Plastic technology

VADODARA INSTITUTE OF ENGINEERING. KOTAMBI.

ACTIVE LEARNING ASSIGNMENT ONManufacturing processes 2

TOPIC : PLASTIC TECHNOLOGY MECHANICAL 3

140803119501 – Anupam Chaturvedi

Topics : Introduction Classification of the plastics Advantages of the plastics Disadvantages of plastics Applications of plastics Properties of plastics Plastic manufacturing processes

Properties of plastic

Low density. To make low weight qith high strength. Anti friction & self lubrication sometimes achieved. Corrosion reaiatance, water profing & noise less

operation of moving path. Low in cost. Insulation of heat & electricity. Chemically stable. Less brittle. Good toughness. Easily moulded. Colour ability.

Advantages of plastic

Probability Strength Plastic is an adourless. Plastic is used in buildings, construction,

packaging etc. Use to make bottles, pens, plastic bags, caps etc. Its very cheap. Its recyclable. Light in weight. Chemical & corrosion resistance.

Introduction

Plastic are easily formed materials.

The advantage to the manufacturer is that plastic products can be mass-produced and require less skilled staff.

Plastics require little or no finishing, painting, polishing etc.

Plastics can be easily printed, decorated or painted.

Plastics are corrosion resistant, and generally waterproof although certain types of plastics such as UPVC can become brittle and it is possible for the sun’s rays to cause the colour of the plastic to fade. It becomes bleached.

Plastics are lighter than metals, giving deeper sections for a given weight, and hence stronger sections.

Two types of plastics1.Thermoplastics2.Thermo setting plastic

Classification of plastics

Thermo plastic

1. Polyethylene 2. Polypropylene 3. Polystyrene 4. Polyvinyl chloride 5. Polytetrafluroaethylene 6. Poly carbonate 7. Acetals

Thermoplastics

There are a wide range of thermoplastics, some that are rigid and some that are extremely flexible.

The molecules of thermoplastics are in lines or long chains with very few entanglements. When heat is applied the molecules move apart, which increases the distance between them, causing them to become untangled. This allows them to become soft when heated so that they can be bent into all sorts of shapes.

When they are left to cool the chains of molecules cool, take their former position and the plastic becomes stiff and hard again. The process of heating, shaping, reheating and reforming can be repeated many times.

Thermo setting plastics

1.Aminos 2.phenolics 3.polyurathenes 4.polyesters 5.epoxides

Thermosetting plastics

The molecules of thermosetting plastics are heavily cross-linked. They form a rigid molecular structure.

The molecules in thermoplastics sit end-to-end and side-by-side.

Although they soften when heated the first time, which allows them to be shaped they become permanently stiff and solid and cannot be reshaped.

Thermoplastics remain rigid and non-flexible even at high temperatures. Polyester resin and urea formaldehyde are examples of thermosetting plastics.

PLASTIC MNUFCTURING PROCESSES

1.Compression moulding processe

2. Transfer moulding process

3. Injection moulding process

4. Extrusion moulding process

5. Blow moulding

6.Celendaring moulding

7. laminating

8. Slush moulding

9. Thermo forming moulding

COMPRESSION MOULDING

This is the process in which the charge is putted into the die . After that the pressure applied from the upper mould. And at last work piece is removed from the die with the use of ejector pin.

TRANSFER MOULDING

This is the same process as the compression moulding.Only the differance of the sprue. As shown in figure.

INJECTION MOULDING PROCESS

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Schematic of thermoplastic Injection molding machine

EXTRUSION MOULDING

BLOW MOULDING

CELENDARING PROCESS

LAMINATING PROCESS

SLUSH MOULDING

THERMO FORMING MOULDING