Dimensions of injection moulded parts are an essential criterion of quality. The compliance with dimensional tolerances succeeds often only by changes of the mould. Changes of shrinkage values by changing processing parameters are limited. Therefore substantial shrinkage values have to be considered in mould design. In this thesis the influence of several processing parameters (holding pressure, melt temperature and mould temperature) as well as wall thickness dependence are examined on linear shrinkage and compared with simulation
results of Moldflow Plastics Insight™ 5.0 revision 1 (MPI 5.0 R1).
The dimensions of the injection moulded parts are rectangular of size 130 x 75 mm and wall thicknesses of 2 mm, 3 mm and 4 mm. The amorphous polymers used in all investigations are polystyrene 454C (PS 454C), manufactured
by BASF AG (Ludwigshafen, D) and acrylnitrile-butadiene-styrene Urtal M122 (ABS Urtal M122), manufactured by ENICHEM POLIMERI (San Donato Milanese, I).
The simulations are performed using a MPI-Midplane, MPI-Fusion and MPI-3D model mesh and real processing parameters. All calculations have been carried out with material data from the internal MPI 5.0 R1 database and default program settings. In addition to shrinkage predictions a comparison of simulated and experimental filling studies are given. Simulation results of the packing and holding stage are compared with experimental pressure distribution. The
temperature differences as well as the cooling behaviour of the mould cavity are measured with infrared thermography and compared with Moldflow Plastics Insight™ 5.0 revision 1 results. The aim of the investigations is to interpret shrinkage predictions with Moldflow Plastics Insight™ in a proper manner.