Negative Luggage Mold with Airflow Stretching for Uniform Thickness
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Solution Overview
Problem
Existing positive-mold blister molding processes for luggage result in uneven thickness, deformation of grains and patterns, and difficulty in achieving design requirements due to stretching, leading to issues like indistinguishable lines and angles on the appearance surface and failure in drop tests.
Innovation Solution
A negative-mold blister mold system with an upper and lower mold assembly, utilizing airflow channels to stretch and mold a sheet evenly, incorporating a convex and concave mold that cooperate to define a molding space, and allowing for integral molding of inserts, ensuring uniform thickness and precise grain or glossy surfaces without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If positive-mold blister molding is used, then the molding process is simple, but the appearance surface lines and angles are indistinguishable and do not meet design requirements
Solution Approach 1:
The patent inverts the traditional positive-mold approach by using a negative mold (concave mold) where the molding surface is on the same side as the appearance surface. This inversion allows the appearance surface to directly replicate the mold's precise features, making lines and angles distinguishable while meeting design requirements.
2Productivity
If the sheet is stretched into bubble shape during blistering, then the molding process is efficient, but the thickness becomes uneven with corners too thin, causing drop test failures
Solution Approach 1:
The patent applies counter-pressure through the upper mold assembly pressing against the lower concave mold during the molding process. This counterbalancing force system prevents excessive stretching at corners and maintains uniform thickness distribution, ensuring corners are not too thin and the luggage passes drop tests.
3Manufacturing precision
If grains and patterns are set on the sheet before molding, then the design requirements can be met, but the patterns deform after the sheet is stretched
Solution Approach 1:
The patent incorporates grains and patterns directly onto the molding surface of the concave mold before the molding process begins. This preliminary preparation ensures that when the sheet is pressed against the mold, the patterns are transferred accurately without deformation, as the mold's rigid structure maintains pattern integrity during stretching.
4Manufacturing precision
If the sheet is clamped on the material frame, then the sheet positioning is simple, but the appearance surface cannot achieve precise grain and glossy surface formation
Solution Approach 1:
The patent creates different local qualities on the molding surface of the concave mold, with specific zones for grain formation and glossy surface formation. The molding surface includes grainy parts and glossy parts in different regions, allowing the sheet to achieve precise surface features in different areas through localized mold surface 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 system ensures the appearance surface meets design requirements, provides uniform thickness, reduces deformation of grains and patterns, enhances strength, and improves market competitiveness by integrating inserts and reducing assembly costs.
Implementation Method 1
air is blown downward through the first airflow channel to stretch the sheet
Implementation Method 2
the heated sheet is adsorbed on the mold by vacuum adsorption
Data Source
AI summary
The present disclosure provides a negative mold for luggage molding and an application thereof. The negative mold includes an upper mold holder (11), a convex mold (12), a lower mold holder (21), a concave mold (22), a lifting platform (23), and a material frame (31). The upper mold holder is arranged with a first airflow channel (111); in the adsorbed state, the upper mold holder abuts against the material frame to define an upper air cavity (112); air is blown downward through the first airflow channel to stretch the sheet (41), while each of the convex mold and the concave mold moves in a direction close to the sheet to define a molding space; in the mold detaching state, each of the convex mold and the concave mold moves toward in another direction away from the material frame to detach the molded sheet.