Rotary Tool Light Barrier Measurement Under Shadowing Interference
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Solution Overview
Problem
Existing methods for measuring and controlling rotary tools in machine tools face challenges in distinguishing between genuine signals and those affected by contamination or interference, leading to inaccuracies and increased downtime due to concentricity errors and damage, which can result in inefficient production processes.
Innovation Solution
A device comprising a processing unit and a light barrier arrangement that determines useful signal components, applies filters to separate interference, and provides information to the numerical control for accurate measurement and control of tool dimensions and condition, including detection of contamination and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser light barrier is used to measure the rotary tool, then the measurement of tool dimensions can be performed, but chips, cleaning fluid, and cooling fluid influence the shadowing of the light beam leading to incorrect radius measurements
Solution Approach 1:
The signal processing is segmented into multiple evaluation steps where the shadowing curve is analyzed in discrete portions. The evaluation device divides the measurement signal into individual shadowing events corresponding to different tool features, allowing selective analysis of valid tool shadows versus contamination shadows based on their temporal and amplitude characteristics.
Solution Approach 2:
An intermediary evaluation device is introduced between the light barrier and the measurement system. This device acts as a mediator that filters and evaluates the raw shadowing signals, distinguishing between genuine tool shadows and interference from chips or fluids before passing validated measurements to the control system.
2Productivity
If vibrations from machine tool operation are present during measurement, then the measurement can be performed in real operation, but the vibrations lead to corrupted signals
Solution Approach 1:
The measurement system is designed to be dynamic and adaptive, continuously evaluating incoming signals during machine operation. The evaluation device adjusts its analysis parameters in real-time to account for varying vibration conditions, allowing measurements to be performed throughout the tool's operational life without requiring static, vibration-free environments.
Solution Approach 2:
The measurement process operates continuously during tool operation rather than requiring intermittent shutdowns. The light barrier and evaluation device work continuously to monitor tool dimensions, with the system maintaining measurement capability despite the continuous vibrations inherent in machine tool operation.
3Reliability
If the measured radius deviates excessively from the reference radius, then runout errors can be detected, but the rotary tool is replaced or stopped leading to standstill of the machine tool
Solution Approach 1:
The system implements feedback control where measurement results are continuously compared against reference values and tolerance thresholds. The evaluation device provides feedback to the control system, enabling real-time adjustments and distinguishing between acceptable variations and genuine defects, thereby reducing unnecessary tool replacements and machine stoppages.
Solution Approach 2:
The evaluation device analyzes multiple parameters of the shadowing curve including amplitude, duration, and temporal patterns rather than relying solely on single radius measurements. By evaluating changes in these parameters across multiple measurement cycles, the system can distinguish between normal measurement variations and genuine tool defects, reducing false alarms and unnecessary interventions.
4Device complexity
If traditional measurement methods are used without signal filtering, then the measurement process is simple, but errors from interference lead to increased downtime
Solution Approach 1:
Signal filtering and evaluation actions are performed preliminarily and continuously in the background before final measurement decisions are made. The evaluation device pre-processes incoming signals, identifying and filtering out interference patterns from chips, fluids, and vibrations before the actual measurement evaluation occurs, thereby preventing erroneous measurements without adding apparent complexity to the measurement process.
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 solution enhances the reliability and speed of the measurement process, reducing errors and downtime by accurately differentiating between tool signals and interference, thereby improving production efficiency and tool maintenance planning.
Implementation Method 1
receive signals at a first measuring position from a light receiving unit that are at least approximately proportional to a shading generated by the rotationally drivable tool and/or at least one cutting edge of the rotationally drivable tool
Data Source
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AI summary
Processing unit for measuring and checking a tool that can be driven in rotation, the processing unit being able to be connected to a light barrier arrangement which comprises a light-transmitting unit and a light-receiving unit, the processing unit being set up to move from the light-receiving unit to a tool that can be driven in rotation and/or or to receive at least approximately proportional signals at a first measurement position due to the shadowing produced by at least one cutting edge of the rotationally drivable tool. The processing unit is also set up to evaluate the received signals and to send control signals to the light barrier arrangement, the evaluation of the signals received by the processing unit comprising the following steps: determining an interference signal component and/or a useful signal component of the received signal; and providing information about the useful signal component, the interference signal component and/or the received signal for forwarding to a numerical control of a machine tool.