超高压水切割多功能特征解析

航空航天对超高压水切割提出了特殊技术要求,笔者应对大尺度曲面复合材料切割,大型叶轮粗加工和特殊精细切割,复合材料的铣削、钻孔、抛光等需求,以国家863计划课题为契机,研制了500MPa压力的特大型专用机翼加工装备和多功能加工中心,本文介绍了这2台先进装备所引发的超高压水射流多功能技术特征,并结合国外同步先进水平解析了实现高难度水切割、铣削等多功能应用的技术模块、参数匹配、工艺方法和试验结果。     

大尺度曲面复合材料水切割的工况与机构研究

应对大尺度曲面复合材料的成型切割工程,本文基于高精度、高速度的切割要求,在美国波音公司水切割应用基础上提出了以提高工作压力来确定高端的水射流工况,在反复的试验基础上建立数学模型,以超高压水切割加工中心成套装备的可靠性运行为目标进行水切割机构的闭环设计。通过应用实例,本项目得出超高压水射流可靠运行与其对复合材料的高精度、高速度切割作业的对立统一经验。本项目理论研究、结构设计、试验应用很好地适应机翼复合材料加工的高技术要求。由此可见,在可靠运行前提下提高工作压力对高精度、高速度加工复合材料是极为重要的。     

500 MPa水切割射流发生装置的设计

超高压水切割技术应用于碳纤维等纤维增强复合材料切割加工,射流压力和工作流量的工况参数是高质高效切割复合材料的重要前提条件。探讨了纤维增强复合材料水切割机理和射流工况参数,介绍了500 MPa压力级的纤维复合材料水切割射流发生装置参数计算,阐述了射流发生装置主要结构,运用有限元分析方法校核射流发生装置主要部件,通过计算、分析和试验表明射流发生装置满足切割射流工况要求。     

超高压水射流切割系统

南京大地水刀股份有限公司成立于1996年,是中国最早、目前规模最大的专业从事"超高压水射流技术"在切割和清洗应用领域的产品研究、开发和生产的省级高新技术企业,目前拥有该领域的国家专利40余项。在制药机械设备制造业,超高压水切割机用于面板、支架构件及其他部件的切割和成形加工。该类机械设备制造过程中呈现出所需材料多样、产品外观及精     

超高压水射流切割系统

南京大地水刀股份有限公司成立于1996年,是中国最早、目前规模最大的专业从事“超高压水射流技术”在切割和清洗应用领域的产品研究、开发和生产的省级高新技术企业,目前拥有该领域的国家专利40余项。在制药机械设备制造业,超高压水切割机用于面板、支架构件及其他部件的切割和成形加工。该类机械设备制造过程中呈现出所需材料多样、产品外观及精度要求较高、非标件多等特点,传统切割方式在材料材质以及加工方式上多存在一定的弊端,     

超高压水射流切割系统

南京大地水刀股份有限公司成立于1996年,是中国最早、目前规模最大的专业从事"超高压水射流技术"在切割和清洗应用领域的产品研究、开发和生产的省级高新技术企业,目前拥有该领域的国家专利40余项。在制药机械设备制造业,超高压水切割机用于面板、支架构件及其他部件的切割和成形加工。该类机械设备制造过程中呈现出所需材料多样、产品外观及精度要求较高、非标件多等特点,传统切割方式在材料材质以及加工方式上多存在     

水切割特性的影响因素及其影响行为分析

介绍了水切割机的工作原理、关键技术问题和重要参数的计算方法,分析了针对特定加工对象(如材料的强度、硬度和厚度等)压力、横移速度、喷嘴直径和靶距等参数对切割特性的影响,为水切割机及其加工工艺设计提供了理论依据。     

