Aqtvlxl机械制造及自动化毕业设计外语文献翻译(6)

Aqtvlxl机械制造及自动化毕业设计外语文献翻译

cutting. Their machinability is generally similar to that of thermoplastics.

Because of the fibers present, reinforced plastics are very abrasive and are

difficult to machine. Fiber tearing, pulling, and edge delamination are significant problems; they can lead to severe reduction in the load-carrying capacity of the component. Furthermore, machining of these materials requires careful removal of machining debris to avoid contact with and inhaling of the fibers.

The machinability of ceramics has improved steadily with the development of nanoceramics (Section 8.2.5) and with the selection of appropriate processing

parameters, such as ductile-regime cutting (Section 22.4.2).

Metal-matrix and ceramic-matrix composites can be difficult to machine,

depending on the properties of the individual components, i.e., reinforcing or

whiskers, as well as the matrix material.

20.9.4 Thermally Assisted Machining

Metals and alloys that are difficult to machine at room temperature can be

machined more easily at elevated temperatures. In thermally assisted machining (hot machining), the source of heat—a torch, induction coil, high-energy beam (such as laser or electron beam), or plasma arc—is forces, (b) increased tool life, (c) use of inexpensive cutting-tool materials, (d) higher material-removal rates, and (e) reduced tendency for vibration and chatter.

It may be difficult to heat and maintain a uniform temperature distribution within the workpiece. Also, the original microstructure of the workpiece may be adversely affected by elevated temperatures. Most applications of hot machining are in the turning of high-strength metals and alloys, although experiments are in progress to machine ceramics such as silicon nitride.

SUMMARY

Machinability is usually defined in terms of surface finish, tool life, force and

power requirements, and chip control. Machinability of materials depends not only on their intrinsic properties and microstructure, but also on proper selection and control of process variables.

译文：

20.9 可机加工性

一种材料的可机加工性通常以四种因素的方式定义：