Mouldability

Mouldability refers to the ease with which a material can be shaped within a mould to produce a part that meets the desired geometry, surface quality, and dimensional tolerances. It describes how readily a material can fill a mould completely and solidify with acceptable defects. In practice, mouldability is influenced by the material’s flow behavior, wetting of the mould surface, and its solidification characteristics.

In casting, injection molding, and other forming processes, mouldability depends on viscosity, temperature, and the interaction between material and mould surface. Materials with high mouldability flow readily into complex features and fill thin sections without trapping air, while materials with low mouldability may form cold shuts, misruns, or incomplete fills.

Factors include intrinsic properties (viscosity, density, surface tension, crystallization or curing kinetics), mould design and surface condition (temperature, coating, venting, draft), and processing conditions (pour rate, pressure, cooling rate). For metals and alloys, fluidity and solidification shrinkage are key; for polymers, melt rheology and strength matter; for ceramics, slurry rheology and particle packing affect fill.

Optimizing mouldability often involves design changes, material selection, or process adjustments to reduce defects and improve cycle times. Poor mouldability can necessitate larger gates, different alloy compositions, or alternative mould materials.

See also: casting, injection molding, rheology, castability.