超高压数控万能水刀切割机研制成功

最近,在南京举办的高新技术展示会上,南京大地水射流有限公司研制生产的超高压数控万能水刀切割机表演切割钢板、石板、海绵等多种硬、软材料,引起参观者强烈反响。 超高压数控万能水刀切割机俗称“水刀”,是“中国第一刀”,填补国内空白,也是具有国际先进水平的平面切割系统,它采用一系列高新技术,由超高压发生系统、CNC三维数控机床、磨料自动传送系统、计算机CAD/CAM辅助设计/辅助制造系统、水射流切割系统等组成。超高压增压系统能把普通水增压至1000～4000个大气压(400MPa),然后使水从一个直径约0.2mm的宝石喷嘴射出成“水箭”,其射速为800～1000m/s,约等于音速的三倍,这种“水箭”可切割钢板、铝板、塑料、皮革、纸张、布匹、     

数控异形泡棉切割机的运动控制

本文主要分析了泡棉切割加工的工艺要求,以及数控加工的轨迹控制,确立了数控异形泡棉切割机的位置控制系统的方案,研究了其硬件配置和软件结构。本课题的研究是数控异形泡棉切割机研制成功的关键,该切割机已研制成功,并交付用户使用,切削效果好。     

在现水切割技术的研究

在现水切割也就是在错综复杂的作业现场(如石化装备检修现场、交通车祸现场等)应用超高压水切割技术对易燃、易爆的各种设备进行切割破拆的作业工程。显然,在现切割很有巿场,基于安全它又必须用水切割这一冷态切割工艺,而现行的针对平面板材的通用水切割机设备又不适应在现切割。对此,笔者提出以250MPa、15k W机组、在现连续有效作业2h的概念,并针对不同作业对象研究出各类执行机构,以短时间有限局部安全破坏的技术理论指导在现水切割作业。     

基于淹没环境的超高压后混合磨料水射流切割试验研究

利用超高压水射流切割试验系统,在80～280MPa压力范围内进行淹没磨料水射流切割试验研究,通过试验及数据分析,验证了后混合淹没磨料射流切割的可行性,得出了磨料粒径和质量流量、射流压力、靶距、切割横移速度等参数对射流切割性能的影响规律,对于脆性和塑性材料,试验中各参数对切割深度的影响基本一致.结果表明:在试验给出的工况条件下,磨料流量存在最佳值,在一定范围内切割深度随磨料流量增加而增加,当磨料流量达到一定值后,切割深度随流量增加反而下降;切割深度与射流压力基本呈线性增长关系;随着靶距的增大,切割深度逐渐减小;切割深度随切割速度的增加呈指数衰减趋势,并且相同试验工况下淹没射流切割深度要大于非淹没状态.试验结果为超高压淹没磨料水射流的实际应用和研究提供了参考.     

On the modelling of abrasive waterjet cutting

Abrasive waterjet cutting operates by the impingement of a high-velocity abrasive-laden waterjet against the workpiece. The jet is formed by mixing abrasive particles with high-velocity water in mixing tubes and is forced through a tiny sapphire orifice. The accelerated jet exiting the nozzle travels at more than twice the speed of sound and cuts as it passes through the workpiece.This cutting process is being developed as a net-shape and near-net-shape machining process for cutting many metals and hard-to-machine materials. The narrow kerf produced by the stream results in neither delimitation nor stresses along the cutting path. This new technology offers significant advantages over traditional processes for its ability to cut through most sections of dense or hard materials without the need for secondary machining, to produce contours, and to be integrated into computer-controlled systems.The abrasive waterjet cutting process involves a large number of process and material parameters which are related to the waterjet, the abrasive particles, and workpiece material. Those parameters are expected to effect the material removal rates and the depth of cut. The purpose of the present work is to propose a model which is capable of predicting the maximum depth of cut for different types of materials using different process parameters. A comparison of the results of the proposed model and the models reported in the literature is introduced along with a discussion of the limitations of those models.On leave from: Mechanical Engineering Department, Suez Canal University, Egypt.On leave from: Industrial Production Engineering Department, Mansoura University, Egypt.On leave from: Mechanical Power Engineering Department, Alexandria University, Egypt.     

