AWJ Performance Characteristics at 600 MPa

2007 ◽  
Author(s):  
Mohamed Hashish
Keyword(s):  
Power Density ◽  
Unit Length ◽  
Operating Cost ◽  
Cutting Speed ◽  
Abrasive Waterjet ◽  
Nozzle Wear ◽  
Kerf Taper ◽  
Stone Cutting ◽  
The Cost ◽  
Jet Power

Increasing the pressure of abrasive waterjet, while fixing the jet power, increases the jet’s power density and thus the cutting speed may increase. This was observed for steel, aluminum, and stone cutting. It was also observed that the kerf taper is less for higher pressure jets. Increasing the pressure while keeping the jet diameter fixed will increase both the power and the power density. This will result in increase cutting speed and less taper. The operating cost of the AWJ process consists mainly of the costs of abrasives, nozzle wear, utility, and maintenance of equipment. The cost per unit length of material (specific cost) is determined based on the cutting speed. It was found that the main advantage of increasing pressure is increasing the cutting speed or reducing the abrasive consumption per unit time or unit length of cut. The highest savings are obtained when the speed is maximized by increasing the pressure and the abrasive flow rate. Several study cases were addressed in this paper using assumptions and simple models to generalize the analysis. The analysis indicates that increasing the pressure from 400 MPa to 600 MPa may result in cost per unit length saving of over 30%.

Trends and Cost Analysis of AWJ Operation at 600MPa Pressure

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Mohamed Hashish
Keyword(s):  
Power Density ◽  
Unit Length ◽  
Operating Cost ◽  
Cutting Speed ◽  
Abrasive Waterjet ◽  
Nozzle Wear ◽  
Kerf Taper ◽  
Abrasive Waterjets ◽  
The Cost ◽  
Jet Power

Increasing the pressure of abrasive waterjet, while fixing the jet power, increases the jet’s power density and thus the cutting speed may increase. This was observed for steel, aluminum, and stone cutting. It was also observed that the kerf taper is less for higher pressure jets. Increasing the pressure while keeping the jet diameter fixed will increase both the power and the power density. This will result in increased cutting speed and less taper. The operating cost of the abrasive waterjets process consists mainly of the costs of abrasives, nozzle wear, utility, and maintenance of equipment. The cost per unit length of material (specific cost) is determined based on the cutting speed. It was found that the main advantage of increasing pressure is increasing the cutting speed or reducing the abrasive consumption per unit time or unit length of cut. The highest savings are obtained when the speed is maximized by increasing the pressure and the abrasive flow rate. Several study cases were addressed in this paper using assumptions and simple models to generalize the analysis. The analysis indicates that increasing the pressure from 400MPato600MPa may result in cost per unit length saving of over 30%.

scholarly journals Augmented Lagrangian preconditioners for the Oseen–Frank model of nematic and cholesteric liquid crystals

2021 ◽  
Author(s):  
Jingmin Xia ◽  
Patrick E. Farrell ◽  
Florian Wechsung
Keyword(s):  
Liquid Crystals ◽  
Augmented Lagrangian ◽  
Augmented Lagrangian Method ◽  
Mass Matrix ◽  
Unit Length ◽  
Mesh Size ◽  
Schur Complement ◽  
Cholesteric Liquid Crystals ◽  
Multigrid Algorithm ◽  
The Cost

AbstractWe propose a robust and efficient augmented Lagrangian-type preconditioner for solving linearizations of the Oseen–Frank model arising in nematic and cholesteric liquid crystals. By applying the augmented Lagrangian method, the Schur complement of the director block can be better approximated by the weighted mass matrix of the Lagrange multiplier, at the cost of making the augmented director block harder to solve. In order to solve the augmented director block, we develop a robust multigrid algorithm which includes an additive Schwarz relaxation that captures a pointwise version of the kernel of the semi-definite term. Furthermore, we prove that the augmented Lagrangian term improves the discrete enforcement of the unit-length constraint. Numerical experiments verify the efficiency of the algorithm and its robustness with respect to problem-related parameters (Frank constants and cholesteric pitch) and the mesh size.

scholarly journals Roughing Milling with Ceramic Tools in Comparison with Sintered Carbide on Nickel-Based Alloys

