Screw and barrel timing cleaning guarantee function Wor […]
Screw and barrel timing cleaning guarantee function
Working characteristics of screw and barrel:
① The screw speed can be realized as a stepless pressure and speed control configuration.
② Linear guide injection instead of guide pillar injection reduces friction during injection and improves injection accuracy (optional).
③ The screw and barrel are made of alloy materials, quenched and tempered and desalted to improve wear resistance. The injection is made of an electronic ruler from Gefferan, Italy, and the position control accuracy can be controlled within 0.1mm.
④ The independent control of the 4-stage injection pressure and speed, and the 4-stage holding pressure and speed is more conducive to the adjustment of the injection process.
⑤ The manual back pressure device (optional with numerical control back pressure) improves the plasticization, exhaust and density of the plastic by the screw. After feeding, a back pressure elimination device is added to prevent the plastic from flowing into the mold when the back pressure of the feeding is used in the production of the product without loosening and causing cold material.
Factors affecting injection molding by screw and barrel
① The relationship between screw speed and production capacity, and the speed is directly proportional to the production capacity of the equipment. That is, the productivity basically depends on the rotational speed, the geometry of the nose and the rod. It has also been confirmed in production. Within a certain speed range, the production capacity is basically proportional to the speed of the rod.
② This relationship has important guiding significance for production practice, and it is one of the important ways for modern single-pole machines to improve production capacity. If the working capacity of each section of the rod and the machine is sufficient, and the main and auxiliary equipment of the extruder are allowed, increasing the speed of the rod can greatly increase the production capacity.
③ The relationship between the geometrical size of the screw and the production capacity, the relationship between the diameter and the production capacity, the productivity is close to the proportional relationship with the square of the rod diameter D, that is, a small increase in the diameter will lead to a substantial increase in productivity.
Common methods for cleaning screw and barrel:
(1) Use barrel cleaner
If the raw materials for injection products are replaced frequently or the plasticization temperature range of the residual material in the barrel is quite different from that of the refueling, in order to save raw materials and improve work efficiency, it is more economical to use a barrel cleaner. The cleaning agent is a kind of rubber-like substance. It does not melt at high temperature in the barrel. It is softened in the screw groove. When it moves forward in the screw groove, it can take away the residual material and make it inside the barrel. Get cleaned up.
(2) Adopt refueling ejection method
If the plasticizing temperature range of the new material to be replaced is higher than the plasticizing temperature range of the residual material in the barrel, the barrel and nozzle can be heated to the lowest plasticizing temperature of the new raw material, and then the new material is added and the air is continuously aired. Inject until there is no remaining material in the barrel.
If the plasticization temperature range of the residual material in the screw barrel is higher than the plasticization temperature range of the material to be replaced, the barrel should be heated to the plasticization temperature range of the residual material in the barrel to remove the residual material. The nozzle material can be added for cleaning later, and new material can be put into production after the last. If the product requirements are high, the first few molds of the new material can be scrapped.