Classification of screws Generally, the screw can be di […]
Classification of screws
Generally, the screw can be divided into ordinary type, gradual type, mutant type, mixing type, separation type, split type and various barrier type, pin type, DIS split type and exhaust type; the number of screw heads can be single head Or change the head and so on
For plastics that are generally free of flame retardant, they can be processed using ordinary general-purpose screws. It is only necessary to select different diameters according to different melt viscosities.
If it is a special plastic, special product or special particle shape plastic, a special screw must be used.
Special screw introduction
The general-purpose screw is superior to a special screw in terms of plasticization and power consumption for a certain type of plastic. The following are the special screws manufactured by various special products and special needs.
PC special screw:
PC is a high-viscosity non-crystalline plastic with poor fluidity. It is easily degraded by heat for a long time. It has large feeding torque, is difficult to melt, and is easy to stagnate. It requires high temperature and high pressure injection. The temperature adjustment range is narrow and the process is not as good as PMMA.
The screw is fully hardened by imported high-alloy steel, which can withstand high torque, high pressure impact, wear resistance, surface plating, corrosion resistance, smooth and non-porosity to reduce surface adhesion and degradation, careful treatment of fine structure, and effective prevention of hiding glue. Low shear design, low heat. Generally take small and medium diameter, molding PCABS + PC, PP-R, flame retardant ABS and other effects. It can also be used to form general plastics and PMMA common products, but the color mixing effect is poor. If the color is added to the plastic, it is necessary to order the enhanced color mixing screw.
Cooperate with the industry's ultra-thin precision molding, provide large and small screw diameter, long and short, increase the injection pressure to 3000Kgf/cm or more, and move the seat forward and transform (after reconstruction, it can be restored to its original state).
PMMA special screw:
PMMA is a high-viscosity non-crystalline plastic. The toughness of the material is strong, it is difficult to melt, easy to stagnate, shear sensitive and easy to degrade, and the fluidity is slightly poor. It must be injected with high temperature and high pressure, and the temperature adjustment range is wide. Good process. The screw compression is relatively large, and it is fully hardened by imported high-alloy steel. It can withstand high torque and high pressure impact. The surface is plated with hard chrome to reduce surface adhesion and degradation. The plasticizing effect is good, the color mixing is good, and the low shear design has low heat. The degradation rate is low. Generally, the intermediate diameter is taken, and the effect of forming PMMA, PP-R, PC, and ABS is better.