淹没磨料射流对金属材料切割性能影响的实验研究

在完全淹没条件下,以Q235号钢板为例,对射流压力、横移速度、靶距、磨料目数、喷嘴型号等主要切割参数进行了考察,分析了这些参数对金属。料切割深度的影响,为水下切割技术提供一些有价值的参考。     

磨料水射流切割混凝土的深度预测模型

在对磨料水射流切割混凝土分析基础上,应用BP人工神经网络理论,建立磨料水射流切割基于射流压力、靶距、磨料粒径、磨料流量、磨料喷嘴直径、磨料喷嘴长度及横移速度等射流参数的深度模型,通过模型预测结果与实验结果的比较,验证模型具有一定的精度,为实际运用和进一步研究提供参考。     

微通道反应器沟槽底面的磨料水射流抛光研究

针对燃料电池微通道反应器的沟槽底面抛光技术难题,开展磨料水射流沟槽抛光仿真与试验研究.采用FLUENT软件,对不同工艺参数下沟槽底部剪切力分布进行了数值模拟;根据仿真结果进行316L不锈钢材料的单沟槽抛光工艺试验,检测分析不同抛光参数下单沟槽底面形貌、材料去除率以及表面粗糙度的变化规律;根据单沟槽底面几何精度和表面粗糙...     

Depth of cut models for multipass abrasive waterjet cutting of alumina ceramics with nozzle oscillation

An experimental study of the depth of cut in multipass abrasive waterjet (AWJ) cutting of alumina ceramics with controlled nozzle oscillation is presented. It is found that this cutting technique can significantly increase the depth of cut by an average of 50.8% as compared to single pass cutting without nozzle oscillation under the corresponding cutting conditions and within the same cutting time. Predictive models for the depth of cut are then developed. The modelling process starts with single pass cutting using a dimensional analysis technique and the particle erosion theories applied to alumina ceramics, before progressing to the development of the models for multipass cutting. The models are finally assessed both qualitatively and quantitatively with experimental data. It is shown that the model predictions are in good agreement with the experimental data with the average deviations of about 1%.     

Modeling surface roughness for polishing process based on abrasive cutting and probability theory

The surface roughness is a variable used to describe the quality of polished surface. This article presents a surface roughness model based on abrasive cutting and probability theory, which considers the effects of abrasive grain shape, grit and distribution feature, pressure on surface roughness. The abrasive grain protrusion heights are thought to close to Gaussian distribution, and then the relationship between the indentation depth and the pressure based on Hertz contact theory is obtained. Surface roughness prediction model is established by calculating indentation depth of the abrasive grains on workpiece surface. The maximum surface profile height (R_y) is approximately equal to the maximum indentation depth of the abrasive grain. The arithmetic average surface roughness (R_a) is equal to the average indentation depth of the abrasive grain. The effects of process parameters such as pressure and grit on R_y and R_a were simulated and analyzed in detail.     

A study on the use of single mesh size abrasives in abrasive waterjet machining

This paper details the studies on the use of single mesh size garnet abrasives in abrasive waterjet machining for cutting aluminum. The influence of three different single mesh size abrasives, pressure, traverse rate, and abrasive flow rate; on depth of cut, top kerf width, bottom kerf width, kerf taper, and surface roughness are investigated. Experiments designed using standard L9 orthogonal array and the analysis of variance helped in the determination of highly significant, significant and weakly significant cutting parameters. Single mesh size abrasives are found to yield decreased surface roughness than multi mesh size abrasives. Based on these studies, response equations are developed to predict the target parameters. Using single mesh abrasives, a practitioner not only can cut faster but also achieve reduced surface roughness.     

