【摘要】：微細(xì)銑削技術(shù)具有高度柔性化,加工材料多樣化,加工效率高,加工精度高等優(yōu)點(diǎn),是微小型零件尤其是復(fù)雜結(jié)構(gòu)零件的有效加工方法之一。然而,微細(xì)銑削在加工高溫合金、結(jié)構(gòu)陶瓷和復(fù)合材料等難加工材料過(guò)程中,存在刀具磨損嚴(yán)重,加工表面質(zhì)量差,加工效率低和加工成本高等問(wèn)題。激光加熱輔助加工通過(guò)在切削前局部加熱待加工材料,降低工件材料的硬度和剪切強(qiáng)度,提高硬脆性材料的延展性,能夠有效的改善材料的切削性能。激光加熱輔助微細(xì)銑削技術(shù)將微細(xì)銑削和激光加熱輔助加工的優(yōu)點(diǎn)結(jié)合起來(lái),通過(guò)合理的選擇激光參數(shù)和切削參數(shù),可以獲得較好的加工效果。本文基于有限元軟件對(duì)脈沖激光加熱輔助微細(xì)銑削的溫度場(chǎng)和微細(xì)銑削過(guò)程進(jìn)行仿真研究,分析了激光參數(shù)對(duì)溫度場(chǎng)分布的影響以及溫度場(chǎng)分布對(duì)微細(xì)銑削過(guò)程的影響,具體工作如下:(1)分析激光加熱過(guò)程中激光與工件之間的熱交換過(guò)程,建立傳熱模型并利用有限元軟件求解。對(duì)脈沖光纖激光器熱源的光源特性進(jìn)行分析,建立脈沖激光熱源模型。(2)利用溫度場(chǎng)有限元仿真模型,分析激光光斑直徑、激光掃描速度和單脈沖能量等激光參數(shù)對(duì)溫度場(chǎng)分布的影響。對(duì)比分析有限元仿真結(jié)果與前期開(kāi)發(fā)的仿真軟件計(jì)算結(jié)果,分析模型簡(jiǎn)化與計(jì)算方法對(duì)仿真結(jié)果的影響。采用紅外熱像儀測(cè)量激光加熱工件的表面溫度,結(jié)果表明試驗(yàn)值與仿真值變化趨勢(shì)相同。(3)簡(jiǎn)化微細(xì)銑削過(guò)程建立二維切削模型,分析切削變形過(guò)程原理以及切削熱的產(chǎn)生。針對(duì)Ti6Al4V鈦合金材料選擇合適的仿真參數(shù),對(duì)比激光加熱輔助微細(xì)銑削與微細(xì)銑削的仿真結(jié)果,最大應(yīng)力降低了約30%,切深抗力降低了約57%,主切削力降低了約20%,說(shuō)明激光加熱材料能夠改善難加工材料的切削性能,仿真結(jié)果表明Ti6Al4V鈦合金的適宜切削溫度為400℃左右。
[Abstract]:Micro milling technology has many advantages, such as high flexibility, diversification of machining materials, high machining efficiency and high machining accuracy. It is one of the effective machining methods for micro parts, especially complex structural parts. However, in the process of machining superalloys, structural ceramics and composites, there are some problems, such as serious tool wear, poor machining surface quality, low machining efficiency and high machining cost. Laser heating assisted machining can effectively improve the cutting performance of the material by heating the material to be machined locally before cutting, reducing the hardness and shear strength of the workpiece material, and improving the extensibility of the hard and brittle material. Laser heating assisted micro milling technology combines the advantages of micro milling and laser heating auxiliary machining, and good machining effect can be obtained by reasonably selecting laser parameters and cutting parameters. In this paper, the temperature field and micro-milling process of pulse laser heating assisted micro-milling are simulated based on finite element software. The influence of laser parameters on temperature field distribution and the influence of temperature field distribution on micro-milling process are analyzed. The concrete work is as follows: (1) the heat exchange process between laser and workpiece in laser heating process is analyzed, and the heat transfer model is established and solved by finite element software. The light source characteristics of pulse fiber laser heat source are analyzed, and the pulse laser heat source model is established. (2) the effects of laser spot diameter, laser scanning speed and monopulse energy on the temperature field distribution are analyzed by using the finite element simulation model of temperature field. The finite element simulation results are compared with those of the previously developed simulation software, and the influence of model simplification and calculation method on the simulation results is analyzed. The surface temperature of laser heated workpiece is measured by infrared thermal imager. The results show that the experimental value is the same as the simulated value. (3) the two-dimensional cutting model is established by simplifying the micro-milling process, and the principle of cutting deformation process and the generation of cutting heat are analyzed. According to the selection of appropriate simulation parameters for Ti6Al4V titanium alloy materials, compared with the simulation results of laser heating assisted micro milling and micro milling, the maximum stress is reduced by about 30%, the cutting depth resistance is reduced by about 57%, and the main cutting force is reduced by about 20%, which indicates that the laser heating material can improve the cutting performance of refractory materials. The simulation results show that the suitable cutting temperature of Ti6Al4V titanium alloy is about 400 鈩，

本文編號(hào)：2504627