Curved Injection-Molded Guide Rail With Core Extraction Slot
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Solution Overview
Problem
Existing methods for manufacturing guide rails for motor vehicle sliding windows are limited in producing arched or curved rails with a C-shaped cross-section, as they either require draft angles for unmoulding or lack precise control over the hollow portion's shape, making it difficult to achieve precise guidance and assembly with additional parts.
Innovation Solution
A guide rail with a tubular profile having a recess and a longitudinal slot, manufactured using injection moulding with a specialized moulding device that includes a curved core and extraction mechanism, allowing for the production of arched or curved rails without draft angles and enabling precise control over the shape and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If injection moulding is used to manufacture guide rails without draft angles, then manufacturing precision is improved, but device complexity increases due to specialized moulding devices with curved cores and extraction mechanisms
Solution Approach 1:
The mould is divided into multiple components including a curved core, extraction device, and injection system that can operate independently. The core is separated from the housing, allowing it to be extracted through the longitudinal slot after injection, enabling complex curved shapes without requiring the entire mould to be overly complicated.
Solution Approach 2:
The longitudinal slot acts as an intermediary element that serves dual purposes: it allows the extraction of the curved core from the mould after injection, and simultaneously forms part of the guide rail's functional structure for receiving guide shoes. This intermediary structure resolves the conflict between achieving complex curved shapes and simplifying the mould design.
2Ease of manufacture
If extrusion is used to manufacture guide rails, then ease of manufacture is improved, but shape flexibility deteriorates as rails must be straight or very slightly curved
Solution Approach 1:
The traditional extrusion process is replaced with injection moulding technology. This substitution enables the manufacture of guide rails with complex curved cross-sections and arched shapes that cannot be achieved by extrusion, while maintaining manufacturing efficiency through automated injection and core extraction processes.
3Productivity
If hollow body injection techniques (PIT, WIT, GIT) are used, then productivity is improved, but manufacturing precision deteriorates due to inability to precisely control hollow portion shape and surface condition
Solution Approach 1:
The curved core is extracted from the mould through the longitudinal slot after injection, allowing the hollow portion of the guide rail to be formed with precise control over its shape and surface conditions. This extraction mechanism enables the use of injection moulding for hollow sections while maintaining the precision needed for guiding functions, overcoming the limitations of traditional hollow body injection techniques.
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 the production of guide rails with precise shape and surface conditions, facilitating the sliding of the guide shoe and allowing for the integration of additional features like longitudinal wings, while overcoming the limitations of existing methods in terms of shape and assembly.
Implementation Method 1
a device for injecting under pressure inside said moulding cavity, plastic material intended for manufacturing said guide rail
Data Source
AI summary
A guide rail made from an injected plastic material includes at least one portion having the shape of a tubular profile longitudinally split over at least one portion of the length. The guide rail is configured to be straight or curved in the shape of an arc of a circle.