Usually screw can be divided into common type, gradient type, mutant, mixing type, separate type, shunt type and various barrier type, pin type, DIS open bar shunt
And exhaust type, etc.; screw heads can be changed for a single head or top.
For general not added flame retardant plastic, the use of ordinary common screw can be processed, only depending on the melt viscosity of the selection of different diameters can be. If
Is more specific performance plastics, special products or special plastic particle shape, you must use the special screw. Universal screw for a certain kind of plastic, in plastics and
Power consumption and other aspects not as special screw superior performance. Here is a variety of special products, special needs and manufacture of special screw for elaborate.
PC special screw
Pc is the high viscosity non-crystalline plastic, poor mobility, prolonged heat easily degradable, feeding torque, difficult to fuse, easy tying, need high melt temperature, high-pressure injection
Shot, material temperature adjustment range is narrow, technology as PMMA.
Imported high-alloy steel screw hardened, effectively withstand high torque, high pressure shock, abrasion, surface plating, corrosion resistance, smooth non-porous to
Reduce surface adhesion and degradation, detailed structure careful handling, possession of glue to effectively prevent, low shear design, small heat. Generally take small diameter, forming PCABS + PC,
PP-R, ABS and other flame-retardant effect. General plastic and can be molded PMMA ordinary products, but the mixing effect is poor. Adding toner, such as plastic, to be made to enhance mixing
Type screw.
Ultra precision molding with the industry, providing large diameter screw piecemeal, short length change, improve injection pressure to 3000Kgf/cm above, shot seat forward transformation (change
Made after normal restitution).
PMMA special screw
PMMA as a high viscosity non-crystalline plastic, qualitative tough feeding torque, difficult to fuse, easy tying, shear-sensitive readily biodegradable, mobility somewhat less, must be high material
Temperature, high-pressure injection material temperature adjustment range, craft better.
Screw compression is relatively large, the use of imported high-alloy steel, hardened, effectively withstand high torque, high pressure shocks, hard chrome plated to reduce surface adhesion and
Degradation of plastics uniform effect, color mixing, low shear design, low fever, degradation rate. Generally the intermediate diameter, forming PMMA, PP-R, PC, ABS and other resistance
Add toner when the effect is good.
CP, CA acidic screw components:
For CP, CA and other acidic corrosive properties of plastic, screw, barrel, and other plastics melt parts in the structure and surface treatment have done a special design.
Screw assembly good corrosion resistance. Recommendation supporting the use of corrosion-resistant bimetallic barrel.
PVC special screw
PVC plastic can be divided into granular and powder, is very sensitive to temperature decomposition, high viscosity, corrosion resistance. Screw design has two features: the surface must
Shall be chrome-plated; no separate plastic apron and sub-meson.
Good plasticizing screw, cut less heat, acid corrosion. Because there is no over apron, not for low viscosity plastics and injection speed more accurate classification system pressure
Products.
There are two screw design: plastic head screw and sub-one; separate plastic head screw and sub-type. High quality requirements of products to fight the system and only a single plastic (PVC) is
Siamese-style most appropriate to use
, Otherwise you can use split, but should pay attention, plastic head screws and separate easily lead to sub-plot material. But the selection of the screw Division I proposal must add special thermometer for precise temperature control,
As required thermal cooling, make PVC products molten plastic tube with forced air cooling measures should be used in conjunction with the screw. Soft PVC toys to fight the system, except
PU, TPU special screw
PU Yi excesses against shear-sensitive, strong adhesion and characteristics of the design, the surface hard chrome plating, feeding smooth, high plasticizing efficiency, low temperature rise.
Soft, EVA foam-type special screw
Low shear and high transport efficiency design, surface hard chrome plating.
PET special rod
PET plastic bottled beverages existing general common plastic raw materials, low viscosity, good fluidity, heat capacity, easy sticky material, the molding temperature is high, but the material temperature adjustment
Section of a narrow range of process is poor, PET injection molding if the material temperature is too high, the screw speed is too fast or too much shear are prone to acidification caused by acetaldehyde.
Requirements for PET and PET preforms plasticizing fast, uniform plasticizing properties, plasticizing screw, high stability, non-stick material, melting fast, did preform blowing
Bottles into the rate. Can also be molded general plastics. But pay attention to the continent in general manufacturers chipped PET preform feed intake will increase, in which case the PET professionals
Screw is not very suitable, whereas ordinary screw chrome more appropriate. It is necessary to attach the nozzle anti salivation devices.
PA6/66/46/6T special screw nails
PA crystalline plastic with low viscosity, high temperature, melting fast, self-lubricating, water fluidity are easy to salivation, temperature-sensitive and easy cold head, hygroscopic Big Easy
Stuck feeding section spiral groove, coloring difficult.
Screw compression ratio, non-return precision, color mixing effect, feed rate stability, high plasticizing efficiency, exhaust effect. Generally the intermediate diameter, forming PA, PP,
LCP and other crystalline low-viscosity plastic effect can also be molded general plastics. For PC, PMMA high viscosity flame retardant ABS plastic and thermal stability is poor does not apply (in
Segment temperature, decomposition), forming POM necessary hard chrome plating. Nozzle Thermostat best and necessary additional anti salivation devices.
PPO special screw
PPO is a non-crystalline materials, difficult to melt, easy tying, shear-sensitive, readily biodegradable.
Recommend the use of double alloys improve the wear resistance, corrosion resistance, C-level can be, smooth screw feeder, a pressure stability.
PBT + GF special screw
PBT resin is saturated, semi-crystalline materials, high melting, crystallization rapidly solidified quickly, easily biodegradable, and the need to add to the pressure-sensitive glass fibers.
To use a double metal to improve wear resistance, according to the amount added woven with C, B, A three kinds of engineering-grade optional screw generate pressure stability. Molding PBT + GF,
PA + GF and other crystalline low viscosity ordinary plastic effect.
Marbling special screw
Two options: A: marbling effect only need to replace the screw; B: Replace the screw feed tube package marbling, plus control of the computer program or modify the electrical plug.
Bakelite, Urea special screw feeding tube group
Heat the oil feed pipe loop heating, double-alloy screw recommendation grade C; old plastic machine can also be converted into a Bakelite Injection
Mixhead enhance mixing effect
Mixing head is the head of another design of plastic, mainly to enhance mixing effect, but when used with the following restrictions: melt glue will cause back pressure increases; Plastic time increase
Long; does not apply to high viscosity plastics such as PMMA, PC and so on. If customers are not satisfied with the general color mixing can be increased melt back pressure and reduce screw speed, there will be some
Effect appears. If customers do not want to use the mixing head plus color mixing effect, but also daisy-type injection meson.
Article Source China Machinery Network: www.fktcc.com