Abrasive Water Jet Machining – The Review
Abrasive water jet machining (AWJM) is a relatively new machining technique. Abrasive Water Jet Machining is extensively used in many industrial applications. AWJM is a nonconventional machining process where material is removed by impact erosion of high pressure high velocity of water and entrained high velocity of grit abrasives on a work piece. There are so many process parameter affect quality of machined surface cut by AWJM. Important process parameters which mainly affect the quality of cutting are traverse speed, hydraulic pressure, stand of distance, abrasive flow rate and types of abrasive. Important quality parameters in AWJM are Material Removal Rate (MRR), Surface Roughness (SR), kerf width, tapering of kerf. This paper reviews the research work carried out so far in the area AWJM.
Material removal analysis in abrasive waterjet cutting of ceramic plates
Abstract Fine ceramics have been recognized increasingly in structural and functional applications on account of their merits of hardness, corrosion resistance, electromagnetic response and bio-compatibility. Due to the need for dimensional control or production optimization, post-sintering machining can be required. Cutting by conventional means is most often practiced, but the associated heavy tool wear is hard to overcome. A waterjet at transonic speed carrying abrasive particles provides an effective means for hard-material removal. Undesired material fracture at entrance and exit can be reduced significantly by sequential abrasive micro-machining. The present paper discusses the kerf formation of a ceramic plate cut by an abrasive waterjet. The mechanism and the effectiveness of material removal are studied first. Different materials are found to possess different removal rates in machining and there also exists a critical combination of hydraulic pressure, abrasive flow rate and traverse speed, below which through-cut for a certain thickness cannot be achieved. The wall finish achieved is determined by the mesh size of the abrasives: sufficient hydraulic pressure with fine abrasives will produce a smooth surface comparable to that from grinding. The kerf is slightly tapered with wider entry due to decreased cutting energy with kerf depth. A high-power input per unit length produces a small taper but a wide slot.
Numerical Simulation of Induction Heating Process of Continuous Casting Slab
Compared with traditional blazing furnace, the Continuous Casting-Direct Rolling is an advanced manufacturing steel technology, which can reduce energy waste, decrease pollution and enhance efficiency. The characteristics of steels during induction heating are complex, the change of material properties with temperature makes exact analysis methods very difficult to implement. Therefore, a powerful computer aided numerical tool (i.e., finite difference analysis) is selected to numerically model the induction heating process in this paper. The mathematic model coupling with electromagnetic field and thermal field was established, and it was solved by finite difference method (FDM), thus the slab temperature distribution and its variation with time were obtained, and the characteristics in whole induction heating process were studied. To validate the program feasible, the results were evaluated and compared with experiment results, which showed that the simulation results are reliable and effective. The skin effect in heating process from the two results was studied and demonstrated, the temperature change caused by different parameters such as the induced power intensity and the corner radian were also presented, which indicate that the slab temperature can be heated uniformly through adjusting these parameters, thus the continuous casting slab can meet the rolling requirement.