Green strength properties of waterjet abrasive waste as potential composition in green mould by Taguchi and ANOVA approach

The sand casting process still continues today due to the cost-effectiveness of materials and processes. There is a wide variety of castings related to composition and size, but silica sand is widely available from coastal line mining and has a negative impact on the environment. Moreover, waste from waterjet cutting of non-ferrous and ferrous metals is practically unhazardous and may potentially be used in sand casting mould. The aim of this paper is to optimize the proportion of coal dust, water and bentonite added to the silica sand mixture and the waterjet cutting abrasive waste as a new way of handling waste with the potential to be used in sand casting manufacturing. The method used was L9 orthogonal array optimization and the composition was qualitatively measured using a green compression strength test and a green shear strength test. Factors were evaluated using the analysis of variance (ANOVA) to find the the critical factors while confirmation test was conducted for the optimal material proportion. The study concluded that the ideal ratio for silica sand mixture with waterjet abrasive waste is bentonite-12%, coal dust-5%, and water-7% for green compression strength while bentonite-12%, coal dust-6%, water-7% for green shear strength. With proper selection, the incorporation of waterjet abrasive waste into the green sand mixture is promising to potentially be used in green sand mould casting without undermine the quality of mould.

Life Cycle Environmental and Economic Comparison of Water Droplet Machining and Traditional Abrasive Waterjet Cutting

Abrasive waterjet (AWJ) cutting is a manufacturing technique, which uses a high-speed waterjet as the transport medium for abrasive particles to erode and cut through metal workpieces. The use of abrasives has significant environmental impacts and leads to the high operating costs of AWJ cutting. Therefore, it is important to investigate whether other metal cutting approaches can perform the same tasks with reduced environmental and economic impacts. One such manufacturing innovation is water droplet machining (WDM). In this process, the waterjet, which is immersed in a sub-atmospheric pressure environment, is discretized into a train of high velocity water droplets, which are able to erode and cut through the metal workpiece without abrasives. However, the cutting velocity of WDM is two orders of magnitude slower than AWJ. In this paper, a comparative life cycle and life cycle cost assessments were performed to determine which waterjet cutting technology is more beneficial to the environment and cost-efficient, considering their impacts from cradle to grave. The results show lower environmental and economic impacts for AWJ compared to WDM due to the AWJ’s ability to cut more metal over the service life than the WDM. Further sensitivity analyses give insight into how the change in abrasive rate is the most sensitive input for the AWJ, whereas the machine lifetime and electricity usage are the most sensitive inputs for the WDM. These results provide a valuable comparison between these alternative waterjet cutting technologies.

Modeling Method and Experimental Study on the Random Distribution of Abrasive Particles in the Jet Cutting Process

The distribution of abrasive particles in fluids is an important research topic in the study of abrasive waterjet cutting processes. However, it is impossible to obtain the accurate distribution law and influencing factors by performing only experiments; therefore, it is necessary to study abrasive waterjet cutting processes with the help of numerical models. The existing numerical models usually adopt the form of artificial settings for the distribution of abrasive particles in fluid. This method cannot accurately simulate the random distribution of particles. In this paper, the random algorithm method is used to simulate the impact azimuth and the random distribution of abrasive particles in water. The smoothed particle hydrodynamics (SPH) method is used to simulate the distribution of abrasive particles and the process of jet impingement. The influence of the particle distribution on the simulation results is studied. Comparisons show that the dent formed by the jet impinging on the target with random abrasive particles is similar to the dent from the actual cut, and the contour distribution of the dent is more uniform than that of the cut. The simulation results obtained by the SPH method are accurate.

Study On Abrasive Particle Impact Modeling And Cutting Mechanism

Abrasive particles play a vital role in the impact on materials during abrasive waterjet cutting. To study the effect of particles on the cutting performance during abrasive waterjet cutting, the mostly irregular shape of the abrasive particles in the actual cutting process needs to be considered. In this paper, the particles are simplified as angular and circular particles. The method of Smoothed Particle Hydrodynamics (SPH) is used to simulate the process of particle impact targeting in abrasive jet cutting. Because the abrasive particle impact causes a large local deformation or removal of the surface of the target material, the traditional grid-based numerical method is not suitable for such problems; thus, the SPH method, which is suitable for the impact problem, is selected to establish the numerical model and solve it. In this paper, the fracture process of abrasive particles with different shapes of impact ductility and brittle target materials is studied by a numerical model. In the modeling process, abrasive particles are modeled as rigid bodies with material properties, the ductile materials is an aluminum alloy, the brittle material is quartz glass, which are simulated by changing the initial input conditions and particle shape, and the model is verified by experiments. The results show that the model successfully reproduces the collision process of particles during abrasive jet cutting, including the deformation mechanisms of plowing, fracture and crushing of the target.

Experimental Study of Abrasive Waterjet Cutting for Managing Residues in No-Tillage Techniques

A laboratory investigation of abrasive waterjet cutting of wheat straws was conducted. The work was aimed at a systematic characterization of the abrasive waterjet cutting capability of wheat straws, as a potential alternative to cutting discs currently adopted in no-till drills and planters for crop residue management. A two level 2IV7−3 fractional factorial design was applied to investigate the influence of abrasive waterjet process parameters on the cutting efficiency of wheat straws. Straw coverage thickness, water pressure, and orifice diameter were found to be the most significant ones. Experimental results suggest that straw cutting mechanism is mostly related to the hydraulic power of the jet. A multiple logistic regression was performed to model the relationship between the cutting efficiency and the jet power. The logistic model was then applied to estimate the average water and power consumption for wheat straw cutting during a no-tillage seeding operation. An average jet hydraulic power of 6400 W would be sufficiently high to guarantee 90% cutting efficiency in presence of heavy residue distribution. The experimental study shows that a small quantity of abrasive powder (50 g·min−1) allows one to increase the jet cutting capability of wheat straws, and to reduce the required maximum hydraulic power, compared to pure waterjet cutting. Results show are potentially relevant for field validation in agriculture based on no-tillage.