Small single screw extruder (mini screw extruder) is currently the most used extrusion molding equipment in the laboratory and the most basic extruder.It is usually composed of motor, transmission mechanism, material cylinder and heating device, screw, head, mouth mode and seat, in addition to speed adjustment, temperature control, pressure measurement and program control systems, so as to adjust the screw speed and setting and control the heating temperature, nose pressure and operating procedures of each section of the extruder. In addition to small extruder, its supporting equipment includes shaping mold of extruder, cooling device (such as small extension machine, small extension machine, small film machine, MDO longitudinal stretching machine, thin film bidirectional stretching machine, etc.), traction device, cutting mechanism, thickness or roundness shape and size control devices, etc.The screw extruder can be divided into single screw extruder and multi-screw extruder.In laboratory application, multi-screw extruder is mainly small double-screw extruder, which is more and more widespread in laboratory extrusion molding, mainly responsible for multi-components of materials, or direct double-screw hybrid extrusion molding.
The small single screw extruder (small single screw extruder) consists of several parts of transmission system, extruding system, heating and cooling system, control system, etc.The basic role of each system is as follows.
(1) Extrusion system It consists mainly of screws and cylinders, and is a key component of the extruder.The effect is to plastic plastic
Make uniform melt and the pressure is established in this process so that the material is continuously, pressure, temperature and quantitatively squeezed by the screw
Machine head.
(2) The transmission system consists of electric motor, speed regulator and transmission device.Its effect is to drive the screw, to ensure the screw
Torque and rotational speed required during the extrusion process.
(3) heating and cooling system It consists of temperature control equipment.Its effect is to ensure the extrusion system through heating and cooling
The molding is conducted within the temperature control range required by the process.
(4)The control system is mainly composed of appliances, instruments and actuators.Its function is to adjust the rotation speed of the screw, the cylinder
Temperature and nose pressure, etc.
Among them, the extrusion system and transmission system are the key part of extrusion molding, lifting the quality and output of extrusion molding products
To work.Extruding system and transmission system mainly include transmission device, feeding device, material cylinder, screw, nose and mouth mold
Part (as shown in Figure 6-1).In addition, heating cooling and temperature control of small single screw extruder are also important for the stability of molding products.The specifications of the single-screw extruder are generally indicated by the size of the screw diameter.
