Patterned Metal Sheets for Durable Injection Mold Surface Transfer
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Solution Overview
Problem
Conventional mold surface forming sheets made of plastic film are prone to breakage at deep creases due to their low durability, especially at the boundary between the cavity and parting line during repetitive injection molding.
Innovation Solution
A method involving a metal sheet with a patterned surface, treated with flame or primer, is fixed to a mold, plastically deformed by molten plastic pressure, and left inside the mold to transfer patterns onto injection molded objects, enhancing durability by plastic deformation and surface treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic film is used as a mold surface forming sheet, then the initial pattern transfer is achieved, but the sheet becomes fragile and breaks at deep creases during repetitive injection molding
Solution Approach 1:
The patent changes the material parameter from plastic film to metal sheet, fundamentally altering the mechanical properties. The metal sheet maintains flexibility for pattern transfer while providing superior strength and durability at deep creases during repetitive molding cycles
Solution Approach 2:
The patent employs a composite structure by combining a metal sheet with a flexible layer or coating that enables pattern transfer. This composite approach provides both the strength of metal and the pattern-forming capability of flexible materials
2Adaptability or versatility
If the metal sheet is made thinner to improve flexibility, then pattern transfer capability increases, but the sheet becomes more prone to breakage
Solution Approach 1:
The patent uses a composite structure where a thin metal sheet is combined with a flexible coating or layer. This allows the metal sheet to remain thin for flexibility while the composite structure provides the necessary strength and durability
Solution Approach 2:
The patent optimizes the thickness parameter of the metal sheet to a specific range that balances flexibility and strength, preventing breakage while maintaining pattern transfer capability
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 metal sheet maintains integrity during repeated molding cycles, reducing the need for frequent replacements and ensuring consistent pattern transfer without breakage.
Implementation Method 1
pressing a portion of the second surface against an inner surface of the mold such that the metal sheet is plastically deformed by pressure of the molten plastic
Implementation Method 2
the metal sheet may be treated by flame treatment or primer treatment
Implementation Method 3
the first surface of the metal sheet is surface treated by flame treatment or primer treatment
Data Source
AI summary
A method of manufacturing an injection molded object includes preparing a flat metal sheet, fixing the metal sheet onto a mold for injection molding, clamping the mold, forming the injection molded object, and ejecting the injection molded object. The metal sheet have a first surface on which a pattern is formed, and a second surface opposite to the first surface. The metal sheet is fixed to the mold with the first surface facing a cavity of the mold. The mold is clamped. Molten plastic is injected inside the cavity. The metal sheet is plastically deformed from the pressure of the molten plastic and the pattern formed on the first surface is transferred onto a product surface. The injection molded object is ejected from the mold after the molten plastic solidifies, with the metal sheet remaining in the mold.