Abstract
As soon as the gate solidifies or the nozzle is closed, the amount of melt inside a cavity remains constant. At this moment, the cavity deformation affects the final product shape and size. A set of simulation procedures has been developed in this study to estimate the cavity deformation which arises during an injection-molding process. A mold-filling program was applied to calculate the molding variables. The estimated cavity pressure, temperature distribution, and clamping force were employed as the boundary conditions in the mold-deformation analysis. A structural analysis program was developed to predict the cavity deformation. Molding experiments were carried out for polymethyl methacrylate (PMMA) wedge-shaped parts. To verify the structural analysis, a strain gauge was installed on the sidewall of the mold. The measured strains agreed with the simulated results. A commercial simulation software package was also used to predict the shrinkage and warpage of injection-molded parts. Numerical results showed the improvement in predicting the shape and size of a final product by taking the cavity deformation into account. The influences of the packing pressure, mold temperature, or melt temperature on shrinkage and warpage were also investigated.
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References
Choi DS, Im YT (1999) Prediction of shrinkage and warpage in consideration of residual stress in integrated simulation of injection molding. Comp Struct 47(1):655–665
Chang TC, Faison E (2001) Shrinkage behavior and optimization of injection molded parts studied by the Taguchi method. Polym Eng Sci 41(5):703–710
Su Y (2002) Analysis on the process parameter of light guide using injection compression molding. Masters thesis, Da-Yeh University, Taiwan
Pantani R, Speranza V, Titomanlio G (2001) Relevance of mold-induced thermal boundary conditions and cavity deformation in the simulation of injection molding. Polym Eng Sci 41(11):2022–2035
Leo V, Cuvelliez CH (1996) The effect of the packing parameters, gate geometry, and mold elasticity on the final dimensions of a molded part. Polym Eng Sci 36(15):1961–1971
Gahleitner M, Bihlmayer G, Sobczak R (1991) Modified Carreau model. Kunstst Ger Plast 81:54–55
AC Technology (1997) C-MOLD reference manual. Ithaca, New York, pp 2–4
Quach A, Simha R (1971) Pressure–volume–temperature properties and transitions of amorphous polymers; polystyrene and poly (orthomethylstyrene). J Appl Physi 42(12):4592–4606
Hieber CA, Shen SF (1980) A finite-element/finite-difference simulation of the injection- molding filling process. J Non-Newt Fluid Mech 7:1–32
Schlichting H (1968) Boundary-layer theory, 6th edn. McGraw-Hill, New York
Han K-H, Im Y-T (1997) Compressible flow analysis of filling and post-filling in injection molding with phase-change effect. Comp Struct 38(1–4):179–190
Cook RD, Malkus DS, Plesha ME, Robert JW (2001) Concepts and applications of finite element analysis, 4th edn. Wiley, New York
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Wu, CH., Huang, YJ. The influence of cavity deformation on the shrinkage and warpage of an injection-molded part. Int J Adv Manuf Technol 32, 1144–1154 (2007). https://doi.org/10.1007/s00170-006-0435-4
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DOI: https://doi.org/10.1007/s00170-006-0435-4