Dynamic Mold Plate Separation for Multi-Component Plastic Sealing
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Solution Overview
Problem
Conventional injection-molding processes for producing multi-component plastic parts, especially large-area molded parts like glazing units, face challenges with stress, warpage, and leakage issues due to high injection pressures and mismatched contours between mold components, leading to suboptimal sealing and quality concerns.
Innovation Solution
A process involving mold plates with depressed zones and controlled movement to ensure solidification and self-sealing during injection, using an opening-force generating device to manage mold plate separation and follow-up pressure, thereby reducing leakages and maintaining high-quality part production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional injection-molding process is used for large-area molded parts, then high injection pressures are required to fill the mold, but this causes stresses and warpage in the molded parts
Solution Approach 1:
The mold plates are moved apart dynamically during the injecting operation rather than remaining fixed. The first mold plate is moved away from the second mold plate at a controlled speed during polymer melt injection, allowing the cavity to expand and reducing the peak injection pressure required, thereby preventing stresses and warpage in the molded part.
Solution Approach 2:
The invention changes the physical state and movement parameters of the mold plates during the molding process. By transitioning from a fixed mold configuration to a dynamically moving mold configuration, and by controlling the separation speed and distance of the mold plates, the injection pressure parameter is reduced while maintaining complete cavity filling.
2Stress or pressure
If mold plates are opened to form pre-enlarged cavity for compression process, then injection pressure is reduced, but sealing leakages occur at the sealing transition region
Solution Approach 1:
The first mold plate is moved away from the second mold plate before the polymer melt injection begins, creating a pre-enlarged cavity that reduces the required injection pressure. This preliminary action of opening the mold plate prevents the need for high peak pressures while maintaining sealing integrity through controlled movement.
Solution Approach 2:
The mold plate separation is performed dynamically at a controlled speed during the injecting operation. The first mold plate moves away from the second mold plate at a specific speed that allows the polymer melt to fill the expanding cavity completely while maintaining sealing effectiveness at the transition region between the black border and the window.
3Ease of manufacture
If conventional injection-molding process is used for molding black border onto glazing unit, then production is simplified, but warpage and sinking occur in the molded part
Solution Approach 1:
The invention introduces dynamic movement of the first mold plate during the injecting operation for molding the black border onto the glazing unit. This dynamic separation reduces peak injection pressure and prevents warpage and sinking while maintaining complete filling of the molding-on cavity, thus preserving ease of manufacture without sacrificing quality.
Solution Approach 2:
By changing the movement parameter of the first mold plate from stationary to moving at a controlled speed during injection, the process maintains its simplicity while eliminating warpage and sinking defects. The parameter change in mold plate position and velocity allows pressure reduction without compromising manufacturing ease.
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 enables the production of high-quality multi-component molded plastic parts with improved sealing, reduced stress, and minimized warpage, while allowing for efficient compensation of shrinkage without the need for pre-enlarged cavities, thus enhancing the overall molding process.
Implementation Method 1
during the injection of polymer melt into the depressed zone, moving apart of the mold plates, the moving apart of the mold plates being controlled in such a way that a solidification of the plastic component with a sealing effect already occurs in the region of the gap forming between the mold plates
Data Source
AI summary
In a process for molding a plastic component onto a prefabricated plastic part, a first mold plate (1) and a second mold plate (105) are closed, a cavity in which the prefabricated plastic part (101) is located being formed between the closed mold plates (1, 105). One of the mold plates (105) is formed with a depressed zone (108) and a polymer feed (115) opening out into the depressed zone (108) for molding the plastic component onto a region of the prefabricated plastic part (101) that lies opposite the depressed zone (108). Subsequently, polymer melt is injected into the depressed zone (108) and, during the injection of polymer into the depressed zone (108), the mold plates (1, 105) are moved apart.