Huang and Tai  have used computer simulations (C-MOLD[TM]) with the assistance of the Taguchi method to determine the effective molding parameters that affect the warpage behavior of a molded, box-shaped geometric part.
 have used the Taguchi method to investigate the warpage problem related to shrinkage variation, which can be reduced by modulating the molding parameters (injection time, packing pressure, packing time, and cooling time) for molded thin-shell features.
A similar approach has been used by Erzurumlu and Ozcelik  to investigate the minimization of the warpage and sink index of molded thermoplastic parts.
Experimental results indicate that warpage is minimized in the first two geometries by processing at the largest values of mold and melt temperature, injection time, and cooling time.
Packing pressure plays a larger role in driving warpage in these geometries, while the importance of injection time is reduced.
Finally, Moldflow's MF/Warp was used to compute the part shrinkage and warpage. The inputs to this calculation were the meshed model from the MF/Flow analysis, Young's modulus parallel and perpendicular to flow, and Poisson's ratio.
The z-direction warpage is quantified by the difference between the z-direction displacements of points [Z.sub.1] and [Z.sub.2].
This study divides all measured shrinkage and warpage data into training sets and testing sets (see the discussion below).
Through analysis and comparison, the simulation results of thickness distribution, temperature field, thermal stress and warpage for plastic part are in good agreement with the experimental results.
For the cooling stage of plastic thermoforming, the thermal-stress and warpage are analyzed, assuming that the thermal deformation during cooling stage is elastic.
Second, the viscoelastic model used here to simulate the thermally induced warpage of the polymeric plate is a linear one (i.e., the strain rate is linearly proportional to the stress); however, in reality, a polymeric material tends to exhibit non-linear viscoelastic properties.
A final series of numerical runs were conducted to compare the behavior of four different material models in predicting the warpage: linear elastic, elastic phase transformation, viscoelastic, and viscoelastic phase transformation models.