Conical Twin Screw Barrel for PVC Extrusion

Product Overview

Conical twin screw barrels are commonly used in PVC extrusion applications where stable plasticizing, material conveying and output consistency are important. They are widely applied in PVC pipe extrusion, PVC profile extrusion, WPC extrusion, PVC sheet extrusion and other rigid PVC processing applications.

Nanhaiya manufactures custom conical twin screw barrels according to machine model, drawings, samples or measured dimensions. The screw and barrel design can be reviewed based on processed material, filler content, output requirement, screw diameter, wear condition and extrusion application.

Our engineering team can review machine information, screw barrel photos, drawings, samples or measured dimensions to support quotation and technical evaluation. This helps confirm a suitable conical twin screw barrel for the customer's extrusion equipment, processed material and working conditions.

Full Technical Specifications

Parameter	Value
Product Type	Conical twin screw barrel
Applicable Equipment	Conical twin screw extruder and related PVC extrusion equipment
Main Applications	PVC pipe extrusion, PVC profile extrusion, WPC extrusion, PVC sheet extrusion and rigid PVC processing
Processed Materials	Rigid PVC, soft PVC, WPC compounds, filled PVC compounds and other materials depending on formulation and working conditions
Common Catalog Specifications	Φ35/Φ77, Φ45/Φ90, Φ50/Φ105, Φ51/Φ105, Φ55/Φ110, Φ60/Φ125, Φ65/Φ120, Φ65/Φ132, Φ70/Φ140, Φ75/Φ150, Φ80/Φ143, Φ80/Φ156, Φ92/Φ188 mm
Custom Max. Size	Up to Φ220 mm (per project requirements and engineering confirmation)
Screw Material	38CrMoAlA
Surface Treatment	Tempering and nitriding treatment; alloy spray welding available as an option depending on material and order requirements
Surface Hardness	HV860-1000
Nitriding Depth	0.5-0.8 mm
Bimetallic Option	Bimetallic screw and barrel / bimetallic alloy layer available
Rotation Type	Counter-rotating (intermeshing)
Machine Matching	Based on machine model, drawings, samples or measured dimensions
Screw Barrel Design	Designed according to processed material, filler content, output requirement, screw diameter, L/D ratio, wear condition and extrusion application
Material Selection	Base material and surface treatment are selected according to application, material abrasiveness and working conditions
Customization	Custom manufacturing according to drawings, samples, machine model or measured dimensions
Quotation Information	Machine model, screw diameter, barrel dimensions, processed material, application, drawings, photos or worn samples are recommended for quotation review
Note	Final specifications should be confirmed according to extruder model, processed material, output requirement, drawing availability and working conditions.

Final specifications should be confirmed by Nanhaiya engineering before production.

Suitable Applications

This product is commonly used for the following applications, depending on material, machine model and processing conditions. Explore related applications on our Screw Barrel Applications page.

PVC pipe extrusion

PVC profile extrusion

WPC extrusion

PVC board / sheet extrusion

PVC conduit extrusion

Foam sheet / PS foam extrusion

Common Processing Issues

Unstable PVC plasticizing: uneven melting or unstable plasticizing may be related to screw design, material formulation, temperature control or screw barrel wear.

Output fluctuation: inconsistent output may occur when screw clearance, barrel wear, feeding condition or machine settings are not matched to the application.

High wear with filled compounds: calcium carbonate, wood powder or other fillers may increase abrasion and require suitable material selection or surface treatment.

Poor profile or pipe quality: dimensional instability, surface defects or poor extrusion consistency may require screw barrel design review.

Specification confirmation: When original drawings are unavailable, machine model, photos, samples and measured dimensions can support specification review and manufacturing confirmation.

What Is This Product?

A conical twin screw barrel is a specialized extrusion component where two intermeshing screws rotate inside a tapered barrel. The screw diameter decreases progressively from the feed hopper to the die outlet, creating a natural compression effect that differentiates it from parallel twin screw designs.

Key Design Characteristics

Gradual compression ratio: The tapering diameter compresses material naturally as it moves through the barrel, reducing the need for aggressive screw geometry.
Gentle shearing: Lower shear rates compared to parallel twin screws, making it well-suited for PVC and other shear-sensitive polymers that degrade under high mechanical stress.
Strong conveying capacity: The conical geometry provides excellent material transport, particularly for dry blend PVC powder, helping to maintain stable throughput.
Compact footprint: A conical extruder of a given feed diameter can often match the output of a larger parallel unit, which can contribute to space savings and may help improve processing efficiency in suitable PVC extrusion applications.

Conical vs. Parallel Twin Screw: When to Choose Conical

The conical twin screw barrel is commonly selected for processing rigid and flexible PVC compounds. Parallel twin screws are typically chosen for compounding and modification applications requiring higher L/D ratios, while conical designs are widely used in PVC profile, pipe, and sheet production due to their temperature control characteristics and may help improve processing efficiency in suitable PVC extrusion applications. The tapering design naturally reduces heat buildup as material progresses, which can help minimize the thermal degradation that PVC is prone to.

What Makes Nanhaiya's Conical Twin Screw Barrel Different

Our conical twin screw barrels are produced in common catalog specifications from Φ35/Φ77 to Φ92/Φ188, covering a range of extruder sizes. Custom barrel sizes up to Φ220 can be produced according to project requirements and engineering confirmation.

