Commercially available steel for indirect SLS (LaserFormtm A6 tool steel) is normally
post-process infiltrated with a copper-based material. While such parts have high thermal
conductivity necessary for short- and medium-run injection molding dies, they are weakened by
the second phase with limited high temperature stability. This paper deals with a modification to
the commercial process whereby a low-melting-point cast iron is substituted for the copper alloy
infiltrant. A predictive model is presented that describes the part equilibrium solid fraction at the
infiltration temperature as a function of the green density and infiltration temperature. In an
experimental study, green parts were fabricated using LaserFormtm A6 tool steel powder. They
were then heated in vacuum to drive off the binder and infiltrated with ASTM A532 white cast
iron. During infiltration, an equilibrium state is established between the solid SLS steel part and
liquid cast iron associated primarily with carbon diffusion from the cast iron into the tool steel.
The equilibrium state is governed by the carbon content of the steel and cast iron, the relative
density of the steel part prior to infiltration and the infiltration temperature. In some cases guided
by Ashby densification maps, pre-sintering of the tool steel green part was performed to increase
the initial relative density of the solid metal.Mechanical Engineerin