磨料水射流在大理石切割中的应用

使用石榴石磨料，在高压磨料水射流数控切割机床上，研究了切割参数（压力、靶距、切割速度）对大理石切割性能（切口宽度、切口锥角、余纹角度）的影响．结果表明：切割速度越大，余纹角度越大；压力越大余纹角度越小．靶距对余纹角度影响不大，余纹曲线相互之间大体平行，且不规则；锥角与喷嘴切割速度成正比，与系统压力和靶距成反比，即欲得到较小锥角需采用小的速度，大的系统压力，小靶矩；切割缝隙宽度与压力、速度成反比，与靶矩成正比．     

浆液磨料水射流切割能力试验及切割深度预测模型

为提高浆液磨料水射流切割能力,运用自研的浆液磨料和切割设备,进行混凝土和岩石切割试验,分析切割压力、喷嘴移动速度、材料单轴抗压强度对切割能力的影响。结果表明：相同工况下浆液磨料水射流切割能力远超纯水射流的,混凝土切割深度显著提高,并且材料强度越大,浆液磨料水射流切割能力优势越明显;浆液磨料水射流能够实现对中—硬砂岩的有效切割（0.5～1.0 h内能切割100 mm深,10 m长）,可以应用于煤矿切顶卸压、切顶留巷、工作面夹矸处理等现场工程;射流喷嘴在切割对象同一位置的冲击时间越长,“水垫”作用越明显,相同切割时间内,喷嘴多次快速移动的重复切割比单次慢速移动的切割效率高。通过分析切割实验结果,以切割压力、喷嘴移动速度、材料单轴抗压强度为变量构建切缝深度预测模型,并在此基础上得到重复切割时以切割次数为变量的切割深度预测模型。     

磨料水射流在大理石切割中的应用

使用石榴石磨料,在高压磨料水射流数控切割机床上,研究了切割参数（压力、靶距、切割速度）对大理石切割性能（切口宽度、切口锥角、余纹角度）的影响. 结果表明：切割速度越大,余纹角度越大;压力越大余纹角度越小,靶距对余纹角度影响不大,余纹曲线相互之间大体平行,且不规则;锥角与喷嘴切割速度成正比,与系统压力和靶距成反比,即欲得到较小锥角需采用小的速度,大的系统压力,小靶矩;切割缝隙宽度与压力、速度成反比,与靶矩成正比.     

高压磨料水射流切割低碳合金钢的试验研究

低碳合金钢广泛应用于压力容器、车辆、桥梁等工业设计之中,通过研究高压磨料水射流对低碳合金钢切割的影响,分析水射流切割特性对切割效果的影响,对提高切割效率及降低切割成本具有一定的参考意义。应用五轴联动数控水刀切割机,对低碳合金钢Q345B进行切割试验,分析了切割压力、靶距和横移速度对切割深度及切割宽度的影响。结果表明,随着切割压力增加,切割深度和切割宽度均有所增加;随着靶距的增加,切割深度先增大后减小,存在最佳靶距,可使切割深度最大而切割宽度逐渐增大;随着切割速度增加,切割深度及切割宽度逐渐减小,但其对切割宽度的影响较小。     

磨料水射流切割石材工艺参数的研究

依据实验结果,探讨磨料水射流技术切割石材的机理,分析切割工艺参数对切割深度的影响,并将切割工艺参数优化．     

磨料水射流切割可视化BP神经网络模型研究

针对磨料水射流切割性能与影响因素间存在复杂的非线性关系,无法用传统数学方法建模的问题,基于BP人工神经网络理论,结合典型材料的切割实验结果,在考虑射流压力、磨料流量、切割靶距、工件厚度、磨料喷嘴直径与切割速度6个因素情况下,建立了磨料水射流切割BP神经网络模型.同时,基于Delphi开发出了可移植的磨料水射流切割速度人工神经网络预测单元,实现了所建网络模型的可视化,为实现网络模型与数控系统的集成提供条件.研究结果表明,该网络模型能快速、准确、可靠地预测切割速度,与数控系统相集成可实现对磨料水射流切割质量的有效控制.     

