In the foundry industry, binders are introduced into the mold to improve casting accuracy and the physical properties (e�g�, mold hardness and strength) of the mold� Currently, organic binders are gradually replacing the hot-box process which uses a thermoset (also known as catalytic binders)� Resin-bonded sand mold systems are thus categorized as a cold-box molding process which uses organic binders�

In mold development systems, the mold quality (which has multiple criteria) is directly influenced by the molding conditions such as percentage of constituents, curing time, and number of strokes� The effective optimization of this process would require a comprehensive understanding of multiobjective (MO) optimization, coldbox molding, and metaheuristics� Over the past years, many research works have been directed toward resin-bonded sand mold systems due to the following factors:

• Excellent adaptive capabilities in a dynamics environment • Good compliance to environmental factors • High casting quality (Ireland, Chang, & Kroker, 2002)�

This approach is power saving and thus highly suitable for large-scale production (Weihua, Yingmin, Xueliang, & Xiuling, 2008)� In most cases, resin-bonded sand mold systems show superb flow behavior� Nevertheless, some introduction of vibration and compaction during the molding process is required� Casting characteristics are very much influenced by the mold properties which are in effect dependent on the process parameters during the mold development process (Parappagoudar, Pratihar, & Datta, 2007)� In this work, the MO optimization model employed for the resin-bonded sand system was developed by Surekha, Hanumantha Rao, Mohan Rao, Vundavilli, and Parappagoudar (2012)� This model was based on a sand mold where phenol formaldehyde was used as a binder and tetrahydrophthalic anhydride was used as a hardener�

The model describing the responses and the outputs of the optimization process was developed by Surekha et al� (2012)� In that work, the mechanical properties of the quartz-based resin-bonded sand core system was modeled using Mamdani-based

fuzzy logic (Mamdani & Assilian, 1975) and genetic algorithm (GA) approaches� The MO representation of the optimization model which consists of four objectives as developed in Surekha et al� (2012) is as follows:

→

→

→

→

f f

f f

process

Maximize Permeability,

Maximize Compression Strength,

Maximize Tensile Strength,

Maximize Shear Strength,

subject to constraints.