PYEONGTAEK, South Korea (June 3, 2004) — Those touring Kumho Tire Co. Inc.'s newest tire plant, in Pyeongtaek, may be excused for thinking it's break time.
The plant, which churns out about 6,000 tires a day, 350 days a year, has no more than 45 employees on staff at any given moment spread out around the $62 million, 263,965-sq.-ft. facility, known as the Automated Production Unit, or APU.
The factory, which started pilot production in September 2003 and reached full capacity before year-end, is the culmination of nearly 11 years of research and development into Kumho's vision of tire production automation, according to Jong-Sun Sun, senior vice president and general manager for Pyeongtaek.
That vision, first set forth in January 1989, focused on eliminating as much as possible upstream component production, storage and transportation, Mr. Sun said. Instead, the plant is laid out to emphasize just-in-time or on-demand supply of tire components at the building station.
The APU concept combines up to nine tire making steps—including calendering, extrusion, tire building and others—into an integrated manufacturing system that reduces the length of the tire production line by a third, to about 2,600 feet, the company said. Tire building is still conventional, though, in the sense that tires are assembled on flat drums and inflated into shape for curing.
The tire building area consists of dual single-station tire builders operating in line. The first builder assembles the casing layers in two stages. The assembled green casing then passes to the second builder, where the bead and belt packages are added before the tread—extruded on site—is added.
A green tire ready for curing leaves the building station about every 48 seconds and is transported by overhead conveyors to the curing area, where it is directed automatically to the correct curing press and fed into and removed from the presses automatically. Two workers oversee the 32 curing presses.
One of Kumho's key objectives in developing APU was increased productivity. The company claims productivity of 251 pounds per man-hour is twice that achieved at its other Korean plants, in Geoksung and Gwangju.
The new plant houses four automated production lines in 184,730 square feet of manufacturing space. Rubber compound is supplied daily by the Goeksung and Gwangju plants, Mr. Sun said.
No more than one to two days' supply of materials is kept at the plant—a short drive from three different car assembly facilities in the area, Mr. Sun said. The plant was set up primarily to supply those factories with original equipment tires on a just-in-time basis.
As a predominantly OE supply plant, Pyeongtaek concentrates on a relatively small size range, producing tires in rim diameters from14 to 20 inches. The APU system is set up to accommodate two size changes per production line per day, Mr. Sun said.
Kumho's ultra-high-performance tire lines, in sizes up to 26 inches, are made at the firm's Gwangju plant.