CHICAGO (July 11, 12:25 p.m. EDT) — Bigger may be better for cheeseburgers and NBA centers, but how about all-electric injection molding machines?
During NPE in Chicago, Ube Machinery Inc. showed the World´s Largest Electric Injection Molding Machine, with 1,550 tons of clamping force. Nobody else has one topping 1,000 tons. Ube´s big Ultima machine dwarfs the next-largest press, a 935-ton Powerline running from Milacron Inc.
Does size matter? That was the high-voltage question in McCormick Place.
Plastics News posed the question to officials of both companies. For their part, although Milacron´s largest is a 935-ton model, officials there don´t feel trumped by the Ube machine.
"No," said Richard Yund, general manager of Milacron´s Elektron Technologies unit. "We still have larger machines under consideration. We haven´t set a time frame at this point."
Milacron´s two top electric-press officials, Yund and David Bernardi, addressed the issue in a May 25 interview in Batavia, Ohio, during a pre-NPE news conference.
They stressed that Milacron can go bigger.
"We introduced large machines, 725 tons, with large injection units, 76 ounces, back in ´95," said Bernardi, director of marketing and sales at Elektron Technologies.
Bernardi said that making machines with larger and larger clamping force was not the problem. "The limitation was on the injection side, not on the clamp side," he said.
Milacron ended up going with a two-stage injection process. First, a fixed screw melts the plastic and feeds a shooting pot, and then a separate plunger sends the shot home. Ube´s machine uses a reciprocating screw, like traditional injection molding.
"We think we have a better melt," Bernardi said. "More shot capacity. Certainly from our standpoint, more cost-effective. Because if you use the reciprocating screw for the large sizes, there have to be huge ball screws" driving it.
Taku Tawarada, Ube´s marketing and sales manager, agreed with some of the statements from the Milacron officials — but he pointed out that plunger technology was popular back decades ago.
"They have a point, yes," Tawarada said in an interview at Ube´s NPE booth. "There are certain materials that would be very nice using that melting pot. But the biggest thing about this plastics industry is that everybody else is using the recipcoating screw."
Tawarada said he thinks the melting pot configuration might be a hard sell in the year 2000, even though it has some advantages.
"I do not agree it is better," he said. ``(But) it is a good application for certain materials." He noted that color changes can be easier with a regular screw than on a plunger machine.
Tawarada conceded that the large ball screws used by Ube — some of the biggest ever made — are expensive. (Ball screws convert the motion from an electric motor into linear motion, like the type needed to power an injection molding machine).
Milacron is planning to increase the clamping-force tonnages of its all-electric machines, officials said, but they gave no details.
"We still maintain that a single drive with a gear drive on the extruder is the best way to do this. It´s extrusion technology," Bernardi said.