Hello there!! We are continuously facing one problem while processing TPU's in single screw extrusion. While processing for some time we get melt pressure stability but after some time melt pressure fluctuates in range from 30 to 35 bar due to which we are unable to achieve uniform outer diameter throughout processing. What can be the possible cause? Very often melt pressure is also not achieved while processing TPU's. Please Help. We get good stability while processing PP, LDPE, PVC but in case of TPU's we face pressure problem everytime. What can be the possible cause?