Carbon Fiber Filament Winding Hal Peterson Rob Haglin
Overview • Design and build a machine capable of carbon fiber filament winding • Empirically test and optimize mandrel
What is filament winding? • Process by which continuous reinforcing fibers are accurately positioned in a predetermined pattern to form a shape (usually cylindrical). • Use machine to wrap composite around mandrel • Mandrel is then removed, leaving hollow composite part • Angles generally set at -45,0,+45
Why filament winding? • Composite shafts have high tensile strength, low compressive strength. • To overcome the weakness in compression. • Gives very high strength/weight ratio • Increases performance in machines or automobiles when utilized, because decrease in weight.
Applications of Filament Winding • Cars • Rockets • Aircraft • Propellers • Blades • Engine parts Any place where weight is an issue, or there is a desire to decrease weight to increase performance.
Winding • Three types of winding • Helical • Circumferential • Polar
The machine • 2 axis movement • Variable speed spindle to hold mandrel • Computer controlled • Various diameters and lengths of shafts • Wide range of wrapping angles
Resin Delivery • 2 main forms • Pre-preg (pre-coated with resin) • Resin bath impregnation
Resin bath • Advantages • Cheaper • Easy to store • Curable at room or elevated temp. • Disadvantages • Inconsistent • Messy
Pre-preg – our choice • Advantages • Comes coated in resin • Most widely used • Can be used in hand lay-up if needed • Disadvantages • More expensive • Storage (low temperature) • Cured at elevated temp
Why we chose Pre-preg • Even disbursement of resin on fibers • Very precise fiber/resin ratio • Better control of fiber placement and angle • Increases precision and repeatability with parts
Curing • Room temp (can take long time) • Only for resin bath-impregnated • Oven (elevated temp) • Increased pressure
Machine Design issues • Design for versatility • Gearing • Wear of pre-preg on eyelet • Machine parts filling up with resin.
User Interface • Needed Information • Fiber Angle • Tube diameter • Tube length • Desired speed - optional • What happens • Instruction set generated from parameters
Instruction Set • Object Oriented Approach • Visual Basic .NET • Decreases programming time • Use supporting programs from Galil • Developers kit • Advanced servo tuning • ActiveX controllers - $695
References • http://www.fibercote.com/pabo6.html • Manufacturing processes for Engineering Materials, 5th Ed. • Material Science and Engineering 6th Ed • http://www.pslc.ws/macrog/mpm/composit/fiber/process/prepreg.htm • Galil user documentation