Transcript ROTATIONAL MOULDING - Welcome to AML 883

PROPERTIES AND SELECTION OF MATERIALS
“ROTATIONAL MOULDING”
Presented by:
Presented to:
GIRIJESH SHUKLA 2008AMD3102
DEPTT. OF APPLIED MECHANICS
IIT DELHI
PROF. M.P. GURURAJAN
DEPTT. OF APPLIED MECHANICS
IIT DELHI
ROTATIONAL MOULDING
.Used for hollow plastics.
.Plastic powder is used.
.create consistency in wall thickness and
density
.It produces strong durable product.
PROCESS
CHARGING THE MOULD
.filling of mould with determined quantity of powder metarial.
.filling of material
More than 80% of all the material used is from the POLYTYLINE family.
Some common materials are:
Polyethylene
Polypropylene
Polyvinyl Chloride
Nylon
HEATING AND ROTATIONAL PROCESS
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Both process happens simultaneously
Time of heating is very critical
Mould is rotated on two perpendicular axies.
No pressure is being applied.
Cooling of mould and De molding
.Bi-axial rotation is continued.
.Cooling is being done by air or water.
.Generally it is being done by fan.
.This process is quite lengthy and very time taking.
Advantages
• A hollow part is made in a single piece with no
weld lines or joints
• Product essentially stress-free
• The molds are relatively inexpensive
• There is no material wastage in this molding
process.
• It is of low cost with respect to the other molding
process.
• Low residual stress
• It is also possible to make multilayer products
• Inserts are relatively easy to mold in
Disadvantages
• The manufacturing times are long.
• The choice of molding materials is limited.
• the material cost are relatively very high
because most the time we will have to add some
additives to make the powder of plastics .these
both the things are very expensive
• There is chance of air trapping in the mould.
• Some geometrical features (such as ribs) are
difficult to mold
Limitation
.temperature
.oxidation
.Thickness
Application
• Tanks- fuel tanks,shipping tanks,oil tanks
• Automotive-door armrest,instruments
panel
• Containers-planters ,airline container
• Toys and Leisure-balls ,ride on toys,
hobby horses
• Marine Industry-dock floats,pool
liners,docking fenders
THANK YOU