The underwater pelletizer units are built up on completely self-supporting frames. The parts of the line that come into contact with water are made from stainless steel. All internal and external panels of the pelletizer sub-cabinet, and the panels of the control cabinet, have undergone a rigorous painting regime using triple priming with each layer being carefully sanded before applying the next layer. The final painting (top coat) consists of two layers of highly resistant epoxy paint. The pelletizer is equipped with six steel cutting blades mounted on a flexible plate attached to a sturdy spring-loaded shaft. The rotating arm (with cutting blades) unit can be adjusted forwards and backwards so that a suitable cutting blade force can be applied to the die face for cutting the extruding molten strands. When cold circulating water is being used for the pelletizer the heat exchanger is cooled ‘externally’ using cold water supplied from a chiller (or from the mains or from a cooling tower, if one is available). The water that passes to the pelletizing unit travels around the cooled copper pipes inside the heat exchanger unit. In this way the cooled circulating cooling water for the pelletizer does not become contaminated since it does not come into direct contact with the water used for cooling the heat exchanger.