Analysis of the welding strength in hybrid polypropylene composites as a function of the forming and overmolding parameters

摘要

>This work investigates the influence of the process parameters on the welding strength in hybrid polypropylene composites manufactured by injection overmolding. A hybrid T‐joint specimen was designed to evaluate the global performance of the welding by means of tensile tests. The effects of the process parameters were evaluated in accordance the design of experiments approach and the maximum strength (UTS) was assumed as response variable. The effects of melt temperature and holding pressure, combined to a variothermal mold‐control system, were investigated. The residual stresses induced by the process were considered by means of coupled thermo‐fluid dynamic/structural finite‐element analysis. Moreover, the topography of the laminate‐side surface was characterized and the process‐induced surface modification was related to the performance of the welding. Results show that the melt temperature contributes to increase the welding strength; conversely, the mold temperature counteracts this effect by increasing the residual stress at the interface. POLYM. ENG. SCI., 58:592–600, 2018. ? 2017 Society of Plastics Engineers