Patterned Metal Sheet 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 breaking at deep creases due to their fragility, especially at the boundary between the cavity and parting line during repetitive injection molding, leading to reduced durability.
Innovation Solution
A method involving a metal sheet with a pattern of projections and depressions is fixed to a mold, where the metal sheet is plastically deformed by molten plastic pressure to transfer a pattern onto an injection molded object, and remains inside the mold for repeated use, enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic film is used as a mold surface forming sheet, then the pattern can be transferred to the injection molded object, but the sheet becomes fragile and breaks at deep creases during repetitive molding
Solution Approach 1:
The invention changes the material parameter from plastic film to elastomer, which fundamentally alters the mechanical properties. The elastomer material provides higher elasticity and resistance to breaking at deep creases, directly resolving the fragility issue while maintaining pattern transfer capability
Solution Approach 2:
The invention uses a composite structure consisting of an elastomer base material combined with a pattern layer. This composite approach allows the elastomer to provide durability and elasticity while the pattern layer ensures accurate pattern transfer to the injection molded object
2Duration of action of stationary object
If the mold surface forming sheet is left in the mold after injection molding, then the pattern transfer function is maintained, but deep creases form at shape boundaries causing the sheet to break
Solution Approach 1:
By changing the material from plastic film to elastomer, the invention fundamentally improves the material's ability to withstand repeated deformation cycles. The elastomer's superior elasticity allows it to recover from the deep creases formed at shape boundaries without breaking, enabling longer service life
Solution Approach 2:
The elastomer material inherently provides cushioning against the stress concentration that occurs at deep creases. This material property预先 compensates for the damaging effects of repeated deformation, preventing breakage before it occurs
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's plastically deformed state allows it to maintain close contact with the mold inner surface, reducing breakage and extending its lifespan, thus increasing the durability of pattern transfer to injection molded objects.
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
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 has 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.