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Effect of machine compliance on mold deflection during injection and packing of thermoplastic parts
Author(s) -
Carpenter Brian,
Patil Sachin,
Hoffman Rebecca,
Lilly Blaine,
Castro Jose
Publication year - 2006
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20527
Subject(s) - mold , deflection (physics) , materials science , composite material , injection molding machine , thermoplastic , finite element method , transfer molding , mechanical engineering , molding (decorative) , engineering drawing , structural engineering , engineering , physics , optics
Abstract Minimizing mold deflection is essential when manufacturing plastic parts to tight tolerances. Both the mold and the machine are compliant and deform upon loading, which can affect the part quality. Therefore, understanding mold deflection during injection molding is critical for determining the final geometry of the part. It is also critical for secondary processes such as the in‐mold coating process. This article presents work in quantifying both mold deflection during an injection‐molding cycle and the effect of machine compliance on mold behavior. The mold cavity pressure obtained using MoldFlow™ was used as input for the subsequent finite element mold deflection analysis. Two different structural models were used: the first model included only the mold, the mold base units and the ejector platen; the second model included the effect of the injection‐molding machine compliance. To validate the model, strain gage rosettes were placed on the mold and the machine. Validating experiments were conducted using process parameters identical to those used in the simulations. A comparison of the experimental and simulation results for both models is presented. POLYM. ENG. SCI., 46:844–852, 2006. © 2006 Society of Plastics Engineers