The arrows on the drawing represent the plastic flow from the sprue, runner, flash gate, and into the part cavity. A very thin, long flash gate is ideal for thin dials, and large flat sections, with an uninterrupted straight edge. This style gate helps to disperse the plastic material into the cavity in a wide pattern.
The gate shown in this cross-section is very long and thin, giving a wide dispersion of plastic material. However, the thin, flash type opening to the cavity will cause problems with low viscosity and most filler type resins.
Enlargement “A” shows a very thin, long scar left from the flash gate. This gate has the advantage of leaving a very small cosmetic mark on the part, as well as being easily removed by hand. A trim fixture could be used if desired.
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