installing coldbox systems must plan how to gas their cores in order to opti- mize quality and cycle times. “You rely on the knowledge of your
Nemak maintains coremaking capabilities for its precision sand and semi-permanent mold lines. “Cifunsa’s Irapuato, Mexico, plant
is a brand new facility,” he said. “Tey had the luxury of designing all of their equipment placement based on process flow, which eliminates handling and waste. If you can match your produc- tion to that, you can really be efficient.” Cifunsa, a part of Grupo Industrial
Saltillo, launched its Irapuato facility in 2004 to serve the growing autoparts needs of the Bajío area (Irapuato, Silao, Queretaro, Aguascalientes, Toluca and Guadalajara). Te facility requires large core volumes produced at a rapid clip to feed its two 60,000-ton annual capacity vertical molding lines. For brass job shop Sloan Valve,
Augusta, Ark., Vondriska said house- keeping is key to efficiency and high equipment uptime. “What makes them the best is
cleanliness, good maintenance and nice flow,” Vondriska said. “You can tell they take care of their equipment.” Te company specializes in cast-
ings weighing less than 25 lbs. and has had to adapt to multiple alloy changes over the years due to changes in the regulatory climate for leaded brass alloys. Sloan’s 160,000-sq. ft. metalcasting facility produces shell and some coldbox cores and runs green sand molding lines with flask sizes of 30 x 20 x 7/7 in. at rates in excess of 300 molds/hour. Te company also maintains permanent molding capabilities. Maintenance is closely tied to
quality and cleanliness, Vondriska said. Pointing to another valve shop, he said Milwaukee Valve, New Berlin, Wis., spares no expense when it comes to upgrading its molding machines and installing the latest PLCs and hydraulic power units. Running an orderly place of busi-
24 | MODERN CASTING April 2012
ness also can lead to human resources benefits, Vondriska said. “Te cleanliness of a [molding
area] goes a long way toward worker morale,” he said. “It also shows that management thinks a lot of that area of the company. I have been in a lot of foundries where management doesn’t care about cleanliness, and conse- quently the people don’t either.”
Coremaking Processes Installing the right coremaking
process for your operation is critical to success, according to Vondriska. A facility must balance cycle times against its need for complexity and surface finish. Olszak said NIBCO’s Nacogdo-
ches, Texas, valve casting plant utilizes coldbox coremaking technology as well as anyone in the industry. “Not only did they invest the
money in the equipment, they had to change the way they were making cores completely,” he said. According to Olszak, facilities
suppliers, whether they are equipment or binder suppliers,” he said. “Tey have people with knowledge of the processes. Tere is some software, but the software works as a guide. You still have to do some optimization.” Vondriska cites Nemak, Monter-
rey, Mexico, as another leader in the use of coldbox core technology. In the 1990s, the company began construct- ing six new casting facilities on its 6.15 million-sq. ft. manufacturing campus. Today, four of the facilities produce cylinder heads via gravity and low pressure semi-permanent molding; the other two make engine blocks using a patented low-pressure precision sand technology. Te engine block core packages are assembled on automated lines and poured in less than a minute. Te massive plants each require exten- sive core production. “Te sheer size is just impressive,”
Vondriska said. But he cautions that the technology needs of each metal- casting facility are different. While some companies are able to optimize cycle times with the use of coldbox, shell can be effective for metalcasters producing more complex parts. “Shell [gives you good] surface finish and dimensional tolerances,” Vondriska said. “It’s great for spindly water jackets, hydraulic valves and little openings.”
Urick Foundry relies on excellent surface finishes for its hand tools, but its new dust collection system threw a wrench in the works.
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