clg presentation
Post on 10-Jan-2017
76 Views
Preview:
TRANSCRIPT
PLASTIC INJECTION
MOULD DESIGN
PRESENTATION BYPARESH CHAUHAN (70)KRISHA DHAMECHA (71)BHUSHAN GHADI (72)SHUBHAM KEDIA (73)
VIDYAVARDHINIS COLLEGE OF ENGINEERING AND TECHNOLOGY, VASAI ROAD (WEST).
THIRD YEAR MECHANICAL DEPARTMENT
CONTENTS INJECTION MOLDING PROCESS. BASIC TERMINOLOGY OF INJECTION MOULDING. SYSTEMS OF MOULDS. FEEDING SYSTEM- RUNNER, GATES. COOLING SYSTEM. EJECTION SYSTEM. CONCEPT OF THREE PLATE MOULD. HOT RUNNER SYSTEM. INNOVATIVE MOULD COMPONENT.
INRODUCTION INJECTION MOULDING IS A PROCESS IN WHICH A POLYMER IS
HEATED TO A HIGHLY PLASTIC STATE AND FORCED TO FLOW UNDER HIGH PRESSURE INTO A MOULD CAVITY, WHERE IT SOLIDIFIES.
THE MOULDED PART IS CALLED AS MOULDING.
TYPES OF INJECTION MOULDING SYSTEM
RAM OR PLUNGER TYPE SCREW TYPE
INJECTION MOULDING PROCESS
Components of injection molding system:
1. Injection unit2. Clamp unit3. Mold
INJECTION UNITINJECTION UNIT HAS TWO
FUNCTIONS:-
1. MELT AND HOMOGENIZE THE POLYMER.2. INJECT THE LIQUID PLASTIC INTO THE MOULD.
CLAMPING UNITCLAMPING UNIT HAS THREE FUNCTIONS:-
1. TO HOLD TWO HALVES OF MOULD IN PROPER ALIGNMENT.2. TO KEEP THE MOULD CLOSED DURING INJECTION BY A CLAMPING
FORCE.3. OPEN AND CLOSE THE MOULD AT THE APPROPRIATE TIMES IN
MOULDING CYCLE.
MOULD Functions of a mold:
1. impart the desired shape to the plasticized polymer.
2. cool the molded part. A mold is made up of:
1. the cavities and cores.2. The material used for making mold is either steel
or aluminium.
WORKING OF INJECTION MOULDING
Advantages of Injection Molding
Parts can be produced at high production rates. Parts require little or no finishing. Close dimensional tolerances can be maintained. Parts can be molded with metallic and non metallic inserts. The inherent properties of the material give many advantages
such as high strength-weight rates, corrosion resistance.
Limitations of Injection Molding
Mold costs are high. Molding machinery and auxiliary equipment costs
are high. Lack of knowledge about the fundamentals of the
process causes problems.
APPLICATIONSCUPS, TOYS, CONTAINERS, KNOBS.AUTOMOBILE PARTS LIKE DASHBOARD, CAR
HANDLES.COMPONENTS WITH COMPLEX THREADS.PRODUCTION OF OF INTRICATE SHAPES.THIN WALLED PARTS LIKE RADIATOR PARTS.
BASIC TERMINOLOGY OF INJECTION MOULD
IMPRESSION CAVITY AND CORE PLATE SPRUE BUSH RUNNER AND GATE SYSTEM REGISTER RING GUIDE PILLAR AND BUSHES PARTING LINE FIXED HALF AND MOVING HALF
CAVITY AND CORE PLATE
SPRUE BUSH
RUNNER AND GATE SYSTEM
FIXED HALF AND MOVING HALF
BASIC SYSTEM OF MOULD
FEEDING SYSTEM
EJECTOR SYSTEM
COOLING SYSTEM
FEEDING SYSTEM CONSIST OF “SPRUE”, “RUNNER”, “GATE”.
RUNNERDESIGN CONSIDERATION:
1. SHAPE OF CROSS SECTION OF RUNNER.
2. SIZE OF RUNNER.
3. LAYOUT OF RUNNER.
SHAPE OF CROSS SECTION OF RUNNER.
SIZE OF RUNNER RUNNER CROSS-SECTION AND VOLUME OF MOULDING
DISTANCE OF IMPRESSION FROM SPRUE.
RUNNER COOLING CONSIDERATION.
CUTTERS AVAILABLE AND PLASTIC MATERIAL USED.
RUNNER LAYOUTIT DEPENDS ON:
1. NUMBER OF IMPRESSION
2. SHAPE OF COMPONENT
3. TYPE OF MOULD
4. TYPE OF GATE.
GATESSIZE OF GATE IS ALWAYS KEPT
SMALL BECAUSE:• CONTROLLS THE FILLING OF MULTI IMPRESSION.
• AFTER DEGRATING ONLY SMALL MARKS REMAINS WHICH DOES NOT AFFECT THE ASTHETICS OF COMPONENT.
• ALLOWS SIMPLE DEGATING.
TYPES OF GATES
Tab gate
Diaphragm gatePin gate
Flash gate Fan gate
Sprue gate
EJECTION SYSTEM CONSISTS OF:
1. EJECTOR GRID
2. EJECTOR PLATE ASSEMBLY
3. METHOD OF EJECTION.
EJECTOR GRID• IN- LINE EJECTOR.
• FRAME TYPE EJECTOR
• CIRCULAR SUPPORT
Methods of ejection
Blade ejectors
Round ejectors
Sleeve ejection
Core pin
Sleeve
Good even ejectionaround bosses but quite expensive.
Air ejection
Air off - spring returns valve to its rear position
Stripper plate ejection
Stripper block
Three plate moulds IT HAS THREE HALVES:
• Stationary plate• Intermediate plate• Moving mould plate.
THREE PLATE MOULD DESIGN HAS FOLLOWING ADVANTAGES:• As the gate is provided at base of cup shaped part it allows more
even distribution of polymer melt.• Allows automatic operation• As mould opens the runner and part are fall because of gravity.
SCHEMATIC DIAGRAM
HOT RUNNER SYSTEM• Increases
themould height.
• Material delivered to the cavities in the same condition as the melt left
the barrel.
• Saved material waste from the sprue & runner.
The 2 plate tool
ADVANTAGES No feed system to be removed.
Reduced mould open stroke.
Reduced shot weight.
Injection time reduced.
Automatic de-gating.
Easier to balance gates.
Increased number of cavities possible.
DISADVANTAGESIncreased set-up times. Warm up period required. Increased tooling costs. Manifold leaks. Higher maintenance costs. Degradation with certain polymers. Heat expansion problems.
INNOVATIVE MOULD COMPONENT
USED IN DIFFERENT FIELDS LIKE:
• Architectural buildings• Appliances• Food service industries• Tooling• Aerospace industries• Automotive industries.
THANKYOU
top related