Extrusion process advantages/disadvantages

Excessive and/or inconsistent residual orientation in polymer sheet induced during the extrusion process can be a vexing problem in thermoforming. Thermoformers work with extruders to keep both machine-direction and cross-direction orientations to 5% or less. Table 3 gives advantages and disadvantages of several thermoformable polymers. 

FIGURE 4.137 Extrusion processes on the example of Fused Deposition Modeling (FDM) Advantages and Disadvantages... 

Compare flowcharts for the prodnction of maize flakes via traditional and extrusion processes. What are the advantages and disadvantages of each process How can you recognize flakes made via extrusion ... 

Film and sheet can, in principal, be made by calendering or by extrusion. Factors that govern the advantages and disadvantages (limitations) of each process can interact in a complex way. Factors to be considered include (1) type of material to be processed, (2) quantity of product to be produced, (3) thickness... 

Reactive extrusion has emerged from a scientific curiosity to an industrial process. Various types of extruders can be used, all with their specific advantages and disadvantages. Further development suffers from lack of kinetic and rheological data at high conversions and from uncertainties about heat transfer and reactor stability. Nonlinear effects in the process can give rise to instabilities that are of thermal, hydrodynamical or chemical origin. 

Film can be produced either by extrusion tubular blowing or flat process. Each has its advantages and disadvantages. These processes result in film with a molecular orientation predominantly in the machine direction (MD). As reviewed later, orienting the film can be in two orthogonal directions that develop superior optical, mechanical, and physical properties. The process is known as biaxial orientation and it can be applied to both tubular and flat film. 

The principle advantage of dry extruder preparation is that no expensive stacked-tray cookers or steam boiler are required, and the total capital investment for facilities under 100 tons per day in size is significantly less than for traditional full-press or solvent extraction processes. Therefore, this means of preparation is commonly applied in very small-scale plants commonly referred to as mini-mills. The primary disadvantage of dry extruder preparation is that the meal produced is higher in fat content than many poultry producers desire, and lower in bypass protein than many cattle producers desire. Thus, meal produced from a full-press mill using dry extrusion preparation generally obtains a lower price than meal produced from a traditional full-press operation. 

As mentioned previously, the drug may be present in one of several forms in the final product. The advantages and disadvantages of each form have been discussed in both injection molding and melt extrusion systems. Solid dispersion systems may be more stable and more easily processed than solid solution systems, but solid solution systems may be produced that are transparent and have increased bioavailability of poorly soluble compounds. Figs. 3 and 4 show the X-ray diffraction patterns for a polymer film containing lidocaine. The absence of the lidocaine peaks in the extruded samples, and the reported... 

Simple addition of a compatibilizer to a mixture of polymers has the disadvantage of high costs. The extrusion compatibilization process, as described here, has the advantage that the copolymer is formed during the mixing process and no extra process step is necessary. 

The shaping of carbon cathode blocks may be performed by extrusion and by vibro pressing. Both processes have advantages and disadvantages. The possible defects in cathode blocks after extrusion and after vibro pressing also differ. 

Basic Principles, Advantages, and Disadvantages Commercial Extrusion-Based RP Processes Fused deposition modeling (Stratsys Inc.)... 

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