2. CONTENTS
History
Resin Transfer molding set up and description
Advantages
Disadvantages
Type of material for which process is used
Properties of the material which affect by RTM process
Applications of resin transfer molding
3. HISTORY
developed by a US navy contract for the development
of 28-ft long personal boat in 1946
Harold John Pollard and John Rees in between 1952 – 1956
plant for fibers and asbestos
fully developed for general aerospace applications in the 1980s
Types :- LCM,RIM,SRIM,RRIM,RTM
6. Typical Preform Fiber Weaves
Polyester resins
Epoxy resins
Phenolic resins and other thermo set resins
Type of material for which process is used
8. Disadvantages
Greater Tooling Design and Construction Skills Required
Higher Tool Cost
Reinforcement loading may be difficult with complex parts
Mold design is complex
9. Properties of the material which affect by
RTM process
Density
Strength
Notched and Unnotched lzod Impact Strength increases
13. May or may not take place under vacuum (assists in
minimizing air entrapment).
Mixer/injection head is inserted into mold.
Injection pressure pushes check valve off its seat and
allows resin to begin filling.
Air is pushed ahead of resin.
14. Contd…
Resin will begin flowing from vent ports-
1. If part design is simple may be full
2. If part design complex, may require slight overfill to vent all
air
Vent ports are pinched off and internal pressure causes inlet
check valve to close
15. Reinforcement used in RTM
TYPE:
E-glass, S-glass
Carbon/Graphite
Aramid
FORM:
Matrices
Fabric
Textile preform architecture (knitted, braided, 3-D
stitched)
PREFORMS:
Preshaping of reinforcement
16. RTM Process Issues
Critical to control infusion rate and flow front of resin so that
it infiltrates fibre preform evenly and completely, but quickly
before gelling.
Resin is injected in centre of part to guard against formation
of air pockets and minimize distance resin must travel.
Care must be exercised to insure reinforcement does not
move during injection (fibre wash).