Mulling vs. Mixing: Why Mulling is Optimal for Sand Preparation

When it comes to preparing green sand for molding, the difference between mulling and mixing is critical. While both processes blend materials, only mulling provides the intense shearing, compression, and activation needed to fully develop the properties of the sand, clay, and additives.

Mixing: Simple Blending

Mixing is a basic process that combines materials with limited energy input. While it evenly distributes sand and binders, it does not break down clay agglomerates or fully activate bentonite. The result? Inconsistent sand properties, reduced mold strength, and a higher likelihood of defects.

Mulling: Sand Conditioning

Mulling goes beyond simple mixing by applying shear forces, compression, and controlled energy to the sand. In Simpson mullers, high-speed muller wheels press the sand against the chamber walls while plows continuously shear and blend the mixture.

This process:
✅ Activates bentonite for maximum binding strength
✅ Enhances sand coating for improved flowability and compaction
✅ Optimizes moisture distribution to prevent casting defects
✅ Reduces variability for consistent mold performance

For foundries demanding stronger, more uniform molds and higher-quality castings, mulling is the only choice. Advanced mulling technology that delivers precision, efficiency, and reliability in every batch.