Although LSR do not shrink in the mold, they often shrink 2.5% to 3% after demolding and cooling. The exact amount of shrinkage depends to some extent on the formulation of that compound.
However, from a mold perspective, shrinkage can be influenced by several factors, including the temperature of the mold, the temperature of the compound when it is demolded, as well as the pressure in the mold cavity, and the subsequent compression of the compound.