1. Injection Molding Technology Material From Dr. Piyawit Khumphong (MTEC)

2. Injection Molding System

3. Tpe of Mold for Injection Molding Two-piece mold Three-piece mold

4. Flow Channels for Molten Plastic Sprue Runner Gate Cavity Sprue Runner Gate Cavity

5. Cooling System for Injection Mold

6. Injection Molding Cycle 1. Filling 2. Repeat Filling (Packing) and Cooling 3. Mold opening 4. Product ejecting 5. Mold closing

7. Temperature and Pressure Setting Unmolten Temp (T) Pressure (P) Degrade Flash Short shot T g + 100 T m + 50

8. Temperature Setting for Injection Molding Machine Depending on Screw (Diameter, D) 1D 1.5D3D D Shot size Viscous heat ====> shear heating

9. Mold Filling Fountain flow Surface Center Skin - core morphology Birefringence microscopy of HDPE

10. Short Shot Discoloration Air traps Burn marks, Black specks-black streaks Brittleness, Fish Eyes Flow marks, Ripples Flash, Jetting, Silver Streaks, Sink Marks Shrinkage and Warpage Weld Lines and Meld Lines Overpacking Flow into thin section Defect Problems in Injection Molded Products

11. Air traps >>> Burn marks Problems that arrived from poor mold design Front View Top View

12. Burn marks Black specks-streaks Brittleness Fish Eyes

13. Flash Jetting Silver Streaks Sink Marks

14. Flow marks Ripples

16. Shrinkage and Warpage

17. Weld Lines and Meld Lines

18. Sandwich-Molding Overmolding Simultaneous Sequential 1. Coinjection 2. Gas assisted 1. Monosandwich 2. Airpress III 1. Core-Back-Technique 2. Sandwich-Overmoulding 3. Insert-Moulding* 4. Outsert-Moulding* 5. Textile-Overmoulding* 6. In-Mould-Labeling* 1. Turntable 2. Transfer 3. Overmoulding-Stackmould Single Cavity Multi-Cavity Multi-component molding

19. Sandwich molding

20. Viscosity ratio Viscosity ratio = viscosity 2nd melt / viscosity 1st melt Desired structure Sandwich molding

21. Simultaneous Technique

22. Sequential Technique core material (B) skin material (A)

23. Monosandwich molding core material (B) skin material (A)

24. core material (B) Monosandwich molding

25. Door Handle Monosandwich molding

26. Compatibility ABSPA6PPPEPSPETPC ABS+?--*++ PA6?+---?* PP--++--- PE--++--- PS*---+-- PET+?---++ PC+*---++ (- ) : No adhesion, (*) : Poor adhesion, (+) : Good adhesion, (?) : N/A or Depend on Condition

27. Depend on Chemical bonding Inter-diffusion >>>>Time & Temp PP-PP under 110 °C >>> Poor adhesion ABS-ABS under 130 °C >>> Poor adhesion Compatibility

28. Corrects: Warpage Shrinkage Section change Surface aesthetics Developments: Cold Gas Injection Water Injection Gas Assisted Injection Molding

29. Airpress III 12 34

30. Bottle Crades Airpress III

31. OVERMOLDING

32. Overmolding can be...  multi colour technique (e.g. buttons for key boards)  multi material technique (hard and soft, e.g. for integrated seals)  in-mold assembling (e.g. hinges, air vents...)

33. Core – Back Technique

34. Transfer - Technique ABS Tray with anti-slip TPE material Tooth Brush with soft-feel TPE material

35. TurnTable Technique Tube shoulder for thoothpaste with barrier layer from PET and over-molded skin from PP

36. Stack-Turning-Technique process phase 1process phase 2 preform Injection unit 2 Main injection unit

37. Stroke 3 2nd injection unit Stroke 2 Assembling Stroke 4 Demolding Stroke 1 1st injection unit Stack-Turning-Technique

38. Vertical turn with the Cube-Technique Production cost reduction about 25% 4 sides of the cube usable Siemens M35 Stack-Turning-Technique