These offered Insulation Risers & Sleeves are made of insulating compounds these are a reliable cost effective approach for optimizing feeding efficiency, lower costs, and improving quality. When filling the mold, these insulating risers first absorb the heat from the liquid metal until it reaches its equilibrium temperature; from this moment, they protect the liquid casting metal against further heat loss. This allows risers of smaller dimensions, resulting in increased yields. Therefore, insulating risers and sleeves delay the beginning of solidification and promote seal-feeding.
It is advantageous to fit the risers and sleeves with a cover that is insulating as well, in order to also prevent the heat loss from the riser's top. Moreover, closed insulating risers and sleeves are used which are provided with a wedge molded into the top that acts as an air core.