American Maplan Corp. said its VSI die head for polyolefin pipe is based on a two-stage distribution concept, since it combines a threaded, kneading spiral mandrel with a spiral lattice basket.
Maplan of McPherson, Kan., claims the combination of the two elements produces a more homogeneous melt and offers better control of wall thickness.
The two-stage process begins with coarse distribution of the mold material in a spiral mandrel with a simple, smoothing thread. In the second stage, the lattice basket gives fine distribution.
The two stages produce a gentle, homogeneous melt. The proc¼ess eliminates dead zones, reduces back pressure, lowers melt temperatures and speeds color changes, the company said.
Maplan also has enlarged the die's processing window.
VSI die heads can produce pipe in diameters of 1.28 inches to 64 inches, at rates of 770-2,640 pounds an hour.
Tel. 620-241-6843, fax 620-241-0207, e-mail [email protected]