Milling Shafts

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 Milling Principle:Milled spline shafts are manufactured by precision metal cutting. Alloy blanks are machined into shafts with accurate spline profiles via CNC milling tools.
• High flexibility: Easy to switch spline sizes by adjusting cutters and programs, perfect for small-batch, multi-spec custom orders.
• Cost advantage: Lower equipment investment and shorter setup cycle, unit cost 20%–30% less than cold-rolled shafts.
• Limitation: The cutting process partially breaks metal grain flow, leaving minor stress notches at tooth roots, so it is not recommended for long-term high-torque, heavy-abrasion production lines.

• 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