Die Cushion Controller Bottom Dead Center Escape
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Solution Overview
Problem
Die-cushion pads in press machines experience elastic deformation during processing, leading to workpiece bouncing when the loading is removed, especially when hydraulic chambers or springs are used to mitigate impact, resulting in unreliable holding of the workpiece.
Innovation Solution
A die-cushion controlling device that includes a position-command-signal outputting section, position detecting means, position comparing section, position controlling section, speed controlling section, and an escape-position-command-signal outputting section, which moves the die-cushion pad downward from its bottom dead center position by a predetermined escape height when the slide reaches the bottom dead center, eliminating shrinkages and preventing workpiece bouncing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bottom dead center locking is conducted when the die cushion is elastically deformed, then the die cushion stops at the bottom dead center position, but the workpiece bounces when loading is removed
Solution Approach 1:
The die cushion is moved downward by a predetermined amount before the bottom dead center locking is executed, preliminarily eliminating the elastic deformation (shrinkage) that would cause workpiece bouncing. This preliminary action ensures that when the loading is removed during locking, the workpiece remains stable without bouncing.
2Object-affected harmful factors
If a hydraulic chamber or spring is provided to mitigate impact, then the impact is reduced, but the die cushion undergoes large elastic deformation causing workpiece bouncing
Solution Approach 1:
Before the bottom dead center locking is executed, the die cushion is preliminarily moved downward by a predetermined amount to eliminate the elastic deformation caused by impact mitigation devices. This ensures that even though the hydraulic chamber or spring is present, the workpiece will not bounce when locking occurs.
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
The solution effectively prevents workpiece bouncing by eliminating shrinkages caused by elastic deformation, ensuring reliable holding of the workpiece during and after processing, regardless of thickness or processing errors.
Implementation Method 1
a compressive force is being applied on the die-cushion pad and the like, thereby elastically deforming the die-cushion pad and the like
Data Source
AI summary
A die-cushion controlling device includes a position-command-signal outputting section for outputting a position command signal of a die-cushion pad; a position detecting section for detecting a position of the die-cushion pad; a position comparing section for outputting a position deviation signal corresponding to a deviation between a target position value based on the position command signal and a position detection value based on a position detection signal; a position controlling section for outputting a position-speed command signal based on the position deviation signal; a speed controlling section for outputting a motor-current command signal based on the position-speed command signal; a servo amplifier for generating a current corresponding to the motor-current command signal; and an escape-position-command-signal outputting section for outputting a position command signal for commanding the die-cushion pad to escape from a bottom dead center position based on a press signal outputted when a slide has reached a bottom dead center.