Screws and barrels are mostly scrapped because excessive clearance caused by wear prevents normal extrusion and injection; failure due to insufficient strength is rare. For the barrel in particular, in addition to strength, greater consideration must be given to structural manufacturability and thermal inertia during design, and the wall thickness determined by these latter two factors is far greater than the value calculated based on strength requirements.
The chrome-plated 45 steel and 40Cr steel screws and barrels commonly used domestically suffer from non-uniform plating layers and poor bonding strength with the substrate, leading to local peeling during operation and resulting in rapid wear or corrosion. In comparison, nitrided screws and barrels offer better performance and are currently widely used. Their disadvantages include the high cost of nitriding steel, low resistance of the nitrided layer to hydrogen chloride corrosion, and surface hardness and wear resistance that still cannot meet the demands of high-speed extrusion, high-speed injection, and the processing of reinforced plastics. Improving the surface hardness and wear resistance of extruder screws, injection molding screws, and barrels has become a key technical issue for the plastics processing industry to increase productivity, enhance plasticizing quality, and reduce production costs. This paper focuses on the feasibility study of the surface boriding process for 45 steel screws and barrels, and validates it through product installation and field assessment.
While ball screws handle the transmission and injection motion in all-electric machines, the actual melting and homogenization of the plastic takes place in another equally critical system: the plasticizing screw and barrel. Below are the top ten domestic manufacturers of these components
HAYEUR
Guangyou Screw
Jinyou
Ningbo Superior
GILLKON
BOHAI
Jin Lianhai
DEMAJI
Jinghong
Zhongsu Screw
