The use of a single-screw extruder with poor mixing results can make the two colorants mixed unevenly, thereby forming irregular lines. The length-to-diameter ratio of the single screw extruder cannot be too large, otherwise the mixing and plasticizing ability is improved, so that the two color materials are completely mixed, and no lines can be seen.
The perforated plate at the junction of the machine head and the barrel can be used or not. If not, a transition ring can be used directly to obtain a thicker texture. Or use perforated plates with different opening ratios or different pore sizes to achieve different effects of dense and dense lines.
Due to the different mold structures of different profiles, the patterns formed are also different. There are continuous, sometimes intermittent, and V-shaped or U-shaped. Even the repeatability of the same mold profile is poor.

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