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 734
Author(s):  
Pablo Fernández-Lucio ◽  
Octavio Pereira Neto ◽  
Gaizka Gómez-Escudero ◽  
Francisco Javier Amigo Fuertes ◽  
Asier Fernández Valdivielso ◽  
...  
Keyword(s):  
Cutting Speed ◽  
High Volume ◽  
Cemented Carbide ◽  
Performance Ratio ◽  
Cost Performance ◽  
Ceramic Tools ◽  
The Cost ◽  
Engine Components ◽  
Coated Carbide ◽  
Milling Tools

Productivity in the manufacture of aircrafts components, especially engine components, must increase along with more sustainable conditions. Regarding machining, a solution is proposed to increase the cutting speed, but engines are made with very difficult-to-cut alloys. In this work, a comparison between two cutting tool materials, namely (a) cemented carbide and (b) SiAlON ceramics, for milling rough operations in Inconel® 718 in aged condition was carried out. Furthermore, both the influence of coatings in cemented carbide milling tools and the cutting speed in the ceramic tools were analysed. All tools were tested until the end of their useful life. The cost performance ratio was used to compare the productivity of the tested tools. Despite the results showing higher durability of the coated carbide tool, the ceramic tools presented a better behavior in terms of productivity at higher speed. Therefore, ceramic tools should be used for higher productivity demands, while coated carbide tools for low speed-high volume material removal.

scholarly journals Impacts of Traverse Speed and Material Thickness on Abrasive Waterjet Contour Cutting of Austenitic Stainless Steel AISI 304L

2021 ◽  
Vol 11 (11) ◽  
pp. 4925
Author(s):  
Jennifer Milaor Llanto ◽  
Majid Tolouei-Rad ◽  
Ana Vafadar ◽  
Muhammad Aamir
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Traverse Speed ◽  
Abrasive Waterjet ◽  
Taper Angle ◽  
Material Thickness ◽  
Abrasive Waterjet Machining ◽  
Kerf Taper ◽  
Waterjet Machining

Abrasive water jet machining is a proficient alternative for cutting difficult-to-machine materials with complex geometries, such as austenitic stainless steel 304L (AISI304L). However, due to differences in machining responses for varied material conditions, the abrasive waterjet machining experiences challenges including kerf geometric inaccuracy and low material removal rate. In this study, an abrasive waterjet machining is employed to perform contour cutting of different profiles to investigate the impacts of traverse speed and material thickness in achieving lower kerf taper angle and higher material removal rate. Based on experimental investigation, a trend of decreasing the level of traverse speed and material thickness that results in minimum kerf taper angle values of 0.825° for machining curvature profile and 0.916° for line profiles has been observed. In addition, higher traverse speed and material thickness achieved higher material removal rate in cutting different curvature radii and lengths in line profiles with obtained values of 769.50 mm3/min and 751.5 mm3/min, accordingly. The analysis of variance revealed that material thickness had a significant impact on kerf taper angle and material removal rate, contributing within the range of 69–91% and 62–69%, respectively. In contrast, traverse speed was the least factor measuring within the range of 5–18% for kerf taper angle and 27–36% for material removal rate.

Factors Influencing the Particle Size Distribution in an Abrasive Waterjet

1991 ◽  
Vol 113 (4) ◽  
pp. 402-411 ◽  
Author(s):  
T. J. Labus ◽  
K. F. Neusen ◽  
D. G. Alberts ◽  
T. J. Gores
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Cutting Speed ◽  
Target Material ◽  
Abrasive Waterjet ◽  
Sieve Analysis ◽  
Size Distributions ◽  
Mixing Process ◽  
Jet Mixing

A basic investigation of the factors which influence the abrasive jet mixing process was conducted. Particle size analysis was performed on abrasive samples for the “as-received” condition, at the exit of the mixing tube, and after cutting a target material. Grit size distributions were obtained through sieve analysis for both water and air collectors. Two different mixing chamber geometries were evaluated, as well as the effects of pressure, abrasive feed rate, cutting speed, and target material properties on particle size distributions. An analysis of the particle size distribution shows that the main particle breakdown is from 180 microns directly to 63 microns or less, for a nominal 80 grit garnet. This selective breakdown occurs during the cutting process, but not during the mixing process.

scholarly journals Cost-Effectiveness Analysis of a Large-Scale Crèche Intervention to Prevent Child Drowning in Rural Bangladesh

