Ejector Plate Curvature for Arc-Shaped Molded Product Removal
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Solution Overview
Problem
Conventional molding devices face difficulties in suppressing flaws during the removal of molded products with inner spaces bent in circular arc shapes due to increased resistance and pressure concentration when using ejector pins.
Innovation Solution
The use of an ejector plate that follows a circular arc shape to reduce resistance and disperse pressure, instead of traditional ejector pins, allows for smoother removal of molded products with inner spaces bent in circular arc shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an ejector pin is used to eject the molded product, then the molded product can be removed from the mold, but the resistance between the molded product and core increases and pressure is concentrated causing flaws on the molded product
Solution Approach 1:
The ejector pin is replaced with an ejector plate that follows a circular arc shape, matching the curvature of the molded product's inner space. This curved geometry allows the ejector plate to conform to the product shape, distributing ejection pressure evenly across the contact surface rather than concentrating it at a single pin point, thereby preventing flaws while enabling effective removal.
Solution Approach 2:
The ejector plate serves as an intermediary element between the ejection mechanism and the molded product. Instead of directly applying force through a pin, the plate mediates the ejection process by providing a larger contact area that distributes pressure, reducing the harmful concentration effect while maintaining the necessary ejection force to overcome resistance.
2Device complexity
If a simple molding device is used, then the device complexity is reduced, but it becomes difficult to mold and remove molded products with inner spaces bent in circular arc shapes
Solution Approach 1:
The ejector plate is designed with a circular arc shape that matches the curvature of the molded product's inner space. This geometric correspondence allows the simple device structure to effectively handle complex curved geometries, enabling the removal of molded products with bent inner spaces without requiring complex multi-component ejection mechanisms.
3Device complexity
If the molded product is ejected along a straight line, then the ejection mechanism is simple, but the resistance between the molded product and core increases for circular arc shaped inner spaces
Solution Approach 1:
The ejector plate follows a circular arc shape that corresponds to the inner space geometry, allowing the ejection path to match the product curvature. This reduces the resistance between the molded product and core by maintaining optimal contact throughout the ejection process, eliminating the need for complex linear ejection mechanisms while effectively reducing ejection resistance.
Data Source
Figure 1A~1C
Figure 2A1~3
Figure 4
AI summary
Provided is a molding device 1 for manufacturing a molded product having an inner space bent in a circular arc shape. The molding device 1 includes: a set of molds 30, 40 which is joinable to and separable from each other, the set of molds 30, 40 being capable of forming a cavity C having a shape corresponding to an outer shape of the molded product in a joined state at the time of molding; a core 50 which has an outer shape corresponding to an inner shape of the molded product, and is used in a state where the core 50 is arranged in the inside of the cavity C which the set of molds forms at the time of molding; and an ejector plate 60 which has a core through hole 62 through which the core 50 passes, and ejects the molded product formed around the core 50 along the circular arc shape in a separated state where the set of molds 30, 40 is separated from each other. The molding device 1 can suppress the generation of flaws on a molded product having an inner space bent in a circular arc shape when the molded product is removed.