Coil Coating Process for Electrical Conductor Tracks
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Solution Overview
Problem
Existing coil coating methods for metal strips face reproducibility issues in achieving stable electrical and magnetic functionalization due to shape changes during processing, which can lead to line breakage in electrical conductor tracks.
Innovation Solution
The conductor tracks are printed on a pre-cured primer layer using a wet-on-wet process, allowing for improved adhesion and reducing internal stresses by enabling a transition zone between the conductor track and varnish, which are then jointly cured to minimize mechanical stresses and ensure a stable coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductor tracks are printed on a fully cured primer layer using conventional methods, then the coating process is simple, but the electrical conductor tracks are prone to line breakage during subsequent shape changes
Solution Approach 1:
The primer layer is pre-cured to a specific degree (gel point or partially cured state) before applying the conductor track, creating an optimized substrate that balances adhesion and stress resistance. This preliminary preparation of the primer layer in a controlled intermediate state resolves the contradiction by enabling reliable conductor track application while maintaining process simplicity.
Solution Approach 2:
The degree of curing of the primer layer is changed from complete curing to a controlled intermediate state (gel point or partial curing). This parameter change allows the primer to provide sufficient adhesion for the conductor track while maintaining flexibility to accommodate subsequent shape changes without causing line breakage, thus improving reliability without significantly increasing complexity.
2Reliability
If the conductor track and varnish are applied separately with full curing in between, then each layer is fully cured for stability, but internal stresses cause line breakage in conductor tracks
Solution Approach 1:
The application of conductor track and varnish is merged into a sequential wet-on-wet process where the varnish is applied while the conductor track is still in a wet or partially dried state. This merging eliminates the need for complete curing between layers, reducing internal stresses and preventing line breakage while maintaining strong adhesion through the transition zone.
Solution Approach 2:
A transition zone is created between the conductor track and varnish layer through the wet-on-wet application process. This transition zone acts as an intermediary that gradually transitions from the conductor track material to the varnish, distributing stresses and preventing sharp stress concentrations that would cause line breakage, while ensuring strong adhesion.
3Manufacturing precision
If sharp-edged conductor tracks are applied, then the electrical connection is precise, but stress concentrations lead to line breakage during deformation
Solution Approach 1:
The transition zone created through wet-on-wet application acts as an intermediary between the sharp-edged conductor track and the varnish layer. This gradual transition distributes mechanical stresses along the interface, preventing stress concentrations at the sharp edges that would otherwise lead to line breakage during deformation, while maintaining the precision of the electrical connection.
Solution Approach 2:
The physical state of the conductor track material is changed from a fully cured rigid state to a wet or partially dried more flexible state during application. This parameter change allows the material to better accommodate sharp edges and stress concentrations, preventing line breakage while maintaining manufacturing precision of the electrical connection pattern.
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 enhances the reproducibility and stability of the electrical functionalization, reducing the risk of electrical line breakage and maintaining functionality even under deformation, such as deep-drawing, while providing high mechanical and chemical resistance.
Implementation Method 1
a curable polymer primer is then applied to this flat side by means of a roller application and cured in order to form an electrically insulating primer layer
Implementation Method 2
a curable polymer varnish is applied by means of roller application and cured in order to form an electrically insulating varnish layer
Data Source
AI summary
A coil coating method for multilayer coating of a continuous metal strip, which is disposed in the strip passage, in which on a flat side of the metal strip, a curable polymer primer is applied by means of a roller application and cured in order to form an electrically insulating primer layer and a curable polymer varnish is applied onto said primer layer by means of roller application and cured in order to form an electrically insulating varnish layer, wherein at least one at least electrically conductive conductor track is printed on at least some areas between the primer layer and the varnish layer is proposed. In order to increase the reproducibility of the coil coating method, it is proposed that the conductor track be printed on some areas of the pre-cured primer layer and that the conductor track and varnish be applied using a wet-on-wet process.