PROCESS
Rotational moulding, also known as rotomoulding, is a manufacturing process for forming many types of thermoplastic articles by using moulds of any shape or size and inserting them into a heated rotational moulding machine. The process consists of five phases: loading (resin is charged into a mould); heating (mould is rotated in an oven around two axes – vertical and horizontal – until all the resin has fully melted and adhered to the mould wall); cooling (the mould continues to rotate within a certain range until the entire inner surface is evenly coated in order to produce a part with consistent wall thickness); unloading (removal of the part); and cleaning (eliminating excess resin from the finished article, especially at the joints). Moulds are fabricated from aluminium or steel and are a vital factor in the whole process since the quality of the parts greatly depends on mould conception.
Advantages
Rotational moulding offers economical advantages over other processes, such as injection moulding, blow moulding or thermoforming, limiting mould production costs to average or low levels. On the other hand, it also offers the ability to produce larger and multi-wall mouldings. With proper design, parts from several pieces can be assembled as one seamless product, resulting in dramatic cost savings and superior strength. Rotational moulding has had a significant increase in usage thanks to its versatility and the ability to handle a vast variety of shapes and sizes: home decor items, technical parts, toys, tanks, reservoirs or containers. The growing demand for more ecological, multi-wall and highly flexible articles has also been a determinant factor to the increasing usage of the rotational moulding technique.
Full Service
Rocha Pulverizadores adopted rotational moulding since late 1970s once the company started producing rotomoulded plastic spray containers, which were made from brass plate steel up until then. At an early stage, these containers were outsourced. However, due to market growth and facing the need to respond more quickly to market demands, the company installed its first rotational moulding machine in 1982 and proceeded with its own production. In 2004, the company set up a new manufacturing unit tailored exclusively for rotational moulding. Rocha Pulverizadores has concentrated most of its production in house (approximately 60%) and the remainder is outsourced to external companies.
Nowadays, having gained the relevant experience and know-how, the company is positioned as a privileged third party to develop innovative rotational moulding projects. We are the ideal partner to fulfil successful projects, whether developing any product from scratch – from design to moulds, final touches, selecting materials and technical advice (“key in hand”) – or providing specialized technology to form plastic articles (whenever mould is supplied by the customer).