前混合高压磨料水射流对混凝土块的切割试验研究

为了解前混合高压磨料水射流对混凝土等材料的切割能力,使用比较研究法,采用移动切割和固定切割两种切割方式,进行磨料与纯水水射流对混凝土块切割深度对比试验、水砂混合磨料与水和棕刚玉混合磨料水射流对混凝土块的切割深度对比试验、不同水砂比(质量比)的水砂混合磨料水射流对混凝土块的切割深度对比实验,分析改变压力、水砂比、靶距对切割深度的影响,结果表明:前混合高压磨料水射流切割比高压纯水切割效果更加明显,对于不同硬度的混凝土块,磨料水射流切割均有明显优势;当靶距达到1 000 mm时,磨料水射流仍有很强的切割能力。     

微磨料水射流三维加工的实验研究

对微磨料水射流技术三维加工进行了实验研究。实验采用特殊设计的微磨料水射流切割头,水喷嘴内径为127μm,聚焦管内径为300μm,碳化硅固体磨料粒子平均直径25μm。微磨料水射流切割头利用螺杆泵送原理直接将微细磨料主动送入切割头混合腔,通过水射流对磨料粒子加速、混合并经聚焦管喷出形成微磨料水射流。螺杆由步进电机驱动,通过控制步进电机转速来精确控制磨料流量。将切割头置于高精度四轴联动数控平台的刀架上,实现对工件的加工。研究表明,通过改变磨料流量可较好地控制微磨料水射流的能量密度。对特定材料,首先设定走刀速度,改变磨料流量就能获得不同的切割深度,实现微磨料水射流车削、磨削、铣削、雕刻等三维加工。微磨料水射流在半导体材料加工、微型电子机械制造以及光学器件生产上具有广阔应用前景。     

新型混合磨料方式下磨料水射流切割中粒砂岩试验研究

为研究混合磨料方式下磨料水射流切割能力的影响因素和最佳切割参数,通过比较前/后混合方式下的磨料水射流切割优缺点,提出先混合磨料后加压的磨料水射流切割方式,并以中粒砂岩为切割对象,采用正交试验进行研究,结果表明:影响磨料水射流切割能力的主要因素有切割速度、切割压力和切割喷头直径,影响权重由大到小为切割速度、切割压力和切割喷头直径;提出切割速度1 mm/s、切割压力50 MPa、切割喷头直径1.5 mm、切割靶距30 mm、切割磨料河砂与水质量配比为1∶8时,切割能力最强。所得结论可为磨料水射流切割系统在煤矿行业中的应用提供理论支持和参数设置指导。     

高压磨料水加工工程陶瓷机理研究

对高压磨料水切割工程陶瓷机理进行研究,分析工程陶瓷破坏机理及切割动态特性,并通过实验论证切割参数对切割深度的影响。     

磨料水射流喷头的研究

在磨料水射流加工中，喷头性能对加工影响很大．本文对射流喷头进行了结构参数设计和性能实验，得出了动力泵压力P与磨料水射流出口处均匀速度V4和磨料喷嘴直径d4的经验公式．与作者推导的理论公式相比，经验公式更符合实际，可以作为设计喷嘴和调整加工状态的依据．试验还证明了现有计算水喷嘴直径的公式是切实可行的，以及喉管距Lc和混合腔直径d3在一定范围内变化时，其加工状态稳定．     

Longhole waterjet rotary cutting for in-seam cross panel methane drainage

In order to improve the efficiency of gas drainage before and during Iongwall extraction,a waterjet rotary cutting system has been developed for in-seam cross panel methane drainage.The purpose of the water rotary cutting system developed was to create artificial fractures along the gas drainage boreholes.During the design of the system,it was perceived that the nozzle geometry is one of the key factors,affecting cutting capacity.Therefore,we studied the structural and geometric parameters of the nozzle and optimized its performance during laboratory tests and numerical simulation.Underground trials conducted in a coal mine,indicate that production of gas drainage before and after cutting significantly increased by up to three times.The advantages of waterjet assisted gas drainage method has been identified as:1) increasing gas drainage efficiency,2) a possible development of a gas drainage fractured network within coal seams associated with panel extraction,and 3) reducing the risk of exceeding gas limits during longwalling.     

