Perforated Reflow Oven Downdraft Layout for PCB Warpage Control
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Solution Overview
Problem
Reflow ovens face challenges in preventing warpage of printed circuit boards during soldering due to temperature-induced deformation, leading to soldering defects and reduced yield, as existing methods using pressure differences are inadequate for all types of boards.
Innovation Solution
A reflow oven design incorporating downdraft modules that generate acting forces via air extractors and pipelines, transferring these forces through perforated steel plates and carriers to maintain boards flat during heating, ensuring uniform heating and preventing warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure difference method is used to press carrier plates, then some warpage can be suppressed, but the force is too small for hard or excessively warped carrier plates, and high pressure difference leads to high air speed that influences product quality
Solution Approach 1:
The carrier plate pressing function is segmented into multiple independent pressing points distributed across the carrier plate surface. Instead of using a single uniform pressure field, the system divides the pressing action into discrete locations, allowing localized control of pressure application to suppress warpage without creating excessive air flow that would affect soldering quality.
Solution Approach 2:
The pressing force is applied locally at specific points on the carrier plate rather than uniformly across the entire surface. This localized pressing approach targets areas of warpage specifically, providing sufficient force to flatten hard or excessively warped carrier plates while maintaining low overall air speed to protect soldering quality.
2Productivity
If thinner carrier plates are used, then productivity and design flexibility improve, but deformation frequency increases due to high temperature
Solution Approach 1:
The system applies pressing force to carrier plates before they undergo reflow soldering, pre-flattening them to prevent deformation during the heating process. This preliminary action ensures that even thin carrier plates maintain their dimensional stability throughout the soldering cycle, enabling high productivity without sacrificing precision.
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
The solution effectively prevents warpage and deformation of printed circuit boards, enhancing the quality and yield of reflow soldering operations by ensuring consistent contact between soldering tin and components.
Implementation Method 1
a negative pressure generating device which generates negative pressure to drive air flow
Implementation Method 2
through heating by spraying hot air and the like, soldering tin is molten for soldering of the circuit board and the electronic elements
Data Source
AI summary
Disclosed is a warpage suppressing reflow oven, which comprises a reflow oven body, where a perforated steel plate circulating device comprising a perforated steel plate is disposed at a reflow-oven inner oven. A plurality of downdraft modules is arranged in the perforated steel plate, and the downdraft acting forces thereof face the upper panel. More than one air extractor is communicated with the plurality of downdraft modules via a plurality of pipelines. Under actuation of the air extractors, the downdraft modules generate downdraft acting forces to the bottom surfaces of the products, so that the products are flatly attached to the universal perforated carriers without warpage in a heat soldering process. Thereby, more uniform heating of the products and better contact of solder joints and effectively improving the yield of reflow soldering operations are achieved.