Plastic Moulding

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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.


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