Detailed Introduction To The Basic Tire Manufacturing Process
2026-09-16
The production of automotive tires consists of a series of technological processes, including raw material processing, batching, raw rubber compounding, rubber mixing, curtain canvas rolling, tread pressing, tire component manufacturing, tire forming, raw tire shaping, and vulcanization.
(1) Raw material processing
Before the raw rubber is molded, the rubber blocks must be placed on the rack of the drying room at a temperature of 50~70°C, graded and stacked in a jump grid, and heated to soften. In summer, heating at 50~60℃ should be no less than 48 hours; no more than 96 hours; in winter, heating should be no less than 72 hours and no more than 144 hours. The purpose of softening is to facilitate cutting and plasticizing processing, and at the same time it can also reduce the moisture content of the rubber block. After the raw rubber is softened, it can be cut into the required small pieces with a rubber cutting machine. Some ingredients require drying, screening, crushing and melting.
(2) Ingredients
Ingredients are to weigh various raw materials including rubber and various ingredients according to the requirements of the production formula to supply the plasticizing and mixing processes.
(3) Refining
The process of changing raw rubber from a strong elastic state to a plastic state is called mastication. The purpose of mastication is to make the rubber have a certain plasticity, so that the compounding agent can be easily mixed into the rubber during mixing, and the rubber compound can be easily rolled and extruded, so as to obtain standard specifications and shapes. Natural rubber is usually refined using a closed (or open) rubber mixing machine. During the mastication process, the raw rubber undergoes mechanical, chemical and thermal effects under the action of the internal mixer drum, resulting in reduced elasticity and increased plasticity. The raw rubber after plasticizing is called plasticized rubber. Today's synthetic rubbers, such as styrene-butadiene rubber and polybutadiene rubber, do not need to be masticated and can be mixed directly.
(4) Mixing
In order to make the rubber material have the specified performance, in addition to raw rubber, various compounding agents must be added to various rubber materials. Mixing is to mix raw rubber and various additives according to the mass ratio specified in the formula, and to make various additives completely and evenly dispersed in the raw rubber. At the same time, the mixed rubber should also have a certain degree of plasticity to facilitate subsequent process operations. The mixed rubber is called compound, or simply rubber. The mixing operation is carried out in a closed rubber mixer.
(5) Curtain and canvas calendering
One of the most important components in tire manufacturing is the rubberized cord and canvas. The process of applying rubber to cord and canvas is called calendering. The purpose of calendering is to bond and isolate the cord layers from each other to prevent friction and heat generation between lines and layers, so that the cord layers form a buffer system that is resistant to flexing and peeling. The glue layer can absorb the impact force acting on the cord, reduce the shear stress between layers, and prevent the cord from getting damp. It can be seen that the calendering of curtains and canvases is actually to make the rubber material cover the curtains and canvas well, fill their surfaces, and make the rubber material soak into the line to a certain depth, so that there is a good connection between the rubber material and the curtains and canvas. Adhesion. Curtains and canvas are calendered on a four-roller or three-roller calender.
(6) Tread pressing out
Because the tread rubber and sidewall rubber have different formulas, they are extruded by two extruders at the same time (some have the same formula and are extruded by the same extruder), and then they are laminated together and pressed by an active roller. Tighten, then cool, measure the thickness, cut and weigh, and roughen the back with a steel roller. It can be connected or not according to the molding process requirements. The tread extrusion system uses a screw extruder. The principle is to fill the rubber material into the cavity of the screw extruder, push it to the machine head by the thrust of the spiral in the cavity, and press the rubber material into a tread shape through the mouth plate.
(7) Tire parts manufacturing
① Curtain and canvas cutting
In the tire manufacturing process, a large amount of curtains and canvas are used. These rubber curtains and canvases include rubber cords for buffer layers, rubber cords for ply layers, and wrapping cloths for wire rings and beads. According to the provisions of the construction schedule, the rubberized curtains and canvas are cut into various tape strips with certain widths and angles as needed. The cutting of rubber curtains and canvas is carried out on horizontal and vertical cutting machines respectively.
