Substrate-Supported Soldering for Low-Melting PET Circuits
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Solution Overview
Problem
The difficulty in recycling printed circuit boards (PCBs) due to the low melting point of substrates like polyethylene terephthalate (PET) which melts during conventional soldering processes, making it challenging to create sustainable electronic connections.
Innovation Solution
A method involving a second substrate with a higher melting point, such as polyimide (Kapton® tape), is attached to the first substrate around the soldering point to provide support as the PET melts, allowing soldering to occur without deforming the conductive traces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional soldering with heat is used on PET substrate, then soldering connection is achieved, but the PET substrate melts due to its low melting point
Solution Approach 1:
A second substrate with high temperature resistance is introduced as an intermediary between the heat source and the PET substrate. This mediator substrate withstands the soldering temperature and prevents direct thermal damage to the PET, enabling reliable soldering connections without melting the original substrate.
Solution Approach 2:
The second substrate is applied locally only around the soldering point area rather than covering the entire PET substrate. This localized approach provides thermal protection where needed while maintaining the recyclable properties and low melting point characteristics of the PET substrate in non-critical areas.
2Manufacturing precision
If a second substrate with higher melting point is added to support the first substrate, then the first substrate can be soldered without deforming, but the device complexity increases
Solution Approach 1:
The second substrate is applied locally only around the soldering point area rather than covering the entire PET substrate. This localized approach provides thermal protection where needed while maintaining the recyclable properties and low melting point characteristics of the PET substrate in non-critical areas.
Solution Approach 2:
The second substrate serves as a temporary protective element that can be removed after soldering is complete. This disposable approach allows for complex soldering operations on temperature-sensitive substrates without permanently increasing device complexity, as the supporting substrate is discarded after serving its protective function.
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 the use of recyclable materials like PET in electronic circuits by maintaining the integrity of conductive traces during soldering, reducing waste and cost through the use of a supporting substrate that withstands soldering temperatures.
Implementation Method 1
The second substrate is smaller than the first substrate and has a melting temperature above the soldering temperature
Implementation Method 2
heat is applied to the soldering point with a soldering head smaller than the second substrate
Implementation Method 3
The first substrate deforms (e.g., melts) proximate the soldering point at the soldering temperature
Implementation Method 4
The soldering material attaches to the soldering pad
Data Source
AI summary
A method for soldering to a conductor on a first substrate with a melting temperature below a soldering temperature is provided. A second substrate is attached to the first substrate around a soldering point. The second substrate is smaller than the first substrate and has a melting temperature above the soldering temperature. A soldering material is applied to the soldering point and the soldering temperature is applied to the soldering point with a soldering head smaller than the second substrate. The first substrate deforms (e.g., melts) proximate the soldering point at the soldering temperature. However, support for the first conductor is provided with the second substrate in place of the first substrate proximate the soldering point where the first substrate is deformed.