Tool Holder Clamping State Detection During Spindle Acceleration
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Solution Overview
Problem
Existing methods for examining the clamping state of tool holders in machine tools are inefficient, often requiring dedicated time periods and separate sensors, which can lead to increased production time and errors due to jammed chips or deformations, affecting processing precision.
Innovation Solution
A method that integrates a motor-driven machine tool with a sensor head on the stator unit to measure spacing and detect deformations in real-time, allowing for continuous measurement during tool changes and start-up phases, using a marking on the rotor unit to determine rotation and speed, and employing Fourier transformations to identify errors without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor head is arranged at a fixed position to measure spacing with respect to the rotor unit, then measurement precision is improved, but loss of time increases due to requiring dedicated examination periods
Solution Approach 1:
The patent applies preliminary action by performing the clamping state examination during the acceleration phase (before steady-state operation), which is a preparatory period anyway. The measurement is integrated into the start-up sequence, so no additional time is needed. The sensor head measures spacing values during acceleration, and the evaluation determines whether clamping is correct before full production begins.
Solution Approach 2:
The patent enables continuous measurement by integrating the spacing measurement into the ongoing acceleration process rather than requiring a separate stationary examination period. The sensor head continuously records spacing values during rotation, allowing the examination to occur naturally as part of the machine's operational sequence without interrupting production flow.
2Productivity
If examination methods are integrated into the processing process, then productivity is improved, but device complexity increases due to additional sensors and systems
Solution Approach 1:
The patent applies universality by making the existing sensor head multi-functional: it serves both as a spacing measurement device for clamping state examination and as a general positioning sensor for the rotor unit. The same sensor head and evaluation system are used for both examination purposes and normal operation monitoring, avoiding additional dedicated examination equipment.
Solution Approach 2:
The patent applies self-service by using the machine's own existing sensor head and evaluation system to perform the clamping examination, rather than requiring separate external examination devices. The rotor unit's own sensor head measures the spacing during acceleration, and the existing evaluation unit processes the data to determine clamping correctness, making the system self-diagnosing.
3Loss of time
If measurement is performed during acceleration phase, then loss of time is reduced, but measurement precision deteriorates due to variable speed conditions
Solution Approach 1:
The patent applies dynamics by adapting the measurement and evaluation method to the dynamic acceleration conditions. Instead of requiring constant speed, the system measures spacing values throughout the acceleration phase and uses the evaluation unit to determine clamping state based on the dynamic measurement pattern. The method accounts for the changing speed conditions during acceleration rather than requiring steady-state operation.
Solution Approach 2:
The patent applies parameter changes by utilizing the acceleration phase itself (changing speed parameter) as the measurement condition rather than requiring constant speed. The evaluation unit analyzes spacing measurements taken during the speed change, determining clamping correctness from the measurement pattern that emerges during acceleration, thus converting a potential disadvantage (variable speed) into the measurement basis.
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
Enables precise, continuous examination of clamping states during processing, reducing production time and costs by detecting errors early, improving processing precision, and allowing for immediate corrective actions during tool changes.
Implementation Method 1
The sensor measures its spacing with respect to the rotor unit
Data Source
AI summary
There is proposed a method for examining the clamping state of a tool holder or tool which is clamped in a tool clamping device of a rotor unit of a motor-driven machine tool unit, with the spacing of the sensor head from a component of the rotor unit being measured, with a recording of at least one time and/or position-related sequence of the spacing values measured with the sensor head, wherein for improved integration of the method the recording of a first and a second time and/or position-related sequence is carried out during an acceleration of the rotation of the rotor unit with respect to the stator unit, in particular when the rotor unit is started up, wherein the time and/or position-related information of the sequence vectors of the first and/or second sequence is scaled using the respective associated current speed (v0).