Papers by Keyword: AWJ

Abstract: Abrasive Waterjet Machining (AWJM) has significant advantages, such as being environmentally friendly, used for machining hard-to-cut materials, and do not cause a heat-affected zone. More machining tests are needed to understand the concept of material machinability in AWJM to increase process flexibility and produce parts with higher productivity, better accuracy, and surface quality. This paper presents drilling and slotting experiments through different metallic materials at fixed machining conditions to evaluate their machinability using AWJM. It introduces new machinability indices that arrange the tested materials concerning their machinability rating. Drilling indices include volumetric removal rate (VRR), penetration rate (PR), specific removal rate (SRR), and taper angle (TA). The paper correlates VRR, PR, drilling power, and Young’s modulus of the tested materials. In the case of slotting, VRR, kerf taper angle (TA), and the average surface roughness, Ra, were measured and used as indices of machinability. Cost analysis was also performed to introduce an economical index of machinability for both AWJ drilling and slotting AWJM operations.

Abstract: In the process of abrasive water jet (AWJ) cutting, there will produce a series of striation shape on the cutting surface of target. In this paper, we define such striation as cutting striation shape. The most research of this paper is the force situation and movement trajectory of water jet in the process of cutting. It is deduced by theory that the cutting surface striation shape is circular arc and find that the radius of circular arc is related to cutting velocity, cutting pressure and the property of cutting material. In the experiment, stainless steel 304 and aluminum 6061 were cut by AWJ and the result shows that the shape of the surface striation is arc-shaped in both material surface. At different cutting pressure, for a same material, K_R is a constant value which is only related to the property of cutting material.

Abstract: Through the experiment of cutting 1060 Aluminum Alloy by Abrasive Water Jet (AWJ), the surface roughness of material which is cut by AWJ is controlled by the cutting work pressure, cutting stand-off distance, cutting traverse speed and the abrasive diameter which used in AWJ. Measuring the cutting surface roughness of 1060 Aluminum Alloy by stereomicroscope and surfagauge, among the factor which can affect the surface roughness, the cutting traverse speed play a dominant role to control the surface roughness in the process of cutting. As the result of the surface roughness of 1060 Aluminum Alloy at different cutting depth is different, which can be separated in two different zones (Smooth area and Rough zone). As the result of experiment, the abrasive diameter has little effect to change the surface roughness between two different zones. The surface quality of rough zone can be improved when change the diameter of abrasive: with the diameter of abrasive increase, the surface quality of rough zone become better. A higher cutting pressure can improve the surface quality of the cutting surface of 1060 Aluminum Alloy. While increase the cutting traverse speed in the process of cutting can decrease the surface quality of 1060 Aluminum Alloy cutting surface. In a certain range, increase the cutting stand-off distance of AWJ can decrease the surface roughness of the cutting surface, and the roughness of cutting surface will change little when the stand-off distance increases to a certain extent.

Abstract: Abrasive waterjet machining (AWJ) is one of the fastest growing non-conventional machining methods. However, low pressure and fine abrasive implemented in AWJ precision machining for reducing the surface damage reduce the efficiency. Therefore ultrasonic vibration is considered to apply on the workpiece to improve the machining efficiency. In order to analyze the effect of the vibration on erosion in AWJ machining, smoothed particle hydrodynamics (SPH) is used to simulate the erosion process for avoiding the mesh distortion in finite element method (FEM) when simulating large deformation and high strain rate problems. The results show that the application of ultrasonic vibration can effectively improve the erosion rate due to the dynamics variation of the erosion process.

Abstract: Carbon fiber-reinforced plastics (CFRP), which are now used in some aerospace applications, is difficult to cut and drill holes in. Moreover, no reports have focused on selecting a suitable drilling method for each aerospace part. This paper discusses many methods of hole generation for CFRP composites, including methods using traditional drill tools and non-traditional methods such as abrasive water jet (AWJ), laser beam and abrasive blast. We look at traditional cemented carbide material tools, polycrystalline diamond (PCD) tools, diamond-like carbon (DLC) coated tools and ceramic tools. Then, comparing the experimental results of these methods from the viewpoints of characteristics, efficiency, cost, and hole quality, we investigate each problem to select the suitable drilling method. As a result, we propose a novel method to strategically obtain the best solutions to generate holes in aerospace parts.

Abstract: An experimental study of a radial-mode abrasive waterjet (AWJ) turning of AISI4340 high tensile steel is presented. The major process parameters, i.e. feed speed, waterjet pressure, abrasive flow rate, nozzle tilt angle, and workpiece surface speed, are considered in a statistical experimental design. The advantages of the radial-mode AWJ turning over the offset-mode turning include maximum jet energy utilization, high surface speed, a variety of nozzle tilt angles and small nozzle standoff distance, to enable high material removal rate (MRR). It is found that the depth of cut is considerably increased when large nozzle tilt angle and high surface speed are used. It also shows that feed speed and waterjet pressure are the two most significant parameters to control the MRR. This preliminary study suggests that the radial-mode AWJ turning is feasible and can yield high material removal rates. Future research to advance the knowledge about this new machining process is also proposed.