Back-Injected Decorative Films for Plastic Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of plastic molded parts with decorative surfaces is complex and costly due to the need for wet coating, which also limits the precision and flexibility in achieving desired tolerances and optical quality.
Innovation Solution
A method involving two decorative films with an opaque coating, where decorative elements are introduced into one film using machining tools like lasers or stamping, and then back-injected with a polymer melt to form the molded part surfaces, eliminating the need for wet coating and enhancing design freedom and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet coating is used to apply protective lacquer and decorative elements, then surface protection and optical quality are improved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by incorporating the decorative elements and protective lacquer into the decorative film before the injection molding process. The film is pre-coated with opaque and transparent lacquer layers and pre-decorated with elements like logos or patterns, then placed into the mold where it is back-injected with polymer melt. This eliminates the need for post-molding wet coating operations, reducing manufacturing complexity while maintaining surface protection and optical quality.
2Reliability
If wet coating is used to apply decorative elements, then surface protection is improved, but positioning precision and tolerance achievement deteriorate
Solution Approach 1:
By pre-applying decorative elements to the film before molding, the patent ensures precise positioning is achieved during the film placement step rather than during post-molding coating. The film's decorative elements are fixed in their final positions before the injection process, eliminating positioning errors that would occur with post-molding wet coating methods.
3Ease of manufacture
If conventional single-film method is used, then manufacturing process is simpler, but design freedom and precision are limited
Solution Approach 1:
The patent segments the decorative film into multiple functional layers: an opaque lacquer layer for background and decorative elements, a transparent protective lacquer layer for surface protection, and optionally a carrier layer. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall manufacturing simplicity through the integrated film structure.
Solution Approach 2:
The patent uses composite material structure by combining multiple lacquer layers and decorative elements within a single decorative film. The opaque and transparent lacquer layers are applied in sequence to create a composite structure that provides both aesthetic functionality and surface protection, enabling greater design freedom while maintaining manufacturing efficiency.
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 reduces manufacturing complexity and cost, achieves higher precision in tolerances (+/â0.1 mm), and allows for flexible, high-quality decorative designs with improved resistance and optical appeal, while enabling individualized designs and efficient production of small series.
Implementation Method 1
the introduction of the at least one decorative element of a decoration into the first decorative film can take place in particular by laser irradiation
Implementation Method 2
back-injecting the decorative films with a polymer melt, so that the first decorative film forms a first surface and the second decorative film forms a second surface
Data Source
AI summary
The invention relates to a method for producing a plastic molded part (1), comprising the steps of:a) providing a first decorative film (11), which at least partially has an opaque coating (112);b) introducing at least one decorative element of a decoration into the first decorative film (11) by machining using a machining tool;c) providing a second decorative film (12);d) placing the decorative films (11, 12) into an injection mold (2) having a first (21) and second mold half (22), which together form a cavity (23) for molding the plastic molded part (1), the first decorative film (11) being placed on a first wall (22f) of the cavity (23) and the second decorative film (12) on a second wall (21f) of the cavity (23) lying opposite the first wall (22f);e) back-injecting the decorative films (11, 12) with a polymer melt, so that the first decorative film (11) forms a first surface and the second decorative film (12) forms a second surface of the plastic molded part (1) opposite the first surface.