Three-roll calender--The important part of sheet extrusion line

The temperature of the slab extruded from the flat die is higher, and it is calendered by a three-roll calender and gradually cooled; at the same time, it also plays a certain traction role, adjusting the speed of each point of the slab to be consistent to ensure the flatness of the board.
The roller calender is composed of three counter-rotating rollers, and the gap between the rollers should be compatible with the thickness of the plate. After cooling, the thick plate is cut into a certain length, and the thin sheet is wound into a roll. The three-roll calender consists of three heated cylindrical rollers with a diameter of 200-300mm. The three rollers are arranged at 45°. The roller is hollow and can be fed with heating and cooling media. The oil heating temperature of the three rollers is 25～250℃, the temperature difference of the rollers is about 3℃, and the length of the roller should be slightly longer than the width of the machine head. The surface of the roller is chrome-plated, and the roughness is below Ra0.01μm. The diameter of the roller should not be smaller than 200mm, and generally not larger than 300mm.
The installation eccentricity of the three rollers shall not exceed 0.025mm, the position of the middle roller is fixed, and the roller distance is adjusted by moving the upper and lower rollers. The adjustment mechanism of the three-roller calender is shown in Figure 9-17. There are two adjustment methods: manual and pneumatic. The shaped roller has a certain medium height.
It should be noted that the three-roll calender is not a calender, and its structure is not as firm as a calender. The thickness of the plate is shaped mainly by the head, and the slab must not be pressed into a thin plate by a calender. It can only have a slight thinning effect on the slab, otherwise the roller will be deformed and damaged.

The distance between the three-roll calender and the machine head should be as close as possible, generally 50-100mm; if the distance is too large, the slab is prone to sag and wrinkle, the smoothness is not good, and it is easy to dissipate heat and cool.

The three rollers of the calender generally adopt chain drive, gear drive or worm gear drive to keep the speed of each roller synchronized. The surface linear velocity of the roller should be adjustable in a larger range, and the maximum surface linear velocity is 2-8m/min. The pulling speed of the roller must be controlled to suit the extrusion volume. For example, for thicker calendered slabs, the linear speed of pulling is 10% to 25% faster than the extruded linear speed, which is different for calendered sheets. , The traction speed is much faster than the calendered thick slab.

Company Profile

Nanjing Sumino Precision Machinery Co., Ltd. is a high-tech enterprise integrating scientific research, production and sales. It has always adhered to the business philosophy of integrity, equality, and customer benefits. In order to better improve the quality of equipment, it has entered a more professional and standardized Production track. We have established independent research and development technologies for seven categories of equipment including plastic sheet material, casting, bi-stretching, non-woven non-woven meltblown cloth, laminating film composite, recycled granulation environmental protection recycling system and coating machine manufacturing system. The center and production department provide a full set of professional technical solutions to meet the special needs of each customer. Among them, the biaxially oriented film manufacturing system includes: BOPP biaxially oriented film manufacturing system, PVC biaxially oriented shrink film production line, PET biaxially oriented film production line, BOPA biaxially oriented film production line, BOPA biaxially oriented film production line, etc.

Company Address: No. 11, Kaifeng Road, Moling Street, Jiangning District, Nanjing City, Jiangsu Province