APS Plastic Systems LLC of Tecumseh, Mich., claims its new intermittent extrusion blow molding machine could replace today's reciprocating-screw technology.
The main difference: material is first delivered to a shot pot, via continuous extrusion, then moved forward to create the parison. That means all material in the pot has received the same treatment during the extrusion process. A reciprocating screw, on the other hand, receives material at different points along the feed section of the screw.
Also, the shot pot creates less linear shear on the resin, since material does not slip back over the flights of the screw, as in the reciprocating-screw process.
The APS machine also does faster parison delivery, and the parisons are very stable, with no twisting.
Dual hydraulic cylinders move the toggle-clamp mechanism, using proportional control.
"Our goal with the APS Shot Pot Machine Line System was to correct or remove as many as possible, if not all, of the problems that have long been associated with reciprocating screw technology," said Phil Bailin, vice president of sales for APS. "Without changing the blow time, we have been able to decrease the cycle by one full second on an eight-second cycle container."
At an open house in Tecumseh, APS ran a Model SP 35-10 intermittent extrusion machine, with a 3.5-inch-diameter screw that had a 24-to-1 length-to-diameter ratio. The press produced 2-liter HDPE handleware containers, 10 at a time, on a seven-second cycle.
An optional hydraulic package can shave another half-second off the time.
Tel. (517) 423-4435.
