Extrusion process of hot gravimetric feeder
1) hot smelting and glue supply
Before the cold feed extruder is extruded, it must be preheated before mixing and cooling. The feeding machine is called hot refining. The heating method and requirement are the same as that of the calender. The temperature and plasticity of the rubber are different according to the requirements of the formula and process, but it is the same for maintaining the uniformity and stability of the temperature and plasticity of the rubber, which is the purpose of the heat smelting.
The quality and output of extruded semi-finished products are also greatly affected by the availability of uniform and uniform rubber. At present, the continuous production of extruder requires a large amount of rubber, and generally the belt conveyor is used for the glue supply method. The adhesive strip with certain width and thickness cut from the open mill will be continuously supplied to the extruder by belt conveyor. The width of the adhesive strip is slightly smaller than that of the feeding port, and the thickness is determined by the amount of rubber required. The size of the extruded semi-finished products is stable and the quality is better. The extruder, which is cooperated with the glue feeding method, adds feeding rollers to the upper part of the feeding port, so that the rubber strip enters the bottom of the screw along the rotating screw. This will improve the feeding capacity and uniformity of extruder. In addition, the glue strips are rolled into a roll, and then the rubber is supplied to the extruder by the feed roller; or the glue strips are cut into a certain length on the shelf, and the artificial feeding is made in sequence. This glue supply method is also adopted on some small machines.
(2) gravimetric feeder extrusion
Extrusion technology includes selection of extruder, preheating equipment, adjusting mouth shape, controlling extruder temperature and extrusion speed.
1. the extruder should be selected according to the specifications, properties and properties of the extruder. The size of the mouth is the main consideration when choosing the equipment. !
The diameter of the extruder screw should be in line with the size or width of the mouth shape. Under the condition of the given aperture, the size of the extruder is too small, which will lead to insufficient pressure at the head of the machine and influence the density of extrusion and rubber. The pressure of the extruder is too large, which leads to the increase of the pressure in the head and the coke burning easily. For the circular shape, the diameter of the screw is generally 1.3-3 times the aperture of the mouth, and the maximum extrusion width is generally 2.5-3.5 times the diameter of the screw for the flat shape (such as the tread type