Die Clamping Unit Inertial Control via Dual Servomotors
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Solution Overview
Problem
In injection molding processes using foaming agents, the core-back operation faces challenges with the movable platen continuing to move due to inertia after the servomotor is stopped, leading to potential over-movement and reduced precision in die clamping units.
Innovation Solution
A die clamping unit is designed with a control device that uses a combination of servomotors to manage the movement of the movable platen, applying a force opposite to its inertia during the core-back operation, ensuring precise control and preventing excessive movement by utilizing tie bar sliding servomotors and die opening/closing servomotors to maintain the platen's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a servomotor is used to move the movable platen during core-back operation, then the platen can be moved at low speed to promote foaming, but the platen continues to move due to inertia after the servomotor is stopped, reducing positioning precision
Solution Approach 1:
The patent applies preliminary anti-action by driving the second servomotor to generate a force in the direction toward the stationary platen during the core-back operation. This counteracting force is applied in advance to offset the inertial force that would otherwise cause the movable platen to continue moving after the first servomotor stops, thereby preventing over-movement and improving positioning precision.
2Device complexity
If a single servomotor is used for core-back operation, then the structure is simpler, but the servomotor must be larger to handle the inertial force, increasing device size and cost
Solution Approach 1:
The patent segments the function of moving the movable platen by using two separate servomotors: the first servomotor is dedicated to moving the platen backward during core-back operation, while the second servomotor applies a counteracting force to manage inertial effects. This functional segmentation allows each servomotor to be smaller and more specialized, reducing overall device size and cost compared to using a single large servomotor.
Solution Approach 2:
The patent merges the functions of two servomotors to achieve precise control during core-back operation. The first servomotor performs the primary movement function, while the second servomotor compensates for inertial forces. By combining these two smaller, specialized motors, the system achieves the performance of a single large motor while reducing overall complexity and cost.
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 allows for precise control of the core-back operation, miniaturization of servomotors, reduced costs, and improved precision in the completion position of the movable platen, thereby enhancing the overall efficiency and accuracy of the injection molding process.
Implementation Method 1
In the core-back operation, an inertial force develops on the movable platen with the movement of the movable platen. Therefore, even if the drive of the servomotor is stopped at completion of the core-back, the movable platen often continues to move under its own inertia.
Data Source
AI summary
A die clamping unit includes a stationary platen, a tie bar which is attached to the stationary platen, a movable platen which is movable forwards and backwards along the tie bar with respect to the stationary platen, a first servomotor which moves the movable platen away from the stationary platen in a core-back operation, a second servomotor which moves the movable platen forwards and backwards to perform die-opening and -closing, and a control device which drives the first servomotor to move the movable platen away from the stationary platen and which drives the second servomotor to apply a force to the movable platen in the direction toward the stationary platen in the core-back operation.