Machine Tool Calibration Sphere Sensing for Accurate Z-Position
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Solution Overview
Problem
Current calibration methods for machine tools, especially five-axis machines, are inaccurate due to manual procedures for determining the Z-position of a calibration sphere, leading to variations among operators and inefficiencies.
Innovation Solution
A calibration device with a deflectable calibration artefact, such as a sphere, attached to a machine tool via a deflection mechanism, allowing for automated measurement of the sphere's position using a sensor and a reference tool, eliminating the need for manual gauge block alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual procedures are used to measure the Z-position of a calibration sphere, then the calibration process can be performed with simple equipment, but the measurement accuracy and consistency deteriorate due to operator-dependent variations
Solution Approach 1:
The patent replaces manual mechanical measurement procedures with an automated sensor-based system. A sensor mounted on the machine tool spindle automatically detects the Z-position of the calibration sphere, eliminating operator-dependent manual gauge block alignment and providing consistent, accurate measurements without requiring complex manual procedures
Solution Approach 2:
The calibration system performs self-measurement by using the machine tool's own spindle and sensor to automatically measure the calibration sphere position. The system eliminates the need for external manual intervention, as the sensor mounted on the spindle autonomously detects the sphere's Z-position through automated probing
2Productivity
If manual gauge block alignment is used to establish sphere center position, then the equipment required is simple, but the calibration time and productivity are reduced due to operator skill dependency
Solution Approach 1:
The patent replaces time-consuming manual gauge block alignment with automated sensor-based measurement. The sensor mounted on the spindle automatically detects the calibration sphere's position, eliminating the need for operators to manually align gauge blocks and significantly reducing calibration time while improving efficiency
Solution Approach 2:
The patent introduces a sensor as an intermediary between the machine tool spindle and the calibration sphere. This sensor acts as a mediator that automatically detects and reports the sphere's Z-position, replacing the manual intermediary process of gauge block alignment and reducing the time required for calibration
3Measurement precision
If a deflection mechanism is added to enable automated measurement, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The patent replaces complex manual measurement mechanisms with a simpler automated sensor system. Instead of using complex mechanical deflection mechanisms or manual gauge blocks, the system uses an electronic sensor mounted on the spindle to automatically detect the calibration sphere's position, achieving high accuracy with reduced mechanical complexity
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 method provides improved accuracy and consistency in machine tool calibration by automating the measurement of the sphere's center position, reducing operator-dependent errors and simplifying the calibration process.
Implementation Method 1
A step of measuring a position of the calibration artefact may also be performed. The deflection of the calibration artefact may be used to measure a position thereof.
Implementation Method 2
The sensor measures the extent of any such movement of the calibration artefact relative to the base.
Data Source
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AI summary
A calibration device (30) for a machine tool is described that includes a base (36) attachable to a machine tool and a calibration artefact (32), such as a sphere of known radius. A deflection mechanism attaches the calibration artefact to the base and allows movement of the calibration artefact (32) relative to the base (36) when an external force is applied to the calibration artefact (32). The deflection mechanism also maintains the calibration artefact (32) in a defined rest position relative to the base (36) in the absence of an applied external force. A sensor (46) is provided for sensing the extent of movement of the calibration artefact (32) relative to the base (36). A method of using the device (30) with a reference tool to accurately determine a position of a calibration artefact (32) is also described.