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Multi-Layer Rubber Calendering Line Is Used To Produce Rubber Sheets And Rubber Conveyor Belts
What industries are calenders used in?
The calender is an important equipment in the rubber processing
process. It is mainly used to make the mixed rubber into a film of
a certain thickness and width or to bond the film with fabrics
(such as cords, canvas, etc.), steel wire and other skeleton
materials. The following are some rubber products that use
calenders:
1. Tire
Tire
In the production of tire casings, the calender plays a key role.
First, it is used to manufacture various components of the tire
casing. For example, the calender can be used to calender the
rubber compound into tread rubber. The tread rubber is the part of
the tire that contacts the ground. Its thickness and surface
quality are crucial to the tire's wear resistance, grip and other
performance.
At the same time, the calender is also used to bond the cord (a
cord-like fabric made of fibers) and the rubber compound. The cord
plays a reinforcing role in the tire and can withstand various
stresses during the tire's driving process. The calender evenly
covers the rubber on the surface of the cord to form structures
such as the belt layer and the carcass cord layer, which can ensure
the strength and stability of the tire.
Inner tube
For the production of inner tube, the calender can calender the
inner tube rubber into a film of uniform thickness. The thickness
requirements of the inner tube are relatively strict. Too thick
will increase the weight and rolling resistance of the tire, and
too thin will easily cause problems such as air leakage. The
calender can accurately control the thickness of the inner tube
film to ensure the quality of the inner tube.
2. Conveyor belt
Ordinary conveyor belt
The rubber covering layer of the conveyor belt is processed by a
calender. For example, when producing ordinary conveyor belts for
conveying materials such as coal and ore, the rubber compound needs
to be calendered into upper and lower covering layers of a certain
thickness, covering the canvas skeleton of the conveyor belt. The
calender can make the rubber covering layer fit tightly with the
canvas, ensuring that the rubber will not easily peel off during
the long-term operation of the conveyor belt, and at the same time
give the conveyor belt good wear resistance, tear resistance and
other properties.
Special conveyor belt
For some conveyor belts with special requirements, such as
food-grade conveyor belts (used for conveying food, etc.), the
calender can calender the rubber material that meets food hygiene
standards into a uniform and smooth surface. The surface of this
conveyor belt cannot have impurities and rough textures to avoid
contaminating food. There are also high-temperature resistant
conveyor belts. The calender can make high-temperature resistant
rubber compounds into corresponding components to ensure that the
conveyor belt can work normally in a high-temperature environment.
3. Hose
Wire braided hose
In the production of wire braided hoses, the calender is used to
make the inner and outer rubber layers of the hose. The inner
rubber layer needs to fit tightly inside the wire braided layer to
provide a sealed environment for the conveyed medium. The outer
rubber layer protects the hose and enables it to resist external
wear and corrosion. The calender can make the thickness of the
inner and outer rubber layers of the hose uniform, ensuring the
quality and service life of the hose.
Fiber-wound hose
For fiber-wound hoses, the calender is also used to make the rubber
layer of the hose. It calenders the rubber compound into a suitable
thickness, and some functional additives such as anti-aging agents,
flame retardants, etc. can be added to the rubber compound to meet
the needs of the hose in different application scenarios. When
combined with the fiber winding layer, the calender can make the
rubber and the fiber fit well and enhance the overall performance
of the hose.
4. Rubber sealing products (such as rubber sealing rings)
O-type sealing rings
When producing O-type sealing rings, the calender can calender the
rubber compound into thin sheets, and then make O-type sealing
rings through subsequent molding processes (such as cutting,
vulcanization, etc.). The calendering process can ensure the
density and uniformity of the rubber material, so that the sealing
ring has good sealing performance during use and can effectively
prevent the leakage of liquid or gas.
Seals of other shapes
For rubber seals of other shapes such as square and rectangular
shapes, the calender can also first make the rubber into a film of
appropriate thickness to provide basic materials for subsequent
molding processing. In addition, the calender can also add some
reinforcing materials or filling materials to the rubber film to
improve the hardness, strength and other properties of the seal to
meet different sealing requirements.
Working principle of rubber calender:
The calender mainly extrude and stretch rubber and other materials
through a series of rollers to achieve the processing purpose.
