Parameter setting of calender

The principle of formulating the design parameters of the calender is to achieve a calendering process to produce a qualified magnetic plate as much as possible. After repeated multi-pass calendering, the internal residual stress of the magnetic plate is very large. After bonding with the PVC film, due to the difference in shrinkage rate between the two, the PVC film and the magnetic plate will be degummed, the edge of the magnetic plate will be exposed, and the magnetic plate will not be flat. etc. phenomenon. Through calculation and experimental correction, we have determined that the best technical parameters of the magnetic plate calender with a width less than 1000mm are: the aspect ratio of the roll is 2.5~3, the middle height is 0.1~0.3‰ of the roll diameter, and the linear speed of the roll is ≤3.5 m/min, the roll surface temperature is 60-80°C, the speed ratio is 1:1, and the edge scraping device, the roll surface temperature and the roll gap display device are configured. There have been different views on the selection of the roll speed ratio. Some people think that the shear force of the roll with a smaller speed ratio (eg 1:1.03) can promote the further plasticization of the pellets during the calendering process. In fact, this plasticizing effect is extremely small, but it will cause the surface of the magnetic plate to be rubbed due to the shearing effect of the differential speed of the rolls and enlarge the small defects.