lesson 11

• Anneal • To subject metal or alloy to a process of heating and slow cooling in order to toughen and reduce brittleness.
• 退火：将金属或合金加热到适当温度，并使之缓慢冷却以 增强其韧性并减少脆性的热处理工艺。 • Assembly • The putting together of manufactured parts to make a completed product, such as a machine or an electronic circuit • 装配：将生产出的零件装配在一起使之成为一个完整产 品，如机器或电子线路。
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• Composite • A complex material in which two or more distinct, structurally complementary substances, especially metals, ceramics, glasses, and polymers, combine to produce structural or functional properties not present in any individual component
Lesson 11 Machine Tool Frames
• Terminology
• Text tour
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• Terminology
• Cast iron • A hard, brittle, nonmalleable iron-carbon alloy, cast into shape, containing 2 to 4.5 percent carbon, 0.5 to 3 percent silicon, and lesser amounts of sulfur, manganese, and phosphorus • 定的形状 的铁碳合金，含有2%至4.5%的碳、0.5%至3%的硅和少量 的硫、锰和磷
3. high-volume 意为“大批量的”。全句可译为： 小尺寸，大批量的机床通常采用铸铁机架，因为它们可以 很容易地分担铸模的成本。
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Advanced forms of these materials, including those with polymer, metal, and ceramic matrices, may change machine tool design dramatically. Both matrix and reinforcing material can be tailored to provide strength in specific axes.[4]
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Although cast iron is a fairly cheap material, each casting requires a pattern.[2] Larger sizes are a limiting factor because of pattern cost, problems with bolted joints, and the need to anneal castings, which is difficult and costly with larger sections. Smaller, high-volume machines usually have cast iron frames because they more easily absorb pattern cost.[3] 2. pattern 在这里指“铸模”。全句可译为： 尽管铸铁比较便宜，但每个铸件都需要有一个铸模。
• 复合材料：由两种或多种不同的，在结构上能互补的物质， 特别是金属、陶瓷、玻璃、高分子材料组合生成的与任何 单独材料都不同的具有新结构或功能的材料。 • Frame • A structure that gives shape or support • 框架：使成形或起支撑作用的结构
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Figure 11.1 A machine tool frame and a FEA model
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Text tour
The material must resist deformation and fracture. Hardness must be balanced against elasticity. The frame must withstand impact, yet yield under load without cracking or permanently deforming.[1] The frame material must eliminate or block vibration transmission to reduce oscillations that degrade accuracy and tool life. 1. cracking or permanently deforming 意为“裂纹或永久变 形”。此句与后面一句可译为：机架必须能够承受冲击，在 载荷作用下不产生裂纹或永久变形。机架材料必须能够消除 或阻碍振动的传递，从而提高加工精度和刀具寿命。
4. reinforcing material 意为“增强材料”。全句可译为： 可以使基体和增强材料在某一个指定的轴线方向上具有所需 要的强度。 Foundations ensure the machine’s stiffness; shock absorption and isolation are secondary considerations.[5] If the machine isn’t stiff enough, the foundation may have to supply the stiffness necessary. 5. shock absorption 意为“减震”。全句可译为： 基础应该保证机器的刚度，减震和隔离是次要的考虑事项。
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Each frame face should be solid, but the machine needs openings for assembly and maintenance. The designer balances aperture number and size against stiffness and strength requirements.[6] 6. 全句可译为：设计人员权衡考虑检测孔的数量和尺寸与刚 度和强度要求之间的关系。 Heat from external or internal sources can be a major cause of error if the frame distorts. External sources include ambient shop conditions, cooling and lubricating media, and the sun.[7] 7. external source 这里指“外部热源”。全句可译为： 外部热源包括车间的环境条件，冷却剂与润滑剂和阳光。