preheat roll

例句：

1. 1. The machine needs to be preheated before it can operate properly.
   机器在能正常工作之前需要预热。
2. 2. The preheat roll is essential for the smooth operation of the machine.
   预热辊对于机器的平稳运行至关重要。
3. 3.The preheat roll is used to warm up the material before it is rolled.
   预热辊用于将材料加热至可卷曲的温度。