Research On Interface Thermal Contact Resistance In Injection Molding

:The thermal contact resistance (TCR) between the mold and parts after the filling stage of injection molding has a critical influence on temperature distribution and cooling rate. To solve this problem, we use designed platform for testing TCR combines inverse heat conduction algorithm for filling interface contact resistance after molding were studied. The main research work and conclusions are as follows:Establish a mathematical model based on a TCR of the cooling phase temperature field.Study the different thickness, different TCR of PC the impact phase of the center layer temperature field and the cooling rate in cooling stage, the effect of TCR of different thickness on the direction of the temperature distribution of PC, the thermal contact resistance has an important impact on temperature distribution in the thickness direction of the workpiece. The thinner parts, the greater impact on the temperature distribution in the direction of part thickness. With the reduction of the thickness of the workpiece, the workpiece cooling rate was increased, the cooling time is reduced. Especially when the thickness of the workpiece into the micro scale, the TCR for the affected parts of the cooling rate is more obvious.According to requirements for measuring injection molding contact resistance,design and construction of injection molding TCR measurement test system. The main work includes:Select temprature measurement sensor Based on Transient measurement principle. Writing Algorithm based on inverse heat conduction and TCR measurement preparation of the completion of the TCR calculation program designing with Matlab. Design and optimization of the melt surface temperature measurement based on infrared window. Provides an experimental platform for thin-walled parts melt surface temperature measurements. And completed the multi-channel temperature data acquisition software based Labview and Advantech data acquisition card providing software support for the TCR temperature measurement experiments.Experimental study on the influence of process parameters and interface environment mechanism of thermal contact resistance, TCR test system designed to accurately measure the temperature of the melt and the mold surface, combined with inverse heat conduction algorithm calculated the time-varying thermal contact resistance curve. The results show that:the mold temperature, the higher melt temperature, the longer the holding time, the greater the holding pressure, the smaller TCR, and holding pressure the most significant influence on the TCR. When the parts are1.5,2mm thickness, when the holding pressure increase to130MPa, TCR don’t increase. As part thickness is2mm, the effect of cavity surface roughness on TCR is very weak. When the thickness of the workpiece into a certain scale, the smaller cavity surface roughness the greater the interface TCR.