Fanuc Ltd. showed three of its all-electric injection molding machines at K 2007, all three with Fanuc robots doing part removal or assembly.
A new press, a Roboshot S-2000i 50B with 50 metric tons of clamping force, molded very fine, narrow-pitch connectors in a four-cavity mold, from liquid crystal polymer. A robot removed the connectors and put them into bags separated by a cavity. A vision system checked the parts.
Fanuc, of Oshino-Mura, Japan, has sold 28,000 all-electric presses since it introduced the first one in 1984. In the U.S., the Roboshot presses are distributed by Milacron Inc. of Cincinnati, under a long-standing agreement.
Fanuc also has played a key role in introducing all-electric injection molding machines to Europe. It hasn't been easy, since all-electrics account for just 10 percent of injection presses sold there, according to Klaus-Ulrich Schmid, sales manager at Fanuc Roboshot Europe GmbH in Neuhausen, Germany.
In Asia, the numbers are nearly flip-flopped, with 75 percent all-electrics and just 25 percent hydraulic machines. The United States is now about split 50-50.
Fanuc targets five markets: medical, connectors, automotive, microparts and precision parts.
At K, Fanuc also molded parts on two other B series machines. A model 100B, with 100 metric tons of clamping force, molded clear polystyrene into clear card cases, the top and box sections, then a robot assembled them together. A 150-tonne press in a portable clean room, model 150B, molded polypropylene medical cannula tubes in a 96-cavity mold, running a 7.5 second cycle.
Fanuc developed the B series because customers asked for a machine that could accommodate larger tools. Engineers increased the tie-bar spacing, and boosted the stiffness of the machine, so it could handle heavier and more-complex molds.
Two-platen technology on the moving side of the clamp gives a uniform clamping force on the mold, good for producing small, high-precision parts in multicavity molds, Fanuc said.
Takeshi Oda, chairman of Fanuc Roboshot Europe GmbH, described the company's manufacturing operation during a K- show press conference Oct. 25. Fanuc builds both robots and injection molding machines - and uses robots heavily to build press components. The highly automated plant has three times as many robots as people.
``Unmanned operation is realized even in the large machining factories by the machining cells,'' Oda said.
All of the parts of the Roboshot - including the clamp, injection unit and servomotors - are made by fully automated production machines.
Oda said the all-electric technology allows the press to make two or three movements at the same time, such as mold closing and injection; metering and mold opening; mold opening and ejecting; and mold closing and ejector recovery. That minimizes cycle time.
Oda said the presses boast fast injection speeds, of up to 1,000 millimeters per second, in a stable press, which is required to mold very thin-wall parts.
All three machines at K 2007 ran injection speeds of 330mm per second.