Improvethermal displacement correction accuracyVSAvoidcorrection system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential temperature measurement function needed for thermal displacement correction, eliminating unnecessary complex multi-coefficient calculation systems. A single temperature sensor measures the temperature of the main body, and a simple linear calculation formula with one coefficient directly computes the thermal displacement correction amount, maintaining high correction accuracy while dramatically reducing system complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using multiple temperature sensors to measure different parts and then complexly combining their readings, the patent inverts the approach by using a single temperature sensor to measure the main body temperature and directly calculating the thermal displacement of other parts based on this single measurement and their relative thermal expansion characteristics, simplifying the system while maintaining accuracy

Inventive Principle:
Principle #13The other way round (Inversion)

2Manufacturing precision

If a thermal displacement correction system uses multiple temperature sensors and various heat source analysis to improve correction accuracy, then the manufacturing precision is improved, but the ease of operation deteriorates as expert knowledge is required

Engineering Contradiction:
Improvethermal displacement correction accuracyVSAvoidcorrection adjustment ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent makes the thermal displacement correction system self-adjusting by automatically calculating the correction amount based on single temperature sensor readings and predetermined coefficient data stored in the control unit. The system performs self-correction without requiring expert operators to manually adjust multiple coefficients or analyze complex thermal patterns, greatly improving ease of operation while maintaining high correction accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the operational parameters from requiring manual adjustment of multiple complex coefficients to automatically using a single temperature measurement with predetermined coefficient data. This parameter simplification allows non-expert operators to easily operate the system while achieving accurate thermal displacement correction through automatic calculation

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a thermal displacement correction system uses fixed correction coefficients to simplify operation, then the ease of operation is improved, but the adaptability deteriorates when environmental conditions vary

Engineering Contradiction:
Improvecorrection adjustment easeVSAvoidenvironmental condition adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic correction system where the correction coefficient is not fixed but automatically selected based on real-time temperature conditions. The control unit stores multiple coefficient values corresponding to different temperature ranges and automatically selects the appropriate coefficient based on the current temperature sensor reading, enabling the system to adapt to varying environmental conditions while remaining easy to operate

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback mechanisms where the temperature sensor continuously monitors the main body temperature and feeds this information back to the control unit, which then automatically adjusts the correction calculation using temperature-appropriate coefficients. This closed-loop feedback system enables automatic adaptation to environmental changes without requiring operator intervention, maintaining both ease of operation and environmental adaptability

Inventive Principle:
Principle #23Feedback

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 configuration enhances thermal displacement correction accuracy and versatility by allowing non-experts to adjust correction magnifications, ensuring precise machining even in varying environmental conditions.

Implementation Method 1

A thermal expansion of each of members constituting a machine tool due to heat generated during an operation of the machine tool and heat from the surroundings of the machine tool is a significant cause that brings the relationship in position between a blade edge of a tool and a machining workpiece to a misaligned state

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3168001B1Machine tool equipped with device for changing setting of thermal displacement correction amount
Publication Date: 2019.12.18 YAMAZAKI MAZAK KK
  • EP3168001B1 patent drawingFigure 1
  • EP3168001B1 patent drawingFigure 2
  • EP3168001B1 patent drawingFigure 3

AI summary

In order to provide a machine tool that enables a worker to highly accurately correct an environmental temperature system thermal displacement correction amount based on temperatures of members constituting the machine tool, the machine tool includes a workpiece holding unit configured to hold a workpiece and be drivingly moved in a predetermined direction and/or drivingly rotated to machine the workpiece, a tool holding unit configured to hold a tool for machining the workpiece and be drivingly moved in a predetermined direction and/or drivingly rotated to machine the workpiece, a plurality of temperature sensors attached to members constituting the machine tool, and an environmental temperature system thermal displacement amount estimation unit configured to calculate an environmental temperature system thermal displacement amount based on temperature values each measured by a corresponding one of the plurality of temperature sensors. In the machine tool, an environmental temperature system thermal displacement correction amount is calculated by multiplying a calculation-based thermal displacement correction amount for compensating the environmental temperature system thermal displacement amount by a correction magnification, and environmental temperature system thermal displacement correction control is performed based on the environmental temperature system thermal displacement correction amount. Further, a graph display function for supporting the adjustment of the correction magnification is provided.