Segmented Electromagnetic Blank Holder Control for Sheet Stamping
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Solution Overview
Problem
Existing stamping technologies, such as hydraulic and electromagnetic blanking, suffer from energy waste and inaccurate blank holder force control, leading to defects like cracking, wrinkling, and springback in stamped workpieces.
Innovation Solution
An electromagnetic stamping method and device that divide the blank holder into areas based on workpiece contour characteristics, using a blank holder force function over time and a negative feedback mechanism to dynamically control the blank holder force, optimizing the forming quality and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional hydraulic or electromagnetic blanking is used, then stamping operation can be performed, but energy waste occurs and blank holder force control is inaccurate
Solution Approach 1:
The blank holder is divided into multiple independent blank holder areas, each equipped with its own electromagnetic actuator and pressure sensor. This segmentation enables independent control of blank holder force in different regions, improving control accuracy while reducing overall energy consumption by activating only necessary areas.
Solution Approach 2:
Different blank holder areas can apply different forces based on local requirements of the workpiece contour characteristics. The system adjusts blank holder force distribution according to the specific geometric features of different regions, achieving precise local control that prevents both over-stressing and under-constraint.
Solution Approach 3:
Pressure sensors in each blank holder area provide real-time feedback on the actual blank holder force to the controller. The controller compares measured values with target values and dynamically adjusts electromagnetic actuator output, forming a closed-loop control system that ensures accurate force control and reduces energy waste.
2Device complexity
If uniform blank holder force is applied, then device structure is simple, but forming quality deteriorates due to inability to accommodate different contour characteristics
Solution Approach 1:
The blank holder is divided into multiple independent areas with individual actuators and sensors, enabling differentiated force application across different regions. This segmentation allows the system to adapt to varying contour characteristics of the workpiece while maintaining a relatively simple overall structure.
Solution Approach 2:
The blank holder force is dynamically adjusted during the stamping process based on real-time feedback from pressure sensors and the specific contour characteristics of the workpiece. This dynamic control enables high forming quality without requiring a complex static structure.
3Reliability
If high blank holder force is applied throughout, then wrinkling is prevented, but energy consumption increases and cracking may occur
Solution Approach 1:
The system applies high blank holder force only in specific areas where wrinkling risk exists, rather than uniformly across the entire blank holder. This localized force application prevents defects while minimizing energy consumption and avoiding excessive stress that could cause cracking in other areas.
Solution Approach 2:
Instead of applying excessive force uniformly, the system applies partial force selectively to areas where it is most needed. The feedback control ensures that force is applied only to the extent necessary to prevent wrinkling, avoiding the harmful effects of over-stressing the material.
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 improves the accuracy of blank holder force control, optimizes the forming quality, reduces energy consumption, and minimizes defects like cracking, wrinkling, and springback in stamped workpieces.
Implementation Method 1
electromagnetic stamping method and device
Data Source
AI summary
The present disclosure relates to an electromagnetic stamping method and an electromagnetic stamping device. The electromagnetic stamping method includes: dividing a blank holder of a stamping device into a plurality of blank holder areas based on a contour characteristic of a workpiece to be stamped; setting a blank holder force function over time for each blank holder area based on a shape characteristic of the blank holder area; collecting blank holder force data of each blank holder area every cycle period t0, and calculating an error between the blank holder force data and a value of the blank holder force function at a current time; and controlling a blank holder force for each blank holder area based on the error, and obtaining the workpiece to be stamped by stamping sheet material under the blank holder force.