Download presentation
Presentation is loading. Please wait.
Published byKelly Joseph Modified over 9 years ago
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.