1. Basic structure and roller configuration
The calender usually has multiple rollers, usually two, three or
four rollers. These rollers are arranged horizontally or at a
certain angle. For example, in a three-roll calender, there are
upper rollers, middle rollers and lower rollers. The diameter and
length of each roller vary according to the purpose of the calender
and the scale of the processed material. The rollers are generally
made of chilled cast iron or alloy steel, and the surface is
processed and ground with high precision to ensure its cylindricity
and surface finish, as this will directly affect the quality of the
calendered product.
The gap between adjacent rollers is adjustable, which is a key
factor in controlling the thickness of the calendered product. The
gap size is accurately adjusted by mechanical or hydraulic devices
to adapt to the calendering of materials with different thickness
requirements.
2. Material transportation and deformation during work
When the rubber material (usually the rubber material after mixing)
is fed between the rollers of the calender, the rotation of the
rollers drives the rubber material forward. For example, in a
double-roll calender, the two rollers rotate in opposite
directions, and the rubber is rolled into the gap between the
rollers under the action of friction. As the rollers continue to
rotate, the rubber is squeezed by the rollers. Since the gap
between the rollers is smaller than the original thickness of the
rubber, the rubber is gradually thinned when passing through the
gap, and the width will also expand according to the shape and
arrangement of the rollers.
In this process, the molecular chains inside the rubber will be
oriented along the calendering direction. This orientation of
molecular chains has a great influence on the physical properties
of the calendered products, such as improving the tensile strength
and tear resistance of the material, but if the orientation is
excessive, it may also cause anisotropy, making the product weaker
in some directions.
3. Work in conjunction with other auxiliary devices
The calender is usually also equipped with a feeding device to
evenly convey the rubber between the rollers. The feeding device
can control the feeding speed and feeding amount of the rubber to
ensure the stability of the calendering process. At the same time,
there is a traction device at the discharge end of the roller,
which is used to pull the calendered material out at an appropriate
speed to prevent the material from accumulating or over-stretching
at the roller.
In order to ensure the quality of calendered products, some
calenders are also equipped with temperature control systems.
Because the physical properties of rubber materials such as
viscosity are affected by temperature, by controlling the
temperature of the rollers, the fluidity of the rubber can be
adjusted, so that the rubber deforms more evenly during the
calendering process, thereby obtaining products with more stable
thickness and quality. For example, when processing some
high-hardness rubbers, appropriately increasing the roller
temperature can reduce the hardness of the rubber, making it easier
to be calendered.
Detailed specification:
XY-3 252 x 720 | XY-3 360 x 1120 | XY-3 400 x 1200 | XY-3 560 x 1680 | XY-3 610 x 1730 | XY-3 710 x 1800 | XY-3 710 x 2130 | |
Roll diameter (mm) | 252 | 360 | 400 | 560 | 610 | 710 | 710 |
Roll working length (mm) | 720 | 1120 | 1200 | 1680 | 1730 | 1800 | 2130 |
Roll ratio | 1:1:1 | 1:1:1 0.733:1:1 0.733:1:0.733 | 1:1:1 1:1.38:1.38 1:1.38:1 | 1:1:1 1:1.5:1 | 1:1:1 1:1.4:1 | 0.5-1 | 1:1:1 |
Middle-roll linear speed r/min | 2-15.9 | 3-20 | 3-26.39 | 3-30 | 5.4-54 | 4-40 | 8-50 |
adjusting np range (mm) | 0-10 | 0-10 | 0-10 | 0-10 | 0-20 | 0-30 | 0-20 |
min. calendering product thickness (mm) | 0.2 | 0.2 | 0.2 | 0.2 | 0.15 | 0.2 | 0.15 |
calendering product width (mm) | 550 | 920 | 1000 | 1500 | 1500 | 1600 | 1900 |
motor power (Kw) | 22 | 45 | 55 | 110 | 160 | 90kw x2 110kw x 1 | 185 |
overall dimension (mm) L x W x H | 3950 1150 1290 | 6500 1500 2440 | 6300 1500 2440 | 7680 2500 3900 | 7010 3950 3730 | 9950 3050 4540 | 7650 4560 4080 |
about weight (ton) | 5.5 | 14 | 18 | 37 | 42 | 90 | 97 |