1. INJECTION MOLDING OF THERMOSET PLASTICSBY
ALOK KUMAR

2. THERMOSET INJECTION MOLDING MACHINE

3. PHOTO OF PLASTICIZING THE RESIN

4. PHOTO OF INJECTION OFTHE RESIN

5. PHOTO OF CROSSLINKING

6. PHOTO OF EJECTION

7. How injection molding works?
                                     

8. Difference between injection molding of thermoset and thermoplastics
 Barrel
Screw
Mold temperature

9. BARREL

10. Process characteristics
Production Rate - high
Can produce intricate parts
Can produce a wide range of part sizes with different press sizes.
Tooling cost - high

11. What is thermoset material?
A material, such as an epoxy or polyester resin, which has the property of undergoing a chemical reaction by the action of heat, catalyst, ultraviolet light, etc., to become a relatively insoluble and infusible substance. They develop a well-bonded three-dimensional structure upon curing. Once hardened or cross-linked, they will decompose rather than melt.

12. Some of the thermoset materials
Phenolics
Urea
Melamine
Unsaturated polyester

13. Specialty of the thermoset polymers for injection molding
Delayed curing even at higher temperature
Good flow properties
Fast reaction at tool temperature
Improved wear characteristics

14. TEMPERATURE IN degree C
MATERIAL
NOZZLE
CYLINDER
MOLD
PHENOLIC
80-100
55-75
UREA
85-115
65-80
MELAMINE
90-110
UN-SATURATED POLYESTERS
70-100
 50-70

15. THERMAL PROFILE OF IM

16. Rheology
   HEAT EXPOSURE TIME
   TEMPERATURE
    SHEARING

17. Rheology of Thermoplastics and Thermosets

18. Advantages of Injection Molding
Material handling is reduced

19. Advantages of Injection Molding
Longer and smaller diameter core
pins may be used

20. Advantages of Injection Molding
Parting line flash can be held to
minimal thickness if the mold is
designed properly and well
maintained

21. Advantages of Injection Molding
Injection molding of thermoset
materials lends itself to
automating the process which can
result in lower piece costs.

22. Disadvantages of Injection Molding
The total amount of scrap produced during injection molding will usually be higher than that for compression molding

23. Disadvantages of Injection Molding
Warpage can be a problem in injection

24. Disadvantages of Injection Molding
The filling of the parts through one or two gates produces parts that have knit lines.

25. Applications Phenolics: Electrical plug and sockets circuit board
cutlery handles

26. Applications Melamine-formaldehyde: Dinnerware Kitchen utensils
Bathroom accessories

27. THANK YOU