Benchmarking molding, coremaking: industry experts stress different process areas and purchasing strategies to optimize molding and coremaking operations.

Vic LaFay, a research and technology development manager for S&B Minerals, Cincinnati, has made metalcasting sand his life's work. So it's no surprise he believes the lynchpin of any world-class molding and coremaking operation is putting in the right sand system.

"Good molding systems come down to mulling," LaFay said. "If you can't mull it, you're dead. It is the heart that keeps the blood flowing."

Not everyone would agree with him, particularly those that have made other metalcasting resources their life's work. But where everyone can agree--whether they champion quality control or core process selection--is that matching the right equipment and processes to your operation is key to being among the best in the business.

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"A lot of foundries have hurt themselves when they went out and bought the latest and greatest mold machine and core machine," said Bill Vondriska, sales manager for Equipment Merchants International, Cleveland.

Sand System

According to LaFay, more than 95% of all molding-related casting defects are due to mulling and the sand mixture, and staying in front of the curve of sand mix technology developments is critical to producing good castings.

"In 2009, we changed to a whole new dust collection system," said Dan Mayton, foundry director for Urick Foundry Co., Erie, Pa., a plant LaFay pointed to as being one of the best molders around. "We wanted to make the shop cleaner. But the net result was we were pulling our fines. We were too clean."

Urick has been using Disamatic high-speed molding machines, designed for quick pattern changes, to produce complex medium-run ductile iron castings for several decades. But when it installed its new dust collector in 2009, the system began drawing more fines from the sand system than ever before. This created problems with surface finish and required the facility to use an excessive amount of new bond material.

"Last year, we started to put dust back into our muller, and that has done wonders," Mayton said. "The dust was over 30% active clay, so basically we are trying to put it back in to get back to the original mix."

LaFay said he respects the company's mission to continuously improve.

"Many of their parts are hand tools, so they need an as-cast product that is perfect and must have the premier molding system out there," he said. "They continuously reinvent themselves. That's what makes their molding department unique."

According to Mayton, reinventing a facility is not always easy.

"We're still working to get it just right," he said.

LaFay said Rochester Metal Products, Rochester, Ind., which produces high volume automotive parts on both Hunter and Disa green sand lines, tweaks its sand mix as often as anyone in the industry. That's critical for a company in a highly competitive market segment.

"[Operations manager] Mike Slaydon is one of those individuals that always wants the newest and latest and greatest," LaFay said. "If there is a new additive, he wants to be on the leading edge. Even if his system is running well, he says 'if it ain't broke, break it."'

Several years ago, Rochester began incorporating causticized lignite into its sand system; now it's moving into an entirely new technology for its Hunter molding line.

"[Slaydon] is the same in the core room," LaFay said. "He just switched in one of the shops to [a new binder system] because he was looking for better performance criteria."

New Technologies

For Harrison Steel Castings Co., Attica, Ind., and Vice President Geoff Curtis, consistency is the name of the game for optimizing the molding and coremaking processes.

"The production and efficiency with which we are able to make molds is equally important to final quality," he said. "It's the things we do in our system to make the same environment over and over again and how we maintain our patterns and handle our cores."

When the company, which produces carbon and low/medium alloy steel castings in the nobake process, installed a thermal sand reclamation unit in 2003, it had to be certain its consistency wasn't affected. Curtis said consistency actually improved.

"New sand goes through expansion in the mold," he said. "That is a variable that needs to be dealt with. But once you have used it and it has gone through the expansion, you don't have that movement of the sand grains [when it is reused]."

Harrison Steel uses both mechanical and thermal reclamation. The thermal unit currently feeds only one of its molding lines, but the company is considering installing one on its second line in order to maintain consistency.

The effective use of reclamation technology makes Harrison Steel one of the best in the country at molding and coremaking, according to LaFay.

"Their reclamation system is state of the art," he said. "Everything right now is about recovery and reclamation. They are the best in the U.S."

In addition to the process benefits, the reclamation system at Harrison Steel reduces the amount of new sand the company must buy for its automated and floor molding lines.

"That is where I see a lot of the growth in the industry," LaFay said. "There is a shortage of raw materials."

Quality and Cleanliness 

Whether you are a sand shop or a permanent mold facility, one aspect of world-class metalcasters is common across the board--quality control and a clean work environment. Vondriska said making high quality products is one of the things that distinguishes Urschel Laboratories, Valparaiso, Ind.

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"When they installed a nobake system [in 2007], they researched it well," he said. 'It is efficient, the flow of the molds through the plant is good, it's laid out well, and it's a clean and nice looking system."

The company spent $4.5 million to install the new nobake line, which replaced its older green sand system. Urschel produces food cutting machinery and wanted equipment that would increase its speed and flexibility and give it the ability to make quality stainless steel parts for its in-house product line.

"We didn't build the nobake line to save money, we did it to save customers," said Rick Urschel, vice president of operations. "The process here is almost priceless. We didn't have any other solution, and if we did, it wasn't a good one."

To find the solution it needed, Urschel sought the opinion of a number of other metalcasters working with stainless steel. It was also able to rent equipment to optimize its molding material. Today, Urschel uses the new line to make frequent pattern and metal changes, and the sand mixer installed with the system is capable of dispensing different recipes to each mold with the push of a button.

Jarek Olszak, Laempe+Reich Corp., Trussville, Ala., agreed with Vondriska that cleanliness and facility layout are keys to maintaining best-in-class molding operations.

"Cifunsa's Irapuato, Mexico, plant is a brand new facility," he said. "They 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 Bajio area (Irapuato, Silao, Queretaro, Aguascalientes, Toluca and Guadalajara). The 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."

The company specializes in castings 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. The 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 business also can lead to human resources benefits, Vondriska said.

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"The 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 consequently 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 installing coldbox systems must plan how to gas their cores in order to optimize quality and cycle times.

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"You rely on the knowledge of your suppliers, whether they are equipment or binder suppliers," he said. "They have people with knowledge of the processes. There is some software, but the software works as a guide. You still have to do some optimization."

Vondriska cites Nemak, Monterrey, Mexico, as another leader in the use of coldbox core technology: In the 1990s, the company began constructing 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. The engine block core packages are assembled on automated lines and poured in less than a minute.

The massive plants each require extensive core production. "The 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."

SHEA GIBBS, MANAGING EDITOR