What types of plastic processing can Conical Screw Barrel be used for?

As the plastic industry's demand for processing efficiency and material adaptability continues to increase, Conical Screw Barrel, as an innovative plasticizing equipment, has gradually become the core equipment for a variety of plastic processing technologies with its unique design and performance advantages.
1. Technical characteristics of conical screw barrels
The main difference between conical screw barrels and traditional parallel screw barrels is that the screw diameter gradually decreases from the feed end to the discharge end, forming a conical structure. This design brings two core advantages: first, the volume between the screw and the barrel is gradually compressed, which enhances the shearing and mixing efficiency of the material; second, the conical surface of the screw increases the contact area with the material, providing higher torque output at the same speed. Therefore, conical screw barrels are particularly suitable for the processing of high-viscosity, heat-sensitive and filled plastics.
2. Applicable process types and technical adaptability
Injection Molding
In the injection molding process, the conical screw barrel achieves rapid plasticization and precise metering through an optimized compression ratio (usually 2.0:1 to 2.5:1). For highly filled materials (filling rate can reach more than 50%) containing glass fiber, carbon fiber or mineral powder (such as calcium carbonate), the conical screw can effectively reduce the problems of fiber breakage and uneven filler distribution. For example, in the production of automotive parts, the processing efficiency of PA66+30%GF material can be improved by about 15%.
Extrusion
For extrusion processes such as PVC profiles and TPE elastomers that require stable melt pressure, the gradual compression characteristics of the conical screw can avoid melt fracture. Especially in the production of rigid PVC pipes, the temperature control accuracy can reach ±1°C, significantly reducing the risk of material decomposition. Experimental data show that after using a conical screw, the Vicat softening point of PVC products increases by about 3-5°C.
Blow Molding
In the blow molding process of large hollow products (such as 200L chemical barrels), the high torque characteristics of the conical screw can ensure the full plasticization of high molecular weight materials such as HDPE. Compared with traditional equipment, energy consumption can be reduced by 8-12%, while the melt uniformity is increased to more than 98%, effectively eliminating the defect of uneven wall thickness of the product.
Thermosetting plastic processing
For thermosetting materials such as phenolic resin and epoxy resin, the low-temperature plasticizing ability of the conical screw can accurately control the reaction process. Through the segmented temperature control system (feeding section ≤80℃, plasticizing section ≤120℃), it can not only ensure the full mixing of materials, but also avoid equipment blockage caused by premature cross-linking.
Special material processing
In emerging fields such as biodegradable plastics (such as PLA/PBAT) and conductive polymers (such as PP/CNT composites), the low shear characteristics of the conical screw can reduce molecular chain degradation. Taking PLA processing as an example, the fluctuation range of melt flow index (MFI) dropped from ±3g/10min to ±1g/10min, and the stability of mechanical properties of products was significantly improved.
3. Typical case analysis
When an international chemical company used conical screw barrels to produce PC/ABS alloys, it successfully reduced the material residue from 2.3% of traditional equipment to 0.8% by optimizing the screw taper (30°) and aspect ratio (18:1), saving more than 200,000 US dollars in raw material costs annually. At the same time, due to the improvement of plasticizing efficiency, the molding cycle was shortened by 12%, and the average daily production capacity increased by 1.2 tons.
4. Technology development trend
With the emergence of innovative designs such as double conical screws and nano-coated screws, conical screw barrels are moving towards multifunctional integration. The HybridCon series products newly launched by a German equipment manufacturer have achieved cross-category processing from LCP liquid crystal polymers to TPU thermoplastic elastomers on the same equipment through the combined screw segment design, and the equipment utilization rate has increased by more than 40%.