With this gate design, the plastic melt is introduced into a mostly rotationally symmetrical part area through several radially arranged feed sections. The spoke-shaped distribution supports uniform filling of ring-, disc-, cup-, or sleeve-shaped injection molded parts and can significantly shorten the flow path compared with one-sided gating. The spoke-umbrella gate is often used when central gating is not sufficient from a design perspective or when better melt distribution around the circumference is required. The number, cross section, and position of the individual spokes influence pressure loss, flow front formation, weld lines, part orientation, and shrinkage behavior. After injection molding, the spoke-shaped gate residues usually have to be removed from the part mechanically or through predefined separation points.
Injection Molding Process: Simulated filling of a cavity via a spoke umbrella
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