axis of weld

例句：

1. 1.The axis of the machine is located at the center of the table.
   机器的轴线位于桌子的中心。
2. 2. The axis of the screw is perpendicular to the plane of the table.
   螺丝的轴线垂直于桌子的表面。
3. 3.The axis of the joint is where the two pieces of metal meet.
   接头的轴线是两块金属相交的地方。