Investigation of process parameters influence in abrasive water jet cutting of D2 steel

In the present experimental study, abrasive water jet (AWJ) cutting tests were conducted on D2 steel by different jet impingement angles and abrasive mesh sizes. The experimental data was statistically analyzed using the simos–grey relational method and ANOVA test. In addition, the outcome of influencing cutting parameters, namely jet pressure, jet impingement angle, and abrasive mesh size on the different response parameters, namely, the jet penetration, material removal rate, taper ratio, roughness, and topography, were studied. Micro-hardness test and surface morphology analysis were employed to examine the D2 cut surfaces at different AWJ cutting conditions. The chemical element study was performed to determine the abrasive particle contamination in the AWJ kerf wall cut surfaces. The ANOVA test result indicated the jet pressure and jet impingement angle as the influencing process parameters affecting the various performance characteristics of AWJ cutting. The overall AWJ cutting performance of the D2 steel has been improved through proper identification of the optimal process parameter settings, namely jet pressure 225?MPa, abrasive mesh size #100, and jet impingement angle 70° by the simos–grey relational analysis.     

前混合磨料水射流切割技术在诱导顶板垮落中的应用

对前混合磨料水射流切割技术在诱导顶板垮落中的应用进行了研究,分析了该技术在井下应用的可行性和安全性。研制了用于井下诱导顶板垮落的磨料水射流切割设备并进行了现场应用试验。该设备可以顺利切割井下锚索锁具,从而诱导上隅角位置坚硬顶板实现自然垮落,防止上隅角位置顶板大面积悬空引起瓦斯积聚造成的安全隐患。前混合磨料水射流切割技术使用方便,安全高效,在井下安全生产中具有广阔的应用前景。     

Cutting meat with bone using an ultrahigh pressure abrasive waterjet

An experimental study of abrasive waterjet (AWJ) cutting of beef, pork and lamb meat with and without bone is presented. Salt particles were used as the abrasives. It has been found that an AWJ could significantly increase the depth of cut with much improved cut quality in cutting pure meat as compared to plain (or pure) waterjet cutting, while a plain waterjet was incapable of cutting bone satisfactorily. The study shows that AWJ cutting produced a very narrow kerf of less than 1 mm and hence resulted in mush less meat loss than the traditional cutting processes, and meat can be cut at room temperature to eliminate the freezing or chilling costs. It is shown that a traverses speed of 20 mm/s can be used to cut through 44 mm thick beef rib bones with good cut quality. When slicing pure meat of 150 mm thickness, the traverse speed of 66.67 mm/s can yield very good cut quality. It is suggested that AWJ cutting is a viable technology for meat cutting. Plausible trends for the depth of cut, cutting rate and cut quality with respect to the process variables are discussed. Recommendations are finally made for the selection of the most appropriate process parameters for cutting meat of a given thickness.     

Parametric Effects on Particle Deposition in Abrasive Waterjet Surface Treatments

The abrasive waterjet (AWJ) has primarily been used for net-shape sectioning of engineering materials. In this study an AWJ was adopted for the surface treatment of commercially pure titanium (cpTi) and the contribution of treatment parameters to material removal and the deposition of particles within the substrate were examined. The surface texture and material removal rate were analyzed using conventional techniques whereas the quantity of abrasive particles embedded within the cpTi surfaces was determined using energy dispersive X-ray analysis (EDXA). Parametric effects related to particle hardness were distinguished from a comparison of surfaces treated with Aluminum oxide, garnet, and crushed glass abrasives. According to an analysis of variance (ANOVA), treatment responses were found to be primarily dependent on the abrasive size, abrasive hardness, angle of incidence, and jet pressure. The minimum and maximum concentration of particles embedded in the AWJ treated cpTi (in percent surface area covered) was 2.5 and 21.6%, respectively. Particle concentration and mean particle size in the cpTi increased with abrasive size, angle of incidence and jet pressure; the particle concentration reached saturation at an angle of incidence near 80°. Although abrasive hardness was important to the treatment responses, an increase in hardness beyond 800 on the Rosiwal scale resulted in minimal changes in material removal or other features of the process.     

Study and evaluation of abrasive water jet cutting performance on AA5083-H32 aluminum alloy by varying the jet impingement angles with different abrasive mesh sizes

This article describes the experimental investigation of abrasive water jet (AWJ) cutting on AA5083-H32 aluminum alloy. In this study, the influence of varying the jet impingement angles and abrasive mesh sizes with different water jet pressures, on the output parameters for the AWJ cutting of the aluminum alloy, was analyzed. The experimental results found that the output parameters, namely, the depth of penetration, top kerf width, kerf taper ratio, surface roughness, and abrasive contaminations, were strongly influenced by the combined effect of oblique jet impingement angles and abrasive mesh sizes on AWJ. Also, it is noticed that oblique jet impingement angles have more influence on the output cutting responses than the normal jet impingement angle, and consequently, each abrasive mesh size has an influence on the different output responses for the AWJ cutting of AA5083-H32. Scanning electron microscope and microhardness tester were used to examine the different cutting regions of the kerf wall surfaces. The Energy-dispersive X-ray spectroscopy analysis was used to confirm the amount of silicon particles embedded in the AWJ cut surfaces. The adequacy checking of the experimental data for the AWJ cutting performance models has been analyzed through the residual plots using the statistical software.     

深水下岩石切割的模拟试验研究

通过自行开发设计的一套深水环境条件模拟试验装置，进行一系列深水环境条件下磨料水射流切割岩石的试验研究。针对岩石切割深度的主要影响因素，分别进行一系列的靶距变化、切割次数变化、射流横移速度变化和不同水深的模拟试验，从而揭示在深水环境条件下岩石切割深度与各主要切割参数的关系和规律，以及水深对岩石切割深度的影响。在深水环境条件下岩石切割技术的生产实际应用中，要综合考虑切割次数和射流横移速度与效率的关系；岩石等材料的合理靶距是一个关键性技术问题，应控制在有效靶距范围内才具有实际意义。     

前混合式磨料水射流喷嘴外流场仿真与实验

通过建立磨料水射流喷嘴有限元模型,对2种不同直径的前混合式磨料水射流的喷嘴外流场进行仿真分析.结果表明,在喷嘴其它几何条件相同的情况下,出口直径对喷嘴的出口速度影响比较大,出口直径越大,出口速度越小;在一定程度上将混合管适当地加长,可以提高磨料射流在喷嘴出口处的速度;磨料水射流最佳的切割距离为喷嘴出口直径的2.0～5.0倍.磨料水射流切割靶体实验结果与靶体冲击仿真结果基本吻合.     

基于神经网络的磨料水射流切割工艺参数智能选择

磨料水射流切割中影响切割深度的因素很多,各工艺参数的选择和合理搭配对切割效果有很大影响,并且难以用精确的数学模型来描述。建立了基于BP神经网络的磨料水射流切割工艺参数智能选择模型,该模型可以映射出切割深度与切割工艺参数之间的关系,并通过多次学习训练达到了较高的精度和较快的收敛速度。     

磨料水射流切割质量的神经网络预测

磨料水射流切割质量影响因素较多,难以建立有效的理论模型,结合实验结果,建立磨料水射流切割质量的神经网络预测模型。结果表明,对于所给定切割参数,该模型能快速、准确、可靠地预测出切割质量。