Panel Drawing Restraining Force Control Using Strain Gauges
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Solution Overview
Problem
Existing methods for monitoring and controlling the restraining force applied to sheet metal panels during drawing operations are unreliable due to issues like wear, contamination, and limited applicability to specific materials, leading to inefficiencies in preventing wrinkles and splits.
Innovation Solution
A system utilizing strain gauges to measure and dynamically control the restraining force applied to sheet metal panels, combined with a laser displacement measuring system to correlate displacement data, allowing for precise adjustment of the restraining force through movable draw beads or pressure pins, and a controller to optimize force distribution across segmented binders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spring-loaded plunger sensor is used to monitor sheet material in-flow, then displacement can be measured, but the approach becomes unreliable due to oil, slivers, and other contaminants
Solution Approach 1:
The patent replaces the mechanical spring-loaded plunger sensor with an electromagnetic sensor system consisting of coils that measure in-flow without physical contact with the sheet metal blank, eliminating contamination issues from oil, slivers, and other contaminants while maintaining measurement capability
2Reliability
If an electromagnetic sensor with coils is used to measure material in-flow, then non-contact measurement is achieved, but the coil insulation is subject to wear and contaminants damage the insulation making it unreliable
Solution Approach 1:
The patent extracts the measurement function from the binder structure by positioning the electromagnetic sensor coils on the die or binder such that they measure in-flow without requiring insulation between the coils and the metal binder ring, eliminating the insulation wear problem while maintaining non-contact measurement
3Adaptability or versatility
If multiple coils are positioned to apply electromagnetic pressure on the sheet metal blank, then restraining force can be controlled, but space requirements increase and the actuator is limited to mild steel applications
Solution Approach 1:
The patent creates a universal restraining force control system that can be applied to various materials including mild steel and other metals by using electromagnetic sensors positioned on the die or binder that measure in-flow and control restraining force through a single actuator, eliminating material limitations and reducing space requirements
4Manufacturing precision
If the binder is subdivided into several segments with individual restraining forces, then force distribution can be optimized, but device complexity increases
Solution Approach 1:
The patent subdivides the binder into multiple segments with individual electromagnetic sensors and actuators that can independently measure and control restraining force at different locations around the blank perimeter, enabling optimized force distribution to prevent wrinkles and splits while maintaining manageable system complexity through modular design
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 enables efficient control of restraining forces, optimizing material inflow and preventing wrinkles and splits by providing real-time data-driven adjustments, enhancing the reliability and precision of sheet metal drawing operations across various materials.
Implementation Method 1
A strain gauge measures the restraining force applied to a local area of one side of the panel
Implementation Method 2
a laser displacement measuring system to correlate displacement data
Data Source
AI summary
A system and apparatus is disclosed for controlling a restraining force applied to a panel. The apparatus includes a die, a binder supporting the panel against the die, and a punch used to draw the panel into the die. A restraining element is disposed on one of the die and the binder that engages a surface of the panel and applies a restraining force onto the panel. A strain gauge is disposed inside at least one of the die and the binder that engages a surface of the panel to measure the restraining force applied to the panel. The level of restraining force applied by the restraining element onto the panel is controlled based upon the restraining force measured by the strain gauge.