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The amount of strain in the stable neck is called the natural draw ratio [6] because it is determined by the material's hardening characteristics, not the amount of drawing imposed on the material. Ductile polymers often exhibit stable necks because molecular orientation provides a mechanism for hardening that predominates at large strains. [7]
In this case the material flow is uniform and provides additional load distribution for the part. For better rigidity and material flow, the general guideline suggests that boss should be connected to nearest side wall. Presence of undercuts in the design can make it difficult to remove the molded product from the molds
Material selection is a step in the process of designing any physical object. In the context of product design, the main goal of material selection is to minimize cost while meeting product performance goals. [1] Systematic selection of the best material for a given application begins with properties and costs of
The synthesis and processing of polyacetylene films affects the properties. Increasing the catalyst ratio creates thicker films with a greater draw ratio, allowing them to be stretched further. [8] Lower catalyst loadings leads to the formation of dark red gels, which can be converted to films by cutting and pressing between glass plates. [20]
Draw resonance has not been found to be a function of the flow rate, however. A polymer melt approaching a Newtonian fluid such as PET can have a drawdown ratio of around 20, whereas highly shear thinning and viscoelastic polymer melts such as polyethylene, polystyrene, and polypropylene may have critical drawdown ratios as low as 3.
Semi-crystalline polymers such as polyethylene show brittle fracture under stress if exposed to stress cracking agents. In such polymers, the crystallites are connected by the tie molecules through the amorphous phase. The tie molecules play an important role in the mechanical properties of the polymer through the transferring of load.
A material property is an intensive property of a material, i.e., a physical property or chemical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one material versus another can be compared, thereby aiding in materials selection.
Successful drawing depends on the flow and stretch of the material. Steels, copper alloys, and aluminium alloys are commonly drawn metals. [4]In sheet metal drawing, as a die forms a shape from a flat sheet of metal (the "blank"), the material is forced to move and conform to the die.