Meltblown Die Design and Extrusion Mechanics
topic
Meltblown dies consist of a linear spinneret row with orifice spacing of 10 to 40 per centimetre and orifice diameter of 0.1 to 0.4 millimetres flanked by two air knife slots delivering air at 200 to 370 degrees Celsius and velocities of 100 to 500 metres per second that simultaneously attenuate and quench the extruded polymer stream into microfibers, with die geometry and air slot angle determining the attenuation efficiency and resulting fibre diameter distribution.
Role
Defines the core fibre formation mechanism that determines achievable meltblown fibre diameter and diameter distribution through the interaction of polymer melt viscosity, extrusion velocity, and air jet velocity and temperature at the die tip, with die design precision being the most critical engineering element governing whether submicron to micron fibre production is achievable at the throughput rates required for economic meltblown production.