② Apply isolation glue to the rubber curtain
The number of ply layers of the tire is mainly determined based on the tire's specifications, purpose, internal pressure, load, and cord strength. In bias tires, since the warps of adjacent plies are usually arranged crosswise, the number of plies in the tire should be an even number (in radial tires, since the cords are arranged in the meridional direction, each layer of ply can be independent work, so an even number of layers is not required). For example, most car tires have 4 to 6 layers, while truck tires have 6, 8, or 10 layers or more. The layers of cord fabric are numbered sequentially from the inside to the outside of the tire. In order to prevent carcass delamination in multi-layer tires and to form a uniform rigid transition between the carcass and the buffer layer, the warp density of the outer ply layer is generally smaller, and the width between the outer ply layers reaches the shoulder and sidewalls of the tire. of several layers of release film. The isolation film is affixed on the surface of a part of the cut rubber cord through a calender according to the provisions of the tire manufacturing construction table. The number of layers of isolation film is determined by the structure and specifications of the tire. The rubber used is the same as the cord rubber. For example, for a truck tire with 10 layers of cords, isolation films are attached to the 7th, 8th, and 9th layers of cords, and for 8-layer tires, isolation films are attached to the 5th, 6th, and 7th layers of cords.
③ Manufacturing of buffer layer
When manufacturing the buffer layer, a ply laminating machine is used, or a special laminating machine can be used. There are two structures of the buffer layer, one is composed of pure rubber layer, and the other is composed of buffer film and buffer rubber cord. Car tires mostly use the former buffer layer, and truck tires mostly use the latter buffer layer. Since the buffer layers have different structures, their manufacturing methods are also different. The buffer layer composed of a pure rubber layer is made by using a calender to produce a film of a certain width and thickness. It is directly attached to the outermost ply of the cut ply by hanging isolation glue; or it can be cut into pieces after sufficient cooling and shrinkage. A rubber strip of a certain length is directly attached when forming the tire; or it can be made into a ring-shaped rubber strip and then used when forming the tire. When manufacturing the buffer layer composed of buffer film and buffer rubber cord, the film of a certain specification and the cut buffer rubber cord are pasted into a ring tube on the laminating machine according to the length specified in the construction standard table for forming the tire. use.
The cords of the rubber cord of the bias tire buffer layer should cross each other at the same angle as the ply, that is, forming an angle of 50° to 52° with the cross section. And the layer close to the ply must also intersect with the outermost cord of the ply. The buffer layer of a radial tire is also called the belt layer. It consists of 3 to 5 layers of steel cords or 4 to 6 layers of fiber cords. The cross section of the cord and tire is at an angle of 70°~75°. The cords of adjacent layers of the belt are also criss-crossed, just like the cords in the ply and breaker ply of a bias-ply tire.
④ Curtain tube manufacturing
At present, tire molding, except for a few small-sized tires that use rubber cord strips to be directly attached to the molding machine head, generally uses a pre-made annular cylinder made of rubber strips that have been cut to a certain width, length and angle before molding. The ring shape is referred to as the curtain tube. Cord sheets are generally composed of two, three or four layers of rubber cord fabrics laminated together. When laminating, in bias tires, the angles of the two adjacent cords cross each other; in radial tires, the carcass cords are arranged in the meridian direction, so all the cords of the radial tire carcass ply The lines do not cross each other. The cord laminating operation is performed on the cord laminating machine.
⑤ Steel ring manufacturing
The steel ring is composed of steel ring filling glue (triangular rubber strip) and steel ring wrapping cloth. The manufacture of wire rings generally uses a small extruder with a linkage device. When the steel wire passes through the die plate of the extruder, the space between the steel wires and the surface of the steel wire are held, and isolation glue is applied to form a glue-hanging steel wire belt. Roll the wire ring into a certain diameter and a certain number of layers on the rolling disk according to the construction schedule, and then cut it. Wrap tape around the joint of the wire ring, stick the triangular tape on the outer circumference of the wire ring, and wrap it with steel ring wrapping cloth to make a steel ring.
(8) Tire shaping
The process of combining the various components into a whole is called molding, and the molded tire is called a "green tire".
(9) Preparing the shape of the raw tire
Universal air shaping machines are currently widely used for tire shaping. Its working principle is to use the pressure of compressed air to shape the green tire and install the water tire in the green tire. A raw tire is a thick-walled hollow cylindrical capsule with a mouth. Steam or superheated water is introduced into the water tire to provide the necessary heat during the vulcanization process of the green tire, thereby accelerating the vulcanization of each component of the green tire and improving the uniformity of vulcanization of the green tire.
(10) Raw tire vulcanization
Green tire vulcanization is the last process in tire manufacturing. Currently, the most widely used method is the vulcanization method using saturated steam and superheated water. During vulcanization, the green tire is placed inside a contoured and patterned steel mold. On the one hand, the heat of external steam (140~160℃) passes through the model and is introduced into the green tire carcass from the outside. On the other hand, superheated water (160~180℃) enters the water tire cavity from the water tire mouth. The superheated water is transmitted to the green tire through the water tire at a very high pressure (1960~2744kPa), causing the green tire to stretch to a predetermined shape and compact it tightly during the heating process, so that the various parts of the tire are tightly combined to achieve precise outlines and clear patterns. There are three types of tire vulcanization equipment: vulcanization tanks, ordinary individual vulcanizers, and stereotyped vulcanizers.
