Tab gate

When the gate leads directly into the part, there maybe surface imperfection due to jetting. This may be overcome by extending a tab from the part into which the gate is cut. This procedure is called tab gating (Figure 2.14g). The tab has to be removed as a secondary operation. 

Tab gate n. In injection molding, a small removable tab of approximately the same thickness as the molded item usually located perpendicularly to the item. The tab is used as a site for edge-gate location, typically on items with large flat areas. 

A tab gate is an extension of the part that connects with the runner, thereby locating shear stresses outside the part. For this reason, tab gates are used with flat, thin parts and for materials such as polycarbonate, acrylics, SAN, and ABS, which develop high levels of shear stress during molding. 

Figure T.l Tab gate. (Ref Schwartz, S.S. and Goodwin, S.H., Plastics Materials and Process, van Nostrand Reinhold, New York, 1982, p. 249)...

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