Multi-Material Hinged Components with Zero Radial Play
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Solution Overview
Problem
The production of kinematic chains from plastic components hinged together faces challenges in managing molding and assembly steps, handling multiple parts, and addressing play between components, which existing methods fail to resolve effectively.
Innovation Solution
A set of components hinged together is produced using multi-material injection molding, where one component with a higher melting point and another with a lower melting point, non-adhesive plastic materials are used, with the articulation pin molded within the first component's hole, and ribs formed around the pin to achieve zero play, eliminating the need for separate handling and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If individual plastic components are molded separately and then assembled, then each component can be optimized independently, but the assembly process becomes complex and time-consuming with multiple handling steps
Solution Approach 1:
The patent combines multiple separate molding operations into a single multi-material injection molding process. The first component is molded in a first cavity, then the mold reconfigures to mold the second component with articulation pins in a second cavity, all in one continuous process. This eliminates separate assembly steps while maintaining component optimization through material selection.
Solution Approach 2:
The articulation pins are pre-formed as integral parts of the second component during its molding process, before any assembly occurs. The pins are molded within the holes of the first component, preliminarily positioning them for zero-play connection without requiring subsequent assembly operations.
2Ease of manufacture
If traditional molding methods are used, then standard materials can be employed, but play occurs between hinged components reducing precision
Solution Approach 1:
The patent changes the material parameter by selecting plastic materials with different melting points. The first component uses a higher melting point material while the second component uses a lower melting point material. This parameter difference enables selective remolding of the second component without affecting the first component, allowing precise control of hinge fit.
Solution Approach 2:
The invention uses composite multi-material construction where two different plastic materials are combined in a single product. The first plastic material (higher melting point) and second plastic material (lower melting point) work together to create both structural components and precision hinge mechanisms with zero play.
3Manufacturing precision
If multiple separate molding operations are performed, then each component can be molded with optimal parameters, but the process complexity and handling requirements increase
Solution Approach 1:
The mold system is made dynamic and reconfigurable, transitioning between different molding configurations. The mold can switch from a first configuration for molding the first component to a second configuration for molding the second component, enabling multiple operations within a single device without requiring separate fixed molds.
4Reliability
If components are assembled separately, then quality control can be performed on each part, but time is lost in handling and assembling multiple parts
Solution Approach 1:
The patent merges the molding of the first component and second component into one continuous process within the same mold. Quality control is maintained for each component through dedicated molding cavities and parameters, while assembly time is eliminated as the components are produced and connected in a single integrated operation.
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 method ensures zero radial play between components and allows for the production of kinematic chains with adjusted axial play, simplifying the process by integrating the assembly within the molding process, reducing the complexity of handling multiple parts and assembly steps.
Implementation Method 1
a second plastic material having a lower melting point than the first material and being non-adhesive to the first plastic material
Implementation Method 2
By exploiting, within the molding process, the chemical incompatibility (non-adhesion) of plastic materials and their shrinkage by cooling, it is possible to achieve a coupling between the components with zero play
Data Source
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AI summary
A set of components (10, 20, 30) hinged to each other, the set comprising a first component (10) having a hole (12, 13) and a second component (20, 30) having an articulation pin (21, 31) coupled to the hole (12, 13) of the first component (10), wherein the set is produced by multi-material injection molding, wherein the first component (10) is made of a first plastic material having a given melting point, wherein the second component (20, 30) is made of a second plastic material having a lower melting point than the first plastic material and being non-adhesive to the first plastic material, and wherein the articulation pin (21, 31) of the second component (20, 30) is molded within the hole (12, 13) of the first component (10).