Plastic Moulding

Introduction:

-A plastic can be defined as any non- metallic material can be moulded into any desired shape.

-The word plastic derived from Greek   plastikos, means "fit for molding".

-Plastic are systematically produce non-   metallic compound. They can be moulded into various form and harden for commercial use.plastic molding product can be seen everywhere.

-Following are example of plastic moulding jars, protective cap, plastic tube, grips, toys, kitchen utensils, bottle and lot of more.

                    Product of plastic

- The basic idea in plastic moulding is inserting molten liquid plastic into a ready  shape mould, for example the mould of a bottle. It will be  allowed  to cool, then it will be remove.

Properties of plastic:

-It is light in weight.

-it is high strength to weight ratio.

-it is relatively inexpensive 

-most plastic are chemically stable.

-it is easily transparent and colored.

-They have good insulation and thermal     property.

- good corrosion resistance.

-it is flexible.

Type of plastic:

All plastic are polymer, it is divided into two type.

1. Thermoplastic material.

2. Thermosetting material.

Thermoplastic material:

- thermoplastic material are soften on application of heat and candy set into desire shape after cooling.

-they can be remelted again and again on application of heat.

-these plastics are processed by injection moulding, blow molding, extrusion moulding, etc.

                   thermoplastic resins

- Example are:

-Polyethylene: packaging, electrical   insulation, milk and water, bottle, film.

-Polypropylene: carpet fibre, automotive   bumpers, microwave container,                   - Polyvinyl chloride(PVC)- sheathing for electrical cable, floor and wall covering, sliding, credit card, automobile instrument panel.

Acrylics - (PMMA: polymethyl methacrylate): paints, plexiglass.poly

Polyamide-(nylon) textile and fabrics, bearing, washer, gear.

PET-(Polyethylene terephthalat) bottle for acidic food like juice, food trays , tapes.

PTFE-(polytetrafluoroethylene): non-stick coating, raincoats, dental floss.

Thermosetting material:

-Thermosetting material is called thermoset.

-it is become soft on application of heat and become hard by  chemical changes it is called thermosetting material.

-the cannot be soften again by application of heat.

-compression moulding and transfer molding method of this process.

-typical thermosetting material include mattress, toys, insulation, cushion.

-silicones: surgical gloves, oxygen masks in medical and other application, joint seals.

-example are melamine, epoxies and polyesters epoxy resins etc.