Domestic bonded ferrite magnet manufacturers all use calenders with bearing bush structure. The bearing pad material is generally copper or nylon, which is lubricated with butter. The bearing bush is easy to wear, causing radial runout during the rotation of the roll, and it is difficult to ensure the dimensional tolerance of the product. Therefore, the calender must choose high-precision double-row radial roller bearings, and use thin oil lubrication to reduce bearing wear and ensure the thickness tolerance of the magnetic plate along the length direction.
Due to the poor fluidity of the pellets, especially the intermolecular force and the deflection of the roll along the width direction, the rolled magnetic plates often appear thick in the middle and thin on both sides along the width direction. Excessive size will cause the coil to be tight in the middle and loose on both sides during winding. To solve the problem of excessive thickness, a complex inverted "L" type four-roll calender can be used. The calender has shaft crossing and shaft pre-bending functions. However, the calender has a complex structure, is expensive, occupies a large area, is inconvenient to maintain, and the cost of plant construction and equipment operation is also high. Therefore, we designed a two-roll open calender with superior performance.
