| 摘要 |
An apparatus for injection molding two compatible polymeric materials, in which two or more plasticizing zones on a screw are used to simultaneously or sequentially plasticize the two materials into a common accumulation space through separate pathways. The charge comprising multiple layers of material is then injected into a closed mold by means of forward axial motion of the screw with respect to its enclosing barrel. Once inside the mold, the first material forms a skin layer, totally or partially surrounding the other material. In this way a part having a plurality of material properties may be produced in a single operation.
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