Punching Load Moment Detection for Scrap Floating Control
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Solution Overview
Problem
Existing punching devices struggle to accurately detect foreign matter, particularly 'scrap floating' phenomena, which can cause product defects and mold damage, as they rely on distance sensors that are prone to errors during faster punching cycles or when foreign matter is not overlapping the workpiece.
Innovation Solution
The implementation of load sensors at multiple points on the die to measure forces and calculate moments around axes, allowing for precise detection of foreign matter by determining deviations from predetermined moment values, and estimating its location within divided quadrants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If distance sensors are used to detect foreign matter, then the detection system is simple to implement, but the detection accuracy deteriorates during faster punching cycles or when foreign matter does not overlap the workpiece
Solution Approach 1:
The patent replaces the optical distance sensor system with a mechanical load sensor system. Load sensors measure the actual punching force applied to the die, and the control device calculates moments around axes to detect foreign matter. This mechanical measurement approach is not affected by punching speed or foreign matter positioning, thereby resolving the contradiction between ease of implementation and detection accuracy.
Solution Approach 2:
The patent changes the detection parameter from distance (optical measurement) to force/moment (mechanical measurement). By measuring the load distribution and calculating moments around orthogonal axes, the system detects foreign matter through force distribution patterns rather than distance changes. This parameter transformation maintains detection capability while eliminating the limitations of distance-based methods.
2Measurement precision
If load sensors are installed at multiple points on the die, then foreign matter detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent segments the die into multiple measurement points by installing load sensors at specific locations (e.g., four corners). Each sensor independently measures local load, and the control device aggregates these measurements to calculate moments around orthogonal axes. This segmentation enables accurate foreign matter detection through distributed measurement while maintaining a relatively simple sensor arrangement pattern.
Solution Approach 2:
The load sensors serve multiple functions: they measure the total punching force, detect foreign matter through moment calculation, and can potentially identify the position of foreign matter on the die. This multi-functionality justifies the added sensor complexity by providing comprehensive measurement capabilities from a single sensor type.
3Reliability
If foreign matter detection is implemented to prevent product defects and mold damage, then manufacturing reliability is improved, but the productivity decreases due to additional detection and stopping operations
Solution Approach 1:
The patent implements a feedback mechanism where load sensor measurements are continuously monitored, moments are calculated in real-time, and foreign matter detection triggers an automatic response. The control device compares measured moments against predetermined thresholds and provides feedback by stopping the punching operation only when foreign matter is detected, thereby maintaining high productivity while improving reliability.
Solution Approach 2:
The detection system operates autonomously using the existing punching force measurements. The load sensors and control device automatically detect foreign matter without requiring additional sensors or manual inspection, and the system self-regulates by stopping only when necessary. This self-service approach minimizes productivity impact while ensuring reliability.
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 approach enhances foreign matter detection accuracy, preventing product defects and mold damage by accurately identifying and stopping the punching process when foreign matter is present, even in scenarios where distance sensors fail, thus improving work efficiency.
Implementation Method 1
load sensors which are disposed respectively at positions where a force applied to the die is transmitted in the punching device, and measure a load in a punching direction
Data Source
AI summary
There is provided a punching device for punching a workpiece into a predetermined shape using a die and a punch, the device including: load sensors which measure a load in a punching direction at at least three predetermined points different from each other; and a control device that calculates a first moment, which is a sum of moments of the measured load around a first axis, and a second moment, which is a sum of moments of the measured load around a second axis, with respect to the first and second axes on a plane perpendicular to the punching direction, and determines that foreign matter is generated in a case where a magnitude of at least one of the first and second moments is deviated from a range of predetermined values.