Graham Engineering Corp., which makes extrusion blow molding machines in York, Pa., has made a round of major improvements to its SPM series of machines that transfer material directly into a shooting pot for delivery of the parisons.
The new model features a larger-diameter (4½ inches), high-output, grooved extruder with a length-to-diameter ratio of 28-to-1. It can shoot more than 35 ounces (1,000 grams) per second. Graham also offers shot capacities of 42, 70 or 105 ounces (1,200, 2,000 or 3,000 grams), independent of extruder diameter.
A compact Knodler gear motor runs quietly. The extruder has a PSI model CSC-125 continuous screen exchanger, an option that is not available on a reciprocating-screw machine.
The machine's die head and manifold feature eight heads on 9-inch center-to-center spacing with 100-point parison programming, three-point front die adjustment, a hydraulic ram-down prefinish and blow pin adjusters that have Graham's toolless adjustment feature.
For handling and trimming, the machine has a double swinging takeout arm, an 8-inch Graham cooling bed and a Graham 24-by-24, four-platen, triple-index trimmer with leak detection.
Graham Engineering has been making shot-pot machines for two years. According to Graham, advantages of the shooting pot include the elimination of the ball spline and maintenance to the thrust bearing; continuous extrusion for better melt and lower stock temperatures; the ability to add automatic or manual screen changers, since the material does not have to travel through the screen pack during parison delivery; less shear, thanks to positive displacement delivery; and a faster shot speed.
The company also said the parison is much more stable, because as the plastic goes into the shooting pot, it has a chance to relax and loses its memory of the extruder rotation, so the parison remains straight as it exits the die heads.
Tel. 717-848-3755, fax. 717-846-1931, e-mail [email protected]