Koplas: Servo-pumps get thumbs up from Korean machinery users

Seoul—Energy savings continue to be high on the agenda at Korean injection machine OEMs as evidenced by offerings on show at the recent Koplas show in Seoul. Conceding the all-electric market to Japanese OEMs, the focus is on deployment of servo-powered hydraulic pumps to realize these energy reductions. The LGH850MEIII from LS Mtron Ltd. (Anyang, Korea) on display at the recent Koplas show in Seoul as one such example. Supplier LS says the machine employs two servo-piston pumps that generate an energy conserving effect of up to 45%.

"This machine is proving particularly popular in the auto sector. We offer servo-pumps as an option but in essence they've become standard because almost all our customers are opting for them," says Lee Jong-Hun, general manager of the Overseas Sales Team at LS.

Woojin PLAIMM (Incheon) has also opted for the hybrid route with its two-platen machine that employs a servomotor for plasticizing. Servo-pumps are also employed; three in the case of a 2000-tonne machine. Machines range in clamping force from 450 to 3000 tonnes, while a 3500-tonne machine should be available by year-end.

Hyundai Injection Machinery's Lee: hybrid injection presses set to become increasingly popular.

Hyundai Injection Machinery (Changnyeong) also reports that its servo-pump option is now essentially the de facto standard for its EDIS two platen direct locking series injection machines (700-3000 tonnes) as well as its smaller SPE machines (650 tonnes and below). The company uses Voith gear pumps and Shenzhen Inovance Technology servomotors its servo-pump system. To ensure its smaller machines are competitively priced, Hyundai outsources production to Guangdong Only Machinery Co. for clamping forces of 70 to 450 tonnes. "We are facing increased competition from Chinese vendors in the Korean market," says  Hyundai's production director Byung-dae Lee.

Lee expects servo-pump-equipped machines to account for 40% of overall shipments this year, and the majority in 2014. "Typically we find the payback period is three years for small machines and four to five years for large machines," he notes.

Dongshin Hydraulics Co. (Busan, Korea) employs two servo-pumps in its K700 (Mucell) injection press that was on show at Koplas. "Energy savings of 30-70% are possible according to assistant manager Kim Hyoung Joon. "Mucell also helps us reduce the injection pressure by 30-50%, and clamping force by 30-80%," he adds.

Woojin has also made improvements to its TN250E all-electric machine, with the adoption of a new toggle mechanism that bends from the inside to the outside, thereby applying more pressure to the center of the mold. Further, while the overall dimensions of the machine are identical, the daylight has been increased by 10% to 1250 mm.

The all-electric employs three servomotors on the injection side to realize an injection speed of 1000 mm/sec. The injection drive system including controller is sourced on a turn-key basis from Austrian vendor B&R (Eggelsberg, Austria).