【作者】 李连荣；

【导师】 唐焱；

【作者基本信息】 桂林电子科技大学 ， 机械设计及理论， 2009， 硕士

【摘要】 具有“冷、软”加工特性的磨料水射流切割技术以其独特的工艺优势在现代切割工业中占有越来越重要的地位。由于固液两相射流自身的“柔性”特点,加工质量和效率受工艺实现过程相关因素波动的影响较为明显,特别是在切割厚度增大时,切口锥度、断面波纹等工艺缺陷趋于严重。目前,磨料水射流切割工艺应用研究集中于提高精度和效率两个方向,本课题正是在此背景下提出,探索在现有加工条件下实施大厚度材料高效切割并保证一定表面质量的有效途径。课题研究主要手段和过程包括:(1)以行业发展现状为依据,在工艺理论上分析研究大厚度材料磨料水射流切割中存在的缺陷及其生成原因,在切割机理、射流结构特性、磨粒受力及运动规律、关键技术等方面寻求解决方法;(2)制订合理工艺参数组合,设计切割正交试验,对45号钢和大理石作为塑性、脆性两种材料的典型代表进行切割试验。采集实际参数,对射流压力、切割速度、靶距和磨料体积浓度等主要参数进行四因素四水平极差正交直观分析,获得影响因素的主次顺序以及最优化参数组合。对所采集的实验数据进行回归分析,确定切割深度、切割质量方程;(3)基于FLUENT工程流体分析软件,对磨料水射流的内外流场进行数值模拟仿真分析,为喷嘴结构参数改进、工艺参数优化提供理论依据;(4)在前面研究的基础上,提出适合大厚度材料加工的磨料水射流切割改进设备的总体设计方案。对目前影响加工效率和质量的关键部件如喷嘴组件、磨料供给装置等进行改进设计,为仿真结果的试验验证创造条件;(5)综合工艺参数、设备、环境等影响因素,提出适合大厚度材料加工的前混合磨料水射流切割工艺参数优化组合并进行相关试验验证。本文从理论分析、实验研究、数值模拟、结构改进设计和工艺参数优化多角度对大厚度材料磨料水射流切割工艺进行了深入研究。结果表明,对现役加工设备进行适应性局部改进和参数组合优化,切割效率可提高50%左右,且加工质量明显改善。我国面临针对性新型设备开发,本研究拓展了磨料水射流切割技术的应用领域,并为其市场推广提供了有效的技术支持。更多还原

【Abstract】 The abrasive water jet cutting technology with“cold, soft”processing char-acteristics occupies an increasingly important position for its unique technical pre-dominance in the modern cutting industry .As the solid-liquid two-phase jet own“?exible”characteristics, related-factors ?uctuations in technology implementationprocedure more obviously in?uence the machining quality and e?ciency. Especiallywith increases of cutting thickness, defective workmanship such as cut taper and cross-section corrugation become badly serious.At present, applied research on abrasive water jet cutting technology fastens onimproving cutting precision and e?ciency in both directions.The subject matter israised in this foregoing context, exploring an e?ective way in the existing processingconditions to ensure high-e?ciency cutting and certain processing quality aiming atheavy-section materials. The main measure and process of this research subjects areas follows:(1)Based on the status quo of the industrial development, cutting defects in pro-cess of abrasive water-jet machining heavy-section materials and the generated reasonsare theoretically analyzed. A solution is quested in aspects of cutting mechanism, jetstructure and its speciality, the regularity of abrasive stress and movement , the keytechnology and etc.(2)A rational combination of technological parameters is implemented, orthog-onal cutting experiment is designed, and cutting marble and 45 steel plate on behalfof both plastic materials and hard brittle materials are experimentized.Then, the mainactual parameters such as jet ?uid pressure,cutting velocity , target-distance and abra-sive volumetrical concentration ,are collected and orthogonally analyzed with regardto four factors and levels,to acquire primary and secondary sequence about in?uencingfactors and to optimize the combination of parameters.In turn, regression analysis onthe experimental datum are proceeded, which to consequently ensure cutting depthand quality equations.(3)Based on FLUENT-engineering ?uid analyzing software, numerical simulationis analyzed on abrasive water jet in internal-external ?ow field, which to provide atheoretical basis to improve the structural parameters of the nozzle and to optimizeprocessing parameters.(4)Based on the previous study, the overall design scheme to improve abrasivewater jet cutting equipment suitable for processing heavy-section materials. Thenimproved design of existing key parts such as the nozzle unit and the abrasive feedwayimpacting on machining e?ciency and quality is made, which to create conditions in order to test and verify the simulation results.(5)Comprehensively considered technology parameters, equipment, and envi-ronmental factors,the optimized process-parameters combination is provided suitablefor pre-mixed abrasive jet cutting heavy-section materials,and coherent experimentalverification is carried out.This article profoundly researches on abrasive water-jet cutting technology in sev-eral points of view, such as theoretical analysis, experimental study, numerical simula-tion, structural design and technological parameters optimization. The results showedthat adaptively improving local active-service process equipment and optimizing thecombination of process parameters may advance the abrasive water jet cutting e?-ciency by 50﹪, and also improve the processing quality. China is faced on a newtype of targeted-devices exploitation. So this study extends the application field of thetechnology and marketing to provide a e?ective technical support.更多还原