Servo Die Cushion Force Control Method
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Solution Overview
Problem
Servo die cushion devices experience response delays and impact issues when generating die cushion force, leading to insufficient force at the start of forming processes, resulting in product defects like wrinkles and galling due to the combination of response and preliminary acceleration distances.
Innovation Solution
A die cushion force control method that involves preliminary pressurization of the cushion pad before the press machine reaches the die cushion waiting position, allowing the cushion pad to apply pressure in the upward direction before collision, thereby reducing impact force and improving response delay without changing the die cushion waiting position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If preliminary acceleration is performed to reduce impact force, then impact force is reduced, but die cushion force response distance increases causing insufficient force at start of forming
Solution Approach 1:
The system performs preliminary acceleration of the cushion pad before the press slide reaches the die cushion waiting position. This preliminary action ensures that when the slide arrives, the cushion force is already applied, eliminating the response delay and ensuring sufficient force from the start of forming without creating excessive impact.
2Speed
If die cushion force response time is reduced, then responsiveness is improved, but impact force increases due to collision
Solution Approach 1:
The control system outputs the die cushion force command in advance before the press slide reaches the die cushion waiting position. This preliminary action allows the cushion pad to accelerate and generate the required force before collision, achieving fast response without excessive impact force.
Solution Approach 2:
The system applies preliminary acceleration to the cushion pad in the upward direction before the press slide collision. This preliminary anti-action counteracts the downward impact force by creating an opposing force that reduces the net impact while maintaining rapid response capability.
3Manufacturing precision
If die cushion waiting position is moved upward to compensate for response distance, then force application is improved, but device complexity increases
Solution Approach 1:
The system replaces mechanical modification of the die structure with a control system that outputs force commands in advance. The control system timing is synchronized with the press slide position, allowing the cushion pad to be in the correct position at the right time without physically moving the die components.
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 method enables earlier and more stable die cushion force action, reducing response delays and impact forces, allowing for effective stretch forming and improving product quality by ensuring consistent die cushion force application from the start of the process.
Implementation Method 1
a servo motor 256 connected to a rotating shaft of the hydraulic pump/motor 254
Implementation Method 2
an oil hydraulic cylinder 220 that supports the cushion pad 210 and allows the cushion pad 210 to generate the die cushion force
Implementation Method 3
the cushion pad 210 preliminarily moves in an upward direction by the preliminary pressurization
Data Source
AI summary
There are provided a die cushion force control method and a die cushion device that can improve response delay of die cushion force without changing die cushion waiting position upward. In the die cushion force control method, a servo motor is driven according to a die cushion force command B previously set and the die cushion force is generated on the cushion pad. The die cushion force control method includes a step of allowing the cushion pad to wait in a predetermined die cushion waiting position at which a die cushion force action will start, and a preliminary pressurization step of outputting the die cushion force command B and preliminary applying pressure to the cushion pad before a slide of a press machine reaches the die cushion waiting position.