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Single rest rubber extrusion mold

For any extrusion mold, the main point of its design is to ensure that the size and shape of the section of the extruded products meet the design requirements. The main factors affecting the following six aspects: ① any rubber material from the extrusion mold extrusion will occur when different expansion, when the hardness of the rubber material from small to large, the extrusion section of the expansion rate from large to small. ② When the extruder temperature from low to high, the extrusion section expansion rate from small to large. ③ When the extruder speed is low and high, the size of the extruded product section changes from small to large. (4) The expansion rate of the extruded product section is different for different kinds of rubber or different rubber content blends. ⑤ The expansion rate of each part of any extruded product section is not the same, and this is especially true for shaped sections. (6) Different design forms of extrusion molds will have different effects on the shape and size of the extruded product section. Here are some design ideas on one of the above factors.

(1) extrusion mold cavity design thickness

Extrusion mold cavity design of 100 degrees must match the specifications of the extruder. In terms of the current general medium-sized extruder, the effective thickness of the cavity of the withdrawal mold if less than 8mm, the dimensional stability of the extruded section is relatively poor, the gel surface is not smooth. In the production process, the extruder screw speed adjustment fluctuations or feed section size changes will make the extrusion mold cavity pressure fluctuations. The effective thickness of the mold cavity is too small will make this pressure fluctuation effect is not enough to be overcome, the rubber material through the cavity surface extrusion and friction deformation to the extruded product section shape and size, the formation of the "wave extrusion" effect; at the same time, the effective thickness of the cavity is too small will result in the extrusion force is too small, so that the extruded products of density At the same time, the effective thickness of the cavity is too small will cause the extrusion force is too small, so that the density of the extruded products, resulting in the surface is not smooth, burrs, poor conformability, on the other hand, the effective thickness of the extrusion die cavity is too large will also affect the normal assembly with the head of the extruder, and make the mold repair difficulties, so that the debugging cycle is too long. Therefore, for general medium-sized extruder, the effective thickness of the cavity of the monomer rubber extrusion mold can be taken as 10 to 15cm.