Machine Tool Accuracy Diagnosis for Thermal Displacement Timing
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Solution Overview
Problem
Existing machine tool accuracy diagnostic methods struggle to effectively address both rapid and gradual temperature changes, leading to inaccuracies in machining and measurement, particularly due to thermal displacement, and often require operator experience to determine timing for displacement correction, which can result in decreased productivity.
Innovation Solution
An accuracy diagnostic device and method that utilize a change amount detection unit to measure temperature changes, deriving first and second change indices to diagnose accuracy changes, and calculate corresponding scores to determine appropriate timing for measurement and correction, enabling automated decision-making for ensuring machine tool accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal displacement correction is performed using temperature sensors and calculated thermal displacements, then accuracy is improved under stable temperature conditions, but accuracy deteriorates when temperature changes are large or rapid
Solution Approach 1:
The system dynamically adjusts the correction approach based on temperature change detection. When rapid temperature change is detected, the system switches from using pre-calculated thermal displacement values to performing real-time actual displacement measurement, ensuring accuracy adapts to changing thermal conditions
Solution Approach 2:
The system implements feedback by continuously monitoring temperature changes and using this information to determine when to perform accuracy diagnosis and correction. The diagnosis result feeds back into the control system to trigger appropriate correction actions, creating a closed-loop system that maintains accuracy under varying thermal conditions
2Manufacturing precision
If measurement for displacement correction is performed frequently to maintain accuracy, then accuracy is improved, but productivity deteriorates due to excessive measurement time
Solution Approach 1:
The system performs preliminary temperature change rate calculation and accuracy diagnosis before actual displacement correction measurement. By evaluating the temperature change rate and diagnosing accuracy status in advance, the system determines whether correction measurement is necessary, avoiding unnecessary measurements and preserving productivity
Solution Approach 2:
The system performs only the necessary portion of measurement based on diagnosed needs. When temperature change rate exceeds thresholds or accuracy diagnosis indicates problems, full correction measurement is performed. When conditions are stable, measurement is omitted or reduced, avoiding excessive action that would harm productivity
3Manufacturing precision
If measurement is performed when temperatures rapidly change to correct thermal displacement, then accuracy is improved, but measurement accuracy deteriorates due to thermal displacement occurring during measurement
Solution Approach 1:
The system performs preliminary diagnosis of accuracy status and temperature change rate before initiating correction measurement. This preliminary action identifies the optimal timing for measurement, ensuring measurement occurs when thermal conditions are stable enough to guarantee measurement accuracy, rather than during rapid temperature changes
Solution Approach 2:
When rapid temperature change is detected during measurement, the system skips the inaccurate measurement and triggers a new measurement cycle after thermal conditions stabilize. This approach avoids capturing erroneous data and ensures measurement accuracy is maintained
4Adaptability or versatility
If operator experience is used to determine timing for displacement correction measurement, then flexibility is improved, but productivity deteriorates due to subjective judgment delays
Solution Approach 1:
The system performs self-diagnosis of accuracy status and self-determination of correction timing based on objective temperature change rate data. The control device automatically decides when correction measurement is needed without operator intervention, eliminating subjective judgment delays while maintaining appropriate flexibility through rule-based decision logic
Solution Approach 2:
The system implements automated feedback loops where temperature sensors continuously monitor thermal conditions, the diagnosis unit evaluates accuracy status based on this data, and the control device automatically triggers correction measurements when needed. This closed-loop feedback system replaces operator experience with objective, real-time decision-making
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
The solution allows for accurate diagnosis and timely correction of machine tool accuracy issues due to both rapid and gradual temperature changes, improving productivity by automating the measurement and machining processes, ensuring high accuracy and stability.
Implementation Method 1
a temperature change in an installation environment of the machine tool and heat generation during an operation thermally deform various portions of the machine tool
Data Source
AI summary
An accuracy diagnostic device for a machine tool diagnoses an accuracy of the machine tool. The machine tool includes a change amount detection unit that measures a change amount. The change amount changes due to an installation environment and an operational motion. The accuracy diagnostic device includes a change-amount-reference-value recording unit that records a reference value of the change amount. The accuracy diagnostic device obtains the change amount measured by the change amount detection unit. The accuracy diagnostic device diagnoses a change of the accuracy of the machine tool based on a first change index derived from a magnitude of a change of the change amount per a predetermined period and a second change index derived from the current change amount and the reference value.