Conical twin screw barrels can be manufactured according to machine model, drawings, samples or measured dimensions. If the required specification is not available in our drawing database, our engineering team can review photos, samples and measured dimensions to confirm manufacturing feasibility and technical details.

Final specifications should be confirmed according to extruder model, processed material, output requirement, drawing availability and working conditions.

Material Options

Nanhaiya manufactures conical twin screw barrels primarily from the following material:

38CrMoAlA Nitrided Steel (Standard)

The standard material for conical twin screw barrels. 38CrMoAlA is an alloy steel widely used in plastic machinery for its good hardenability and consistent nitriding response. After tempering and nitriding treatment, it achieves a surface hardness of HV860-1000 with a nitriding depth of 0.5-0.8 mm. This material is suitable for standard PVC processing and general-purpose extrusion applications.

Bimetallic Screw and Barrel (Optional)

For applications with higher wear-resistance requirements — such as processing highly filled PVC compounds or abrasive wood-plastic composites — a bimetallic screw and barrel with a bimetallic alloy layer is available. This option provides enhanced wear resistance compared to standard nitrided steel. Final material selection should be confirmed according to your processed material, filler content, and operating conditions.

Material Selection Guide

Standard PVC formulations: 38CrMoAlA with tempering and nitriding treatment is typically sufficient.
Highly filled or abrasive compounds: Bimetallic screw and barrel recommended for enhanced wear resistance.
Custom material requirements: Custom sizes may be available upon engineering confirmation.

Surface Treatment Options

Tempering and Nitriding Treatment (Standard)

The standard surface treatment for Nanhaiya conical twin screw barrels is tempering followed by nitriding. This process produces a hard, wear-resistant surface layer with a surface hardness of HV860-1000 and a nitriding depth of 0.5-0.8 mm. The nitrided layer offers good fatigue resistance and minimal dimensional distortion, making it suitable for PVC profile and pipe extrusion applications.

Bimetallic Alloy Layer (Optional)

For demanding applications involving highly filled compounds or abrasive materials, a bimetallic alloy layer can be applied to the screw and barrel surfaces. This treatment enhances wear resistance compared to standard nitriding. For more details on this process, see our alloy spray welding service page.

Customization Options

Nanhaiya offers customization for conical twin screw barrels to match your specific equipment and production requirements. Common catalog specifications range from Φ35/Φ77 to Φ92/Φ188. Custom barrel sizes up to Φ220 can be produced according to project requirements and engineering confirmation.

Conical twin screw barrels can be customized according to machine model, drawings, samples or measured dimensions. If the required specification is not available in our drawing database, our engineering team can review photos, samples and measured dimensions to confirm manufacturing feasibility.

Custom Manufacturing Process

Requirement review: Share your extruder model, existing screw/barrel dimensions (or photos/drawings), processed material, and target output.
Engineering confirmation: Our technical team reviews the specifications and confirms feasibility, material selection, and surface treatment.
Quotation: We provide a detailed quotation including price, lead time, and technical recommendations.
Production: Precision machining, heat treatment, and quality inspection per confirmed specifications.
Delivery: Packaging for international shipping with installation guidance.

What Can Be Customized

Screw diameter and taper ratio for non-standard sizes
Flight geometry and compression ratio for specific PVC formulations
Material and surface treatment for abrasive or corrosive compounds
Vent port position and barrel heating zone configuration
Screw tip and die adapter geometry for profile-specific tooling

Final specifications should be confirmed according to extruder model, processed material, output requirement, drawing availability and working conditions. For custom screw design inquiries, contact our engineering team.

What Information Do We Need for Quotation?

To support an accurate quotation and technical review for a conical twin screw barrel, please provide the following information when possible:

Extruder type and machine model
Screw diameter, barrel dimensions and L/D ratio if available
Processed material, such as PVC, WPC, filled PVC compound or other formulation
Application, such as PVC pipe, PVC profile, WPC profile, PVC sheet or foam board extrusion
Current production issue, wear condition or required specification
Drawings, samples, measured dimensions or worn screw barrel photos

Our team will review the information and follow up with pricing, manufacturing feasibility and technical support.

Conical Twin Screw Barrel FAQ

What is a conical twin screw barrel used for?

A conical twin screw barrel is commonly used in PVC extrusion applications, including PVC pipe extrusion, PVC profile extrusion, WPC extrusion, PVC sheet extrusion and related rigid PVC processing.

Can you manufacture a conical twin screw barrel according to an existing machine or sample?

Yes. Nanhaiya can manufacture conical twin screw barrels according to machine model, drawings, samples, photos or measured dimensions.

What information is needed for a conical twin screw barrel quotation?

Please provide the extruder model, screw diameter, barrel dimensions, processed material, application, wear condition and any available drawings, photos, samples or measured dimensions.

Can the screw barrel be customized for PVC or WPC materials?

Yes. The screw barrel design, material selection and surface treatment can be reviewed according to PVC, WPC, filler content, output requirement and working conditions.

Do you provide conical twin screw barrels for PVC pipe and profile extrusion?

Yes. Conical twin screw barrels can be produced for PVC pipe extrusion, PVC profile extrusion and other PVC extrusion equipment based on machine and application requirements.

More technical FAQs (1)

Can you support projects without original drawings?

Yes. If original drawings are not available, machine model, photos, samples and measured dimensions can help our engineering team review the required specification and confirm manufacturing feasibility.