The Pictures below are of RUPP snowmobile sprockets, they were
obsolete parts out of production for several years. The customer,
A RUPP parts dealer, still had requests for the parts. To keep
tooling cost down, the molds were made in house.
With the intricate area around the teeth being cast with a 95A
polyurethane, bonded inside the mold and faced off.
As opposed to having a machine shop machine the teeth out of
aluminum. Which would have almost tripled the mold cost.

Below are picture of the compression type molds, the parts
were made of 95A polyether urethane. Flexable to -60 F