Rotational molds are also known as roto casts or spin casts. This is used predominantly for the molding of plastic but is also applied to other types of metals as well. In its earliest form, Rotational molds were used to make small plastic containers but its efficiency was soon questioned as very little of them were produced after a long process of heating and cooling, and which for obvious reasons, was not commercially viable.
But with the new age rotational molds, these glitches have been overcome and it has emerged as the most efficient way of manufacturing plastic containers.
Firstly, the required quantity of polymer is put into the mold which is first in powdered form. Then it is heated slowly and upon heating the mold starts rotating for even heating.
The polymer melts and starts adhering to the walls of the mold in the process. Even when the heat is cut off, the mold still goes on rotating to avoid the hot melted polymer from dripping and settling untidily.
The cooling itself is done by a fan but not too fast as that will result in the plastic shrinking from such variations of temperature. Both the heating and the cooling are gradual processes which are very time consuming.
However, with the recent improvements, it has become possible to regulate the temperature and unlike earlier times, the results are much better now as things are not done on the basis of speculations anymore, resulting in perfectly formed plastic containers.
By making plastic containers out of thermoforming molds, the entire process has become very cost effective. And with still more innovations to come, it will become absolutely flawless for the manufacturing of any kind of molds.