New Fuel-Tank Machine Moves Molds, Not Parisons.

Two rail-mounted pivoting mold carriages and a stationary continuous-extrusion head are said to more than double the output rate of auto gas tanks compared with current production methods. The new PFT (Plastic Fuel Tank) machine from JSW Plastics Machinery of Japan (U.S. blow molding office is in Marietta, Ga.) is designed to produce six-layer tanks of HDPE, EVOH, tie resin, and regrind. The model NB150-2CCE-MLG uses two separate but synchronized mold carriages that slide under the extruder head to clamp and blow the parison, then pivot away from the head for cooling while the second mold comes in under the head. At the cooling station, the part is filled with air at -30 F. After cooling, the mold carriage swings back toward the head but stops at an intermediate position for robotic part removal.

As compared with current six-layer gas-tank production with stationary molds and a moving head, the JSW system is said to reduce unpredictable air-draft effects on parison wall thickness. Shorter parison hang time reduces drawdown problems, and less flash is also said to result. The new design also reportedly allows larger parison diameters, and choice of top, bottom, and side blowing.

Two PFT machines have been running for about eight months at Yachio (a Honda subsidiary in Japan), molding tanks for the Honda Civic at cycle times well under one minute, or more than twice as fast as production elsewhere, JSW says. Yachio plans to start up a PFT machine at a new plant in Marion, Ohio, near the Honda of America factory.