operating costs are kept down. Heated options, although more
In some cases, metalcasters may opt to transfer molten metal from a furnace directly to the mold to eliminate hand-pouring.
Casting facilities using unheated
vessels in a high production environ- ment often utilize holding furnaces or other types of melting devices that can maintain a constant source of molten metal to provide a high enough volume of metal to feed production. Heated devices are more flexible in molten metal delivery and often eliminate the need for holding fur- naces. Typically associated with batch melting, a heated pouring device can act as the holding furnace. One of the most basic ways to
automate is with a driven ladle, according to Bill Pflug, manager, automated pouring systems, Induc- totherm Corp., Rancocas, N.J. Not 100% automated, it allows the opera- tor to maneuver the ladle to pour a mold without physically doing the work. Facilities can take that a step further by incorporating devices that provide feedback to the ladle’s control, either with a camera, laser or sensors. Te feedback allows the sys- tem to automatically control the pour. With automatic ladle pouring, you
can exchange the ladle with another for more metal or alloy changes, Con- rad pointed out. Beyond a driven ladle, a vessel with a stopper rod nozzle or valve that will control the pouring from the
bottom reduces slag compared to an open-air ladle. These first few options are unheated, so the molten metal is losing temperature as soon as it leaves the furnace. But, capital and
costly, provide another level of control in the metalcasting facility, and are well suited for producing thin- sectioned castings, such as fittings and manifolds. Pressurized furnaces can be used to fill the mold directly or transfer metal to the mold via a launder before filling the mold using a stopper nozzle or valve similar to an unheated ladle. Capital and operat- ing costs are higher, but the pouring operation can be better controlled. Permanent mold and diecast- ing shops often opt for robotic ladling—where pouring profiles are programmed into the robot to pour different weights for each mold— incorporated into cells. Tis has been a popular choice in North America, according to Brown, although he sees that changing. “The majority of North Ameri-
can companies are still using ladles,” he said. “But they are moving away from ladles and part of that is that the quality of the metal to make sophisticated castings is driving the
Bottom-pouring devices lend extra control and better metal quality compared to manual pouring with a typical spouted ladle.
February 2015 MODERN CASTING | 35
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