Inductive Heating for Glass Hot Foil Stamping
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Solution Overview
Problem
Conventional hot foil stamping methods face challenges in maintaining process temperature stability due to factors like material differences in embossing dies and glass workpieces, leading to potential damage or uncontrolled adhesion of the embossing foil, especially when using thermally curing printing inks with varying degrees of curing.
Innovation Solution
The method involves inductive heating of the embossing die and the printed image, using UV-curing printing ink with a non-reactive thermally volatile solvent, and incorporating inductively heatable components in the primer and embossing die to control temperature directly at the transfer area, ensuring precise and stable process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional thermal heating methods are used for hot foil stamping, then the embossing die can be heated, but the temperature control is sluggish and delayed causing temperature fluctuations that damage the embossing foil or cause uncontrolled adhesion
Solution Approach 1:
The patent replaces conventional thermal heating (conductive heating through heating plates) with inductive heating using electromagnetic fields. The embossing die contains ferromagnetic particles that are directly heated by induction, eliminating the intermediate thermal conduction step and achieving rapid, precise temperature control without the sluggish response and temperature fluctuations of conventional methods.
Solution Approach 2:
The patent changes the heating mechanism from thermal conduction to electromagnetic induction, fundamentally altering the heating parameters. The inductive heating system allows for rapid heating and precise temperature control by adjusting electromagnetic field parameters, enabling the process temperature to be maintained within the narrow required range without the delays and fluctuations inherent in conventional thermal systems.
2Manufacturing precision
If thermally curing printing ink is used as a primer, then adhesion promotion is achieved, but the degree of curing is difficult to control due to varying wall thickness and storage conditions, leading to inconsistent stamping quality
Solution Approach 1:
The patent replaces thermal curing of printing ink with UV curing. Instead of relying on temperature-dependent chemical reactions that are sensitive to wall thickness and storage conditions, the printing ink is cured by exposure to UV light, which provides consistent and controllable curing regardless of the glass workpiece's thermal history or geometry.
Solution Approach 2:
The patent changes the curing mechanism from thermal to photopolymerization. The printing ink contains photoinitiators that trigger polymerization upon UV exposure, providing a curing process that is independent of thermal conditions. This eliminates the variability caused by different wall thicknesses and storage temperatures, ensuring consistent adhesion promotion and stamping quality.
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 allows for precise control of process temperature, maintaining high-quality hot foil stamping by compensating for temperature fluctuations and ensuring consistent adhesion, reducing the risk of damage and improving the haptic and optical appearance of the finished product.
Implementation Method 1
One idea of the invention is to inductively heat at least part of the embossing die and at least part of the printed image during and/or immediately before hot foil stamping
Implementation Method 2
the printed image being printed with a UV-curing printing ink
Data Source
Figure 1~2
AI summary
The method involves partially providing a glass workpiece (3) with a print image (6) from printing ink (7), where the print image provides a defined surface structure in form of a relief to the workpiece. A part of an embossing stamp (2) or a part of the print image is inductively heated during and/or immediately before a hot film stamping. The heating is controlled and/or regulated depending on temperature of a workpiece surface. The printing ink is completely cured for at the time of the hot film stamping and simultaneously comprised of defined solvent contents. An independent claim is also included for a device for printing a glass workpiece with a hot embossing film using an embossing stamp.