(5)其次是拉伸问题最近许多小型挤压机都采用牵引机进行牵引,以防止多孔挤压时端头不齐,并可以把弯曲小的材料排列到平台上。因此,出现了许多无人化的拉伸工程。然而,因为大型型材断面较大,所以采用牵引机牵引,其效果也不是很理想的。而且,挤压型材在通过模具后,被强制冷却,在此过程 (5) The second is the stretching problem. Recently, many small extruders use a tractor for traction to prevent misalignment of the ends during multi-hole extrusion and to arrange small, curved materials onto the platform. Therefore, there have been many unmanned stretching projects. However, due to the large profiles of large cross-section, so the use of tractor traction, the effect is not very satisfactory. Furthermore, the extruded profile is forced to cool after passing through the die, during this process