Rotational molding is a creative process used for the manufacture of hollow containers. The other term coined for the process is roto molding. The process started its operation from early period starting from 1940. In the early days the process does not pick its place in manufacturing market as it was considered to be slow with respect to time factor of production and so used for producing less production of hollow containers. In recent days up gradations in the process like use of powered plastic resulted in speeding up the process and there by takes its significant stand for production using the process.
Phases in Rotational Molding :The Rotational molding has four different phases involved in the process. They are:
- Loading
- Heating
- Cooling and
- Removal
Let us discuss each of the above phase in detail:
Loading :The polymer used for the process is generally taken as powder and is first weighed to measure the amount needed for this process. After this, the weighed powder is loaded in mold which constitutes the phase of loading.
Heating :In this phase the mold which was loaded is rotated and heated using an oven. The heating process is continued till all the polymer gets into melted stage. Essential care must be taken not to overheat or under heat. This is because, if overheating is done then it causes the strength of the polymer to get reduced and there by having impact on quality of product. In a similar manner if under heating is done then melting process would not have completed fully which also have impact on final product. Essential care must be taken to do the heating operation to the exact level.
Cooling :Among the four phases of rotational molding the phase of cooling takes more time and the process of cooling is done generally using fan. It is essential for the cooling process to be done because then only the polymer would attain the stage of solidification. Essential care must be taken in this phase also to maintain the range in rate of cooling.
Removal :The removal phase is the last stage of rotational molding process in which the final product is removed.
Advancements in Process of Rotational Molding :As suggested above in the rotational molding process it is very essential to maintain the temperature during heating and range during cooling phase. In earlier days this was very tiring for users to do it based on assumptions and trials. However in recent development monitoring of temperature and range of cooling can be monitored efficiently and easily and thus the tiring process of trials and assumptions has been removed. The advancement enhances the quality of the final product produced. Research and studies are ongoing on the process of rotational molding to make it more improvised. Some of the areas in which more studies are going on are for making the time taken for the process also coined as cycle time to be much little. This is because, if the above is achieved it would help in achieving much more efficient quality product.