Plate rolls: what they are and what they are for

Plate rolls: what they are and what they are for

Plate rolls are made up of two or more rollers that rotate in the opposite direction alternating between them, through which the material to be transformed passes. The rollers are positioned by setting the distance and inclination between them which give the specific thickness and shape. The number of cylinders and the speed of rotation vary according to the material, the surface finish to be obtained and the technology applied.

The calendering process uses the plate roll to extrude the material, forming a bead or ribbon passed through a system of heating rollers that make up this system. The material exits the extruder in a new shape and texture and in the desired thickness and surface finish. The calendering process takes place through the heated rolls or be performed with only the pressure of the rolls. In the case of heated rollers, heat is used to plasticise the materials to be transformed and loosen chemical bonds. In the case of unheated rollers, it is the pressure the rollers create on the material that generates the heat needed to break chemical bonds and thin the materials.

4 Rolls Plate Bending Machine: RI72 series from 1960Seravesi

The RI72 series of 1960Seravesi is an integral oleodynamic drive rolling machine composed of 4 rollers with double infeed. The rollers have a linear movement with bronze guides. The 4 Rolls Plate Bending Machines, RI72 series from 1960Seravesi, are available with capacities from 25 mm up to 300 mm and roll lengths from 1000 mm up to 6000 mm.

One of its main features is the positioning accuracy of the rollers maintained over time thanks to the linear guide system. The lower rollers are guided inside the structure of the machine, eliminating the possibility of play due to wear of the machinery, as opposed to what happens on machines with planetary system (PSG ”) / levers.

Another peculiarity is the simplicity of use and maintenance thanks to an easy accessibility of the hydraulic parts and thanks to the diagnostics present in the control panel always within reach of the operator.

Features of 1960Seravesi RI72 series :

  • Invitation with minimal rectilinear section, thanks to the high thrust force of the cylinders on the lower rollers which, thanks to the linear movement, are mounted directly under the rollers and do not use any lever system;
  • Roller positioning accuracy maintained over time thanks to the linear guide system. The lower rollers are guided inside the machine structure, eliminating the possibility of play due to wear of the machinery, as opposed to what happens on machines with planetary system (PSG ”) / levers;
  • Cancellation of the sliding friction of the rollers, guaranteed by a system of lubricated bronze guides;
  • Perfect parallelism of the lower rolls ensured by a system that uses double linear potentiometer for each roll. The rolls are independently adjustable and easily tilted to allow the execution of conical calendering;
  • Robustness characterized by carpentry and massive linear structures;
  • High working speed and reliability , as well as ease of use and maintenance thanks to an easy accessibility of the hydraulic parts and to the diagnostics present in the control panel always within reach of the operator.

STRUCTURE RI72 of 1960Seravesi (CE certified rolling machine):

Base made of electro-welded steel and subjected to normalization heat treatment. The support shoulders of the movement cylinders of the rollers are made of electro-welded steel and subjected to normalization heat treatment.

The rollers in special carbon steel (C45 or C50) are subjected to heat treatment.

  • 2 rollers are motorized with n°2 planetary reducers + n°2 hydraulic motors for the rotation of the same;
  • The side rollers and the lower roll have independent positioning movement through hydraulic cylinders;
  • Side rollers tilt electronically (controlled by PLC) for the production of conical sheets;
  • Translation of the lateral and lower rollers with a system of rectilinear guides;
  • The rotation system of the rollers is achieved by means of 2 hydraulic motors coupled to 2 planetary gearboxes directly keyed on the rollers;
  • Automatic speed / pressure compensation between the upper and lower rollers.

The linear potentiometers mounted on each roller (two for each roller) allow the electronic control of the parallelism of the rollers, while the radial bearings mounted on all the rollers are SKF or FAG brand double crown orientable.

From 2 pumps up to 6 for the larger sizes for maximum thrust in line and in rotation. Having a system with several pumps, we always have the simultaneous movement, i.e. the possibility of both rotating and pressing at maximum capacity, and in the event of a pump failure, still use the machine even if with reduced performance.

The cylinders are made of alloy steel and carbon steel, with chromed rod and use seals from leading brands. The hydraulic unit is composed of a motor pump unit, solenoid valves, maximum pressure valves which guarantee the protection of the system from overload.

Furthermore, the hydraulic opening bracket allows horizontal extraction of the product tube and the centralized and automatic lubrication system is equipped with a pump with autonomous tank programmable from the operator panel.