| 摘要 |
<p>An extrusion die for producing a tubular mesh profile has an annular outlet with an external mechanism involving two annular arrays of sets of blades which can shift radially to block or release the melt outflow. Circumferentially adjacent blades move out of phase so that as one blocks the flow, the other allows it to pass. Used for producing extruded mesh profiles of constant thickness with staggered spacing of successive rows of holes. Compared with mechanisms which intermittently block all the flow necessary to produce the perforated pattern, the die with balanced intervention of two sets of knives allow the process to run at higher throughputs and with a relatively constant die backpressure. Setting/maintenance/replacement of the blades is relatively easy because of their external position on the extruder/die head system.</p> |