(1) Raw material processing
Before the raw rubber is molded, the rubber blocks must be placed on the rack of the drying room at a temperature of 50~70°C, graded and stacked in a jump grid, and heated to soften. In summer, heating at 50~60℃ should be no less than 48 hours; no more than 96 hours; in winter, heating should be no less than 72 hours and no more than 144 hours. The purpose of softening is to facilitate cutting and plasticizing processing, and at the same time it can also reduce the moisture content of the rubber block. After the raw rubber is softened, it can be cut into the required small pieces with a rubber cutting machine. Some ingredients require drying, screening, crushing and melting.
(2) Ingredients
Ingredients are to weigh various raw materials including rubber and various ingredients according to the requirements of the production formula to supply the plasticizing and mixing processes.
(3) Refining
The process of changing raw rubber from a strong elastic state to a plastic state is called mastication. The purpose of mastication is to make the rubber have a certain plasticity, so that the compounding agent can be easily mixed into the rubber during mixing, and the rubber compound can be easily rolled and extruded, so as to obtain standard specifications and shapes. Natural rubber is usually refined using a closed (or open) rubber mixing machine. During the mastication process, the raw rubber undergoes mechanical, chemical and thermal effects under the action of the internal mixer drum, resulting in reduced elasticity and increased plasticity. The raw rubber after plasticizing is called plasticized rubber. Today's synthetic rubbers, such as styrene-butadiene rubber and polybutadiene rubber, do not need to be masticated and can be mixed directly.
(4) Mixing
In order to make the rubber material have the specified performance, in addition to raw rubber, various compounding agents must be added to various rubber materials. Mixing is to mix raw rubber and various additives according to the mass ratio specified in the formula, and to make various additives completely and evenly dispersed in the raw rubber. At the same time, the mixed rubber should also have a certain degree of plasticity to facilitate subsequent process operations. The mixed rubber is called compound, or simply rubber. The mixing operation is carried out in a closed rubber mixer.
(5) Curtain and canvas calendering
One of the most important components in tire manufacturing is the rubberized cord and canvas. The process of applying rubber to cord and canvas is called calendering. The purpose of calendering is to bond and isolate the cord layers from each other to prevent friction and heat generation between lines and layers, so that the cord layers form a buffer system that is resistant to flexing and peeling. The glue layer can absorb the impact force acting on the cord, reduce the shear stress between layers, and prevent the cord from getting damp. It can be seen that the calendering of curtains and canvases is actually to make the rubber material cover the curtains and canvas well, fill their surfaces, and make the rubber material soak into the line to a certain depth, so that there is a good connection between the rubber material and the curtains and canvas. Adhesion. Curtains and canvas are calendered on a four-roller or three-roller calender.
(6) Tread pressing out
Because the tread rubber and sidewall rubber have different formulas, they are extruded by two extruders at the same time (some have the same formula and are extruded by the same extruder), and then they are laminated together and pressed by an active roller. Tighten, then cool, measure the thickness, cut and weigh, and roughen the back with a steel roller. It can be connected or not according to the molding process requirements. The tread extrusion system uses a screw extruder. The principle is to fill the rubber material into the cavity of the screw extruder, push it to the machine head by the thrust of the spiral in the cavity, and press the rubber material into a tread shape through the mouth plate.
(7) Tire parts manufacturing
① Curtain and canvas cutting
In the tire manufacturing process, a large amount of curtains and canvas are used. These rubber curtains and canvases include rubber cords for buffer layers, rubber cords for ply layers, and wrapping cloths for wire rings and beads. According to the provisions of the construction schedule, the rubberized curtains and canvas are cut into various tape strips with certain widths and angles as needed. The cutting of rubber curtains and canvas is carried out on horizontal and vertical cutting machines respectively.
② Apply isolation glue to the rubber curtain
The number of ply layers of the tire is mainly determined based on the tire's specifications, purpose, internal pressure, load, and cord strength. In bias tires, since the warps of adjacent plies are usually arranged crosswise, the number of plies in the tire should be an even number (in radial tires, since the cords are arranged in the meridional direction, each layer of ply can be independent work, so an even number of layers is not required). For example, most car tires have 4 to 6 layers, while truck tires have 6, 8, or 10 layers or more. The layers of cord fabric are numbered sequentially from the inside to the outside of the tire. In order to prevent carcass delamination in multi-layer tires and to form a uniform rigid transition between the carcass and the buffer layer, the warp density of the outer ply layer is generally smaller, and the width between the outer ply layers reaches the shoulder and sidewalls of the tire. of several layers of release film. The isolation film is affixed on the surface of a part of the cut rubber cord through a calender according to the provisions of the tire manufacturing construction table. The number of layers of isolation film is determined by the structure and specifications of the tire. The rubber used is the same as the cord rubber. For example, for a truck tire with 10 layers of cords, isolation films are attached to the 7th, 8th, and 9th layers of cords, and for 8-layer tires, isolation films are attached to the 5th, 6th, and 7th layers of cords.
