Experimental analysis on the bonding conditions of thermoset-thermoplastic composite parts manufactured by the hybrid single shot method

The hybrid single shot method is an innovative manufacturing technique that allows thermoset composite sheets to be formed and cured while they are also bonded into an injected thermoplastic body all in a single integrated operation. This integration concept is complex in nature but promising to overcome the drawbacks of the traditional procedures for manufacturing such multi-material structures by reducing the cycle time, energy consumption, and cost of the required tools and machinery. In this study, CF/Epoxy prepreg sheets are selected as the inserted material which is then later deformed and bonded to an injected body made of a polypropylene compound. The bonding between these two dissimilar materials is mostly achieved by taking the advantages of the melt penetration and the tackiness of the prepreg sheet. Therefore, an experimental study is here designed and carried out to evaluate the bonding conditions of the final hybrid parts regarding several influential process parameters. To better monitor the process and analyze the physics behind this integration, a set of real-time process variables are measured and analyzed using an instrumented experimental setup. The results show that the pre-heating time has the largest effect on the bonding strength, and the best combination of the deformation and bonding strength is achieved when the cavity pressure and temperature are at the highest level compared to the other experiments. The maximum bonding strength attained in the optimum process settings was 6.8 MPa which shows a 51% improvement compared to the average value of the other experiments.