Transcript Composite Manufacturing Processes

Dr. Yiping Qiu
Composite Manufacturing Processes
 Thermoset composites
Short fiber reinforced
Continuous fiber reinforced
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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
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
Prepreg forming
 Advantages:
 orientation of fibers can be changed
 consistent
 high productivity
 Disadvantages:
 continuous process needs more customers
 limited shelf life
 delamination
Prepreg forming
Pressure molding
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
Filament winding
Filament winding
Filament winding products
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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
Pultrusion
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
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
Sheet molding
 Advantages
 High productivity thus inexpensive
 consistency
 Disadvantages
 low volume fraction.
 Only board can be made.
Bulk molding
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/vart
m.htm
Vacuum Assisted Resin Transfer Molding
 Advantages?
 …
 Disadvantages?
Filament Placement