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Composite Manufacturing Processes. Dr. Yiping Qiu. Composite Manufacturing Processes. Thermoset composites Short fiber reinforced Continuous fiber reinforced Prepreg resin transfer Thermoplastic composites Commingle Impregnated. Composite Manufacturing Processes. Processes:
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Composite Manufacturing Processes Dr. Yiping Qiu
Composite Manufacturing Processes • Thermoset composites • Short fiber reinforced • Continuous fiber reinforced • Prepreg • resin transfer • Thermoplastic composites • Commingle • Impregnated
Composite Manufacturing Processes • Processes: • Hand Lay-up • Pre-preg forming • Pressure molding • Vacuum bagging • Filament winding
Composite Manufacturing Processes • Processes: • Pultrusion • Spray method • Sheet molding • Bulk molding • Resin transfer molding
Hand lay-up • Advantages: • low cost tools • versatile: wide range of products • Disadvantages: • time consuming • easy to form air bubbles and disorientation of fibers • inconsistency
Prepreg forming • Machine
Prepreg forming • Advantages: • orientation of fibers can be changed • consistent • high productivity • Disadvantages: • continuous process needs more customers • limited shelf life • delamination
Pressure molding • Advantages: • wide range of shapes • integrate parts • consistency • structural stability • relatively simple • Disadvantages: • high cost of machine • time consuming to heat up, cool down and curing • expensive molds (strong materials required) • no intricate parts • large volume of products
Vacuum bagging • Process
Vacuum bagging • Advantages: • simple design • any fiber/matrix combination • ok with cheap mold material • better quality for the cost • Disadvantages: • cannot be heated up too much • breeder clothe has to be replaced frequently • low pressure (760 mm Hg the most) • slowest speed • inconsistency
Filament winding products • Compressed air tanks • High-pressure CO2 tanks and bottles • Water softener systems • Rescue air tanks • Sail boat masts • Compressed Natural Gas tanks • Defense/Aerospace systems • Lightpoles
Filament winding • Advantages: • using existing textile processes. • quick, easy to handle package. • parts can have huge size. • Disadvantages: • spinning speed is limited due to resin penetration and splashing, traveler speed and yarn breakage. • curing by heat is not easy to apply. • shape of the products limited (only cylindrical possible).
Pultrusion • Advantages: • Automated processes. • High speed. • Versatile cross-sectional shape. • Continuous reinforcement. • Disadvantages: • Die can be easily messed up. • Expensive die. • Mainly thermoset matrix.
Spray method • Advantages: • Continuous process • Any materials can be used as mold. • Error can be corrected by re-spraying. • Disadvantages: • Slow. • inconsistency. • No control of fiber orientation. • Only one side finished. • Environmental unfriendly.
Sheet molding • Advantages • High productivity thus inexpensive • consistency • Disadvantages • low volume fraction. • Only board can be made.
Bulk molding • Advantages • Highest volume fraction for short fiber reinforced composites (50%) • Good mechanical properties • Finish can be applied • Inserts and attachments possible • Disadvantages • High temperature and high pressure • Random fiber orientation • Cannot be used for intricate parts • Staple fibers only.
Resin transfer molding http://www.plastech.co.uk/Mtrtm.html
Resin transfer molding • Advantages • Components will have good surface finish on both sides • Selective reinforcement and accurate fiber management is achievable • Ability to build-in fiber volume fraction loadings up to 65% • Uniformity of thickness and fiber loading, uniform shrinkage • Inserts may be incorporated into moldings • Tooling costs comparatively low • Uses only low pressure injection • Low volatile emission during processing • Ability to produce near net shape moldings • Process can be automated, resulting in higher production rates • Ability to mould complex structural and hollow shapes • Low resultant voids • Ability to achieve from 0.5mm to 90mm laminate thickness • Disadvantages • waste some material (spill) • curing time long • hard for intricate parts
Vacuum Assisted Resin Transfer Molding • http://www.futuremediacreations.com/technoire/vartm.htm
Vacuum Assisted Resin Transfer Molding • Advantages? • … • Disadvantages?