| 摘要 |
PURPOSE:To prevent twisting from developing so as to produce a highly rigid truss structural body by a method wherein time lag and lead are given to the extrusion of resin by successively unmasking the respective slopes of the extrusion orifice having triangular waveform of a die using two masks. CONSTITUTION:In order to produce a truss structural body by extrusion-molding resin, firstly, the aperture 21a of a main mask 21 is moved at a certain speed from the first slope 11 of the extrusion orifice 10 of a die 1 to the second turning point P2 and, after reversing the moving direction, moved at the same speed as mentioned above to the first slope 11 and a turn-back movement, in which the moving direction is reversed, is performed again. Simultaneously with the start of the movement of the main mask 21, the aperture 22a of a sub-mask 22 is moved from the terminal of the fourth slope 14 of the extrusion orifice 10 to the third turning point P3 at the same speed as mentioned above and, after reversing the moving direction, moved to the terminal of the fourth slope 14 at the same speed and the turn-back movement, in which the moving direction is reversed, is repeatedly performed. Thus, time lag and lead are given to the extrusion of resin, resulting in preventing twisting from developing. |
