round concave molding

例句：

1. 1. Thecarpenter used a round concave mold to shape the wooden door.
   木匠使用一个圆形凹模来塑造木制门。
2. 2. The engineer designed a round concave mold for the new machine.
   工程师为新机器设计了一个圆形凹模。
3. 3.The molding process involves shaping the material into a round concave shape.
   成型过程涉及将材料塑形成圆形凹形。