Resin powder for solid freeform fabrication, device for solid freeform fabrication object, and method of manufacturing solid freeform fabrication object

A method of manufacturing a solid freeform fabrication object, comprising:

• forming a layer including a resin powder,
• wherein the resin powder has a 50 percent cumulative volume particle diameter of from 5 to 100 μm, a ratio (Mv/Mn) of a volume average particle diameter (Mv) to a number average particle diameter (Mn) of 1.50 or less, and satisfies at least one of the following conditions (1) to (3):
• (1):
• Tmf1>Tmf2 and (Tmf1−Tmf2)≥3 degrees C., where Tmf1 represents a melting starting temperature of an endothermic peak as the resin powder is heated to a temperature 30 degrees C. higher than a melting point of the resin powder at a temperature rising speed of 10 degrees C. per minute for a first time, and
• Tmf2 represents a melting starting temperature of an endothermic peak as the resin powder is heated for the first time, cooled down to −30 degrees C. or lower at a temperature falling speed of 10 degrees C. per minute, and heated to the temperature 30 degrees C. higher than the melting point at a temperature rising speed of 10 degrees C. per minute for a second time, and
• both Tmf1 and Tmf2 are measured in differential scanning calorimetry measuring according to ISO 3146, wherein the melting starting temperature of the endothermic peak represents a temperature at a point −15 mW lower from a straight line parallel to X axis drawn from a site where quantity of heat becomes constant after endotherm at the melting point finishes to a lower temperature side,
• (2):
• Cd1>Cd2 and (Cd1−Cd2)≥3 percent,
• where Cd1 represents a crystallinity obtained from an energy amount of the endothermic peak when the resin powder is heated to a temperature 30 degrees C. higher than the melting point of the resin powder at a temperature rising speed of 10 degrees C. per minute for a first time, and Cd2 represents a crystallinity obtained from an energy amount of the endothermic peak as the resin powder is heated for the first time, cooled down to −30 degrees C. or lower at a temperature falling speed of 10 degrees C. per minute, and heated to the temperature 30 degrees C. higher than the melting point at a temperature rising speed of 10 degrees C. per minute for a second time, and
• both Cd1 and Cd2 are measured in differential scanning calorimetry measuring according to ISO 3146, and
• (3):
• C×1>C×2 and (C×1−C×2)≥3 percent,
• where C×1 represents a crystallinity of the resin powder obtained by X-ray diffraction measuring, and C×2 represents a crystallinity obtained by X-ray diffraction measuring as the resin powder is heated to the temperature 30 degrees C. higher than the melting point thereof at a temperature rising speed of 10 degrees C. per minute, cooled down to −30 degrees C. or lower at a temperature falling speed of 10 degrees C. per minute, and thereafter heated to the temperature 30 degrees C. higher than the melting point at a temperature rising speed of 10 degrees C. per minute in nitrogen atmosphere;
• and
• irradiating the layer with electromagnetic waves to melt the layer, and
• wherein said resin powder comprises at least one thermoplastic resin selected from the group consisting of a polyolefin, a polyarylketone, a polyphenylene sulfide, a liquid crystal polymer, a polyacetal, a polyimide and a fluorochemical resin,
• the resin powder has an average circularity of from 0.83 to 0.89 in a range in which the resin powder has a particle diameter of from 0.5 to 200 μm,
• the resin powder is constituted by resin particles having a pillar-like form,
• the resin powder has no shell portions, and
• a proportion of pillar-like form particles to resin powder of 90% by mass or greater.