Design and manufacture of calender

The key to the design of the two-roll open calender is the roll structure, material selection, roll surface treatment and technical parameter determination, followed by function configuration. In terms of roller structure, we have adopted a medium-height design with a super-large roller diameter that is different from the rubber and plastic products industry, where medium-height=(D-d)/2. The purpose is to compensate for the deflection and deformation of the roll caused by the rolling stress, and to increase the rolling force in the middle of the roll to force the magnetic powder particles to flow to both sides. Hollow rollers and peripheral drilling rollers suitable for oil heating and water heating. After production practice, the heating methods of the two pass types can meet the requirements of the process for the temperature fluctuation error of the roll surface. In terms of material selection, we use alloy chilled cast iron materials with good wear resistance and strong rigidity, and the hardness of the rolling face is HS72-75. However, alloy chilled cast iron rolls are often due to casting defects and the possible corrosion of additives in granular materials on the roll surface, resulting in "ice-like cloud spots" on the roll surface after a short period of use, and it is impossible to roll out a smooth surface. It is necessary to carry out special treatment on the roll surface. Special treatment mainly includes surface spraying wear-resistant material and hard chrome plating. We use the latter. In order to enhance the bonding strength of hard chrome and alloy chilled cast iron, nickel plating is required before chrome plating, and the thickness of chrome plating layer after grinding is generally 0.05-0.08mm. It should be specially pointed out that when producing a magnetic plate covered with PVC film on one side, the horizontal two-roller calender is preferably configured as one chrome-plated roll and the other as an alloy chilled cast iron roll. Because the surface of the magnetic plate rolled by the alloy chilled cast iron roll is relatively rough, it is beneficial to enhance the bonding strength of the PVC film and the magnetic plate.