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Rotomoulding has grown into one of
the fastest moving sectors of polymer.
Rotational moulding, or rotomolding
or roto molding, is a method of moulding plastics which is ideal for the production of hollow
articles, particularly sizeable. A truly staggering array of
products can be made by roto moulding, including big and small
Tanks, Materials handling
products like tubs, crates, pallets
and drums, environmental
products like litter bins, road
cones, bollards and temporary traffic dividers, Automotive products like truck mudguards, diesel fuel tanks,
underbody tanks, toolboxes, tractor consoles and engine cells, Water sports
products like kayaks, canoes and
boats, Large toys and playground equipment, Home and garden product including plant pots, garden ornamentation,
composters, water softener cabinets and many more…
Rotomoulding is a most cost effective
alternative to blow moulding, vacuum forming, GRP moulding and
fabrication, and is ideal for shaping complex customised
mouldings that have features such as intricate contours,
undercuts, molded-in inserts and double walls.
History of RotomouldingIt is believed that earliest exponents of the
process were the Chinese. Probably Rotational Moulding process
was used to mould the Terracotta Army of Emperor Qin Shihuang
in the 3rd century BC. In the 1940s commercially the
rotational moulding process was first developed for use with
liquid polyvinyl chloride formulations (PVC plastisols).
Development in the use of the process was
delayed in the early years because it was regarded as a quite
time-consuming method with limited material range and product
shape possibilities.
In the late 1950s, the first major breakthrough
came when powdered polyethylene grades were developed for
rotational moulding.
There was a steady growth in the usage of
rotational moulding in the 1960s and 1970s as more
polyethylene grades became available and other plastics were
also found to be rotomouldable.
More recently, there has been steadily
increasing interest in the process as there are productions of
more and more sophisticated shapes, material suppliers develop
grades specifically suited for the process. Also manufacturers
of machinery improve the efficacy of the equipment and expand
new, improved materials and machinery.
Rotomoulding: MaterialsIn Roto molding more than 80% of all the material used is
polyethylene (PE), a polymer with immense versatility
ranging from food grade to vandal-resistant and flame
retardant grades for handling waste materials, fuels and
corrosive substances. PVC plastisols, Nylons, polypropylene
are other artificial compounds.
Natural
Materials: It is only been possible quite recently, but
natural materials can also be used. Through the use of real
sands and stone chip, sandstone composite can be created which
is 80% natural non-processed material.
What is molding?
Molding or casting
is the process of manufacturing by shaping pliable raw
material using a rigid frame or model called a mold. A
mold or mould is a hollowed-out block that is filled with a
liquid like plastic, glass or metal. The liquid hardens or
sets inside the mold, adopting its shape. A mold is the normally
opposite of a cast. The manufacturer who makes the molds is
called mold maker or mould maker.
Types of molding
- Powder metallurgy and ceramics
- Compaction plus sintering
- Plastics Injection molding
- Compression molding
- Transfer molding
- Extrusion molding
- Blow molding
- Rotational molding or Rotomolding
- Thermoforming Reaction
- Injection Molding
- Laminating Expandable bead molding
- Foam molding
- Vacuum plug assist molding
- Pressure plug assist molding
- Matched mold
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