TECHNOLOGY: Injection Pressure

The news at this year’s K Show was “electric”– as in electric injection molding machines. Prior to the show (when this report was written) at least ten companies had announced plans to introduce their first all-electric models at the show. Yet the show also saw the introduction of a wide array of groundbreaking technologies in other areas, such as co-injection, control systems and novelty molding configurations.

ELECTRICS RUSH IN

Engel introduced the world’s first commercially available all-electric tiebarless machine. Called e-motion, it will be manufactured at Engel’s Guelph, ON facility, and is initially being offered with a clamping force of 60, 110 or 165 tons. The machine combines the benefits of both electric and tiebarless technologies, including high precision, greater energy efficiency and improved molding economics and versatility.

The e-motion machines differ from Engel’s standard hydraulic tiebarless models in the incorporation of a five-point toggle clamp. As well, the Flexlink compensation linkage, which works to keep the platens parallel, is mounted behind the stationary platen rather than behind the moving platen. Independent servo drives provide simultaneous operation of all machine functions, delivering fast cycle times.

Krauss-Maffei launched its Eltec line of hybrid electric machines in four sizes ranging from 55 to 165 tons. The machines are based on the company’s two-platen C series. Plastication and injection movements are controlled by dedicated AC servomotors; while an enclosed hydraulic system provides clamping force.

Battenfeld Injection Molding Technology showcased its new line of EM fully electric machines, beginning with a 176-ton model. The machines are similar to the company’s all-electric CDK-SE series, but come in a wider range of sizes, with more injection and clamping options. The injection unit is powered by two servo motors and a belt-driven, planetary-roller screw. An enhanced control system processes position information more quickly, facilitating greater precision than on the CDK-SE series.

Demag’s Ergotech El-Exis E Series machines feature electric drives for all main movements and an integrated power pack for secondary movements such as core pull and ejection. The auxiliary hydraulic unit uses only 1/10th of the oil required for an all-hydraulic machine. The E series provides an overall energy savings of 45 to 55 percent in comparison to hydraulic machines.

Negri Bossi introduced two new presses in its VE line of all-electric machines, 176- and 231-ton models. The presses have a toggle-clamp design that is geared for high-performance applications. Negri Bossi also launched its new hybrid V 700 machine equipped with a variable-frequency electric screw drive to reduce energy consumption.

Arburg has leaped into the electric market with the launch of its 88-ton Allrounder 420 A 800-350 model. The machine features five-point toggle clamping and combines hydraulic and electromechanical drive concepts into one machine. In the basic version, all the main axes are directly, servo-electrically driven. Ejector and core pulls can be moved either hydraulically or electromechanically, depending on the application.

EYE-OPENING INNOVATIONS

It wouldn’t be a real K Show if there wasn’t some show-stopping technology. Indeed, there is.

Twinshot Technologies introduced its patent-pending co-injection process that permits the production of multi-material parts with a sandwich construction using a slightly modified standard injection molding machine.

“In traditional co-injection you have two independent screws and barrels,” says Joe McRoskey, technical specialist for Twinshot. “You also usually need to have an expensive manifold to bring the two materials together uniformly. With our technology you only need one barrel, and no special manifold.”

McRoskey says Twinshot employs a unique multi-screw assembly, which is essentially a screw inside a screw. The inner screw acts as an extruder for one of the materials, while the outer screw acts as a reciprocating screw for plasticizing of the second material. The arrangement provides for the separation of different melts during the recovery portion of the cycle.

The technology is designed to be retrofitted to existing machines and is 35 to 40 percent cheaper than the cost of buying a new co-injection machine, according to McRoskey. He says Twinshot plans to license the technology to retrofitters, and is also looking to offer the technology to injection molding machine OEMs as well.

Krauss-Maffei formally launched its injection molding compounding (IMC) machine capable of in-line compounding directly upstream of an injection molding unit. A KM 1000-6100 IMC produced a car tailgate. The part was produced in a back-compression process where a multi-layer film is inserted in the mold and glass-filled ABS compound is injected behind it to produce a finished part.

In place of a conventional plasticizing unit, an IMC machine has a special injection unit yoked with a co-rotating twin-screw extruder.

Husky Injection Molding Systems Ltd. demonstrated a 880 Hylectric machine with a two-cavity pail mold. The Hylectric machine combines the energy efficiency of an all-electric machine with the performance of a hydromechanical machine. Husky also demonstrated an in-line compounding process for long-fibre-filled parts in a one-step process on a 330-ton Hylectric at the Werner & Pfleiderer exhibit.

Ferromatik Milacron demonstrated a 495-ton K-Tec high-performance, multi-component machine equipped with a horizontal stack-turn molding system. The patented mold system, which employs the so-called “cube technique” is made by Foboha, and allows twice as many cavities to be incorporated in the mold without increasing the size of the machine. Cycle time is shortened, and productivity enhanced as parts can be cooled on the non-injection sides of the cube.

While only a small sampling of the K Show’s wares, you get the picture: The bar for world-class injection molding technology just got raised.