8.3.1 Numerical Control (NC)
?Numerical control has also made machine tools more
versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide variety of parts, each involving an assortment of widely varied and complex machining processes.
?具有数控的机械设备比之前手工操作的设备功能
更多，一台NC机械设备可以自动生产各类零件，每一种都涉及到各种复杂工艺的一种分类
?
Assortment 混合物 ；分类
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8.3.1 Numerical Control (NC)
?Numerical control has allowed manufacturers to
undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tools and processes.
?数控可以使制造者生产一种产品，从经济的角
度来看，这种产品是不可能利用手工控制设备及工艺生产出来的。
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?Question p113）（
8.4 solid freeform fabrication (SFF) methods 快速原型制造方法
?Several manufacturing processes are available to
make the important transition from computer aided design (CAD) to a prototype part. Several new technologies began to make their appearance after1987.
?一些制造工艺可以将CAD转变为原型零件。1987
年后，一些新技术开始出现。
Assortment 混合物 ；分类
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?
8.4 solid freeform fabrication (SFF) methods 快速原型制造方法
?In that year, stereolithography (SLA) was first
introduced by 3D Systems Inc., and over the next five years several rival methods also appeared. This created the family of processes known as solid freeform fabrication (SFF). SFF processes are sometimes described as:
?立体层叠扫描首次有3D系统公司发明。在其后的5年里，相继出现了其它几种具有竞争性的方法。快速原型制造工艺由此建立。SFE工艺有时被描述为：
?
Assortment 混合物 ；分类
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