PCB Copper Layer Layout for THT Solderability and Heat Isolation
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Solution Overview
Problem
Existing printed circuit boards using Through Hole Technology (THT) face challenges with poor processability in selective or wave soldering due to full-surface copper structures acting as heat sinks, preventing adequate soldering tin passage and connection to components.
Innovation Solution
A printed circuit board design with current-conducting layer plies arranged in succession in the thickness direction, where one ply reaches the connecting element and another is at a distance, allowing for improved heat input and solderability without heat traps, enabling connections to various plated-through components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full-surface copper structures are used in printed circuit boards, then electrical connectivity is improved, but solderability of THT components deteriorates due to heat sink effect
Solution Approach 1:
The copper layer is segmented into two distinct regions: a first copper layer region that contacts the connecting element for electrical connectivity, and a second copper layer region that is spaced from the connecting element to avoid heat sink effect. This segmentation allows the board to simultaneously achieve good electrical connection and good solderability by preventing the copper from acting as a heat trap during the soldering process.
Solution Approach 2:
Different regions of the copper layer are given different properties: the first region (near the connecting element) provides electrical connectivity, while the second region (farther away) provides thermal isolation during soldering. This local differentiation of copper layer properties resolves the contradiction between needing electrical connection and avoiding heat sink effect.
2Reliability
If copper plies are positioned close to connecting elements, then electrical connection is improved, but heat management deteriorates during soldering process
Solution Approach 1:
The copper layer is divided into two spatially separated regions relative to the connecting element. The first copper layer region is positioned to ensure electrical connection, while the second copper layer region is positioned at a distance to prevent excessive heat absorption during soldering, thus managing temperature effectively.
Solution Approach 2:
The spacing between the second copper layer region and the connecting element acts as a thermal buffer or intermediary, preventing direct heat transfer from the soldering zone to the copper layer, thereby improving heat management while maintaining electrical connectivity through the first copper layer region.
3Ease of manufacture
If copper plies are positioned far from connecting elements, then heat sink effect is reduced, but electrical connectivity deteriorates
Solution Approach 1:
The copper layer is segmented into two functional regions: the first copper layer region positioned close to the connecting element to ensure electrical connectivity, and the second copper layer region positioned farther away to reduce heat sink effect and improve solderability.
Solution Approach 2:
Different regions of the copper layer serve different functions: the first region prioritizes electrical connectivity by being close to the connecting element, while the second region prioritizes thermal management by being spaced away, thus resolving the contradiction locally across different zones of the same layer.
Data Source
AI summary
The disclosure relates to a printed circuit board having at least two current-conducting layer plies, wherein the current-conducting layer plies extend in an axial direction of the printed circuit board and are arranged in succession in a thickness direction of the printed circuit board. A component fastened by THT is arranged on one side of the printed circuit board. At least one connecting element extends through the printed circuit board through a passage opening in the thickness direction. The current-conducting layer ply is adjacent to the component fastened by THT reaches as far as the connecting element and the current-conducting layer ply that is remote from the component fastened by THT is at a distance from the connecting element.