3D Flex Soldering Bent State Carrier
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Solution Overview
Problem
Conventional flex circuit attachment methods fail to maintain a bent state during surface mounting and reflow operations, leading to stress-induced flattening and adverse shifting of components, which limits the utility of flexible circuits in compact electronic devices with protruding features.
Innovation Solution
A manufacturing method involving a carrier with a removable portion that allows the flexible circuit to be bent and maintained in a predetermined geometry, using high-temperature tape or adhesive to secure the bend during reflow, and subsequent separation of the carrier to ensure the bend is retained after soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the flex is bent prior to surface mounting and reflow, then the flex can accommodate protruding features and achieve compact device design, but stresses from bending cause flattening of the flex and adverse shifting of components
Solution Approach 1:
The flex circuit is segmented from its carrier board, allowing independent manipulation of the flex portion to create precise bends while keeping the carrier intact for component placement. This segmentation enables the flex to be pre-bent to accommodate protruding features without affecting component positioning accuracy during subsequent assembly steps.
Solution Approach 2:
The flex circuit is pre-bent to the desired configuration before component attachment. By performing the bending action in advance and securing the flex to the carrier at specific attachment points, the flex maintains its pre-formed shape during surface mounting and reflow operations, enabling accommodation of protruding features while preserving manufacturing precision.
2Ease of manufacture
If conventional surface mounting and reflow methods are used on a bent flex, then standard manufacturing processes are maintained, but the flex flattens and components shift adversely
Solution Approach 1:
The carrier board serves as an intermediary structure that supports the flex circuit during manufacturing. The flex is attached to the carrier at multiple points, and the carrier provides mechanical support to maintain the bent geometry of the flex during surface mounting and reflow operations, preventing flattening while allowing standard manufacturing processes to be used.
Solution Approach 2:
The mechanical constraints on the flex circuit are modified by attaching it to the carrier at specific points along its length. This changes the boundary conditions of the flex, allowing it to maintain a bent configuration under thermal and mechanical stresses during manufacturing, rather than returning to a flat state.
3Manufacturing precision
If the flex remains flat during attachment, then component positioning is stable, but the flex cannot accommodate protruding features in compact devices
Solution Approach 1:
The flex circuit is segmented from the carrier board, allowing the flex portion to be independently shaped into bends to accommodate protruding features. The attachment points provide stable reference positions for component placement, maintaining manufacturing precision while enabling the flex to navigate around obstructions in compact device designs.
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 successful surface mounting and reflow operations on flexible circuits with protruding features, maintaining the desired bend and ensuring reliable electrical connections without residual stress, thus enhancing the design flexibility and functionality of compact electronic devices.
Implementation Method 1
heating the flex and the solder until the solder adheres and forms around the electrical connections
Data Source
AI summary
In some designs, getting a flexible circuit (flex) to assume a bent state can be helpful in efficiently routing electrically conductive pathways. One efficient way to implement soldering of flexes in a bent state during a reflow operation is to manipulate paneling that hold batches of the flexes to reliably maintain a suitable bend in those flexes. In some embodiments, a flex can be surface mounted to a portion or the whole of an electric device during a reflow operation during which the bent state is maintained by paneling that is at least partially attached to a periphery of the flex. Another solution is to utilize vacuum or hot glue fixtures to maintain a bend in the flex during surface mounting and reflow operations.