Reflow Soldering Oven With Thermal Imaging Self-Correction
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Solution Overview
Problem
Existing SMT manufacturing systems face limitations in identifying critical parameters such as component pitch, solder paste viscosity, solder flux type, and inter-metallic compounds, which can lead to solder joint defects and reduced PCB reliability.
Innovation Solution
A reflow soldering oven equipped with thermal infrared cameras for real-time thermal imaging, enabling self-correction of oven profiles, conveyor speed, heated zones, and fan speed based on thermal maps compared to thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermocouples are used to measure heat in the reflow soldering oven, then temperature measurement is possible, but the measurement capability is limited across a wide area
Solution Approach 1:
The patent replaces mechanical thermocouple-based temperature measurement with infrared thermal imaging technology. The infrared camera captures thermal radiation from the PCB and solder paste, converting it into temperature distribution maps. This substitution enables full-area temperature measurement without physical contact, resolving the contradiction between measurement precision and coverage area.
2Measurement precision
If known SPI systems are used to inspect solder paste, then visual inspection is possible, but critical parameters such as component pitch, solder paste viscosity, and solder flux type cannot be identified
Solution Approach 1:
The patent utilizes changes in thermal parameters (temperature, thermal conductivity, specific heat) of solder paste and flux under reflow conditions to infer critical process parameters. By analyzing thermal response characteristics during heating and cooling cycles, the system determines solder paste viscosity, flux type, and component pitch without direct measurement, thus gaining information that visual inspection cannot provide.
Solution Approach 2:
The system implements feedback by comparing actual thermal profiles with reference profiles to identify deviations caused by variations in solder paste viscosity, flux type, or component pitch. This feedback mechanism enables continuous monitoring and identification of critical parameters throughout the reflow process, transforming a simple inspection system into an analytical measurement system.
3Productivity
If conventional reflow soldering ovens are used, then soldering process is possible, but real-time self-correction of oven profiles and process parameters is not available
Solution Approach 1:
The patent implements self-service by enabling the reflow oven to automatically monitor its own thermal performance and correct deviations without external intervention. The infrared camera continuously maps temperature distribution, and the control system automatically adjusts heating zones, conveyor speed, and fan operation to maintain optimal thermal profiles. This self-correcting capability ensures consistent solder joint quality while maintaining high manufacturing efficiency.
Solution Approach 2:
The system introduces dynamics by making oven parameters (heating zone temperatures, conveyor speed, fan speed) adjustable in real-time based on actual thermal conditions. Rather than fixed static profiles, the oven dynamically adapts its operation to compensate for variations in PCB design, solder paste properties, and environmental conditions, thereby maintaining reliability while preserving productivity.
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 system effectively reduces solder joint defects by ensuring precise temperature control and process adjustments in real time, enhancing PCB reliability and manufacturing efficiency.
Implementation Method 1
at least one thermal infrared camera positioned within the oven that provides thermal imaging processing
Implementation Method 2
a first heated zone that heats and maintains a temperature of the PCB and a second heated zone that heats and maintains a temperature of the PCB
Implementation Method 3
a conveyor belt to convey the PCB through the first heated zone and the second heated zone
Data Source
AI summary
A reflow soldering oven for soldering and/or bonding component leads both electrically and mechanically to pads on a PCB in an SMT manufacturing system. The soldering oven includes at least one thermal infrared camera that generates thermal images of the PCB to provide thermal imaging processing to monitor and correct temperature deviations in real time. The oven generates a heat map using the thermal images and compares the heat map to a thermal gradient to provide real time profiling and to initiate changes like temperature control or the oven belt-speed monitoring to offer self-correcting capabilities.