A study on thermal characteristics according to thermal contact resistance in hot plate welding process

When a washing machine is rotating with the laundry in it, it tends to lean to one side. This tendency causes a serious vibration. The balance of a washing machine plays an important role in order to reduce the vibration by injecting the sand or the salt water into the balance of washing machine. The hot plate welder is used to prevent the contents from outflowing. The thermal characteristics of the hot plate and the balance have to be considered for reducing the defects in plastic welding. The hot plate welder brings about many problems that may lead to an accident. The workers are protected by the loading/unloading system for the washing machine balance in the hot plate welder. This system requires direction recognition and location information of the balance. In this paper, thermal analysis of the hot plate welder for the washing machine balance is performed. The heat source of the hot plate welder plays a really important role in welding the washing machine balance. The temperature distribution of the hot plate and that of the washing machine balance are obtained by finite element analysis. The temperature of the hot plate is measured by the infrared temperature sensor in order to find the thermal contact resistance. The thermal strain of the plastic balance is predicted by thermal-structural coupled analysis.