Rotational Moulding Flashcards
What are the advantages of rotational moulding?
Low pressure process - cheap
Great thickness distribution for complex shapes
Zero waste
Products don’t have flow-induced defects
What are the disadvantages of rotational moulding?
Long cycles due to heating and cooling requirements - expensive equipment required for a carousel machine to shorten time per unit
Poor fusion and mixing - risk of voids
Mainly for low molecular weight polymers which have worse physical properties
Why is rotational moulding so slow?
Heating and cooling requirements of the mould
Low rotation speeds used to minimise deformation stress
How are process times decreased in rotation moulding?
Multiple moulds rotate on a carousel system
What are the most likely sources of defects in rotation moulding?
Internal/surface voids - due to imperfect coalescence of powder particles
Imperfect mixing causing nucleation of pigmented or filled crystalline materials
