Spindle Thrust Monitoring for Small-Diameter Hole Tool Breakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing machining methods fail to effectively detect tool breakage or thrust variations during the machining of small diameter holes, where the machining resistance and load are small, making it difficult to accurately determine tool breakage or thrust changes.
Innovation Solution
A machining method that involves measuring a reference thrust of a spindle without a workpiece, determining thresholds based on this measurement, and comparing the machining thrust with these thresholds while machining, using a machining apparatus with a feed device, thrust measurement device, and determination units to detect tool breakage or thrust variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threshold-based tool breakage detection method is used, then tool breakage can be detected, but the detection accuracy is insufficient for small diameter holes where machining resistance is small
Solution Approach 1:
The patent measures reference thrust values before actual machining operations under identical machining conditions (feed rate, spindle speed, tool type) and stores these baseline values. During machining, the current thrust is compared against these pre-measured reference values to detect anomalies. This preliminary measurement approach enables accurate detection of tool breakage in small diameter holes by establishing a baseline for comparison, resolving the issue of insufficient detection accuracy when machining resistance is small.
Solution Approach 2:
The patent changes the detection parameter from fixed threshold comparison to dynamic reference-based comparison. Instead of using a predetermined fixed threshold, the system measures and stores reference thrust values under specific machining conditions, then compares actual thrust against these dynamic references. This parameter change allows the detection system to adapt to different machining conditions and accurately detect tool breakage even when absolute thrust values are small.
2Device complexity
If fixed threshold values are used for breakage detection, then the detection process is simple, but the system cannot adapt to variations in thrust due to feed coordinates and environmental conditions
Solution Approach 1:
The patent transforms the detection system from static fixed thresholds to dynamic adaptive thresholds. The system measures reference thrust values under actual machining conditions (including different feed coordinates, feed rates, and environmental conditions) and uses these dynamic references for comparison. This dynamic approach allows the system to adapt to variations in thrust caused by different feed coordinates and environmental factors while maintaining relatively simple detection logic.
Solution Approach 2:
The patent implements a feedback mechanism where reference thrust values are measured, stored, and used for comparison during machining. The system continuously monitors current thrust against the stored reference values and provides feedback when deviations indicate tool breakage. This feedback loop enables the system to adapt to changing machining conditions while maintaining simple operation, resolving the contradiction between complexity and adaptability.
3Reliability
If tool breakage detection is implemented, then machining reliability improves, but false detections may occur due to thrust variations from feed coordinates and environmental factors
Solution Approach 1:
The patent applies local quality by measuring and storing reference thrust values for specific local machining conditions ( particular feed coordinates, feed rates, and environmental conditions). Instead of using a single global threshold, the system creates localized reference profiles for different machining scenarios. This allows accurate detection within each local condition while avoiding false detections that would occur when comparing against inappropriate generic thresholds.
Solution Approach 2:
The patent performs preliminary measurement of reference thrust values under each specific machining condition before detection begins. These pre-measured references account for environmental factors and feed coordinate variations inherent to each condition. By establishing these baselines in advance, the system can accurately distinguish between normal thrust variations due to conditions and actual tool breakage, significantly reducing false detections while maintaining high reliability.
Data Source
AI summary
When machining small diameter holes, tool breakage and torque fluctuation at the machining point are detected. The machining method includes: measuring a reference thrust of a spindle when the spindle is fed from a machining feed start point to a machining end point in a direction in which the spindle extends under a machining condition without machining a workpiece; determining a threshold with respect to a feed coordinate based on the reference thrust; measuring a machining thrust of the spindle with respect to the feed coordinate while machining the workpiece; and comparing the machining thrust with the threshold with respect to the feed coordinate.