The main working parts are two opposite-direction inwardly rotating hollow or drilling rollers. The device is called the front roller on the operator's side. It can be moved horizontally back and forth by manual or electrical action to adjust the roller distance to meet the operating requirements. The rear roller is fixed and cannot be moved back and forth. The two rollers are generally the same size and each rotates at different speeds. The raw rubber or rubber material is rolled into the gap between the two rollers with the rotation of the rollers, and is strongly sheared to achieve the purpose of plasticizing or mixing. Open mills are also used in departments such as plastics processing.
Open mill is the abbreviation of open plastic refining machine. In plastic products factory, people are used to calling it two-roller. Opening mill is a kind of mixing plastic equipment which is applied earlier in plastic product manufacturing plants. In the calender production line, the role of the open mill before the calender and after the mixer is to mix and plasticize the uniformly mixed raw materials to provide a more homogeneous melt for the calendering and molding of plastic products. In the production of cable materials, the open mill can directly mold the powdered material mixed according to the formula into a molten material, and then press-mold it into a sheet belt to cut the pelletizer into granules. In the floor leather production line, it can directly provide the base coat for mixing and plasticizing for bucky leather. The recycled waste plastic film (sheet) can also be re-molded on the open mill and re-made.
The open mill has a simple structure, is relatively easy to manufacture, easy to operate, and easy to disassemble. Therefore, it is widely used in plastic products enterprises. The disadvantage is that the workers consume a lot of physical energy. In high temperature environments, manual mixing is required to turn the mixing materials, and the number of times of manually turning and mixing the plastic pieces has a greater impact on the quality of the raw material mixing.
Safe operation of open mill
Open mill is one of the main equipment of rubber plant. Opening mill rubber mixing operation is an accident-prone process, which includes personal accidents and equipment accidents.
In recent years, on the one hand, due to the rapid increase in rubber enterprises, especially the large number of rural rubber enterprises in rural villages and towns, a large number of young workers without strict training have been put into rubber refining jobs, and violations of safety operations have been widespread. On the other hand, as the production capacity of the rubber mill is continuously strengthened, and because some steel radial tires and wide-section tires require increased tread rubber hardness, the lateral pressure of the rubber mill is increased, resulting in frequent damage to the safety sheet and rollers. A tube break accident occurred. Therefore, the safety status of the rubber mixing operation is not optimistic.
Protecting laborers' safety and health in production is an important policy in China. Protecting state property and promoting production development are important responsibilities of enterprise management. Therefore, as far as rubber enterprises are concerned, the safety of startup operations should be taken seriously.
1: make preparations
Before driving, you must wear a leather wristband. During the mixing operation, wear a mask. Avoid waist ropes, belts, rubber, etc., and clothing is strictly prohibited. Check carefully for debris between the large and small gears and rollers. During each shift, the emergency braking device must be pulled to check whether the brakes are sensitive and reliable (the front rollers must not rotate for more than a quarter of a week after the vehicle is braked). It is strictly prohibited to use the emergency braking device to shut down the vehicle during normal operation. If two or more people operate together, they must respond to each other and confirm that there is no danger before driving.
It is necessary to grasp the temperature rise rate during the preheating and heating of the rollers, especially in the cold winter in the north. The outside of the rollers is consistent with room temperature. High-temperature steam is suddenly introduced into the rollers. The temperature difference between the internal and external temperatures may be above 120 ° C. 130.0 ～～ I 50.OMPa, which has exceeded U.1 = 140.OMPa of cast iron. If the rubber is added too early, the roll Jane is very vulnerable to damage under the superposition of lateral pressure. In order to be safe, it should be warmed up in an empty car, and the regulation that the heating speed is controlled at 1 ～ 2'C / min is very difficult to implement, and it needs to be highlighted to the operator.
The rubber material should also be checked before feeding. If there are hard metal impurities mixed with the rubber, it will be put into the rubber mill, which will cause a sudden increase in lateral pressure and easily cause equipment damage.
2: correct operation
First of all, it is necessary to adjust the roller distance and maintain the balance of the roller distance. If the rollers at both ends have different adjustments, the rollers will be eccentrically loaded and the equipment will be easily damaged. This is strictly prohibited.
Feeding habits are usually added from the power input end, which is actually unreasonable. From the moment diagram and torque diagram, the feed should be at the gear ratio. Because the synthetic bending moment and torque at the transmission end are larger than the gear ratio gear end, adding a hard block of rubber to the transmission end first is of course more likely to damage the equipment.
Of course, don't add big hard rubber material to the middle section of the roller first, here the synthetic bending moment is bigger, up to 2820 tons cm.
The feeding amount should be gradually increased, the weight of the feeding block must not exceed the provisions in the equipment instruction manual, and the feeding order should be continued from small to mainland. As shown in the figure, if a large piece of rubber is suddenly added to the roll distance, it will cause overload and rush, which will not only damage the safety gasket, but also damage the roller if the safety gasket fails.
When operating, first cut (cut) the knife, and then pick up the glue. The film is not cut (cut). Do not pull hard. It is strictly forbidden to use one hand to feed on the roller, and the other to pick up the material under the roller. If the rubber jumps and is not easy to roll, do not press the rubber by hand. When pushing the material, you must make a half fist, and do not exceed the horizontal line at the top of the roller. When measuring the roller temperature, the back of the hand must be opposite to the direction of rotation of the roller.
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