A new foam machining process, a rapid heat ablation (RHA) process using a rotary hot tool as rapid prototyping and manufacturing (RPM) technologies, has been developed to overcome some fundamental disadvantages, such as excessive cutting time and leftover materials caused by the cutting mechanism. A hot tool of a rotary type was designed to fulfill requirements for RHA process. To investigate thermal characteristics of heat ablation using rotary hot tool, process parameter studies were conducted by experimental approach. The effective heat input per mass which represents heat input, tool speed and material density was defined. Based on the experimental results, correlation between kerfwidth and effective heat input per mass can be determined. Theoretically, the correlation between kerfwidth and process parameters was also derived. To verify the practical applicability of the RHA process, three-dimensional parts were ablated. In particular, surface roughness of the part which was fabricated by the layered manufacturing process can be improved by RHA process.