Part accuracy and quality in rapid prototyping process using solid powder in the part cake are typically dependent upon thermal system and powder properties. The part cake is a rectangular mild steel cylinder with movable part plate piston. For maximum thermal stress reduction in the part-building process, about 1.27 cm or 2.54 cm initial solid powder was uniformly laid in the part cake. The powder was then warmed to a certain temperature before sintering. The amount of moisture present in the solid powder will have significant impact on the required warm-up time. In the moisture vaporization process, solid powder temperature in the computational cell will remain at 100°C until the moisture mass fraction reaches zero. The warm-up time of the cell will increase as the moisture content of the powder increases. Reference data has yet to be published on warm-up times, therefore machine operators will find variances in warm-up times. To better predict the warm-up time for the solid powder heating process with moisture vaporization in the warm-up stage of the part cake, a vaporization code model was developed that can also simulate the heating process with vaporization for any solid particle mixed with any liquid agent.
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