dimensions , and properties. This is achieved by means of a transformation process: extrusion, molding, calendering , coating , thermoforming , etc. The process, in order to achieve the above objective, usually involves the following operations: solid transport , compression, heating, melting, mixing, shaping, cooling, solidification, and finishing . Obviously, these operations do not necessarily occur in sequence, and many of them take place simultaneously.

在其最一般的情况下，聚合物加工涉及固体（有时侯是液体）聚合物树脂以一种不规

则的形式（例如粉末、颗粒、珠子）转化成一种具有特殊形状、尺寸和性能的固体塑料产品。这借助于转换加工：挤出、模塑、压延、涂敷、热成型等。为了获得上述目的，加工通常涉及下述操作：固体输送、压缩、加热、混合、成型、冷却、固化并完成。显然，这些操作不必按序发生，而许多可以同时发生。

Shaping is required in order to impart to the material the desired geometry

and dimensions. It involves combinations of viscoelastic deformations and heat transfer, which are generally associated with solidification of the product from the melt. 成型是为了给予材料所需要的几何形状和尺寸。它涉及粘弹形变和热传递，这种粘弹形变和热传递是和产品从熔体的固化（或冷却）相联系的。

Shaping includes : (1) two-dimensional operations , e.g. dieforming,

calendering and coating , and (2) three-dimensional molding and forming operations. Two-dimensional processes are either of the continuous , steady state type )e.g. film and sheet extrusion , wire coating , paper and sheet coating ,calendering ,fiber spinning , pipe and profile extrusion , etc. ) or intermittent as in the case of extrusions associated with intermittent extrusion blow moulding. Generally, moulding operations are intermittent, and, thus, they tend to involve unsteady state conditions. Thermoforming, vacuum forming, and similar processes may be considered as secondary shaping operations, since they usually involve the reshaping of an already shaped form. In some cases, like blow molding, the process involve primary shaping (parison formation) and secondary shaping (parison inflation ).

成型包括：（1）二元操作，例如，口模成型、压延和涂敷，（2）三元的模型和成型操

作。二元的操作要么是连续的，固定形状（例如薄膜和板材，电线涂布，纸和平面涂布，