A method of making nonwoven webs comprising providing a spinneret including a pattern of conduits forming an extrusion region; directing only a first stream of molten propylene polymer into a region adjacent the first side of the spinneret, directing only a second stream of molten propylene polymer into a region distal to the first side of the spinneret, extruding only the first stream propylene polymer through the exit openings in a first zone where the exit opening comprises exit ports in the first zone having a first density; extruding only the second stream propylene polymer through the exit openings of a second zone where the exit opening comprises exit ports in the second zone having a second density less than the first density; and the second zone is distal to the first side with the first zone being between the second zone and the first side.

A liquefier assembly for use in an extrusion-based additive manufacturing system, the liquefier assembly comprising a downstream portion having a first average inner cross-sectional area, and an upstream having a second average inner cross-sectional area that is less than the first inner cross-sectional area, the upstream portion defining a shoulder configured to restrict movement of a melt meniscus of a consumable material.

In the manufacture of extruded polymers there are a number of surface defects referred to as sharkskin, snakeskin and orange peel which all generally relate to the rheology of the polymer melt. A severe form of surface defect is melt fracture which is believed to result when the shear rate at the surface of the polymer is sufficiently high that the surface of the polymer begins to fracture. That is, there is a slippage of the surface of the extruded polymer relative to the body of the polymer melt. The surface generally can't flow fast enough to keep up with the body of the extrudate and a fracture in the melt occurs generally resulting in a severe loss of surface properties for the extrudate. A polymer extension process is disclosed wherein these undesirable surface defects are eliminated.

A honeycomb extrusion die (120) with improved wear properties. Extrusion die has a die body (121) with inlet (122) and exit (123) faces, feedholes (124) with feedhole entrances (124A) and outlets (124B), and a plurality of die pins (126) having side surfaces (128) configured to define a matrix of intersecting slots (130). At least some of the intersecting slots and die pins define a slot structure with divots (132) formed in the side surfaces of the die pins between the feedholes and the exit face, entrance slot portions between the feedhole outlets and the divots, the entrance slot portions having an entrance slot width W.sub.A, and exit slot portions between the divots and the exit face, the exit slot portions having an exit slot width W.sub.B, wherein W.sub.A>W.sub.B over an entire slot length. Methods of manufacturing honeycomb structures using the honeycomb extrusion dies and of fabricating the extrusion dies are provided as are other aspects.

A sizer for cooling an extrudate, which includes a core and a housing. The core includes an extrusion channel which accommodates the extrudate, a core cooling channel, and a core vacuum channel in fluid communication with the extrusion channel. The housing includes a housing cooling channel and a housing vacuum channel. The core cooling channel is in fluid communication with the housing cooling channel, and the core vacuum channel is in fluid communication with the housing vacuum channel.

A performance of a die is improved. An injection hole IH, a nozzle NZa and a nozzle NZb are formed in a center member DIa of a die DI to extend from an extrusion surface ES to an injection surface IS. A heat source HT and a plurality of heat insulating layers HI1 are arranged inside the center member DIa. One of the plurality of heat insulating layers HI1 is adjacent to the nozzle Nzb and is closer to the extrusion surface ES than the heat source HT. The other of the plurality of heat insulating layers HI1 extends in a direction from the extrusion surface ES toward the injection surface IS at a position being farther from the nozzle NZb than the heat source HT.