Mold cycle time tends to be driven primarily by the length of time it takes to cool the plastic material until the part can be ejected from the mold. The sections of the molded part that take the longest to cool are the hot-spots.

Brass baffle blades have been used the same way for decades—to redirect coolant flowing through a cooling channel into another intersecting cooling channel. The most familiar application of the baffle blade is as a pointer to a hot-spot in a mold, improving overall cooling efficiency.

The most common arrangement for mold cooling design is a series of cooling channels that run parallel to the parting line, or molding, surface. Occasionally, as dictated by molded part geometry, it is advantageous to reroute the coolant flow up toward the parting line.

A molded part with deep-draw geometry—a drinking cup, for example—will cool better if coolant is directed up into the standing core shape, the interior of the drinking cup in our example. The baffle blade is a proven method for redirecting coolant flow in these cases.

The baffle blade is essentially a bidirectional, straight line, from a coolant channel to a hot-spot and then back to the coolant channel. The blade splits a bored cooling channel into two half-circles. When the coolant runs into the baffle blade, it is redirected into the first of these two half-circles. The coolant travels up the front side of the baffle blade and is then redirected, 180o, onto the back side the baffle blade. The coolant then flows back to the coolant channel and continues on its way through the mold cooling system.