According to the type of process
Mixing process: When mixing, the roll needs to have strong shear and extrusion capacity to fully mix rubber and various compounding agents. Rolls with large diameter and moderate length can be selected, which can provide a larger contact area and pressure, so that the rubber mix is more uniform. At the same time, the roughness of the roll surface should be moderate, too smooth is not conducive to the grasping and cutting of the rubber material, too rough may lead to excessive wear or impurities of the rubber material.
Calender process: The rubber rolls used for calender require high surface accuracy to ensure uniform film thickness and smooth surface. It is usually necessary to select a roll with high hardness and good rigidity to withstand the greater pressure during the calender process and prevent the roll deformation from affecting the quality of the film. In addition, the temperature control performance of the roll is also very important, because the change in the temperature of the rubber during the calendering process will affect its flow and forming effect.
Molding process: The molding process has specific requirements for the shape and size of the roll. For example, when producing rubber pipes, it may be necessary to use a roll with a specific camber or groove to shape the outline of the hose. At the same time, the elasticity and flexibility of the roll should be moderate, so that it can adapt to the deformation of the rubber material during the molding process and avoid damage to the rubber material.
Consider rubber material properties
Hardness: Different rubber materials have different hardness, and it is necessary to choose the appropriate roll hardness according to the hardness of rubber. Generally speaking, for rubber with high hardness, such as nitrile rubber, etc., rollers with relatively high hardness should be selected to ensure sufficient pressure transfer and processing effect; For rubber with low hardness, such as natural rubber, roll hardness can be appropriately reduced to avoid excessive extrusion resulting in excessive deformation or surface damage.
Viscosity: The rubber with larger viscosity is easy to adhere to the surface of the roll, affecting the processing quality and efficiency. For this type of rubber, rolls with good surface finish and anti-viscosity should be selected, such as those treated with chromium plating or special coating, which can reduce adhesive adhesion and facilitate cleaning and operation during processing.
Chemical properties: Some rubber materials have special chemical properties, such as oil resistance, corrosion resistance and so on. If the processed rubber has these characteristics, then the rubber material of the roll also needs to have the corresponding chemical resistance to prevent chemical erosion of the roll during the processing process, affecting its service life and processing effect. For example, when processing nitrile rubber, because nitrile rubber has good oil resistance, the roll should also choose oil-resistant rubber materials, such as nitrile rubber or polyurethane rubber.
Pay attention to roll quality and performance
Material quality: The metal core of the roll should have sufficient strength and rigidity to support the rubber layer and withstand the pressure during processing. The quality of the rubber layer is also crucial, to choose reliable quality, stable performance of the rubber material, to ensure that the roll has good elasticity, wear resistance and aging resistance. You can evaluate the quality of the material by looking at the roll material report, quality inspection certificate, etc.
Processing accuracy: The high-precision roll can ensure the dimensional accuracy and surface quality of the rubber material during the processing. Check the processing accuracy of the roll, including the roundness, cylindricity, surface roughness and other indicators of the roll body, which should meet the corresponding rubber processing requirements. Generally speaking, the rolling and forming process requires higher processing accuracy of the roll, and it is necessary to select a roll with higher accuracy grade.
Transmission performance: Good transmission performance can ensure that the roll runs smoothly and the speed is uniform during the working process, so as to ensure the consistency and stability of rubber processing. Select a roll with a reliable transmission device, such as the use of high-quality bearings, gears and other transmission components, and the transmission system should have an appropriate speed range to meet the requirements of different rubber processing processes for roll speed.
Combine production scale and cost
Production scale: If it is large-scale production, it is necessary to select rolls with high production efficiency and good durability to reduce equipment downtime and maintenance costs. For example, large two-roll or multi-roll mills can be selected, equipped with automated loading and unloading devices to improve production efficiency. For small-scale production or experimental production, you can choose some small, simple roller equipment to reduce equipment investment costs.
Cost factors: including equipment procurement costs, operating costs and maintenance costs. Under the premise of meeting the requirements of rubber processing technology, try to choose cost-effective rolls. At the same time, to consider the service life of the roll and maintenance costs, some good quality, durable roller although the procurement cost is higher, but in the long run, can reduce the overall cost. For example, choosing a roll with reliable quality can reduce downtime and increased production costs associated with frequent roll changes.