| HotFlo! | Technical Information | |
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The sketch above shows the basic details of the way circular runners can be used to create a tapered tangential runner feeding a long thin gate which is used for many types of Die Cast parts.
From the tapering circular runner, a Vee shaped Lead-in zone, with a constant converging angle, directs the molten metal into the Gate-Land through which it passes to fill the cavity. The gate can be cut into both die-halves as shown here, or alternatively, into one half only. A good rule of thumb is to make the entry of the Lead-in at least twice the the Gate-Land depth.
There are three predominant kinds of Gate-Land design, depending on the post processing requirements.
Trim PressWhen the runner is to be removed from the casting by a trim press operation which shears through the Gate-Land, it is usually of constant depth from the Lead-in to the Cavity. |
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Hand Break-offWhen the runner is to be removed by hand, creating leverage through a bending action, the the Gate-Land depth usually tapers so that the thinnest point is right next to the outside edge of the Cavity. This produces a clean break-off between the runner and the casting. |
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Hand Break-off and PolishWhen the casting has to be hand or machine polished after a hand break-off, the Gate-Land is sometimes designed with the thinnest point slightly away from the outside edge of the casting as shown here. This is done so that any metal which pulls away at the gate region, due to the bending action, will not penetrate the casting surface at the gate. Instead, it purposely creates a small ridge of metal on the edge of the casting which is removed by linishing or polishing. In this way, a high quality surface can be created at the gate line |
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The sketches here illustrate these Gate-Land designs cut into one die-half only. The same principles can be used for gates cut into both die-halves. |
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| Document Control | Issue 1 | 1st July 2000 | www.hotflo.com |
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