Why yongte equip concial twin screw extruder for making WPC profiles?

Yongte equip special designed conical twin screw extruder for making WPC profiles to ensure the production stably and product quality.

Advantages of Yongte WPC extruder

1,  The core advantage of Yongte conical twin-screw extruder is that the screw channel depth gradually changes with the taper. In the feeding section, the deep screw channel design can accommodate a large amount of wood flour and plastic mixture (wood flour filling is usually 30%-70%), resulting in high conveying efficiency and preventing wood flour accumulation and blockage. In the plasticizing section, the screw channel gradually narrows, and the screw meshing gap is small (usually 0.1-0.3mm), generating a gradual shearing force that breaks down wood flour agglomerates from weak to strong, while simultaneously allowing the plastic matrix to fully melt. This avoids excessive local shearing that could lead to wood flour carbonization or plastic degradation, and also avoids insufficient shearing that could result in incomplete plasticizing. This gradual screw channel design, combined with the fully meshing structure of the two screws, achieves the effects of gradual shearing and strong meshing, precisely adapting to the WPC production requirements of high-filler.

2， The interlocking design of Yongte counter-rotating conical twin screws causes the two screws to scrape and compress against each other, creating a composite effect of "stretching-shearing-mixing." This uniformly coats the wood flour particles in the molten plastic, eliminating the separation between the plastic and wood flour. This significantly improves the "interfacial bonding quality" between the plastic matrix and the wood flour, resulting in a 10%-20% increase in the flexural strength and impact strength of the produced wood-plastic composites, and  surface to be smooth and uniform

3， Wood-plastic composite (WPC) formulations are flexible (e.g., PE/WPC, PP/WPC, PVC/WPC, fillers such as wood flour/bamboo flour/rice husk powder, with adjustable filler content from 30% to 70%). Yongte conical twin-screw extruders can adapt to different WPC formulations by adjusting the plasticizing section temperature and shear strength, or by changing the screw thread design.

4， The tapered structure of Yongte conical twin-screw extruder creates a "pressure gradient" along the axial direction of the material within the screw, enabling efficient conveying of highly filled wood flour and plastic mixtures without the need for additional feeding devices. The gradual plasticizing process reduces the residence time of the wood-plastic material in the barrel (typically 8-15 seconds), not only avoiding wood flour carbonization or plastic degradation caused by prolonged high temperatures, but also improving production efficiency and reducing energy consumption (a 37KW 65mm conical twin-screw extruder can achieve an extrusion output of 250kg/h, while a 90mm diameter single-screw extruder of the same power can only achieve an extrusion output of about 150kg/h).

5. The barrel of Yongte conical twin-screw extruder is typically divided into 3-5 heating zones (feeding zone, compression zone, plasticizing zone, homogenizing zone, and die head zone). Combined with the shear heating generated by the twin screws, it can achieve a process of "low-temperature feeding - gradient heating - constant-temperature homogenization," avoiding localized high temperatures (wood flour in wood-plastic composites is prone to carbonization above 200℃, and the plastic matrix also requires strict temperature control). The two screws scrape against each other for self-cleaning, reducing material residue in the screw gaps and preventing residual material from carbonizing and mixing into the finished product, causing "black spot" defects on the product surface.

6. WPC extrusion line require long-term continuous operation (typically 24 hours a day without interruption). Yongte's WPC conical twin screw extruders use bimetallic screws and SKD wear-resistant barrels, equipped with direct-drive vertical gearboxes, resulting in higher production stability. The axial force generated by the tapered structure of the conical twin screw is evenly borne by the thrust bearing at the tail of the barrel, resulting in reasonable load distribution, less screw wear, and a long service life (especially in high-filler wood-plastic production, where the abrasiveness of wood flour causes significant screw wear, the force design of the conical screw is more resistant to wear). The tightly meshed structure reduces material "backflow," resulting in smaller pressure and temperature fluctuations during production, more stable dimensional accuracy of wood-plastic products, and a lower scrap rate.

Summary

Yongte's conical twin-screw wood-plastic composite WPC extruder achieves uniform plasticization, improves production efficiency, and enhances product quality through its design of gradual shearing, strong meshing and mixing, and precise temperature control. This results in the efficient production of wood-plastic products with good mechanical properties and aesthetically pleasing surface quality. if you are looking for high quality WPC extruder machine, Yongte is a reliable supplier and partner. Contact Yongte for the latest Quotation!

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