machining marks

例句：

1. 1.The engineer carefully marked each piece of metal with a laser to ensure uniformity.
   工程师小心地用激光在每一块金属上标记，以确保均匀。
2. 2. The machine's markings are clearly visible on the surface of the product.
   机器上的标记在产品的表面上清晰可见。
3. 3. During the manufacturing process, machining marks can be used as evidence of the workmanship.
   在制造过程中，加工痕迹可以作为工艺水平的证据。