Solid freeform fabrication processes offer the manufacturing flexibility for tools with low thermal inertia and internal conformal channels for rapid thermal cycling in injection molding. This article analyzed each step of a rapid thermal cycling process and provided quantitative guidance for tooling design. The proposed design methodology was tested on a three-dimensional (3D) printed benchmark tool with truss support. Rapid cooling test on the benchmark tool resulted in the mold time constant shorter than 2.3 s and the cavity temperature uniformity better than 3 degrees C. Preliminary tests demonstrated the technical feasibility of using a solid freeform fabrication process to fabricate low thermal inertia tools for improved heat management in injection molding. POLYM. ENG. SCI., 49:305-316, 2009. (C) 2008 Society of Plastics Engineers