Two-Conductive-Layer Flex Foil Milling from Both Sides
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Solution Overview
Problem
Existing dry milling processes are inadequate for patterning flex foils with two conductive layers from both sides, leading to variations in thickness and spacing during the milling process.
Innovation Solution
A method involving the use of dual cliché patterns and milling wheels to selectively remove layers on both sides of the flex foil, with the first pattern removing the first conductive and insulating layers on one side and the second pattern removing the second insulating layer on the opposite side, while maintaining precise control over the milling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing dry milling processes are used for patterning flex foils with two conductive layers, then the milling process can be performed, but variations in thickness and spacing occur during the milling process
Solution Approach 1:
The patent divides the milling process into two separate operations: a first milling operation that mills one surface of the flex foil, and a second milling operation that mills the opposite surface. Each operation uses its own dedicated milling wheel and cliché pattern, allowing independent optimization of each milling process to maintain consistent thickness and spacing without the complications of attempting to mill both surfaces simultaneously
Solution Approach 2:
The patent transitions from a single-sided milling approach to a dual-sided milling approach by adding milling capability in the opposite dimension (the other surface of the flex foil). This allows the process to address thickness variations by compensating on the opposite surface, thereby improving overall manufacturing precision
2Manufacturing precision
If a single cliché pattern is used for milling, then the process is simpler, but it cannot selectively remove layers on both sides of the flex foil with precise control
Solution Approach 1:
The patent segments the cliché pattern into two distinct patterns: a first cliché pattern with first raised portions for milling one surface, and a second cliché pattern with second raised portions for milling the opposite surface. Each pattern is optimized for its specific milling operation, enabling precise selective removal of conductive and insulating layers on each surface independently
Solution Approach 2:
The patent employs inversion by creating a second cliché pattern that is essentially the reverse or complement of the first pattern, designed to mill the opposite surface. This allows the milling process to address features on both surfaces with equal precision, compensating for any variations introduced during the first milling operation
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
Enables precise patterning of flex foils with two conductive layers from both sides, ensuring consistent thickness and spacing, thereby facilitating higher density connections.
Implementation Method 1
dry milling one side of the web using a first cliché pattern including raised portions and non-raised portions to selectively remove at least one of the first conductive layer and the first insulating layer
Data Source
AI summary
A method for milling flex foil includes providing a web (14) of flex foil including a substrate; a first conductive layer arranged on one surface of the substrate; a second conductive layer arranged on an opposite surface of the substrate; a first insulating layer arranged adjacent to the first conductive layer; and a second insulating layer arranged adjacent to the second conductive layer. The method includes dry milling one side of the web using a milling wheel (20-1) and a first cliche pattern (25-1) (including a rotating drum (24-1) and a flexible substrate (26-1)) including raised portions and non-raised portions to selectively remove at least one of the first conductive layer and the first insulating layer. The method includes dry milling an opposite side of the web using a milling wheel (20-2) and a second cliche pattern (25-2) including upper raised portions, lower raised portions and non-raised portions to selectively remove the second insulating layer.