New mini grabs maximum attention at Arburg event

A new micromolding unit focused on the very tiniest of applications grabbed big attention at the annual Technology Days event last week at injection molding machine manufacturer Arburg. The three-day event in Lossburg, Germany at the company's HQ drew a crowd of more than 4100.

Even many who are not engaged in micromolding took time to eye the new micro-module, which was mounted on an all-electric Allrounder 270A (35 tonnes' clamping force) and molded eight gear wheels to a cycle, all from less than a single standard—not micro-granulate—pellet.

The wheels, weighing 0.001g apiece and measuring 1.58 mm around their outer diameter, were removed from the mold by one of the company's Multilift H automation units with a vacuum-equipped gripper, and then were funneled into eight test tubes.    

According to the manufacturer's Herbert Kraibühler, managing director, technology, the unit relies on plasticizing with a screw, and not a plunger-type system. Plunger-type micromolding units typically process only micro-granulate, which is more costly than regular granulate and also not as broadly available. The new module also helps ensure that dwell times for melt are kept short so that molten plastic doesn't degrade in the barrel.    

A two-part module handles preparation, dosing and injection of the melt. First, a servo-electrically driven screw pre-plasticising section, installed at a 45° angle to the horizontal injection unit, actually melts the material. The plasticising screw used is similar in design to a conventional three-zone screw. The molten material is then transported from the pre-plasticising stage to the 8mm injection screw, which really only serves to transport the melt to the mold. This tiny screw is fitted with a non-return valve.

The microinjection module is designed specifically for use on electric Allrounder A machines with a size 70 injection unit.

Arburg reports that of the more than 4100 visitors it welcomed last week, about 45% traveled to Lossburg from outside the country. The largest group from outside Germany came from Italy (160 attendees), with about 120 from the U.S. and almost 100 from Brazil. —Matt Defosse