HotFlo! Why it Works HotFlo! technology

Circular versus Trapezoidal Runners

Most traditional Die Casting runners have a cross section in the shape of a trapezium.

Why is this so ?

There are two main reasons.

 Circular or trapezoidal

Firstly, with the toolroom milling technology available in the past, it was the easiest way to create a runner with a continuously reducing area. A standard flat ended milling cutter could be set to machine a rectangular groove which decreased in depth away from the sprue. By re-cutting each side with a taper, the trapezoidal shape was created which could be easily ejected from the die.
 
Secondly, the traditional Die Casting sprue hole and post dictated that a trapezoidal runner-type sprue was the only practical solution. It made little sense to have a trapezoidal sprue runner and a circular feed runner, so the trapezium became imbedded as the traditional Die Casting runner.


However, two new developments have made tapered circular runners a practical alternative for use in hot chamber Die Casting.

The first development was the sophisticated CNC milling machines with their associated software, new coated cutters and high speed machining techniques. It is now an easy task to program a mill to create a circular runner which reduces continuously in cross sectional area and also goes smoothly around bends. In fact, it is now an easier task that milling a sharp cornered trapezium. And machining hardened toolsteel is an everyday occurrance.

The second development is the HotFlo! hot sprue technology, which automatically creates a circular flow path from the nozzle to the runner.

For the first time, tapered circular runners are now a practical reality for use in hot chamber Die Casting.

It is not mandatory that circular runners be used with a HotFlo! system, but they offer many benefits, and no downsides, for those Die Casting companies willing to adopt them.

  Circular Runner Circular Runners
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