https://www.avient.com/sites/default/files/2020-10/tpe-injection-molding-guide.pdf
The shrinkage values reported by Avient are determined using a 0.125” thick plaque.
Typical Tool Steel for Injection Mold Construction Steel Type Steel Properties Mold Component P-20 Pre-hardened, machines well, high carbon, general-purpose steel.
The use of a small amount of a dusting agent such as talc or calcium carbonate can minimize agglomeration during the grinding process.