Implications for high-speed milling of thin-walled parts 薄壁结构件高速铣削

2010-10-13 17:33:13 作者:huright 来源: 浏览次数:0

It is essential to establish that thin-walled products are the weaker elements in all the important phenomena that a®ect milling accuracy: ² they are more prone to distortion due to residual stresses, ² they bend more easily, ² they vibrate more easily. The next subsections will go deeper into how these in°uences for high-speed milling of thin-walled products di®er from traditional milling. Residual stresses Thin-walled products will be more prone to distortion due to residual stresses. According to Marusich & Askari, the machining-a®ected layer - in which the residual stresses occur - is on the order of 1 mm for Al7050; on the same length scale as the wall thickness of aerospace structures can be [Marusich & Askari 2001]. Marusich & Askari did not use high-speed machining, in which the cutting forces will generally be lower than when using a traditional milling process. Regardless, these stresses pose a problem in practice. Bending For conventional products, the cutter will usually be bending far more than the workpiece. When machining thin walls, the workpiece geometry may be the weaker of the two, or both workpiece and cutter may bend. This is all very dependent upon the momentary state of the workpiece being machined. Vibrations The resulting products (and thus intermediate workpiece forms) are more °exible than traditional milled products. This makes them bend more easily, and it makes them also vibrate more easily. Especially during ¯nishing passes - when a workpiece portion is already thin - there is a risk of excessive vibrati关键是要确立,薄壁产品,是所有元素较弱 
一个重要现象®等铣削精度: 
²他们更容易变形,由于残余应力, 
²他们更容易弯曲, 
²他们更容易地震动。 
下一小节将深入探讨如何在° uences这些高速铣床 
薄壁产品从传统铣床迪®呃。 
残余应力 
薄壁产品将更加容易变形,由于残余应力。 
到Marusich与阿斯卡里,机加工,一® ected层 - 其中的残余应力发生 
- 是在1毫米为Al7050秩序;在同一尺度的壁厚 
航空航天结构可以是[Marusich与阿斯卡里2001]。 Marusich与阿斯卡里并没有 
使用高速切削,切削力其中一般低于当 
使用传统的铣削加工。无论如何,这些压力造成在实践中的问题。 
弯曲 
对于常规产品,刀具通常会远远超过工件弯曲多。 
在加工薄壁工件的几何形状可能是较弱的两个,或 
工件和刀具都可以弯曲。这一切都非常依赖于一时 
对被加工工件的状态。 
振动 
(和因此中间工件形式)产生的产品比更° exible 
传统的研磨产品。这使得它们更容易弯曲,这让他们也 
振动更容易。特别是在¯ nishing传递 - 当一个工件部分 
已经瘦 - 有一个过度振动的风险。


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