Injection Mold Orientation for Sprueless Part Design Freedom
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Solution Overview
Problem
Existing injection molding processes face limitations in design freedom due to the need for a nozzle injection point, leading to costly modifications and increased material consumption, particularly in medical devices like autoinjectors or injection pens.
Innovation Solution
The method and injection mold design allow for a non-axial opening direction, enabling rotational orientation of the molded part and eliminating the need for a sprue, thus enhancing design freedom and reducing material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If direct injection molding without sprue is used, then material consumption is reduced, but design freedom is limited due to nozzle placement requirements
Solution Approach 1:
The patent introduces a rotational degree of freedom by allowing the molded part to be rotated about an axis perpendicular to the opening direction. This enables the nozzle to be positioned at various angular locations on the part surface, transforming a 2D placement constraint into a 3D solution space. The part can be oriented at different angles during molding, providing multiple possible nozzle injection points without requiring mold modifications.
2Device complexity
If conventional axial opening direction is used, then mold structure is simple, but design freedom of molded parts is reduced
Solution Approach 1:
The patent makes the mold opening direction variable rather than fixed. The opening direction can be changed by rotating the part about an axis perpendicular to the opening direction, allowing the same basic mold structure to accommodate different part geometries and nozzle positions. This dynamic adjustment capability enables flexible part design while maintaining relatively simple mold construction.
3Adaptability or versatility
If partial hot runners or cold runners are used, then design freedom is improved, but material consumption increases
Solution Approach 1:
The patent extracts and eliminates the sprue (excess material channel) from the injection molding process by enabling direct injection molding. Through rotational orientation of the part, the nozzle can be positioned to inject material directly into the cavity without requiring a separate sprue channel. This removes the source of material waste while maintaining design flexibility.
Data Source
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AI summary
The invention relates to a method for injection molding a part using an injection mold in an injection molding machine, wherein the injection mold comprises a nozzle side and an ejector side, comprising the following steps: moving the injection mold into a closed position in which the nozzle side and the ejector side are in contact with each other, and moving the injection mold into an open position in which the ejector side and the nozzle side are moved away from each other in an opening direction. According to the invention, the opening direction deviates from an axial direction defined by a direction of movement of the injection molding machine.