Flexible-Surface Molding Tool for Undercuts and Open Films
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Solution Overview
Problem
Existing mold technologies for forming moldable materials, such as plastic films and fibrous materials, are limited by the need for complex tools with moving components and cannot form parts with undercuts or films with openings due to pressure equalization through openings, and require overpressure or underpressure to deform materials.
Innovation Solution
A molding tool with a first and second tool component, where the second component has a flexible material that deforms without requiring negative or positive pressure, allowing the moldable material to be pressed against the first component's surface by overpressing, enabling the formation of undercuts and structures without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional thermoforming tools with overpressure or underpressure are used to deform films, then the film can be deformed, but films with openings cannot be formed because air introduced or sucked in through the openings leads to pressure equalization
Solution Approach 1:
The invention changes the pressure parameter from applying overpressure or underpressure to applying only overpressure. This allows films with openings to be formed successfully because the overpressure is sufficient to deform the film without requiring vacuum suction that would equalize through the openings. The film is deformed by the stretching aid pressing it against the mold wall, and overpressure ensures complete contact without being equalized through openings.
2Shape
If complex molds with moving components are used to manufacture products with undercuts and edges, then the desired shapes can be achieved, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The invention uses a stretching aid that acts as a flexible forming surface to press the film into the cavity. This flexible aid can conform to complex cavity shapes including undercuts and edges without requiring complex moving mold components. The stretching aid deformable pressing surface adapts to the cavity geometry, enabling production of complex-shaped products with simple tooling.
3Ease of operation
If stretching aid presses film into cavity without pressing against shaping inner wall, then film can be positioned, but final forming cannot occur without generating negative or positive pressure
Solution Approach 1:
The invention merges the positioning function and the final forming function into a single step by applying overpressure. The stretching aid presses the film into the cavity and, with the application of overpressure, ensures complete contact between the film and the shaping inner wall of the cavity. This eliminates the need for separate pressure generation systems for positioning and forming.
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
Enables the formation of complex shapes, including undercuts, in molded parts using simple means, without the need for additional pressure and moving components, and allows the production of films with mesh-like structures and fibrous materials with reduced auxiliary material use.
Implementation Method 1
overpressing the at least one second tool component after reaching a bottom dead center within the cavity, whereby a flexible material which forms at least a portion of the second mold surface is deformed
Data Source
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AI summary
A molding tool (30) and a method for producing molded parts (200) from a moldable material are described, comprising at least one first tool component (32) and at least one second tool component (40), wherein the first tool component (32) has a cavity (36) with a first molding surface (37), and wherein the second tool component (40) has a second molding surface (45) and at least partially a flexible material which forms at least a section of the second molding surface (45). In a first step, a moldable material is introduced into the cavity (36), and then the second tool component (40) is moved into the cavity (36) by relative displacement of the first tool component (32) and the second tool component (40), wherein a second molding surface (45) of the second tool component (40) moves the moldable material at least partially against the first molding surface (37).Subsequently, the second tool component (40) is overpressed after reaching a bottom dead center (uT) within the cavity (36), thereby deforming a flexible material that forms at least one section of the second mold surface (45) and through the deformation the flexible material presses the malleable material against a corresponding section of the first mold surface (37).