The calender pressure adjustment of the three-roll calender usually needs to consider a variety of factors, and the following are some common adjustment methods:
1. Mechanical adjustment
Adjusting roller spacing: by mechanical device, change the distance between the upper roll and the middle roll, the middle roll and the lower roll, so as to change the calender pressure. This usually requires the use of specialized adjusting screws or handles to operate.
Change the parallelism of the rollers: Ensure that the three rollers are parallel to each other to evenly distribute the pressure. If the rollers are not parallel, it may cause local pressure to be too large or too small.
2. Hydraulic system adjustment
If the equipment is equipped with a hydraulic system, the calender pressure can be controlled by adjusting the hydraulic pressure. This is usually done by operating a hydraulic control valve that increases or decreases the pressure of the hydraulic oil, thereby changing the force applied to the roll.
3. Adjust according to material characteristics
For plastic sheets of different materials and thicknesses, different calendering pressures are required. For example, thinner or softer materials may require less pressure to avoid overextrusion that can cause deformation or rupture; Thicker or harder materials may require greater pressure to achieve the desired calender effect.
4. Pilot production adjustment
Before formal production, trial production can be carried out, and the calendering pressure can be gradually adjusted by observing the surface quality of the sheet after calendering, until satisfactory results are obtained.
5. Refer to process parameters
Refer to the equipment's operating manual and previous production experience to determine the initial calender pressure setting range according to the specific production process requirements and material type, and then fine-tune it based on this.
For example, when producing PVC plastic sheets, if the surface of the sheet appears indentation or folding, it may be necessary to appropriately reduce the calendering pressure; If the sheet surface is not smooth enough, it may be necessary to increase the pressure. For example, in the production of thinner PP sheets, the initial pressure should be set low, and then gradually increase, while observing the sheet quality to find the best pressure value.
It should be noted that when adjusting the calendering pressure, it should be carried out gradually to avoid excessive pressure changes that have adverse effects on product quality and equipment. At the same time, we should pay close attention to the operating status of the equipment and the quality of the sheet, and adjust and optimize in time.
