NUMERICAL-SIMULATION OF BLOW MOLDING - PREDICTION OF PARISON DIAMETERAND THICKNESS DISTRIBUTIONS IN THE PARISON FORMATION PROCESS

In our previous study, we calculated the time course of parison length in the parison formation stage, but it could predict only the parison area swell. The next target in our study is to calculate the parison diameter and thickness swell. Annular extrudate swell simulation is ne cessary for the understanding of various kinds of swelling ratios in b low molding. We have examined three kinds of swells (outer diameter, t hickness, and area swells) obtained from simulation results of annular extrudate swell, using the Giesekus model, and have developed a metho d of predicting parison outer diameter and thickness swell values. The predicted values of parison outer diameters are discussed in comparis on with experimental data, and reasonable results are obtained by the proposed method. This prediction method could also be applied to the p arison formation process using a parison controller. As a result, it i s possible to predict approximately the whole process of parison forma tion by numerical simulation.