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Weld lines can be caused by several different problems: Low temperature of injection moulding machine barrel; Inadequate back pressure; Injection pressure or injection speed is too low; Low mold temperature; Small injection gates and/or runners; Improper location of injection gate; Too many gates; Excessive gate land length; Improper flow rate ...
A casting defect is an undesired irregularity in a metal casting process. Some defects can be tolerated while others can be repaired, otherwise they must be eliminated. They are broken down into five main categories: gas porosity, shrinkage defects, mould material defects, pouring metal defects, and metallurgical defects.
During an extrusion process it is essential to consider the surface finish of exposed product surfaces. As a general rule, the narrower an exposed surface, the more uniform its finish becomes. Webs, flanges and abrupt changes in metal thickness may show up as marks on the opposite surface of an extrusion, particularly on thin sections. The ...
Extrusion profiles with holes are very difficult to produce because they can not be just produced by a simple die, so it should be practiced to reduce the number of holes as much as possible. With steels and other less extrudable materials, holes in asymmetrical shapes should be avoided because they lead to unsymmetrical stresses which cause ...
Profile extrusion, the extrusion of complex shapes such as rain gutters, structural supports, and other components, brings with it some of the most complex die designs of any extrusion process. [6] This difficulty is due to two primary concerns: producing the initial, still molten profile, and then controlling for asymmetrical shrinkage and die ...
Die swell occurs in instances of polymer extrusion, in which a stream of polymeric material is forced through a die, a specialized tool in manufacturing to shape or cut polymeric materials. Die swell is an instance where a polymer stream is compressed by entrance into a die, and is followed by a partial recovery or "swell" back to the former ...
Extrusion is a manufacturing process used to make pipes, hoses, drinking straws, curtain tracks, rods, and fibre. [1] The granules melt into a liquid which is forced through a die, forming a long 'tube like' shape. The shape of the die determines the shape of the tube. The extrusion is then cooled and forms a solid shape.
Inclusions can create problems in the casting when they are large and in too high concentration. Here are examples of problems related to inclusions: Pinholes in light gauge foil; Flange cracks in beverage containers; Surface streaks in bright automotive trim and lithographic material; Breakage in wire drawing operation; Increased tool wear and ...