磨料水射流加工工程陶瓷工艺参数对加工效率的影响

研究用磨料水射流加工工程陶瓷，通过分析各工艺参数对加工效率的影响，提出了一种优选工艺参数的方法。     

固着磨料加工碳化硅反射镜的材料去除率及表面粗糙度的理论研究

本文基于固着磨料加工碳化硅反射镜的微观作用原理，理论上定量分析探讨了金刚石磨料压入碳化硅工件的深度对材料去除率、光学元件表面粗糙度的影响，分别获得了材料去除率数学模型及粗糙度的仿真计算结果。通过去除率及粗糙度的实验与理论模型的对比结果来看，实验值虽与理论值有偏差，但基本稳定在同一数量级内，由此验证了理论分析的正确性。固着磨料工艺的这一易于理论预测的特性对实际的光学加工有着极为重要的意义，因此这种较为新颖的固着磨料工艺在碳化硅反射镜加工领域内有着广阔的应用前景。     

铝合金高速切削表面粗糙度的实验研究

使用硬质合金刀具对LY12高强度铝合金进行了高速精密切削试验。研究了切削条件、切削用量对加工表面粗糙度的影响。高速切削试验表明:提高切削速度与减小进给量有利于改善铝合金工件的加工表面质量;当切削速度超过某一范围后,随着切削速度的进一步提高,加工表面粗糙度的降低并不明显。     

Dependence of the surface roughness on the cutting energy in abrasive superfinishing

The roughness of the machined surface is considered in relation to the cutting energy in superfinishing. The cutting energy is a generalized characteristic of superfinishing and depends in a complex manner on numerous factors.     

利用摩擦学系统理论对磨粒流加工过程的分析

简介当前磨粒流加工技术的现状,得到了磨粒流和工件表面的摩擦以及导致的材料去除是该加工过程的核心问题.利用摩擦学系统理论,构建了针对磨粒流-工件表面的摩擦学系统框架,得到了系统的主要结构元素、元素的特性和相互之间的关系.归纳了磨粒流加工过程中材料去除的摩擦学机理,并讨论摩擦学机理与该摩擦学系统的关系,对从摩擦学角度认识磨...     

Effects of cutting fluids on drilling aluminium casting alloy 390

The primary objective of this research project was to compare the tool wear resulting when a semi-synthetic cutting fluid was used, to that from use of a premium soluble oil. The secondary objective was to determine the effects of cutting speed, drill diameter, and fluid concentration, on tool wear. The experiments contained two key elements: (1) cast aluminium alloy 390 was used as the workpiece material and (2) deep-hole drilling to a depth greater than two diameters was performed. Numerous drilling tests were performed with each cutting fluid using a flood application. To meet the primary objective, an experiment was designed for each cutting fluid and the wear on the lands of twist drills was measured. The secondary objective utilized a statistically-designed 2³ factorial experiment which evaluated the effects that moderate and relatively high cutting speeds, two drill diameters, and two levels of fluid concentration, had on tool wear. After analysis of the test results, it was concluded that concentration had the most significant effect on land wear when the experimentally-formulated semi-synthetic cutting fluid was used. Cutting speed was the most significant factor when drilling with the commercially-available premium soluble oil. Tool wear while using the semi-synthetic fluid was slightly less than that for the premium soluble oil.     

Influence of cutting fluids on surface finish of holes drilled into aluminium 390

The primary objective of this research was to compare the surface finish resulting when using a semi-synthetic cutting fluid to that of a premium soluble oil. The secondary objective was to determine the effects of drill diameter, cutting speed, and fluid concentration on surface finish. The surface measurements were made on the walls of 6.350 and 9.525 mm lind holes drilled 25.4 mm into aluminium 390. Each cutting fluid was introduced using a flood application. Additional factors in the experimental design for each cutting fluid included two levels of cutting speed and two levels of fluid concentration. Variations in drill diameter, cutting speed, and the interaction between these factors were significant with respect to surface finish for both the semi-synthetic fluid and the soluble oil. Fluid concentration for the semi-synthetic fluid also had a significant effect on the surface finish. The surface finish produced while using the semi-synthetic fluid was approximately the same as that with the soluble oil.     

