Correct operation of an open mill first requires adjusting the roll gap to maintain balance. If the roll gap adjustments on both ends are inconsistent, causing uneven loading on the rollers, it can easily damage the equipment, which is strictly prohibited. After work, cut off the power and close the water and steam valves.

For safety, before starting the machine, we should follow these rules:

1. Before turning on the open mill, you must check if the electrical system (current, voltage, etc.), oil circuit (lubrication of the reducer, bearings, etc.), and water circuit are normal! Then put on leather wrist guards (wearing gloves is strictly prohibited), wear a mask for mixing operations, and avoid wearing belts, ropes, rubber bands around your waist, and avoid wearing clothes while operating. Carefully check for any foreign objects between the large and small gears and rollers. Every shift, the emergency brake must be tested to check if the braking is sensitive and reliable (if it is a knee-operated device, you must get used to contacting the brake device with your knee). During normal operation, the emergency brake must not be used to stop the machine. When two or more people operate the open mill, they must respond to each other and confirm that there is no danger before starting the machine.

2. The temperature rise during roller preheating must be controlled, especially in the cold winter in the north. When the external temperature of the roller is consistent with the room temperature, if high-temperature steam is suddenly introduced into the roller, the temperature difference between the inside and outside may exceed 120℃. The temperature difference can cause roller stress to reach 130.0～150.0 MPa, which exceeds the U.1=140.0 MPa of cast iron. If the material is added too early, under the combined action of horizontal pressure, the roller is very easily damaged. For safety reasons, preheating should be done without material, and lubrication should be carried out simultaneously without material. Material should only be added when the temperature reaches or is close to the set temperature. This must be emphasized to the operators.

3. The material should also be checked before being added to the open mill. If it contains hard metal foreign objects, and these are added to the mill with the material, it will cause a sudden increase in horizontal pressure, which will damage the equipment.