cast steel linings the conglom- erate produces continued to grow. By 2010, the board was ready to focus on modernizing, optimizing and expanding the two North American businesses to increase their combined annual production from 43,750 to 52,500 tons. Te two facilities are com-
mon in their product mix and general process flow, but they had different needs to improve productivity for a higher “sweet spot.” “Tis isn’t full capacity—it
is our comfortable run pace,” said Bill Grau, plant manager at Duluth. “It’s where we aren’t working overtime and can sup- ply that tonnage every day, no matter what comes up.” To increase the sweet spot, both metalcasting facilities needed to identify and elimi- nate bottlenecks. In Duluth, the constraint was in heat treat capacity and process flow. “Like every foundry
you’ve visited, in the finishing department we had castings everywhere,” Grau said. “You don’t see that anymore. It flows through very quickly.” In 2011, ME Elecmetal spent $24 million between the two North American cast- ing facilities. In Duluth, that included adding onto its exist- ing building for additional heat treating space, adding space to its mold cooling barn, address- ing volatile organic compound (VOC) emissions and imple- menting melting best practices. Te Duluth facility makes its cast-
remote control for one of its melt charge cranes. “In the melting depart-
ment, we were focused on best practices: How do we get rid of the waste? What’s the best melt time we can get?” Grau said. “We optimized the two furnaces we had, and that achieved our projected ton- nage goal for 2011.” In the nobake casting facil-
ity in Tempe, much of 2011’s projects were focused on the shakeout systems, the sand system and automated pouring lines. Tis additional equipment resulted in upgrading the electri- cal substation capacity as well. “One of its problems was that it could mold faster than it could get sand,” Grau said. “And Tempe battled to cool the sand. So they concentrated on mak- ing sure they got enough sand to their mold table, properly balanced the shakeout to the molds and modified conveyors to handle all the mold sizes.” Prior to the upgrades,
Two years of plant optimization has resulted in an increase of 50 net good tons per day in Duluth.
ings via V-process molding, in which a vacuum acts as the sand binder, holding the mold together. After the vacuum is released, the mold collapses into loose sand around the still-hot casting. Te mound of sand around the casting acts as an insulator, so the flasks are moved to a separate building for cooling. Because Duluth’s existing building was com- pletely filled, it added 122 x 150 ft. of space for an additional 108 flasks to cool. At the molding line, ME Elec-
metal uses an alcohol wash, and VOC emissions were approaching the maximum limit of their permit. A water-based alternative would add operational complexity and cost more than $1 million. Instead, Duluth installed a $350,000 carbon absorp- tion system to maintain compliance even at its highest production rate. In the melt room, Duluth improved
its furnace gunning equipment, added a third charge bucket and a second ladle transfer cart, and implemented
Tempe would shake molds too large for the shaker deck out on the floor. Sand would be returned to the system with a bobcat skidder. Te unbalanced sand system and elevation changes slowed down the sand movement in its west shakeout to 5 tons an hour. It had been originally designed for 25. Tempe moved the sand cooler unit closer to the shakeout and mixer, instead of behind the plant, for better cooling efficiency and installed
a balanced shakeout system capable of moving 50 tons of sand an hour in its west shakeout area and 50 tons of sand in the east shakeout area. Te shakeout deck in the east area was increased to 14 x 14 ft. to accommodate the large floor-molding flasks. Te next year, the Tempe facility
focused on efficiency. “In 2011, both Duluth and Tempe
were going through these major changes,” Grau said. “When major changes are being implemented you
January 2013 MODERN CASTING | 31
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