Extrusion International 3-2024

36 Extrusion International 3/2024 New Solution for PVC Pipe Extrusion In 2022, PVC accounted for 9.1% of the 58.7 million tonnes of plastics produced in the EU. Within the European community, the market for pipes for construction purposes recorded approximately 6.3 million tonnes of PVC, 60% of which consisted of rigid PVC pipes and 40% of flexible ones. As the latest Euroconstruct report shows, the construction sector in the last three years has recovered sharply in almost all Eurozone member states, with a growth rate of +2.1% calculated over the three-year period 2020 to 2023. Good news, therefore, for players specialising in the production and industrial processing of PVC, demand for which will continue to be positively influenced by recent investments in public and private construction. The challenges of PVC pipe extrusion: production flexibility, parameter control, and reduction of setup times The production of PVC pipes is characterised by nu- merous challenges: wide diameter range, pipe strength, consistent quality of the extruded output, and minimi - sation of waste. The performance of a line is therefore closely related not only to the optimisation of the indi- vidual extrusion process, but to the system’s own ability to achieve high levels of production flexibility to meet the heterogeneous requirements of the various pipe applications. Furthermore, the physical properties of PVC make the extrusion process particularly delicate. This polymer is in fact characterised by high thermal sensitivity and tends todegrade at temperatures as lowas 180°C, a parameter close to its melting temperature. In this sense, in order to avoid compromising the quality of the output, it is necessary to limit the time it stays in the head. Once melted, the material proceeds into the barrel, so the main parameters to be controlled are barrel tempera- ture, extruder flow rate, screw speed, pressure, and melt temperature. With a view to increasing production flexibility and in light of the parameters to be met for the setup of an extrusion line, there is a need to reduce the setup time of extrusion plants. In the specific case of PVC pipes, changing the diameter and thickness of the product re- quires a complex setup, characterised by horizontal fit - ting of new components, recalibration and adjustment of the configuration on the entire line, with an overall impact of 83 h/year of work not directly aimed at pro - duction. Bausano changes the game: industry expertise that makes the difference Bausano is meeting this challenge head on by devel- oping an innovative PVC pipe head capable of covering a diameter range from 125 mm to 400 mm, with low flow rates (around 500 kg/h), preventing material deg - radation and excessive dwell times in a perfect balance between volume, flow rate, and production range. As well as being compact in size, this unique Bausa - no solution reduces the number of heads from two to one, which has a positive impact on customers in terms of both overall investment and reduced mould setup times. In addition, the modular design of some parts of the head facilitates cleaning and maintenance for the operator during assembly and disassembly. The spe- cial head was then combined with an MD 92/30 Next - mover extruder without induction, featuring specially designed screws to process different dry blend formula- tions, from those containing the highest to those con - taining the lowest quantities of additives. PIPE EXTRUSION