高速铣削过程中表面粗糙度变化规律的试验研究

在高速铣削试验的基础上 ,研究分析切削速度与进给量对加工表面粗糙度的影响。试验数据表明 ,切削速度的提高有利于改善加工表面粗糙度 ,当切削速度超过某一范围后 ,随切削速度的进一步提高 ,加工表面粗糙度的降低并不明显 ,有时还会使表面粗糙度增加。根据试验结果 ,对具体工件材料与刀具材料匹配选择合理的切削速度与进给量范围 ,可以获得最小加工表面粗糙度值     

磨料射流切割钻杆的喷嘴设计

在高含硫油气田中,为避免剪切闸板发生硫化物应力腐蚀开裂,采用前混合磨料射流替代剪切闸板切割钻杆.将S135钻杆51/2″作为研究对象,选取圆锥带圆柱段型喷嘴.通过分析磨料粒子在喷嘴内的加速过程,对喷嘴的结构参数进行了系统研究,得出啧嘴的加速性能和收敛性能达到最佳时的具体结构尺寸.并且计算出磨料颗粒与钻杆材料接触时的最大剪应力,校核了设定参数在理论上的可行性.     

Effects of area discontinuity at nozzle inlet on the characteristics of self-resonating cavitating waterjet

The current research on self-resonating cavitating waterjet(SRCW) mainly focuses on the generation mechanism and structure optimization. Researches relating to the influences of disturbances at nozzle inlet on the characteristics of the jet are rarely available. In order to further improve the performance of SRCW, effects of area discontinuity(enlargement and contraction) are experimentally investigated using three organ-pipe nozzles. Axial pressure oscillation peak and amplitude as well as aggressive erosion intensity of the jet are used to evaluate the effects. The results reveal that area enlargement and contraction affect the peak differently, depending on the inlet pressure, nozzle geometry, and standoff distance; while area contraction always improves the amplitude regardless of these factors. At inlet pressures of 10 MPa and 20 MPa, area discontinuity improves the peak at almost all the testing standoff distances, while this only happens at smaller standoff distances with the inlet pressure increased to 30 MPa. The capability of area discontinuity for improving the amplitude is enhancing with increasing inlet pressure. Moreover, the cavitation erosion ability of the jet can be largely enhanced around the optimum standoff distance, depending on the type of area discontinuity and nozzle geometry. A preliminary analysis of the influence of area discontinuity on the disturbance waves in the flow is also performed. The proposed research provides a new method for effectively enhancing the performance of SRCW.     

铝合金高速切削表面粗糙度影响因素研究

为有效降低高速切削中铝合金的表面粗糙度值,通过多因素正交试验和单因素试验对各铣削参数进行研究,结果显示:各参数对铝合金表面粗糙度影响程度从大到小的顺序是:切削深度、主轴转速、每齿进给量、行距,且转速为18000r/min,每齿进给量为0.075mm,行距和每齿进给量一致,选择较小的切削深度时,在铝合金表面可获得较好的加工质量。     

Optimization of machining parameters in the abrasive waterjet turning of alumina ceramic based on the response surface methodology

A study on the radial-mode abrasive waterjet turning (AWJT) of 96 % alumina ceramic is presented and discussed. An experimental investigation is carried out to explore the influence of process parameters (including water pressure, jet feed speed, abrasive mass flow rate, surface speed, and nozzle tilted angle) on the material removal rate (MRR) when turning 96 % alumina ceramic. The experiments are conducted on the basis of response surface methodology (RSM) and sequential approach using face-centered central composite design. The quadratic model of RSM associated with the sequential approximation optimization (SAO) method is used to find optimum values of process parameters in terms of surface roughness and MRR. The results show that the MRR is influenced principally by the water pressure P and the next is abrasive mass flow rate m _a . The optimization results show that the MRR can be improved without increasing the surface roughness when machining 96 % alumina ceramic in the radial-mode abrasive waterjet turning process.     

影响铸铝合金ZL108切削力主要因素分析

为了获得合理的利用YG8刀具加工铸铝合金ZL108的切削参数,建立一个4水平5因素的正交实验对影响ZL108切削力主要因素进行了切削实验,并采用极差分析的方法对实验结果进行分析。依据实验分析结果,确定了加工ZL108时采用的合理的削用量和刀具角度参考值。     

MQL平面磨削参数的分析与优化

在最小量润滑(minimum quantity lubricant)方式下,通过磨削区的有效流体流量及磨削区产生的流体动压力对加工参数、砂轮及工件都会产生影响,很多参数需要校正优化.为了获得较高的加工质量、优化的参数和较低的成本,应用了正交设计法、信噪比分析法和方差分析法.