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ME3263E/TME3263
DESIGN FOR MANUFACTURING & ASSEMBLY
Homepage: http://courses.nus.edu.sg/course/mpeleeks/personal/index.htm
A/P Lee Kim Seng Deputy Head (Outreach) Mech Mechanical Engg Dept. National Univ. of S’pore
Room: EA 04-17
Tel: 6516 2574
mpeleeks@nus.edu.sg
ME3263E
DESIGN FOR MANUFACTURING & ASSEMBLY
http://courses.nus.edu.sg/course/mpeleeks/personal/ME3263%20eBook/index.html
http://courses.nus.edu.sg/course/mpeleeks/personal/Injection%20Mould%20e_Learning/E-Training.html/index.html
TYPICAL APPLICATIONS
Plastic Injection Moulding
A/P Lee Kim Seng
Features of Injection Molded Plastic Part
A/P Lee Kim Seng
Examples Injection Molded Plastic Part
Injection Molding
A/P Lee Kim Seng
Injection molding technology is a method of processing predominantly used for thermoplastic polymers.
It consists of heating thermoplastic material until it melts, then forcing this into melted plastic into a steel mold, where it cools and solidifies.
The increasing sophisticated use of injection molding is one of the principal tools in the battle to produce elegant product structures with reduced part counts.
Injection Molding
A/P Lee Kim Seng
In order to exploit the versatility of injection molding technology for economical manufacture, it is necessary to understand the basic mechanisms of the process and related aspects of the molding equipment and materials used.
A TYPICAL INJECTION MOULDING SYSTEM
Clamping unit
Injection Unit
Chiller
Dryer Mould Controller
Chiller : Heat Exchanger
Outlet Manifold Mould
Inlet Manifold
Pump
Clamping unit
Injection Unit Dryer Mould
Controller
Chiller
Insert molding
Blow molding
Rotational molding
Vacuum forming
Injection molding
Plastic molding processes
Clamping unit
Injection Unit Dryer Mould
Controller
Chiller
Gas injection molding
Plastic dip coating
Expanded PS molding
Stretch blow molding
Other types of plastic molding processes
Extrusion Blow Molding
A TYPICAL INJECTION MOULDING SYSTEM
A TYPICAL INJECTION MOULDING SYSTEM
Basic Phases in Injection Moulding
Mould Closes 1st Stage Filling 2nd Stage Packing Cooling and Plasticising Mold Opens Part Ejected.
1. Mould closes. Screw moves forward for injection.
2. Filling Completes. Screw continues moving forward for packing.
3. Screw in full forward position. Packing completes. 4. Cooling and Plasticising.
5. Cooling completes. Mould opens for part ejection.
Moulding Sequence
Injection Moulding Cycle
1. 1st Stage Filling
2. 2nd Stage Packing
3. Cooling
4. Mould Opens
5. Part Ejected
6. Mould Closes
A. Remaining Cushion
B. Holding Pressure Volume
C. Injection Volume
D. Decompression
Injection Molding Operations
Fountain Effect Flow Hot resin flow from the middle of the flow channel to the walls and
cools
Pressure Curves
(1) Hydraulic Pressure (2) Injection Pressure (Pressure in front of screw) (3) Pressure in Gate (4) Pressure near Gate (5) Pressure far from Gate
(5) (4) (3) (2) (1)
Basic characteristics of a Cavity Pressure Curve
Start Injection Melt reaches sensor position Cavity is volumetrically filled (Switch
Over) Peak Cavity Pressure 4~5 The volume
change due to cooling of the melt is compensated by additional melt pressed into the cavity.
Freezing point at the gate. Atmospheric pressure. 1 2
3
4
5
6
Optimised Process Conditions
Optimised Process Conditions
CAD CAM
Material CAE IPC
Mould Design MouldManufacturing
ProductDesign
A SINGLE CAVITY MOULD
Mould Base
TWO CAVITIES MOULD
INJECTION MOULDS
Mold Layout
Designing a mold for a new project
Continuing a mold design for an existing project
Data Preparation •Load Part •IMOLD CSYS •Scale Factor •Containing Box
Data Preparation
•Load Assembly
Filling Module •Layout •Gate Design •Runner Design
Mold Base
•Choose Type •Enter size
Parting
•Parting Line •Insert Creation
Lifter Design
Slider Design
Cooling Design
Ejector Design •Design Ejection •Edit Ejection
Standard Library
Proceeding on with where you
have left off
Hot Runner Design •Manifold Selection •Manifold Design •Nozzle Design •Gate Design
Electrode Design
IMOLD
Runner System Several types of runners
single part runner multiple part runner
• symmetrical runner • non-symetrical runner
runner-less designs with hot manifolds
Sprue Guidelines
The sprue must not freeze before any other cross section. This is necessary to permit sufficient transmission of holding pressure.
The sprue must de-mold easily and reliably.
Dco ≥ tmax + 1.5 mm Ds ≥ Dn + 1.0 mm α ≥ 1º - 2º tan α = Dco - Ds / 2L
Sprue
Runner Guidelines Common runners Full-round runner Trapezoidal runner Modified trapezoidal runner (a combination of
round and trapezoidal runner) Half-round runner Rectangular runner
Sprue Gate
Fan Gate Tunnel Gate
Side Gate Pinpoint Gate
Submarine Gate
Different type of gates available
Gate System
A/P Lee Kim Seng
Standard gate positions
Standard gate
position
Standard gate
position
Standard gate position
Gates & Runners
A/P Lee Kim Seng
Gates & Runners
Where would you put the Gating for the part shown ?
Hot Runner System The ideal injection molding system delivers molded parts of uniform density, and free from all
runners, flash, and gate stubs. To achieve this, a hot runner system, in contrast to a cold runner system, is employed. The
material in the hot runners is maintained in a molten state and is not ejected with the molded part. Hot runner systems are also referred to as hot-manifold systems, or runnerless molding.
FIGURE 1. Hot runner system types: (a) the insulated hot runner, (b) the internally heated hot-runner system, and (c) the externally heated hot-runner system
A/P Lee Kim Seng
Cam Operated Sliders
Finger Cam Pin
A/P Lee Kim Seng
Hydraulic Operated Sliders
A/P Lee Kim Seng
Slider
Ejector Pin
Type #1 Type #2
Type #3 Type #4
Type #5
A/P Lee Kim Seng
Ejector Pin
A/P Lee Kim Seng
Lifter
Ref:
Application of Multimedia and Internet Technology in e_Learning of Industrial Design.
Dr Shum SP, Simon
IMCC 2002, Xiamen China
http://us.share.geocities.com/chanwingkin1981/project.swf
E_Learning
A/P Lee Kim Seng
Multi Colours Moulding
A/P Lee Kim Seng
Thank You
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