Machinery used to manufacture various rubber products such as tires, including general rubber machinery, tire machinery and other rubber product machinery 3 categories.
Rubber machinery in general “Machinery for preparing rubber or semi-finished products, including raw material processing machinery, rubber mixing machines, extruders, calenders, curtain canvas pre-treatment devices and cutting machines.
Rubber mixing machines are divided into two types: open type and closed type.
Open rubber mixing machine: It is mainly used for hot mixing, tablet pressing, rubber breaking, plasticizing and rubber mixing. It consists of rollers, roller bearings, roller pitch adjustment device, emergency brake device, frame, machine base, transmission device, and heating and cooling system.
The working principle of the open rubber mixer is: raw rubber or rubber material is fed into the nip by friction between two rollers rotating at different speeds and subjected to strong shearing and compression to increase the degree of plasticity. This double roller open rubber mixing mill began to be used in production in 1826. Its structure is relatively simple and it is still commonly used in modern times.
Closed Rubber Mixing Machine: It is mainly used for plasticizing and mixing rubber. It has one more mixing chamber than the open mixer. After the raw rubber and compounding agent are loaded into the mixing chamber from the feed hopper, the material door is closed, the upper bolt of the pressing device is pressed down, and the two rotors of the mixing chamber mixture rotate in opposite directions at different or the same speed.
The charged rubber material is subjected to constant agitation, rolling and strong kneading between the rotors, between the rotors and the mixing chamber, which leads to oxidation and chain scission, which increases plasticity. At the same time, the rubber material is evenly dispersed and mixed due to shearing, so as to achieve the purpose of mixing the rubber.
Since the invention of the elliptical rotor enclosed rubber mixer in 1916, the enclosed rubber mixer has developed rapidly in the rubber industry. Subsequently closed rubber mixers with other types of rotors appeared. The mixing cycle of a modern closed rubber mixer is 2.5-3 minutes and the maximum capacity of the mixing chamber is 650 litres.
The extruder is used to extrude treads, inner tubes, hoses and various rubber strips, and is also used to coat cables and wire products. The most common is the screw extruder. Its working principle is: the rubber material is stirred, mixed, plasticized and compacted in the barrel by rotating the extrusion screw, and then it moves in the direction of the machine head and finally extrudes a product of a certain shape. From the mouth Depending on the needs of the product, various machines can be used for compound extrusion of a variety of rubber materials.
Screw extruders are divided into two types: hot feed and cold feed. Hot feed extruders generally feed strips that have been preheated by an open rubber mill. The rubber material fed by the cold feed extruder does not melt with heat, so the hot melt equipment can be omitted.
The calender is mainly used for pasting or rubbing curtain canvas, rubber material pressing, laminating, pressing and embossing. The main working part of the calender is the roller, and the number of rollers is usually 3 or more. When rubber material with a certain temperature and plasticity is fed into the gap of counter-rotating rollers, it is strongly squeezed and stretched under the action of friction to form the required product. The first calender was made and used in production in 1857, and it has been continually improved thereafter.
Especially since the 1950s, the development of the plastics industry has strongly promoted the improvement of high-precision and high-speed calenders. In order to obtain calendered products with a uniform thickness, new calenders are generally equipped with roll deflection compensation devices. The thickness of the calendered semi-finished product is measured with special equipment, and some calenders are also equipped with an automatic thickness adjustment system controlled by an electronic computer.
Tire Machinery
This type of machinery includes tire building machines, tire displacement machinery, tire molding vulcanizers, bladder vulcanizers, cushion belt vulcanizers, tube splicers and tube vulcanizers, as well as tire machinery, retreading machinery tires and recovered rubber production machinery. More than 60% of the world’s rubber is used to make tires, so tire machinery occupies an important place in rubber machinery. Figure 2 is a flowchart of tire production.
The tire making machine is used to roll and process various components such as rubber cord, wire cord, and tread into a green tire. According to the purpose, it is divided into two categories: ordinary tire making machines and radial tire making machines.
The cords of the cords of the common tire carcass intersect at a certain angle. When forming, the cord tube is first placed in the building drum, and then wire loops are placed on both sides, and the cushioning layer and tread rubber are covered in the middle to form the shape. The green tire becomes cylindrical.
The main difference in the structure between radial tires and ordinary tires is that the cords of the cushion layer and the axis of the carcass are 90° 75° (almost orthogonal), so the diameter of the cushion layer does not it can be changed significantly after molding, so the carcass is made. After that you need to expand to the rough final shape and then attach the damping layer. Therefore, the structure of the radial tire making machine is also different from that of the ordinary tire making machine.
A molding machine completes the entire radial tire building process, which is called the one-time molding method. The carcass is made by a modified ordinary tire making machine, and then formed on the radial tire making machine, which is called the two-stage forming method.
Microwave Heating Technology for Rubber Processing
