One of the aesthetical and functional defects associated with rotational moulding is the presence of small air bubbles inside and on the surface of moulded products. To resolve the problem, Persico, headquartered in Nembro (Bergamo, Italy), carried out a number of tests comparing the results from different types of polyethylene moulded under the same thermal conditions but with different inner mould pressures.
The Leonardo rotational moulding machine easily, directly and precisely controls the mould temperature, monitors the product inner temperature, and pressurizes and depressurizes the moulds.
The tests have given excellent results with different materials (MFI from 3 to 9) and thicknesses (from 3 to 9 mm), experimentally showing that vacuum rotational moulding by "Leonardo" eliminates bubbles both inside and on the surface of products.