75 mm Twin Screw Extruder Screw Elements for Food Processing Applications

This case involves a 75 mm co-rotating twin screw extruder used in food processing applications, including continuous extrusion and mixing of food-grade materials.

The production line processes:

• Starch-based materials
• Protein-based compounds
• Food modification formulations
• Extruded food ingredients

During long-term operation, the original screw elements experienced increased wear, leading to reduced process stability and inconsistent output.

The customer required an OEM replacement screw element system to restore stable operation while maintaining full compatibility with the existing 75 mm extruder.

The key requirements included:

• Compliance with food-grade continuous processing
• Improved wear resistance
• Stable dimensional performance during long operation
• Reduced process fluctuation caused by wear
• Full compatibility with existing equipment

Material selection became a critical factor due to the nature of food processing applications.

Food materials exhibit:

• Strong viscosity variation
• Localized high shear zones
• Continuous thermal-mechanical loading

This leads to gradual but consistent wear on screw surfaces.

Food extrusion lines require:

• Continuous operation
• Stable conveying performance
• Batch-to-batch consistency

Screw wear directly impacts process stability.

Food processing applications require materials with:

• Stable structural performance
• Reliable wear resistance
• Long-term dimensional stability
• Consistent surface condition

A modular screw system was designed for the 75 mm extruder, including:

• Optimized conveying sections
• Reinforced mixing zones
• Adjusted compression regions

To match the rheological behavior of food materials.

Cr12MoV tool steel was selected for the screw elements.

Key characteristics include:

• Good wear resistance
• Stable heat treatment response
• High structural strength
• Suitable for medium to high-load applications

Heat treatment was carefully controlled to ensure uniform material performance.

Manufacturing processes included:

• CNC precision machining
• Heat treatment control
• Secondary dimensional correction
• Surface finishing

• Coordinate Measuring Machine (CMM)
• Length and diameter measurement
• Spline compatibility verification

• Chemical composition analysis
• Hardness testing
• Heat treatment verification

• 75 mm twin screw extruder fitting test
• Rotation stability check
• Intermeshing clearance validation

During food extrusion operation, the screw system demonstrated:

• Improved operational stability
• Smoother material conveying
• Reduced wear rate
• Enhanced batch consistency

The system met the requirements of continuous food processing applications.

This project addressed wear and stability challenges in a 75 mm twin screw extruder used for food processing applications through:

• Cr12MoV material selection
• Optimized screw design
• Precision manufacturing and inspection control

The solution provides a stable and reliable OEM replacement option for food-grade twin screw extrusion systems.

Food materials such as starch and protein-based compounds exhibit viscoelastic behavior under high shear and temperature, causing continuous abrasive wear on screw surfaces during long-term operation.

Cr12MoV is a tool steel with good wear resistance and heat treatment stability. It is suitable for medium-load food extrusion applications with continuous operation requirements.

Screw wear may lead to:

• Reduced conveying efficiency
• Poor mixing uniformity
• Unstable residence time
• Reduced batch consistency

Key factors include:

• Proper wear-resistant material selection
• Optimized screw design
• Controlled processing conditions
• Regular inspection and maintenance

Yes. Through reverse engineering, spline measurement, and CMM inspection, OEM replacement screw elements can achieve full dimensional compatibility with existing equipment.