Canadian Plastics

Hasco harnesses electromagnetism for clean-room valve gating system

You don't have to be a physicist to understand electromagnetism, but it certainly helps. Basically a force created by the interaction of electric and magnetic particles, electromagnetism exerts a push...

November 1, 2006   By Mark Stephen, associate editor



You don’t have to be a physicist to understand electromagnetism, but it certainly helps. Basically a force created by the interaction of electric and magnetic particles, electromagnetism exerts a push/pull effect on material objects that accounts for virtually all of the phenomena that we encounter in our day-to-day lives.

And now Hasco GmbH + Co KG is using this same force for its new Z1081 electromagnetic valve gating system, which is designed to enable faster production times and reduce the likelihood of contamination for such clean-room applications as medical technology and food packaging, as well for other applications where contamination by oil or lubricants inside an injection machine mold could spell disaster.

Believed to be the first system of its kind on the market, the Z1081 differs from traditional oil or oiled air-pressure activated valve gates in that its trigger is an electromagnetic charge initiated by short 24-volt (V) impulses sent from an injection molding machine. Eight electromagnets precisely guide and position the needle in the cylindrical in-gate, minimizing wear on the mold and thus time spent on mold maintenance.

The Z1081 can be used with almost any existing injection molding machine — hydraulic, all-electric or hybrid — without the processor having to resort to sophisticated external controls.

Additionally, fitting dimensions of 50×50 millimetres (mm) allow for a close cavity pitch in multi-cavity molds.

And the good news for the set-up crew is that adjustments to the valve needle’s position, or a change to the needle itself, can be done from the back of the mold, through the clamping plate, without having to dismantle the drive unit.

Hasco says one key feature is the Z1081’s electrically-driven needle valve, which lets plastics processors run leaner, faster operations and produce fewer bad parts.

“To be able to operate the valve gate simply with electricity in a clean-room environment is a big plus over conventional hydraulic or air valve gate systems because leakage and contamination of the produced parts are eliminated,” Louis Hbert, president of Toronto-based Hasco Canada Inc., said. “This can dramatically increase production levels.”

Cleanliness is not the system’s only advantage over traditional needle drives, however. “The Z1081 also simplifies tooling,” Hbert added. “If you use a piston, you have to bore those piston holes and this requires precision and accuracy. The Hasco system basically has a box with everything built in. It makes a big difference for assembly purposes.”

Hasco’s electromagnetic valve gate debuted in June, at the National Plastics Exhibition (NPE) 2006 in Chicago, where it was used on an 88-ton Arburg Inc. 420A all-electric injection molding machine, with a 32-cavity mold, to produce dart tips weighing 1.8 grams.

The Z1081 ‘s only weak spot, Hbert said, is in the manufacture of large parts, which require large pins to shut the material flow. “The Z1081 does not have the power to sustain the injection force if the pins are larger than three mm,” he explained. “Pin sizes larger than that will require a larger unit, which has not been designed yet.”

That limitation aside, as long as a parts producer has access to 24 V, Hbert said, the Hasco valve gate system can operate. “And if they don’t have access to 24 V, we can supply a PowerPC to boost [the] amperage,” he added.

So while it may still take a physicist to grasp all the complexities of electromagnetism, the potential value in using an oil-free valve gate system in the manufacture of clean-room applications is something anyone can comprehend.

Hasco Canada Inc. — Division of Hasco America (Toronto, Ont.); www.hasco.com; 800-387-9609


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