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 Rotomoulding
It 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.
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Rotomoulding: Materials
In 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.
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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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