![]() Due to the nature of convection heating the temperature distribution in the zones is near homogeneous. The temperature can be independently controlled in each zone however the velocity of the inflowing streams is usually fixed. ![]() The ovens are divided into zones (6–12 zone is usual) every zone contains an upper and a lower nozzle-matrix. The nozzle-matrix generates numerous gas streams perpendicularly to surface of the soldered assembly. ![]() Usually the heating of the assembly is achieved by a convection reflow oven which mainly applies the nozzle-matrix heater system. The reflow process heats the entire assembly to a temperature beyond the melting point of the solder alloy which wets the contact surfaces and forms the joints. The preparatory steps of the process are the printing of solder paste to the contact surfaces (pads) of the PWB, and the component placement onto the deposited solder paste. This process is applied when surface mount devices (SMDs) are attached to printed wiring boards (PWBs). Reflow soldering is the most widespread soldering technology used in the electronics industry for surface mounted technology (SMT). These results can be useful during the overview of the actual assembly design and manufacturing rules. Therefore the effect of the soldered assembly, the different component sizes, the position of the conveyor belt and the vent hood between the zones on the gas flow velocity space was studied by CFD simulations. The gas flow space cannot be examined by classical experimental methods due to the extreme circumstances in the reflow oven. The gas flow velocity space is one of the most important parameter of the local heat transfer coefficient in the oven. The temperature can be independently controlled in each zone however the velocity of the influent streams is usually fixed. The ovens are divided into zones every zone contains an upper and a lower nozzle-matrix. Convection reflow ovens usually apply the nozzle-matrix heater system which generates numerous gas streams perpendicularly to surface of the soldered assembly. In this paper, numerical study of the gas flow velocity space is presented in a convection type reflow oven.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |