Thursday, August 8, 2013

Products design with plastics

 
some plastic products



There are different advantages as same as some disadvantages when we are using plastic for product designing. 

Advantages
  • No corrosion
  • Light weight
  • Low processing temperature (compare to the metal)
  • Low energy requirement for processing
  • High strength can be achieve if needed
  • Non toxic, non smell, non taste etc
Disadvantages
  • Plastic has temperature dependent characteristics
  • Less dimension stability
If we are going to design a plastic product we have to consider about some factors. They are application of the product, service life, service temperature, environment concerns and other specific customer requirements. 

Now a day’s some commercial plastics are there widely used for product design.  

Polyethylene (PE)





It is generally milky white brittle material which can easily crack. It has different classifications according to its density and branching. LDPE (low density polyethylene), HDPE (high density polyethylene), LLDPE (linear low density polyethylene) are the most common and important types of them. Mainly they are used for film and packaging applications.

Polypropylene (PP) 
More ductile material than polyethylene and it is not easily cracked. It has good resistance to fatigue. Mainly used in plastic furniture applications.

Polyvinyl chloride (PVC)

Generally there are two types called UPVC (un-plasticizer) and PPVC (plasticizer). Each one has different properties and different applications as follows.

PPVC
UPVC
Relatively soft
Relatively hard
Used for cable insulation, soft bottle squeezed etc.  
Used for piping, roofing, doors, window frames etc.

Polystyrene (PS)

It has good resistance to water, but swells in solvents. It is brittle, not strong and cheaper material. Generally used for packaging and food containers like yogurt containers.

Nylon

Nylon has high strength as same as dimension stability. Generally used for cloths and mechanical engineering applications like aircraft propellers, gear wheels.

When we design a plastic product we have to consider about different modes of deformations can be happen in plastics. Some of them are tension, compression, torsion, simple shear, bending. They will discuss in detail future.