The main body is the extruder and head, in addition to feeding, shaping, cooling, hauling, cutting and winding and other auxiliary equipment (see color chart). In the rubber processing also includes vulcanizing devices. In the actual production of the main body and auxiliary equipment is often connected to a unit to use.
Extruder
-Single-screw extruder and twin-screw extruder according to the number of screws
Single-screw extruder
Single-screw extruder is in the heated barrel with a rotating screw, the outer portion of the barrel is equipped with a heating and cooling device, there is a radial feeding port at one end. The other end is axially connected to the head. The screw is the key component of the extruder. The main technical parameters of single-screw extruder are screw diameter, L/D ratio (ratio of screw length to diameter), screw speed range, drive motor power, barrel heating power and machine capacity. The screw diameter determines the production capacity of the extruder and the maximum allowable cross-section of the product. Different materials require different screw geometries and L/D ratios. Modern plastic extruder widely used combination screw, distribution mixing screw, as well as in the screw with a barrier or pin, etc., in order to improve plasticization, improve production capacity and product quality .
Twin-screw extruder
Twin-screw extruder has two screws rotating in the ∞-shaped heated barrel. The screws can be categorized into engaged and non-engaged type; combined and non-combined type; isotropic and anisotropic rotation. The isotropic engaging type and anisotropic engaging type are used more. The former is used for plastics *** mixing, filling and reinforcing, producing a variety of compounds; the latter is used for processing hard PVC products.
Head and die
The head and die are located at the front of the barrel, which are the warm flow and modeling part of the extruder. By changing the head and die, semi-finished products with different specifications and shapes can be extruded.
(1)The head is located in the front part of the body, installed between the end of the screw and the mouth mold, the role of the head is to make the rubber material from the state of screw movement into the state of linear movement, and at the same time, the formation of the necessary pressure and a certain shape of semi-finished products.
(2) The mouth type is located in the front part of the head, which is used for molding semi-finished products and controlling their specification size. By changing the pattern, an extruder can prepare semi-finished products of different sizes and shapes. The requirements for the port shape are to try to ensure laminar flow of rubber, no dead spots and to strive for minimum pressure drop. There are two main types of mouth shape: normal mouth shape and special mouth shape.
Ordinary mouth type is generally divided into two kinds: one is a steel plate with a certain geometric shape, used for extruding solid and sheet semi-finished products, such as tread, rubber strips, rubber sheets, etc.; the other consists of mouth type, core type and core type support, used for extruding hollow semi-finished products, such as inner tubes, hoses, etc..
Specialty mouth type mainly includes double-roller head mouth type and orientation mouth type, which is a new type of mouth type design.