③ Manufacturing of buffer layer
When manufacturing the buffer layer, a ply laminating machine is used, or a special laminating machine can be used. There are two structures of the buffer layer, one is composed of pure rubber layer, and the other is composed of buffer film and buffer rubber cord. Car tires mostly use the former buffer layer, and truck tires mostly use the latter buffer layer. Since the buffer layers have different structures, their manufacturing methods are also different. The buffer layer composed of a pure rubber layer is made by using a calender to produce a film of a certain width and thickness. It is directly attached to the outermost ply of the cut ply by hanging isolation glue; or it can be cut into pieces after sufficient cooling and shrinkage. A rubber strip of a certain length is directly attached when forming the tire; or it can be made into a ring-shaped rubber strip and then used when forming the tire. When manufacturing the buffer layer composed of buffer film and buffer rubber cord, the film of a certain specification and the cut buffer rubber cord are pasted into a ring tube on the laminating machine according to the length specified in the construction standard table for forming the tire. use.
The cords of the rubber cord of the bias tire buffer layer should cross each other at the same angle as the ply, that is, forming an angle of 50° to 52° with the cross section. And the layer close to the ply must also intersect with the outermost cord of the ply. The buffer layer of a radial tire is also called the belt layer. It consists of 3 to 5 layers of steel cords or 4 to 6 layers of fiber cords. The cross section of the cord and tire is at an angle of 70°~75°. The cords of adjacent layers of the belt are also criss-crossed, just like the cords in the ply and breaker ply of a bias-ply tire.
④ Curtain tube manufacturing
At present, tire molding, except for a few small-sized tires that use rubber cord strips to be directly attached to the molding machine head, generally uses a pre-made annular cylinder made of rubber strips that have been cut to a certain width, length and angle before molding. The ring shape is referred to as the curtain tube. Cord sheets are generally composed of two, three or four layers of rubber cord fabrics laminated together. When laminating, in bias tires, the angles of the two adjacent cords cross each other; in radial tires, the carcass cords are arranged in the meridian direction, so all the cords of the radial tire carcass ply The lines do not cross each other. The cord laminating operation is performed on the cord laminating machine.
⑤ Steel ring manufacturing
The steel ring is composed of steel ring filling glue (triangular rubber strip) and steel ring wrapping cloth. The manufacture of wire rings generally uses a small extruder with a linkage device. When the steel wire passes through the die plate of the extruder, the space between the steel wires and the surface of the steel wire are held, and isolation glue is applied to form a glue-hanging steel wire belt. Roll the wire ring into a certain diameter and a certain number of layers on the rolling disk according to the construction schedule, and then cut it. Wrap tape around the joint of the wire ring, stick the triangular tape on the outer circumference of the wire ring, and wrap it with steel ring wrapping cloth to make a steel ring.
(8) Tire shaping
The process of combining the various components into a whole is called molding, and the molded tire is called a "green tire".
(9) Preparing the shape of the raw tire
Universal air shaping machines are currently widely used for tire shaping. Its working principle is to use the pressure of compressed air to shape the green tire and install the water tire in the green tire. A raw tire is a thick-walled hollow cylindrical capsule with a mouth. Steam or superheated water is introduced into the water tire to provide the necessary heat during the vulcanization process of the green tire, thereby accelerating the vulcanization of each component of the green tire and improving the uniformity of vulcanization of the green tire.
(10) Raw tire vulcanization
Green tire vulcanization is the last process in tire manufacturing. Currently, the most widely used method is the vulcanization method using saturated steam and superheated water. During vulcanization, the green tire is placed inside a contoured and patterned steel mold. On the one hand, the heat of external steam (140~160℃) passes through the model and is introduced into the green tire carcass from the outside. On the other hand, superheated water (160~180℃) enters the water tire cavity from the water tire mouth. The superheated water is transmitted to the green tire through the water tire at a very high pressure (1960~2744kPa), causing the green tire to stretch to a predetermined shape and compact it tightly during the heating process, so that the various parts of the tire are tightly combined to achieve precise outlines and clear patterns. There are three types of tire vulcanization equipment: vulcanization tanks, ordinary individual vulcanizers, and stereotyped vulcanizers.
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