CONTROL SYSTEM FOR MACRO ADJUSTMENT OF A POLYMERIC MELT FORMING SLOT TYPE DIE

摘要

A system (100) for adjusting the gap of a slot die for producing a polymer web. The system includes a slot die 10 having a polymer reservoir 10C extending between a polymer inlet 10A and a melt outlet 10B. The melt outlet 10B has a first edge 12A and a second edge 12B each extending longitudinally along the melt outlet 10B. The second edge 12B is opposite the first edge 12A. The plurality of actuators 20 move the second edge 12B along a plurality of positions along the length of the second edge 12B. The first edge 12A is spaced apart from the second edge 12B by a gap GC having an adjustable profile. A pressure sensor 30 communicates with the reservoir 10C and measures the pressure of the polymer in the reservoir 10C. The control unit 60 with the algorithm 60A associates the profile of the gap GC with the pressure in the reservoir 10C. Algorithm 60A is configured to generate control signal 62 such that the profile of the gap becomes uniform.