1. Composite Manufacturing Processes
Dr. Yiping Qiu

2. Composite Manufacturing Processes
Thermoset composites
Short fiber reinforced
Continuous fiber reinforced
Prepreg
resin transfer
Thermoplastic composites
Commingle
Impregnated

3. Composite Manufacturing Processes
Hand Lay-up
Pre-preg forming
Pressure molding
Vacuum bagging
Filament winding

4. Composite Manufacturing Processes
Pultrusion
Spray method
Sheet molding
Bulk molding
Resin transfer molding

5. Hand lay-up

6. Hand lay-up Advantages: Disadvantages: low cost tools
versatile: wide range of products
Disadvantages:
time consuming
easy to form air bubbles and disorientation of fibers
inconsistency

7. Prepreg forming
Machine

8. Prepreg forming

9. Prepreg forming Advantages: orientation of fibers can be changed
consistent
high productivity
Disadvantages:
continuous process needs more customers
limited shelf life
delamination

10. Prepreg forming

11. Pressure molding

12. Pressure molding Advantages: Disadvantages: 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

13. Vacuum bagging
Process

14. Vacuum bagging Advantages: Disadvantages: 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

15. Filament winding

16. Filament winding

17. Filament winding

18. 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

19. Filament winding Advantages: Disadvantages:
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).

20. Pultrusion

21. Pultrusion

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

23. Spray method

24. Spray method Advantages: Disadvantages: 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.

25. Sheet molding

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

27. Bulk molding

28. Bulk molding Advantages Disadvantages
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.

29. Resin transfer molding

30. 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

31. Vacuum Assisted Resin Transfer Molding

32. Vacuum Assisted Resin Transfer Molding
Advantages? …
Disadvantages?

33. Filament Placement