Induction Heating Tool Layer Stack for Cycle Time Reduction
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Solution Overview
Problem
Existing tools for forming plastic materials face inefficiencies in heating and cooling processes, leading to longer production cycles and increased costs, despite advancements in inductive heating and cooling technologies.
Innovation Solution
A tool design featuring a stack of layers including a coil carrier, an electrically conductive intermediate layer with lower resistivity than the top layer, a thermal resistance layer, and a backing layer with lower resistivity, allowing for efficient heat generation and distribution while enabling quicker cooling through integrated cooling ducts and a conduction frame for improved contact and pressure equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thick top layer is used to maintain heat, then heat retention is improved, but cooling time increases and production cycle lengthens
Solution Approach 1:
The tool is divided into distinct functional layers: a thick backing layer for heat generation and retention, a thin intermediate layer for electrical conduction, and a thin top layer for rapid cooling. This segmentation allows each layer to optimize its specific function without compromising others.
Solution Approach 2:
Different layers have different thicknesses and material properties optimized for their specific functions. The backing layer is thick for heat retention, while the top layer is thin for rapid cooling. This local differentiation resolves the contradiction between heat retention and cooling speed.
2Productivity
If cooling ducts are placed close to the top layer for efficient cooling, then cooling effectiveness is improved, but water boiling occurs at high temperatures
Solution Approach 1:
A thin electrically conductive intermediate layer is placed between the cooling ducts in the backing layer and the top layer. This intermediate layer acts as a thermal buffer, allowing efficient cooling while preventing direct contact between high-temperature top layer and cooling water, thus avoiding boiling.
3Power
If a ferromagnetic steel top layer is used for heating, then heating efficiency is improved, but heat distribution precision decreases
Solution Approach 1:
The ferromagnetic steel top layer is replaced with a non-ferromagnetic austenitic steel top layer. The heating function is extracted to the backing layer which contains the induction coils. This separation allows the top layer to provide precise heat distribution without the unwanted magnetic effects that cause uneven heating.
4Speed
If the top layer is made thin for rapid cooling, then cooling speed is improved, but electrical conductivity decreases
Solution Approach 1:
The tool uses a composite layered structure where a thin austenitic steel top layer provides rapid cooling, while an electrically conductive intermediate layer compensates for the reduced electrical conductivity. The composite structure maintains overall electrical conductivity while enabling fast cooling.
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 design enhances the efficiency of the heating and cooling processes, reducing production cycle times and maintaining high precision heat development patterns, thereby improving the overall efficiency and cost-effectiveness of plastic forming tools.
Implementation Method 1
The coil generates an oscillating magnetic field that, by inducing eddy currents, heats the mould or tool in the vicinity of the surface
Implementation Method 2
The coil generates an oscillating magnetic field that, by inducing eddy currents, heats the mould or tool
Implementation Method 3
The coil generates an oscillating magnetic field that, by inducing eddy currents, heats the mould or tool
Implementation Method 4
A thermal resistance layer is placed between the intermediate layer and the top layer, the thermal resistance layer comprises a heat resistive plastic such as a polyimide
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
The present disclosure relates to a tool, such as an embossing tool, comprising a stack of layers for heating an active tool surface. The stack comprises: a coil carrier layer (21) including at least one wound coil for generating an oscillating magnetic field, an electrically conductive top layer (25), being adjacent to the active tool surface, and a backing layer (27), being positioned beneath the coil carrier layer as seen from the top layer, the backing layer being electrically connected to the top layer at the edges where windings of the coil turns, and having a lower resistivity than the top layer. An electrically conductive intermediate layer (23) is located between the coil carrier layer and the top layer and has a lower resistivity than the top layer. A thermal resistance layer (29) is placed between the intermediate layer and the top layer, the thermal resistance layer comprising a heat resistive plastic material such as a polyimide.