Investigating the effect of different substrates on condensation heat transfer during vapour phase soldering

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Dr. Géczy Attila
Department of Electronics Technology

The purpose of my diploma thesis was to investigate the effect of 4 different substrates of film condensate layer during the vapour phase soldering. I explored the literature of the topic, I summarized the process of the vapour phase soldering, I discussed the advantageous properties, the industrial applications, and I mentioned the latest research findings on the subject. I also summarized the literature of methods of heat transfer mechanism, regarding the heat transfer of Newton’s law, I defined the Nusselt number, and I specified the heat transfer coefficient. Before my work, I discussed the previous results of the topic in my department, mainly focusing on the simulatons based on Finite Difference Method. I explained the methods of temperature measurements, highlighting the thermocouples and the data collection mechanisms.

As a first part of my work, I assembled a design of experiment, measuring the thermal profile on the different substrates, and on the local measuring points. I implemented the investigations in two different constructions, called test case „A” and „B”. During the test case of „A”, I calculated a constant size of surfaces, and I set its corresponding heat capacity. The results were evaluated in Excel worksheets and MATLAB software also. Based on the results of this test case, the substrates with lower heat capacity had more steep gradient profile, as the substrates with higher heat capacity. Then, in test case of „B”, I set the heat capacity to a constant value, and I calculated back the size of surfaces. During the result of test case „A”, the heat capacity has significant influence on the temperature profiles, so I expected much closer heating proper of temperature profiles. As a result of test case „B”, the heat gradients run much closer as expected, but not run completely together. That is an important conclusion, that heat transfer mechanism was influenced by other phisical parameters with the exception of heat capacity, the investigation of ratio of the side length/thickness and the thermal diffusivity is an important task in this topic.


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