Toothbrush Metal Core Embedding in Injection Mould
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Solution Overview
Problem
Existing manufacturing processes face challenges in combining plastic and metal materials to create a toothbrush with a metal core, particularly in maintaining the core securely fastened in the mould and preventing plastic material leakage during injection, which affects the quality and ergonomics of the final product.
Innovation Solution
A manufacturing process involving a mould with support platforms and ribbing to securely hold the metal core in place, combined with the use of a protection membrane over the bristle tufts to prevent plastic leakage during injection, ensuring effective bonding and aesthetic appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal core is introduced to enhance strength and reduce dimensions, then the toothbrush becomes more ergonomic and structurally sound, but the manufacturing process becomes more complex and difficult to control
Solution Approach 1:
The metal core is pre-positioned and secured to the mould before plastic injection, ensuring proper alignment and preventing movement during the injection process. This preliminary securing action resolves the contradiction by enabling the use of metal cores without complicating the manufacturing process.
Solution Approach 2:
A securing mechanism acts as an intermediary between the metal core and the mould, facilitating easy attachment and removal of the core while maintaining position during injection. This intermediary component simplifies the overall manufacturing process despite the introduction of metal materials.
2Productivity
If plastic material is injected at high pressure to ensure proper filling, then the manufacturing efficiency is maintained, but plastic material leaks between the tufts and the housing holes
Solution Approach 1:
The tufts are pre-molten to form enlarged ends that fit tightly within the housing holes before plastic injection. This preliminary action creates a seal that prevents plastic material from leaking between the tufts and housing holes during high-pressure injection, maintaining both productivity and precision.
Solution Approach 2:
The physical state of the tuft ends is changed from solid to molten and back, creating an enlarged diameter that provides a tight fit within the housing holes. This parameter change (phase transition and dimensional change) prevents material leakage while allowing high-pressure injection for efficient manufacturing.
3Strength
If the tufts are molten to form enlarged ends for anchoring, then the bonding strength is improved, but plastic material seeps in between the tuft heads and the plate
Solution Approach 1:
The tufts are molten to form enlarged ends that create a tight interference fit within the housing holes before the plastic injection process. This preliminary action prevents plastic material from seeping in between the tuft heads and the plate during injection, while still achieving strong bonding through the molten phase.
Solution Approach 2:
The tuft ends are melted and enlarged before plastic injection to create a secure anchoring structure. This preliminary action ensures that when plastic is injected, it cannot seep between the tufts and housing holes, preventing material waste and maintaining bonding integrity.
4Reliability
If the toothbrush is made primarily of plastic for resistance to external agents, then corrosion protection is achieved, but the structural strength and elastic properties are reduced
Solution Approach 1:
The toothbrush combines plastic material for the handle and protective components with a metal core for structural strength and rigidity. This composite construction achieves both corrosion resistance from the plastic and high strength from the metal, resolving the contradiction between these two properties.
Solution Approach 2:
The metal core is nested within the plastic handle structure, with the plastic providing external protection and the metal providing internal structural support. This nested configuration allows the plastic to protect against corrosion while the metal core delivers the required structural strength and elastic properties.
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
The process securely embeds the metal core within the plastic body, preventing material leakage and enhancing the ergonomic design and aesthetic appeal of the toothbrush, while maintaining the structural integrity and quality of the product.
Implementation Method 1
said lower half-mould is coupled with an upper half-mould provided with at least one ribbing apt to come in contact with said metal core at least in a position between said support platforms and opposite thereto with respect to the core
Implementation Method 2
injecting molten plastic material into said mould cavity for the manufacture of at least part of the toothbrush handle
Data Source
AI summary
A molding process and a mold for manufacturing a toothbrush of plastic material with a resistant inner core, is disclosed. It is provided to manufacture a resistant inner core, and to introduce it into a mold cavity having opposite footprints belonging to a lower half-mold and an upper half-mold and to subsequently inject molten plastic material into the mold cavity for manufacturing at least part of the toothbrush handle. A resistant metal core is placed into a respective footprint of the lower half-mold in contact with at least two support platforms, adapted to support the core in the proximity of a central line of the mold cavity, and before the injection of structural plastic material, to couple the lower half-mold with an upper half-mold having at least one ribbing to contact with the metal core at least in a position between the support platforms and in a position opposite thereto.