Please see the "Recommended Time Increment for Thermal Studies" section of SOLIDWORKS Simulation Help topic "Thermal - Options". You can also find similar information in SOLIDWORKS Knowledge Base (KB) solution S-059741. Pay close attention to your material properties (especially specific heat) when considering the thermal diffusivity equation in the aforementioned references. In addition, make sure that all initial temperatures are applied to entire solid bodies, not just faces. Otherwise you will have internal nodes with initial temperatures of absolute zero.
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