Monday, 13 May 2013

Rotational moulding and more



Rotational moulding.  A measured amount of  polymer powder is placed in a mould. The mould is then rotated in a complex motion  in an furnace or oven until the polymer lines the mould cavity. Polymer home heating tanks are made by this method.




4.    Heat forming, (Vacuum Forming).

This uses sheets of polymer, which are clamped and heated. The heat is then removed and the mould is forced up through the polymer sheet, a vacuum is applied which pulls the polymer against the mould. The polymer is allowed to cool and the polymer sheet then removed.







5.    Foaming.

Polymers, which are converted into sponge like materials, are formed or expanded.  A foaming agent is mixed with the resin. The combination is heated during moulding. The products, which are produced, have a very low density. Both rigid and flexible foams can be produced.



6.     Lamination.

Impregnating sheets of paper or cloth with a resin can produce high strength polymers. Layers of this material are bonded, by allowing the resin to set into a solid structure. Heat and pressure are often used in this process.


7.    Machining.

Polymers supplied in rods, tube or sheet can be machined into their final shape. These materials can be machined by both hand tools and machines but can require different cutting speeds.


8.    Welding.

Polymers are used to make variety of components for example in cars the bumpers, grill etc. But these can crack due to light impact, using a hot air welding tool can repair these cracks. The welding tool provides heat to make the polymer molten. A filler rod of the same polymer is fed in through a special nozzle.



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