下模（9），待经受冲切的薄金属板（8）放置在该下模上；

A lower die (9) on which thin sheet metal (8) to be subjected to punching is placed;

双极板是质子交换膜燃料电池的核心组件之一，采用薄金属板制备双极板能够提高燃料电池的比功率、降低生产成本。

Polar plate is one of the core components in polymer electrolyte membrane fuel cell(PEMFC) stacks. Metal materials are used for polar plate to reduce cost and improve performance.