Numerical analysis of residual stresses and deformation of injection moulded parts manufactured from polymeric composite with different processing conditions
Dariusz Kwiatkowski, Adam Gnatowski, Jacek Nabiałek
Quarterly No. 4, 2011 pages 294-298
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abstract Simulations of the injection moulding process of polypropylene with a glass fibre content were conducted using special software - MOLDFLOW PLASTICS INSIGHT ver. 4.1. A seven - parametric rheological Cross - WLF model was chosen for the research. For holding phase simulation as well as to determine the inner stresses and deformation of the parts, the pvT dependence should be known. The Tait equation was used in the numerical calculations. In the first step of the simulation a solid model of the part was created using the Master Modeller modulus of I-DEAS NX software. A sample for cracking resistance tests, of the SENB type, with runners was modelled. Then the cooling conditions were introduced to the program. The next step modelled the injection mould geometrical shape and mesh creation. The crucial moment in the simulation is the introduction of the data describing the processed polymer properties. They were the thermal properties as well as the rheological and mechanical properties of the injected composite: PP with a 25% glass fibre content. In the next step, the processing conditions were entered into the simulation program (Moldflow Plastisc Insight ver. 4.1). The simulation research was conducted on the basis of the design of an experiment that was prepared with the use of Statistica 6.0 software. The changes of four processing parameters were taken into account: holding pressure, injection temperature, injection velocity and mould temperature. The simulations were made for extreme values of these parameters. The results of the numerical simulations of the residual stresses and strains on the injection moulded parts are presented graphically and conclusions were drawn from them.