“Tubing and Profile Extrusion Seminar/Laboratory”
At Harrel, Inc. E. Norwalk, CT
Course Leader: Chris J. Rauwendaal
April 13-15, 2010
Introduction
• Basic extruder components
• Screw, barrel, and feed system
• Grooved feed extruders
• High speed extruders
• Screw drive systems
• Breaker plate and screens
• Gear pumps
• Heating and cooling
• Instrumentation and control
Important polymer properties
• Melt flow properties
• Thermal properties
• Viscous heat generation
• Optimizing process conditions
• How to set process conditions
Requirements for efficient extrusion
• Efficient machinery
• Efficient operation
• Efficient changeover
• Maintenance
• Resin quality• Training
• Statistical process control
• Design of experiments
• Data acquisition system
• Instrumentation and control
Functional aspects
• Solids conveying
- Feeding methods
- Gravity induced conveying
- Drag induced conveying
- How to improve solids conveying
• Plasticating
- Contiguous solids melting
- Dispersed solids melting
- How to improve melting
• Melt conveying
- Drag flow
- Pressure flow
- Leakage flow
• Mixing
- Basic mechanism of mixing
- Distributive mixing
- Dispersive mixing
- How to improve mixing
• Energy efficiency
- Measuring energy efficiency
- Preheating the resin
- Starve feeding
- Screw design
Screw Design
• Standard extruder screw
• Barrier type extruder screws
• Multi-stage screws for venting
• Mixing screws
Die Design
• General rules and guidelines
• Methods of flow balancing
• Types of extrusion dies
- Profile dies
- Tubing dies
- Other types of dies
• Analysis of dies
• Coextrusion dies
• Case studies of die design
