How do surface mount components withstand heat of reflow while through hole components can not?

Some online tutorials about soldering TH components, like transistors and ICs, are delicate components and can be easily damaged by heat. When it comes to soldering surface mount IC and components, some prefer to use a reflow oven which heats up the them to a temperature above the melting point of solder. So why?

PCB Assembly, PCB Materials
December 8, 2023

One of the key points to answer your question is thermal stress.

When you apply heat to one pin of a device, there is a sudden and huge temperature difference between that point and the rest of the device. That difference is stress, and the result can be a material breakout.

In an oven, on the other hand, all the board is put under a controlled, gradual thermal rise. ALL the points of the device are at almost the same temperature, so there are no thermal stresses (or they are much smaller than) they were when you applied the soldering tool to ONE pin and the rest of the device is at room temperature.

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

Oliver Smith

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