sion/spheronization affects the properties of the resulting pellets. Pharmaceutical scientists originally directed their focus to extrusion, spheronization and drying which can be seen from the literature. Only a few authors reported investigations concerning the impact of the granulation step. Baert et al. investigated ternary mixtures of microcrystalline cellulose (MCC), a drug substitute and...

Twist extrusion process is a rather new route to produce highly strained materials. In this process, severe plastic deformation is applied by large shear strains. In current article, required energy for twist extrusion by use of admissible velocity field together with the upper bound technique is predicted. The proposed model is capable of considering the effect of various parameters such as di...

The dimensioning of injection heads for the extrusion of rubber profiles is exclusively based on empiric knowledge of the non-linear flow behaviour of elastomers. Thus, the design of injection heads is carried out with subject to the used rubber blend, whereas the geometry of the appropriate profile is achieved by empiric adaptation of the extrusion die. This was one of the motivations for a re...

Introduction Bar extrusion is a process in which a block of metal (billet) is forced to flow by compression through a tool (die) opening of a smaller crosssectional area than that of the original billet. There are two basic types of bar extrusion: direct and indirect. The most important and common method used is the direct extrusion (Lange 1988). Figure 1 shows the principle of direct bar extru...

Polymers for hot melt extrusion must exhibit thermoplastic characteristics in order to permit the melt extrusion process and they must be stable at extrusion temperatures. Other relevant characteristics are: suitable glass transition temperature (Tg) of 50–180 °C, low hygroscopicity and no toxicity since larger amounts of polymer are used [1]. Extrudability of a polymer is mainly determined by ...

1 AAN013 shear rate behavior. For example, gauge variation can be caused by variable post-extrusion die swell, and warpage can occur from non-uniform relaxation during cooling of an improperly formulated injection molding compound. Also, by testing at low enough shear rates so that the measurements are in the melt’s linear viscoelastic region, the data can be linked directly to the polymer’s mo...

Binary and ternary blends of poly(lactic acid) (PLA), polystyrene (PS) and acrylonitrile-butadiene-styrene (ABS) were prepared using a one-step extrusion process. Rheological and mechanical properties of the prepared blends were determined. Rheological properties were studied using a capillary rheometer, shear rate, shear stress, non-Newtonian index, shear viscosity and flow activation energy w...