Reactive Metal Coating Transfer for Heat-Safe Flexible Substrates
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Solution Overview
Problem
High thermal heat loads during the deposition of low melting temperature metals on flexible substrates cause wrinkling and creasing, limiting coating speeds and potentially damaging the substrates in web substrate systems.
Innovation Solution
A method and apparatus that involve delivering a molten metal or metal alloy onto a cooled quenching surface of a rotating casting drum, where it solidifies, and then transferring the solidified layer to a flexible substrate, using a transfer liquid and surface protection films to prevent sticking and ensure efficient transfer, while decoupling thermal heat load from deposition rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the deposition rate is increased to achieve higher coating speeds, then productivity is improved, but the thermal heat load causes the web material to wrinkle and crease, damaging the flexible substrate
Solution Approach 1:
The process is divided into two separate stages: (1) deposition of molten metal onto the cooled processing drum, and (2) transfer of the solidified metal layer to the flexible substrate. This segmentation allows the deposition to occur on the drum at high rates while the substrate is exposed to minimal thermal load during the transfer stage, resolving the contradiction between productivity and substrate damage.
Solution Approach 2:
The cooled processing drum acts as an intermediary carrier between the deposition source and the flexible substrate. The drum absorbs the thermal heat load during deposition, allows the metal to solidify, and then transfers the solidified layer to the substrate. This intermediary approach enables high deposition rates without directly exposing the substrate to harmful thermal loads.
2Temperature
If the thermal conductance between the flexible substrate and the processing drum is increased to control temperature rise, then the substrate temperature is reduced, but the coating speed must be limited, reducing productivity
Solution Approach 1:
The process separates the deposition function (performed on the processing drum) from the substrate coating function. The drum can be operated at high rotational speeds for efficient deposition while the substrate is only briefly exposed during transfer, allowing high productivity without excessive substrate heating.
Solution Approach 2:
The processing drum rotates continuously, maintaining a constant supply of cooled surface area for deposition. This continuous operation allows sustained high deposition rates while the brief transfer time ensures the substrate does not accumulate excessive heat, maintaining both temperature control and productivity.
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 increased deposition rates without substrate damage, enabling higher throughput in manufacturing flexible layer stacks with low melting temperature metals while maintaining substrate integrity.
Implementation Method 1
forming a material layer stack over the rotating casting drum by delivering a molten metal or molten metal alloy toward the quenching surface of the rotating casting drum
Implementation Method 2
the quenching surface of the rotating casting drum is cooled to a temperature at which the layers of the material layer stack solidify
Data Source
AI summary
A method and apparatus for manufacturing a flexible layer stack, and to a flexible layer stack. Implementations of the present disclosure particularly relate to a method and apparatus for coating flexible substrates with a low melting temperature metal or metal alloy. In one implementation, a method is provided. The method includes delivering a transfer liquid to a quenching surface of a rotating casting drum. The method further includes forming a material layer stack over the rotating casting drum by delivering a molten metal or molten metal alloy toward the quenching surface of the rotating casting drum. The method further includes transferring the material layer stack from the rotating casting drum to a continuous flexible substrate, wherein the quenching surface of the rotating casting drum is cooled to a temperature at which the layers of the material layer stack solidify.