CLG PRESENTATION

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