Browsing by Subject "plastic parts"

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Microstructural Observation and Mechanical Property Evaluation of Plastic Parts Obtained by Preheat Free Laser Sintering
(University of Texas at Austin, 2012-08-22) Niino, Toshiki; Haraguchi, Hisashi; Itagaki, Yutaro; Hara, Kentaro; Morita, Susumu
Tensile test on preheat free (PF) processed part was performed it is shown that ultimate strength is the same as that from conventional process when relative density is the same. Microstructural observation showed that decomposition occurs during PF process. Microstructure of PF processed part is similar to those of amorphous. It is indicated that preheat free process can improve geometrical precision. PGA to which conventional process cannot be applied was successful processed by PF. Tensile test on preheat free (PF) processed part was performed it is shown that ultimate strength is the same as that from conventional process when relative density is the same. Microstructural observation showed that decomposition occurs during PF process. Microstructure of PF processed part is similar to those of amorphous. It is indicated that preheat free process can improve geometrical precision. PGA to which conventional process cannot be applied was successful processed by PF.
Numerical Simulation of the Temperature History for Plastic Parts in Fused Filament Fabrication (FFF) Process
(University of Texas at Austin, 2019) Zeng, D.; Rebandt, Matthew; Lacaria, Giuseppe; Lee, Ellen; Su, Xuming
Fused Filament Fabrication (FFF) is one of the major Additive Manufacturing (AM) processes for polymer materials. In FFF process, repetitive heating and cooling cycles occur when the filament is dispositioned onto a build platform to fabricate a three-dimensional part. The uneven temperature gradients and non-uniform cooling in the part may cause significant amount of warpage. The current practice of making an AM part to match the design intent is largely relied on time consuming trial-and-errors. Numerical simulation is an effective way to predict warpage. Accurate prediction of the thermal history during the FFF process is key for the success of warpage simulation. In this paper, an integrated approach is developed in LS-DYNA to model the FFF process and predict the temperature profile. Different from the traditional approaches, the tool path and FEM mesh are decoupled in this study to enable the flexibility of FEA mesh generation and improve computational efficiency. An innovated micro thermocouple is used to measure the temperature history inside the parts. The evolution of the thermal history is predicted and compared to the measurement data to demonstrate the accuracy and efficiency of the developed simulation model.