| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase productivity and at the same time, enhance the shape accuracy of a bent pipe by forming a premolded straight pipe of a thermoplastic resin easily to the desired shape without the necessity to prepare a dedicated molding die for bending for each of different types of bend under an automated manufacturing system, when molding the premolded straight pipe to the three- dimensionally complicated and meandering shape. SOLUTION: The part intended for bending of a premolded pipe 6 is brought into contact with the activated part of an ultrasonic oscillator 60, and thereby is thermally softened by the ultrasonic oscillation effects. Next, a first bending roll 42A (a second bending roll 42B) is rotated in such a state that the outer peripheral face of the part to be bent is kept in contact with the first bending roll 42A (the second bending roll 42B). Finally, the part to be bent is deformed by bending along the outer peripheral face of the first bending roll 42A (the second bending roll 42B).</p> |
