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Binders Continue to Hold Researchers Focus

May 18, 2009
Progress toward emission free casting gets help from suppliers efforts to develop and commercialize sand binding processes.

Letcast, a consortium of metalcasting industry suppliers that focus on developing and promoting low-emission sand-binding methods, have introduced a new binder they explain lowers airborne emissions significantly over phenolic binders. The XLink Binder System (for which a trademark has been applied) has been under research and development over several years, including collaboration with The Pennsylvania State University.

The consortium includes J.B. DeVenne Inc., Furness-Newburge Inc., and GMBOND, Hormel Foods, each one a developer of processors and/or equipment for treating foundry sand. They formed Letcast in 2006 to educate metalcasters about low-emission technologies (LET) and their applications; to establish working relationships with federal, state, and local environmental agencies regarding ways to reduce metalcasting emissions; and to encourage foundries and regulators to work together and to implement low-emission technologies that will benefit workers, the environment, and neighborhood relations.

Part of Letcast’s stated mission is to substitute 80% highemission sand processes with low-emission technology, without sacrificing capability where necessary.

The XLink binder system uses “innovative high-temperature purging and vacuum processes” to achieve what the developers say are manufacturing productivity results that are competitive with the industry’s current standard. Also, they explain that the process can be adapted to fit existing core machines, so foundries can incorporate the new process to their production methods.

In addition to the lower emission levels, Letcast says that the XLink binder system exhibits superior hot strength, and maintains and improves casting shakeout.

A coremaking process that its developers call “emission free” was developed and patented by Ashland-Sudchemie-Kernfest GmbH, a joint venture of Sud-Chemie and Ashland Inc. It is being used commercially to produce cores at a new plant in Germany.

The Inotec process is an inorganic system. The claim that the binder is emission-free is based on the fact that it has no silicates, meaning that a coremaking operation that uses it needs no air extraction or amine-washing functions.

In April Sd-Chemie’s WD-Giesserei-Technik GmbH business unit inaugurated a new plant in Moosburg, Germany, where it will use Inotec to produce a line of casting cores. WD-Giesserei-Technik already produces Inotec cores at another plant in Fuldabruck, Germany.

The Moosburg plant will supply core packages for BMW’s foundry in Landshut, Germany. The cores are to be used in the foundry’s production of a new, aluminum 6-cylinder engine. BMW aims to reduce its use of organic binders, and will use only inorganically bonded cores from 2010 onward.

Sd-Chemie says the Inotec binder system strengthens its “broad, green chemistry portfolio” of process and environmental catalysts, bentonite-based additives, water treatment, catalysts for second-generation biofuels, and heavy metal free plastic additives.

Dr Hans Jrgen Wernicke, deputy chairman of the managing board of Sd-Chemie AG, stated: “With the development of core production, hitherto unique in this form, optimized to the Inotec binding agents, we make a significant step forward to realizing our vision of emission-free foundry processes in the automotive industry.”

Thresher’s ‘Green’ Core Development
Thresher Industries Inc., a Hanford, CA, manufacturer of aluminum, magnesium, and metal-matrix composite castings, is taking credit for its own “eco-friendly” coremaking development. The company says its Nautilus Core is not a sand product at all, nor is it a foam core.

The Nautilus Core is the product of Thresher’s proprietary biodegradable process for manufacturing cores for aluminum and magnesium casting. The system results in a product that can be removed easily through high-pressure steam or water, and it can rest in areas not suitable for a sand or foam core. The technology can be used to produce internal and runner shapes as well as passages in virtually any metal casting, including high-pressure and permanent mold castings, or even plastic parts.

“The Nautilus Core is an excellent tool that helps us reduce material costs by as much as 80% and waste by 100%. We are continuing to develop and refine this process in order to provide greater customer satisfaction, attract a broader client base, and enhance our revenues,” states Thresher president and CEO Tom Flessner. “Our innovative, high-strength metal-matrix composites, when used with the Nautilus Core, offer engineers unique capabilities and unprecedented freedom in design.”