Tubular Plastic Injection Mold With Thermal-Compensating Core Alignment
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Solution Overview
Problem
Injection molds for manufacturing tubular plastic parts face challenges in maintaining precision due to thermal expansion, leading to wear and misalignment of core tips, which complicates the formation of precise tubular parts.
Innovation Solution
The injection mold design incorporates a bushing in the second mold half that is partially displaceable laterally and axially, featuring a bore to receive the core tip, with clamping segments and conical surfaces for alignment and sealing, and an actuator for adjusting the bushing position to compensate for thermal expansion and minimize wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the core tip is fixed in the mold cavity, then the molding precision is maintained, but thermal expansion causes misalignment and wear of the core tip
Solution Approach 1:
The bushing is designed to be displaceable relative to the mold cavity, allowing it to dynamically adjust its position to compensate for thermal expansion of the core tip. This dynamic adjustment maintains precise alignment between the core tip and mold cavity throughout the molding process, preventing misalignment and wear.
Solution Approach 2:
The bushing's position is allowed to change as a parameter in response to thermal expansion. By permitting controlled displacement of the bushing, the system accommodates dimensional changes in the core tip due to temperature variations, maintaining consistent molding precision without fixed rigid constraints.
2Device complexity
If the bushing is made fixed to prevent movement, then structural simplicity is maintained, but thermal expansion causes misalignment and wear
Solution Approach 1:
The bushing transitions from a fixed static structure to a dynamic movable structure. This allows the bushing to respond to thermal expansion forces and maintain proper alignment with the core tip, preventing misalignment while avoiding the need for complex adjustment mechanisms.
Solution Approach 2:
The bushing is designed as a separate, movable component distinct from the mold cavity structure. This segmentation allows the bushing to independently adjust its position to accommodate thermal expansion, maintaining precision without requiring the entire mold structure to be complex.
3Reliability
If the core tip is allowed to move freely, then thermal expansion is accommodated, but positioning precision and sealing are compromised
Solution Approach 1:
The bushing serves as an intermediary element between the core tip and the mold cavity. It provides a controlled interface that allows the core tip to expand thermally while maintaining precise positioning and sealing, mediating between the need for movement accommodation and positioning accuracy.
Solution Approach 2:
The bushing provides localized control over the core tip's movement. Rather than allowing free movement throughout, the bushing creates a specific constrained zone that permits thermal expansion in controlled directions while maintaining precision in critical positioning and sealing areas.
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 design ensures precise alignment and sealing of the core tip, reducing wear and producing high-quality tubular plastic parts with minimal burrs, while accommodating thermal expansion, thus enhancing the mold's operational efficiency.
Implementation Method 1
Thermal expansion of various components of the injection mold during operation complicate the core tip being received in a precise manner
Implementation Method 2
The bushing comprises a bore suitable to receive a tip of the core in a closed position of the injection mold
Data Source
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AI summary
An injection mold (1) for the manufacturing of at least one tubular plastic part comprising a first mold half (2) comprising a first mold plate (3) and a second mold half (4) comprising a second mold plate (5) being arranged displaceable with respect to each other in an axial direction (Z) between an open position and a closed position. The injection mold further comprises at least one core (6) protruding from the first mold plate (3) and the second mold plate (4) comprising at least one cavity (7) suitable to receive the core (6) of the first mold half (2) to form a molding cavity (8) in the closed position of the injection mold (1) for receiving molten plastic material therein to form the tubular plastic part. A bushing (9) is advantageously arranged in the second mold half (4) adjacent to a dorsal end (10) of the cavity (7) at least partially displaceable with respect to the second mold plate (4), said bushing (9) comprising a bore (11) in a closed position of the injection mold (1) suitable to receive a tip (12) of the core (6).