Individually Controllable Heating Elements for Thermoformable Plastic Marking
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Solution Overview
Problem
Existing methods for marking thermoformable plastics face limitations in heat transfer efficiency and surface contamination, which hinder effective marking processes.
Innovation Solution
A system with individually controllable flatly distributed heating elements featuring varied topography and heating structures, capable of local heating, is used to create unique markings on workpieces during thermal forming processes, utilizing Joule heat for efficient surface structuring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic radiation through a cavity is used for marking, then marking can be achieved by generating convex bulges, but heat transfer from the radiation device to the workpiece is limited and the cavity can become contaminated
Solution Approach 1:
The heating system is divided into multiple individually controllable heating zones or heating elements distributed over the surface. Each heating element can be controlled independently to heat specific areas of the workpiece, allowing precise marking while maintaining high heat transfer efficiency through direct contact heating rather than radiation through a cavity.
2Reliability
If electromagnetic radiation through a cavity is used for marking, then marking can be achieved, but the cavity can become contaminated which reduces or prevents heat transfer
Solution Approach 1:
The workpiece marking function is extracted from the forming tool, allowing the marking operation to be performed by a separate, dedicated marking device. This enables the forming tool to remain clean and uncontaminated while the marking device handles the marking process, eliminating the contamination problem associated with using the forming cavity for marking.
3Manufacturing precision
If individually controllable heating elements with varied topography are used, then high precision marking with many unique patterns is achieved, but device complexity increases
Solution Approach 1:
Different areas of the heating element surface are given different topographies (flat, convex, concave) to create various marking patterns. Each local area has a specific quality suited for its marking function, allowing high precision marking with multiple unique patterns while keeping the overall device relatively simple through a unified heating element design.
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 approach enables efficient and contamination-free marking of thermoformable plastics with high precision and a large number of unique patterns, allowing for optical structures recognizable by the human eye, without the need for additional downstream processes.
Implementation Method 1
the surface structure is at least partially electrically heatable by the heating structure
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
Device (1) for marking a workpiece (6) that has been formed at least partially in a thermal primary or secondary forming process, wherein the device (1) has a plurality of heating elements (2) distributed over a surface, assigned to a surface (10) directed towards the workpiece (6) and individually controllable for local heating of a workpiece surface (60), wherein each of the heating elements (2) comprises a solid material (11) with a surface structure (40) and a heating structure (3), wherein the surface structure (40) has at least one selectively varied or statistical topography (4), wherein the surface structure (40) is at least partially heatable by the heating structure (3).