The effect of injection molding process parameters on mechanical and fracture behavior of polycarbonate polymer

Abstract

In this work, the mechanical and failure behavior of injection molded aviation standard optical grade polycarbonate (PC) was investigated through uniaxial tensile testing. The effect of different injection molding process parameters including injection velocity, packing pressure, cooling time, mold temperature, and melt temperature were determined to observe their effect on yield and postyield behavior of PC. Out of these examined parameters, the mold and melt temperature show significant effect on mechanical behavior of studied polymer. The yield and flow stresses in polymer increase with the increase in mold and melt temperature during injection molding. However, other process parameters i.e., packing pressure, injection velocity, and cooling time showed little effect on mechanical performance of the polymer. The molded specimens were annealed at different temperatures and residence time to evaluate its effect on mechanical behavior and fracture morphology. The yield stress increases gradually with the increase in annealing temperature and time. The annealing treatment also changed the failure mode of PC specimens from ductile to brittle. In addition to process parameters, the effect of increased loading rate was also undertaken which shows substantial effect on mechanical and failure behavior of PC.

Size and print path effects on mechanical properties of material extrusion 3D printed plastics

“…2 a, the PC exhibits brittle failure when printed in a type IV dogbone at raster angles of 0°/90°. This is counter to injection molded PC, which exhibits ductile failure [ 63 ], but consistent with brittle fracture observed with other 3D printed PC dependent on build orientation and testing rate [ 57 ]. However, decreasing the specimen size to type V with the same print conditions leads to ductile failure as shown in Fig.…”

Extrusion and Injection Molding of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) (PHBHHx): Influence of Processing Conditions on Mechanical Properties and Microstructure

“…This microstructure results in increased elongation at break values because the randomly curled and oriented polymer chains can be stretched to a further extent [76]. In addition, increased elongation values at M = 80 • C are also likely to be related to lower residual stress of the polymer chains induced by slower cooling rates of the melt during molding [71,77].…”

Constant Temperature Approach for the Assessment of Injection Molding Parameter Influence on the Fatigue Behavior of Short Glass Fiber Reinforced Polyamide 6

“…It can be ass that these effects will be more evident in the results of the fatigue tests. Based on the results of the quasi-static tests, it is obvious that especially a higher melt temperature (as seen in [33] for a PA6,6-based nanocomposite) and higher mold temperature (as shown by [31] for polycarbonate and [32] for polypropylene), but also a higher injection volume flow rate can lead to higher mechanical properties. It can be assumed that these effects will be more evident in the results of the fatigue tests.…”

“…Therefore, a defined characterization of the process influences on the fatigue properties of the GFC is of great importance [ 18 , 28 ]. In various publications, the influence of fiber orientation in injection molded composites [ 20 , 25 , 29 , 30 ] as well as the influence of matrix material and different crystallization states on the fatigue properties have been characterized [ 24 , 31 , 32 ]. With regard to the process influences in injection molding, a significant influence of the melt and mold temperature as well as the volume flow on the dynamic strength and stiffness of the resulting GFC was demonstrated [ 15 , 33 ].…”