Injection Mold Positioning Device for Gap-Free Insert Overmolding
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Solution Overview
Problem
Conventional injection molding processes leave gaps around components like bolts and screws, necessitating additional anti-corrosion coatings and increasing costs, as centering pins prevent complete encapsulation with plastic.
Innovation Solution
An injection mold design featuring a positioning device with a spring unit and pin unit that holds components in place during molding and releases as internal pressure from the injection material exceeds the spring force, ensuring complete encapsulation without additional post-processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If centering pins are used to hold the molded part in the cavity, then the molded part can be positioned and kept at a distance from the tool wall, but gaps remain around the centering pin engagement areas preventing complete encapsulation with plastic
Solution Approach 1:
The centering pins are designed with elastic resilience, allowing them to be compressed during injection molding. This dynamic property enables the pins to yield to the injected plastic mass, allowing complete encapsulation of the molded part while maintaining positioning accuracy during the molding process
Solution Approach 2:
The physical state of the centering pins changes during the process - they transition from a rigid positioning state to a compressed state during injection. The elastic deformation parameter allows the pins to accommodate the plastic flow and enable full encapsulation while maintaining their positioning function
2Ease of manufacture
If the molded part is not completely encapsulated with plastic, then the positioning function is maintained, but additional anti-corrosion coating processes are required increasing manufacturing costs
Solution Approach 1:
The harmful effect of gaps is eliminated by allowing the centering pins to be completely encapsulated by the injected plastic. The pins are extracted from their traditional fixed position and allowed to move elastically, enabling the plastic to flow around and encapsulate them entirely, thus eliminating the need for separate anti-corrosion coating processes
3Object-generated harmful factors
If resilient centering pins are pressed against the molded part, then complete encapsulation becomes possible, but the positioning force must be sufficient to hold the part during injection
Solution Approach 1:
The centering pins apply partial positioning force - sufficient to hold the molded part in position during molding, but not so excessive that they resist the injected plastic mass. This balanced force level allows both positioning functionality and complete encapsulation to be achieved simultaneously
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
Enables full overmolding of components without gaps, eliminating the need for additional anti-corrosion coatings and reducing manufacturing costs by ensuring complete encapsulation with injection molding material.
Implementation Method 1
a spring unit (9) which presses the pin unit (10) against the component (5)
Implementation Method 2
the pin unit (10) is pushed away from the component (5) by the pressure of the injection molding material (14)
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present invention relates to an injection molding tool (1) for the full-circumferential overmolding of components and to a corresponding method therefor. The injection molding tool (1) comprises a first tool component (2) and a second tool component (3), wherein a cavity (4) for inserting a component (5) is formed between the first tool component (2) and the second tool component (3), and wherein the second tool component (3) has at least one magnet (6) which, after insertion of the component (5) into the cavity (4), prefixes a holding element (7) of the molded part, and wherein the first tool component (2) comprises a positioning device (8) in order to exert pressure on the holding element (7) arranged in the component (5) during the closure of the two tool components (2, 3).