Molding Tool Elastic Deformation Coating Seal
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Solution Overview
Problem
Existing methods for coating molded parts in injection molding machines face challenges such as dust deposition during conveying, inadequate sealing for low-viscosity coatings, and high reject rates due to insufficient sealing, leading to reduced coating durability and quality.
Innovation Solution
A method where the molded part is arranged in a cavity of a molding tool with a partial cavity that changes volume based on the applied closing force, allowing for pressure-filled coating introduction and cross-linking, which balances resin shrinkage through elastic deformation, eliminating the need for a separate stamping core and ensuring a seal even with low-viscosity coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate stamping core is used for coating the molded part, then the coating can be applied in the injection molding machine, but the device structure becomes more complex
Solution Approach 1:
The invention extracts and eliminates the separate stamping core from the molding tool, retaining only the essential cavity structure. The coating is applied directly into the cavity without requiring the complex stamping core mechanism, thereby simplifying the device structure while maintaining coating quality.
Solution Approach 2:
The cavity structure serves multiple functions: it forms the molded part and simultaneously provides the coating application space. This multi-functionality eliminates the need for separate stamping cores, reducing device complexity while achieving reliable coating application.
2Reliability
If a seal is formed between the molded part and molding-tool half, then the coating can be contained, but the seal fails with very low-viscosity coatings
Solution Approach 1:
The invention employs dynamic sealing where the sealing force is adjusted during the coating process. The molding tool applies pressure to maintain sealing contact between the molded part and molding-tool half, ensuring reliable sealing even for very low-viscosity coatings that would otherwise escape.
Solution Approach 2:
The invention changes the pressure parameter during coating application. By applying increased pressure from the molding tool, the sealing force is enhanced to accommodate coatings with varying viscosities, including very low-viscosity coatings that would normally compromise seal integrity.
3Ease of manufacture
If the molded part is conveyed from injection molding machine to lacquering chamber, then the coating can be applied separately, but dust and particles are deposited on the molded part
Solution Approach 1:
The invention merges the coating application process with the injection molding process. The coating is applied directly in the molding machine's cavity, eliminating the need for separate conveying and lacquering chambers. This integration prevents dust and particle deposition that would occur during transport.
Solution Approach 2:
The coating application is performed preliminarily within the molding process itself, before the part is removed from the machine. This preliminary action in a controlled environment prevents subsequent contamination during conveying to separate lacquering chambers.
4Manufacturing precision
If the closing force is increased during cross-linking, then the partial cavity volume reduces to balance resin shrinkage, but the seal pressure increases
Solution Approach 1:
The invention dynamically changes the closing force parameter during the cross-linking process. The force is increased to compress the partial cavity and balance resin shrinkage, achieving precise coating volume control while managing seal pressure through controlled force application.
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
This method simplifies the coating process, improves seal quality, and reduces reject rates by adapting the partial cavity volume to resin shrinkage, ensuring high coating quality and durability, particularly effective for low-viscosity coatings and clear or colored lacquers.
Implementation Method 1
the volume of the partial cavity changes as a function of the closing force which is applied to the molding tool
Implementation Method 2
During the cross-linking, however, the volume of the coating mass decreases due to shrinkage
Implementation Method 3
the increase of the closing force, due to elastic deformation of the molding tool and/or elastic deformation of the molded part (1), causes a reduction of the partial cavity in terms of volume
Data Source
AI summary
In a method for coating a molded part (1), in particular a molded part produced by injection molding, the molded part (1) is arranged in a cavity (2) of a molding tool (3), wherein a partial cavity (4) between the molded part (1) and a first molding-tool half (5) of the molding tool (3) remains when a closing force (F) is applied to the molding tool (3) at a first closing-force level. A coating mass (6) is introduced into the partial cavity (4) and the coating mass (6) is cured/cross-linked. The closing force (F) of the molding tool (3) is increased during the curing/cross-linking of the coating mass (6), wherein the increase in the closing force (F) causes a volume reduction of the partial cavity (4) due to elastic deformation of the molding tool (3) and/or elastic deformation of the molded part (1).