Twin Screw Cold Rolling Shaft

The shaft is the core transmission shaft of twin-screw extruders. All screw elements are sleeved on it. It transfers torque from gearbox to drive screw rotation for conveying, mixing and plasticating materials. There are two mainstream types: milled spline shaft and cold-rolled spline shaft, distinguished by spline forming craft with different strength, service life, cost and customization performance for diverse production conditions.

• Core Cold Forming Principle
  Spline rolling is a chipless forming process without material cutting. Hardened dies exert extremely high pressure (50,000 psi or above) to squeeze and displace metal blanks to form spline teeth.
• Complete Continuous Metal Grain Structure
  Unlike cut splines that sever grain lines, cold rolling pushes metal grains to flow following the tooth profile, keeping the grain structure fully continuous without fracture.
• Dual Strengthening Advantages
  The unbroken continuous grain flow greatly improves the overall structural strength of the spline;
  Work hardening takes place on tooth surfaces, lifting surface hardness and generating residual compressive stress to counteract fatigue damage.
• Performance Superiority Over Machined Splines
  Under the same raw material condition, cold-formed rolled splines achieve up to 35% higher strength and remarkably better fatigue resistance than splines processed by cutting.

• Optimized Meshing Structure for Even Load Distribution
  Splined shafts serve as reliable engineering solutions for torque transmission. Multiple integrated spline teeth engage precisely with matching grooves inside the hub, spreading mechanical load uniformly over the full circumference of the shaft.
• Eliminate Stress Concentration & Enhance Fatigue Resistance
  Traditional connection structures often suffer from concentrated force on a single spot. By distributing pressure across dozens of spline teeth, this design removes hazardous stress risers, drastically boosting the component’s ability to withstand long-cycle fatigue loads.
• Symmetrical Layout Ensures Stable High-Speed Operation
  The symmetrical spline geometry delivers inherent dynamic balance. It supports smooth, low-vibration rotation at high RPM, perfectly satisfying the high-speed working requirements of modern industrial machinery.

• DIN 5480 Involute Splines
• JIS-B-1603 Splines
• GB3478 Splines
• Hexagonal Keys
• Flat Keyway & Semi-Circular Keys
• Rectangular Splines

This wide compatibility ensures seamless installation across various extruder models and torque transmission systems.

• High-Torque Alloy Steel Construction: Provides world-class mechanical reliability under heavy-duty extrusion operations.
• Dual Manufacturing Options: Both milling and cold-rolling shafts available to meet different cost-performance needs.
• Precision & Longevity: Optimized structure, surface treatment, and inspection ensure long service life and consistent quality.
• Customizable Spline Standards: Fully compatible with multiple international specifications (DIN, JIS, GB).

• Different forming processes 
  Milled shafts are manufactured by cutting and removing excess metal. Cold-rolled shafts are formed through cold plastic deformation of metal without material removal. 
• Distinct metal grain structure and mechanical performance 
  Milling severs metal grain flow and creates stress notches at tooth roots, resulting in average strength and fatigue resistance. Cold rolling makes metal grains flow continuously along tooth contours and triggers work hardening. It increases surface hardness by 15%–25%, torsional strength by 20%–30%, and extends fatigue life by over 50%
• Gap in machining precision and transmission performance 
  Cold rolling adopts die forming to achieve tight dimensional tolerances and smooth tooth surfaces, delivering tight assembly fit and low vibration & noise at high speed. Milled shafts leave tool marks on tooth surfaces, with inferior precision and surface finish. 
• Varied material utilization and production efficiency 
  Cold rolling achieves over 90% material utilization and cuts processing time by up to 60% for mass orders. Milling only reaches 60%–70% material utilization with lower mass-production efficiency.
• Different applicable production scenarios 
  Milled shafts allow quick specification changes by adjusting cutters and programs, suitable for small-batch, multi-model and non-standard customized orders. Cold rolling requires exclusive dies for each spline size, ideal for mass continuous production of standard extruder models.
• Contrasting cost input 
  Milling requires lower equipment investment, with unit cost 20%–30% cheaper than cold-rolled shafts. Cold rolling demands higher upfront investment on rolling machines and dies with higher single-piece price, yet lower comprehensive cost under long-term large-volume production.
• Different structural integrity & working condition adaptability 
  Integral cold-rolled forming avoids cutting-induced stress concentration, offering higher rigidity and impact resistance. After nitriding or chrome plating, cold-rolled shafts gain excellent wear and corrosion resistance for heavy-duty high-abrasion lines such as glass fiber and high-filled compounding. Milled shafts fit light-load working conditions including low-torque, low-filler production and laboratory trial runs.

• Targeted Material & Process Optimization: Optimize base material formulation and heat treatment processes to improve wear resistance, corrosion resistance and impact resistance
• Custom Production per Drawings & Samples: Precisely manufacture replacement elements perfectly compatible with your equipment
• 100% Full Inspection Before Delivery: Complete dimensional quality inspection with full inspection reports
• 24-Hour Responsive After-Sales Service: Exclusive after-sales channels with 24-hour response time
• Professional Selection & Process Consultation: Technical advice on screw element configuration, material selection and screw arrangement solutions
• Reverse Engineering & Non-Standard Customization: High-precision reverse engineering for obsolete equipment models
• Rapid Prototyping & Small-Batch Trial Production: Support for new solutions to shorten R&D cycles
• Service Life Assessment & Optimization Guidance: Regular product status tracking and wear detection
• Flexible Stock & Delivery Guarantee: Safety stock service for regular spare parts and urgent orders

• Properties: High precision, high quality, long service life, wear-resistant, corrosion-resistant and durable.
• Compatibility: Compatible with most well-known extruders