PVC Sheet Calender Tech
PVC Sheet Calender Tech
Calender (calender) is, according to some form of arrangement between two or more rolls, at a certain temperature, the rubber or plastic pressed into a certain extension of the film thickness and surface shape, and the fiber or canvas curtain steel cord were hanging plastic machinery. Calender roller can be divided according to the number two rollers, three-roll, four and five-roll rolling machine; in accordance with the arrangement of the roller can be divided into an "L", "T" type, "F" type " Z "type and the" S "type.
In addition to ordinary precision calender calender main parts and equipment, the increase of rolling guarantee the accuracy of the device.
Pressure-type calender for the pressing plastic material into a certain cross-sectional shape and a certain thickness.
Universal rolling mill, capable of eraser, gum paste and tablet work.
Experiment with calender for testing.
Characteristic parameter editing
Characterization parameters calender, many of them there are number of rollers and their arrangement type, diameter and length of the roller, the roller speed range, ratio and production capacity, rolled products, the minimum thickness and thickness tolerances of the roll transverse pressure and drive power.
Length and diameter of the roller is the working portion of the roll length and diameter. This is a standard size characterization calender characteristic parameters.
1, the length of the roller
Roll length can characterize the most significant of rolled products. Since both ends of the need to stay out of the striker plate sited, therefore, the effective length of the roller is the roller length minus the non-working surface length (approximately 15% of the roller length).
2, the roller diameter ratio
The ratio of working part length and diameter of the roll is called the aspect ratio. Roll aspect ratio (or roller diameter) mainly affects rolling
Article the dimensional accuracy of the thickness (excluding diameter rollers). It is in addition to the performance, material and length of the working portion of the roll of rolled material related, mainly depends on the quality requirements of rolled products.
3, roller diameter and transverse pressure and power, aspect ratio and stiffness relationship
Relationship between roller diameter and transverse pressure and power are shown. The larger the roller diameter, the larger the horizontal pressure, the greater the required drive power is almost a linear relationship.
The main impact of the aspect ratio of the roll stiffness of the roll, Fig diameter φ610mm roll rigidity ratio in different aspect ratios. The figure shows the aspect ratio of the greater rigidity worse.
4, roller length, diameter and aspect ratio determination
Roller length, diameter and aspect ratio of the main products in accordance with the requirements of the production process is determined, i.e., according to the type of material being processed, the range of the thickness of rolled products and width, roll calendering speed (i.e., production requirements) and other claims.
In order to ensure the dimensional accuracy of the thickness of rolled products, based on practical experience, the roller diameter ratio should be limited within the following range (except diameter roll):
Processing soft material (e.g. rubber), generally an aspect ratio of 2.5 to 2.7. A maximum of 3;
Hard material machining, take an aspect ratio of about 2.0 to 2.2.
Roll length, standard series diameter: φ360 × 1120; φ450 × 1200; φ550 × 1600; φ610 × 1730; φ710 × 1800
And various other plastics machinery, rolling machine from the rack, and some of the pressure roller means, transmission, and heating systems, adjusting the composition, usually made of cast iron frame, mounted directly on the sides or cast iron base for Supporting pressure roller bearings, shaft pre-bent cross or pressure roller device, the pressure roll adjusting device, lubrication equipment and other auxiliary equipment. Pressure roller by the chilled cast iron, cast steel, according to its aspect ratio of the bending strength of the pressure roller material selection, about 2.6 to 3.5. For bending force generated by the pressure roller to compensate uneven thickness caused by defective products, the pressure roller made more drum-shaped, also use pre-roll crossing means and roll bending means to eliminate uneven thickness of the article. Each pressure roller with a separate drive motor. Pressure roller heated by steam or hot water is generally required at both ends of the temperature difference of no more than 1 ℃. Each pressure roller are independent automatic heating system. Modern calender roller bearings used in place of a conventional sliding bearings, to save energy, improve the accuracy of bearing life and product thickness.
Depending on the specifications of the rolling mill, the production of soft PVC film thickness is also different, ranging from 50 ~ 1000m, the minimum thickness of the hard PVC film is 60m
Pressed into a sheet, and to achieve the mechanical alignment of the magnetic powder particles, to improve the binding properties of the binder and the magnetic powder particles.
For the rolling process, product dimensions, surface quality is the most important control parameter. Coil Dimensions general requirements along the length and width direction of the thickness tolerances are ± 0.015mm and ± 0.05mm; the surface should be smooth, smooth. If you can not reach these requirements, it is difficult to ensure that subsequent coating PVC film and uniform magnetic plate bonding pressure, affect bond strength.
Domestic bonded ferrite magnet manufacturers have adopted the calender bearing structure, bearing materials generally copper or nylon, using grease lubrication. Bearing wear, resulting in the roll radial runout during rotation, it is difficult to ensure product dimensions. Therefore, be sure to use calender high precision double row spherical roller bearings, and using oil lubrication, reducing bearing wear, to ensure that the longitudinal direction of the magnetic plate thickness tolerances.
Since the pellet is illiquid, particularly affected intermolecular forces and roll bending deformation, rolling out of the magnetic plate along the width direction often occur in the middle on both sides of a thin thickness along the width direction of the phenomenon. Oversize cause intermediate coil winding tight when both sides loose. Thickness tolerance solve this problem may be complex inverted "L" shaped four-roll calender. The calender has a shaft axis cross and pre-curved features. However, the rolling mill complex, expensive, occupies a large, maintenance inconvenience, plant and equipment cost and higher operating costs. Therefore, we designed the superior performance of a two-roll open calender.