phases.
1.1.2.1 Filling
The clamp unit keeps the empty mold closed. The screw moves forward as a ram
and forces the melt into the mold cavity.
1.1.2.2 Packing
When the mould is filled, the screw is held in the forward position or moves with a
small displacement to maintain a holding pressure, during which time the material
cools down and shrinks, allowing a little more material to enter the mold to
compensate for volumetric shrinkage of the material. The packing phase is also
called the holding phase.
1.1.2.3 Cooling
At some stage of packing, the gates have completely frozen. Eventually the cavity
pressure is reduced to zero or a low value. The part continues to cool down and to
solidify. Meanwhile, the screw starts rotating and moving backward, and the next
plasticizing stage takes place.注塑成型
注塑成型，是通过模具来生产同种产品的一个循环过程，是应用最广泛的高分子加工操作。这个过程的主要优势是以高生产率来重复制造具有复杂的几何图形的零件的能力。
论文网1.1.1    注塑机
注塑机的历史可以追溯到由凯悦兄弟发明的包装机，他们在1872年获得了美国专利发明塑化樟脑硝酸纤文的模具机器。这台机器包含了一个可将塑料注入模具加热缸的基本柱塞。活塞式设备于1946年被螺杆注射机所取代。从那时起，致使往复式螺杆注塑机随着一步步的改进下沿用到现在。图1.1为一个典型的往复式螺杆注塑机。主要是它包含两个不同的单位，注射单元通常由两部分组成，即进料卡、旋转螺杆和加热筒的部分以及包含模具的夹紧装置。注塑机的更多细节由约翰在1994年被发现。
模具注塑成型英文文献和中文翻译(6):http://www.751com.cn/fanyi/lunwen_17300.html