Effects of process parameters on surface roughness in abrasive waterjet cutting of aluminium

Abrasive waterjet cutting is a novel machining process capable of processing wide range of hard-to-cut materials. Surface roughness of machined parts is one of the major machining characteristics that play an important role in determining the quality of engineering components. This paper shows the influence of process parameters on surface roughness (R_a) which is an important cutting performance measure in abrasive waterjet cutting of aluminium. Taguchi’s design of experiments was carried out in order to collect surface roughness values. Experiments were conducted in varying water pressure, nozzle traverse speed, abrasive mass flow rate and standoff distance for cutting aluminium using abrasive waterjet cutting process. The effects of these parameters on surface roughness have been studied based on the experimental results.     

超高压征复密封的设计

超高压水切割的运行平稳、可靠、主要取决于超高压往复密封。作将250MPa超高压往复密封设计为锥形套筒与填料组合密封结构,利用锥形套筒的弹性变形在柱塞与套筒之间产生一定的间隙,造成较大的压降差,再利用填料密封阻泄,取得满意效果。     

Using the acoustic sound pressure level for quality prediction of surfaces created by abrasive waterjet

The paper deals with an innovative way of cutting materials by abrasive waterjet with a view to increase its quality. In the research work, we were concerned with the search for a relationship between surface roughness and noise in the abrasive waterjet cutting process. Innovation lies in the use of negative characteristic of the technology—noise, which is a carrier of information about the quality of cutting process. In this way, the noise can be positively used in the on-line control of the technological process. The final result is a project for control of the process of abrasive waterjet cutting of materials by means of feedback according to the on-line measurement of acoustic pressure level L _aeq (dB). Instantaneous information about the state of cut according to the instantaneous value of L _aeq amplitude allows the automatic regulation of traverse speed of cutting head v _p (mm.min^?1), which is, together with the pressure p (MPa), one of the most important technological factors of control of production technology from the point of view of economic indicators and qualitative indicators of a semiproduct. The proposed model has been experimentally verified and was simulated in Matlab.     

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。     

Parameter design for cut surface characteristics in abrasive waterjet cutting of Al/SiC/Al2O3 composite using grey theory based RSM

The abrasive mixed waterjet was successfully employed to cut many materials including austenitic steel, inconel and glass for a variety of industrial applications. The present work focusses on studying the surface roughness, striation zone and striation angle in Abrasive waterjet cutting (AWJC) of Al/SiC/Al₂O₃ composite. The water pressure, traverse speed, abrasive flow rate and stand-off distance were included as the dominant parameters in the study. The features of striation zone (length and angle) and surface roughness were observed as the responses for each of the cutting trials planned as per Taguchi’s L₁₈ orthogonal array. Parameter design was performed using the grey theory based response surface methodology (g-RSM) by following the method of simultaneous optimization to forecast the optimal cutting condition. All the studied parameters and their interactions were found to have a substantial effect on the observed responses. Significant improvements were observed in the responses obtained with the optimal parameter setting predicted by the g-RSM approach. The Atomic force microscopy (AFM) images and P-profile plots were also studied to observe the texture of the cut surface.     

A finite element-based model for pure waterjet process simulation

The utilization of abrasive waterjet (AWJ) cutting/drilling, and in particular its application into hard-to-cut materials, is growing. However, the mechanics of AWJ cutting is complex; the material removal process is not fully understood and, consequently, it has not been accurately modeled. In the current study, work was undertaken to mesh in a first stage the waterflow into the waterjet nozzle in order to use the finite element (FE) method to simulate the pure waterjet flow. The main objective is to investigate and analyze in detail the workpiece material behavior under waterjet impingement; a non-linear FE model (using LS-DYNA 3D code) has been developed, which simulates the erosion of the target material caused by the high-pressure waterjet flow. A combination of Eulerian–Langrangian elements is used for the waterjet and the target material, respectively, in order to handle their interaction. Damaged zones can be localized on impinged materials. Elements’ failure is handled by introducing a threshold strain after which Langrangian elements are removed. The results obtained from this numerical simulation (velocity profile, stress, erosion stages) show a good agreement with the results from previous experimental work that is available in bibliography. The next step of the research will be focused on the simulation of the whole procedure using various abrasives.