projection grinder

例句：

1. 1. The engineer used a projection grinder to smooth the surface of the metal.
   工程师使用投影研磨机来平滑金属的表面。
2. 2. The projector grinder was used to polish the glass before it was displayed.
   投影研磨机被用来在展示前抛光玻璃。
3. 3. The projector grinder is an essential tool for any laboratory technician.
   投影研磨机是任何实验室技术人员必备的工具。