Optimization of abrasive water jet cutting of ductile materials

Full factorial design of experiments was developed in order to investigate the effects of jet pressure, abrasive mixing rate, cutting feed, and plate thickness upon three response variables, surface finish of cutting wear zone, percentage proportion of striation free area, and maximum width of cut. The set of sixteen experiments was performed on each of the following two ductile materials: AISI 4340 (high strength low alloy steel, hardened to 49HRc) and Aluminum 2219. Analysis of Variance (ANOVA) was performed on experimental data in order to determine the significance of effects of different parameters on the performance measures. It was found that cutting feed and thickness were highly influential parameters, while abrasive mixing rate is influential upon surface roughness only. Strong interaction was found between jet pressure and workpiece material. Multi-criteria numerical optimization was performed in order to simultaneously maximize/minimize different combinations of performance measures.     

金刚石厚膜刀具的试验研究

通过聚晶金刚石 (PCD)和CVD金刚石厚膜的特性分析、试验和应用 ,得出金刚石厚膜刀具兼有单晶金刚石和金刚石薄膜涂层优点外 ,更具有精加工和超精加工的优越特性 ,应用前景广阔 .     

车削加工过程中切削力的试验研究

运用DEFORM仿真软件对金属切削过程进行仿真实验,以金刚石为切削刀具,AISI52100淬硬钢为工件材料,采用正交仿真实验分析切削速度、进给量、切削深度对切削力的影响规律,并给出实验范围内的最优加工参数组合,当切削速度vc=120 m/min、进给量f=0.10 mm/r、切削深度为时ap=0.1 mm,切削力达到最小。最后运用回归分析方法建立切削力的经验模型,对得到的经验公式进行显著性检验,证明经验公式的可信性。     

Deformation analysis of transversely isotropic coal-rock mass with porous and cracks

Coal-rock as a typical sedimentary rock has obvious stratification, namely it has transversely isotropic feature. Meanwhile, deformation leads to coal-rock mass having the characteristics of different porous and crack structures as well as local anisotropy. Equivalent axial and circumferential strain’ formulas of the pure coal-rock mass specimen with a single crack were derived through the establishment of equivalent mechanical model of standard cylindrical coal-rock specimen, and have been widely used to a variety of media combined different structures containing multiple cracks. The complete stress strain curve of a real coal-rock specimen was obtained by the CTC test. Additionally, according to the comparison with the theoretical value, the theoretical mechanical model could well explain the deformation characteristics of coal-rock mass and verify its validity. Further, following features were analyzed: strain normalized coefficient and elastic modulus (Poisson’s ratio) in vertical and parallel direction to the stratification, stratification angle, porosity, pore radius, normal and tangential stiffness of crack, and the relationship of different crack width with different tangential stiffness of crack. Through the analysis above, it substantiate this claim that the theoretical model with better reliability reflects the transversely isotropic nature of the coal-rock and the local anisotropy caused by the porous and cracks.     

自由曲面模具磁力研磨的试验研究

基于三杆五自由度并联机床进行了对自由曲面模具磁力研磨的试验研究.实验分析了利用球型磨头对工件磁力研磨时,磁场强度、研磨间隙、磨粒粒度等因素对自由曲面模具表面研磨质量的影响.利用五自由度并联机床不仅可以去除自由曲面模具表面的切削残留痕迹,降低模具的表面粗糙度,还解决了传统手工研磨方式所引起的工件研磨质量不一致的缺陷.拓宽了三杆五自由度并联机床的应用范围.