INDUSTRY COMPONENT

Screw Shaft

A precision rotating shaft with helical flights that conveys, compresses, melts, and meters polymer materials in extrusion systems.

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Component Specifications

Definition
The screw shaft is the core rotating component in polymer extrusion screws, featuring precisely engineered helical flights along its length. It performs multiple functions: feeding solid polymer pellets, compressing them to remove air, melting through shear heating, mixing additives, and metering molten polymer at constant pressure. Its geometry (length-to-diameter ratio, flight depth, pitch) determines extrusion efficiency, mixing quality, and output stability.
Working Principle
Rotational motion converts electrical energy into mechanical work that transports polymer materials through sequential zones. The helical geometry creates drag flow that conveys material forward while generating shear heat through viscous dissipation. Compression zones increase pressure to eliminate air pockets and enhance heat transfer. Metering zones stabilize output through precise clearance control between flights and barrel.
Materials
Nitride-hardened alloy steels (AISI 4140, H13), bimetallic constructions with wear-resistant coatings (stellite, tungsten carbide), corrosion-resistant alloys (17-4PH stainless) for aggressive polymers. Surface hardness: 58-62 HRC minimum. Core toughness: 35-40 HRC.
Technical Parameters
  • L/D_ratio 20:1 to 40:1
  • Diameter_range 25mm to 300mm
  • Surface_finish Ra 0.4μm or better
  • Flight_clearance 0.1-0.3% of diameter
  • Compression_ratio 2:1 to 4:1
  • Straightness_tolerance 0.05mm/m
Standards
ISO 13445, DIN 16742

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Screw Shaft.

extrusion screw shaft polymer screw design plasticizing screw metering screw twin screw shaft wear-resistant screw screw geometry Screw Shaft Screw Shaft in Rubber and Plastic Product Manufacturing

Parent Products

This component is used in the following industrial products

Polymer Extrusion Screw

Rotating helical component for plasticizing and conveying polymer melts in extrusion systems.

View Product Details

Ball Screw Assembly

A precision mechanical component that converts rotary motion into linear motion with minimal friction and high efficiency.

View Product Details

Screwdown Mechanism

A mechanical device used to precisely adjust the roll gap in rolling mills.

View Product Details

Engineering Analysis

Risks & Mitigation
  • Flight wear reducing throughput
  • Shaft bending from thermal stress
  • Corrosion from halogenated polymers
  • Fatigue cracking at drive spline
FMEA Triads
Trigger: Abrasive polymer compounds
Failure: Progressive flight wear reducing compression ratio
Mitigation: Apply hardfacing coatings (WC-Co), implement gradual material transitions, use barrel temperature profiling
Trigger: Thermal cycling during startups
Failure: Residual stress accumulation leading to shaft bending
Mitigation: Follow controlled heating protocols, use induction preheaters, maintain straightness tolerance <0.1mm/m

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±0.025mm diameter tolerance, ±0.05° helix angle consistency
Test Method
Coordinate measuring machine (CMM) verification, ultrasonic thickness testing, dye penetrant inspection for cracks

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What causes screw shaft wear in extrusion?

Abrasive fillers (glass fibers, minerals), corrosive additives, improper material transitions (cold starts), and barrel misalignment cause progressive flight wear that reduces output and mixing efficiency.

How often should screw shafts be inspected?

Visual inspection every 500 operating hours, dimensional measurement every 2000 hours, and non-destructive testing (magnetic particle) annually or after processing abrasive materials.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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