Three-dimensional modeling apparatus and ejection unit

A three-dimensional modeling apparatus comprising:

• a drive motor;
• a screw that has a groove formation surface in which n spiral grooves and n spiral walls are formed, the screw being rotated by the drive motor, the n spiral grooves being formed between adjacent outer sides of the n spiral walls, the n being a natural number of two or more;
• a barrel that has a facing surface facing the groove formation surface, the barrel having a communication hole that is formed at a center of the facing surface, the barrel having a heater;
• wherein the groove includes a central portion, a vortex-shaped portion, and a material introducing portion, the central portion faces the communication hole;
• a nozzle that is configured to eject a modeling material supplied via the communication hole;
• a modeling table facing the nozzle and receiving the modeling material from the nozzle, a tip of the nozzle and the modeling table being spaced apart from each other;
• and
• a moving mechanism disposed below the modeling table, the moving mechanism being configured to move the table toward the nozzle or away from the nozzle,
• wherein ends of the n spiral grooves are connected to each other at a center area of the groove formation surface,
• a width of each of the n spiral grooves of the screw is smaller than a width of the ridge of the screw, and
• Ss is an average sectional area that is an arithmetic mean between a maximum sectional area and a minimum sectional area of each of the n spiral grooves, Ls is a length of each of the n spiral grooves, Sn is a sectional area of the nozzle, Ln is a length of the nozzle, and 0.03≤n½×(Ss/Ls)/(Sn/Ln)<5.00.