Optimised polymer flow through annular die head

Abstract

The aim with this thesis was to contribute to the development of die heads used for polymer pipe production. Different solutions to improve die heads were pondered before the decision to focus on a coating, best suited for new die heads, was made.

Several different coatings were evaluated with a rotational rheometer that usually is being used for material rheology property analyses. Here the measuring head of the rotational rheometer had been coated, which meant that new theories had to be developed in order to make comparisons between coatings possible. Pipe production simulations were done on the received rheological data to see how much better one coating would be compared to another. Simulated wear tests that simulates the cleaning of die heads were conducted to see if the normal cleaning methods or tools had to be changed in any way.

The results obtained showed that it is possible to use a rotational rheometer for this kind of analyses as long as the tested coatings differs enough from each other. It was possible to produce a grouping of the tested coatings, though, it was not possible to say how much better one coating is compared to another. The wear tests showed that changes would be needed concerning the cleaning tools depending on which coating is used.