Composite Manufacturing Processes

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Composite Manufacturing Processes

• Dr. Yiping Qiu

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Composite Manufacturing Processes

• Thermoset composites
• Short fiber reinforced
• Continuous fiber reinforced
• Prepreg
• resin transfer
• Thermoplastic composites
• Commingle
• Impregnated

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Composite Manufacturing Processes

• Processes
• Hand Lay-up
• Pre-preg forming
• Pressure molding
• Vacuum bagging
• Filament winding

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Composite Manufacturing Processes

• Processes
• Pultrusion
• Spray method
• Sheet molding
• Bulk molding
• Resin transfer molding

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Hand lay-up
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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

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Prepreg forming

• Machine

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Prepreg forming
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Prepreg forming

• Advantages
• orientation of fibers can be changed
• consistent
• high productivity
• Disadvantages
• continuous process needs more customers
• limited shelf life
• delamination

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Prepreg forming
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Pressure molding
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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

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Vacuum bagging

• Process

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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

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Filament winding
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Filament winding
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Filament winding
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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

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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).

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Pultrusion
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Pultrusion
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Pultrusion

• Advantages
• Automated processes.
• High speed.
• Versatile cross-sectional shape.
• Continuous reinforcement.
• Disadvantages
• Die can be easily messed up.
• Expensive die.
• Mainly thermoset matrix.

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Spray method
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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.

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Sheet molding
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Sheet molding

• Advantages
• High productivity thus inexpensive
• consistency
• Disadvantages
• low volume fraction.
• Only board can be made.

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Bulk molding
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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.

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Resin transfer molding
http//www.plastech.co.uk/Mtrtm.html
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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

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Vacuum Assisted Resin Transfer Molding

• http//www.futuremediacreations.com/technoire/vart
  m.htm

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Vacuum Assisted Resin Transfer Molding

• Advantages?
• Disadvantages?

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Filament Placement