2021 ◽  
Author(s):  
Y. Natalia Alfonso ◽  
Adnan A Hyder ◽  
Olakunle Alonge ◽  
Shumona Sharmin Salam ◽  
Kamran Baset ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Societal Perspective ◽  
Large Scale ◽  
Operating Cost ◽  
Cost Effective ◽  
Economic Benefits ◽  
Program Cost ◽  
Rural Bangladesh ◽  
Life Years ◽  
The Cost

Abstract Drowning is the leading cause of death among children 12-59 months old in rural Bangladesh. This study evaluated the cost-effectiveness of a large-scale crèche intervention in preventing child drowning. Estimates of the effectiveness of the crèches was based on prior studies and the program cost was assessed using monthly program expenditures captured prospectively throughout the study period from two different implementing agencies. The study evaluated the cost-effectiveness from both a program and societal perspective. Results showed that from the program perspective the annual operating cost of a crèche was $416.35 (95%C.I.: $222 to $576), the annual cost per child was $16 (95%C.I.: $9 to $22) and the incremental-cost-effectiveness ratio (ICER) per life saved with the crèches was $17,803 (95%C.I.: $9,051 to $27,625). From the societal perspective (including parents time valued) the ICER per life saved was -$176,62 (95%C.I.: -$347,091 to -$67,684)—meaning crèches generated net economic benefits per child enrolled. Based on the ICER per disability-adjusted-life years averted from the societal perspective (excluding parents time), $2,020, the crèche intervention was cost-effective even when the societal economic benefits were ignored. Based on the evidence, the creche intervention has great potential for reducing child drowning at a cost that is reasonable.

The Changing Retail Cost Model

2020 ◽  
pp. 145-157
Author(s):  
Alan Treadgold ◽  
Jonathan Reynolds
Keyword(s):  
Business Models ◽  
Cost Model ◽  
Operating Cost ◽  
Sustainable Performance ◽  
Additional Costs ◽  
New Entrants ◽  
To Come ◽  
Established Firms ◽  
The One ◽  
The Cost

This chapter examines the changing retail cost model. As established firms re-think existing business models, most will need to come to terms with a rather different operating cost model than the one they have been used to in a pre-internet era, when retailing was conducted entirely out of physical stores. Equally, new entrants may struggle to achieve sustainable performance without understanding the full implications of their evolving cost base. In an omni-channel world where shoppers are, as we have discussed, showing much more appetite to shop online and across multiple touchpoints, the implications for the cost model of traditional retailers are considerable. The extent to which any additional costs of omni-channel retailing become ‘baked in’ to the model is also up for discussion.

Study on Machining of Cracking Notches for Automotive Connecting Rod Using WEDM

2010 ◽  
Vol 447-448 ◽  
pp. 228-232
Author(s):  
Yong Jun Tang ◽  
Yuan Bo Li ◽  
Yong Jun Zhang ◽  
Chun Qiang Zhou
Keyword(s):  
Cutting Speed ◽  
Connecting Rod ◽  
Electric Discharge Machine ◽  
Fracture Splitting ◽  
Discharge Machine ◽  
Wire Electric Discharge Machine ◽  
The Cost ◽  
The Relationship ◽  
In Virtue Of ◽  
Splitting Process

In order to resolve the problem of connecting rod notches machining, a new process of WEDM (Wire Electric Discharge Machine) has been presented, and it is greatly possible that expensive laser process can be replaced by WEDM in virtue of its unique advantages. Firstly, process parameters of notch have been analyzed, and project of machining notch using WEDM has been introduced, including measures to achieve good-quality notch. The relationship between cutting speed and power supply parameters has been investigated, and it is discovered that micro-crackle on bottom of notch are greatly effect to fracture splitting process, also new idea of active controlling micro-crackle has been presented. Finally, fracture splitting machining has been carried out. The cost and entrance standard of fracture splitting process are greatly dropped owing to new breakthrough of machining notch using WEDM.

Life Prediction of Cutting Tool by the Workpiece Cutting Condition

2011 ◽  
Vol 223 ◽  
pp. 554-563 ◽  
Author(s):  
Noemia Gomes de Mattos de Mesquita ◽  
José Eduardo Ferreira de Oliveira ◽  
Arimatea Quaresma Ferraz
Keyword(s):  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Operating Conditions ◽  
Production Costs ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Workpiece Material ◽  
The Cost

Stops to exchange cutting tool, to set up again the tool in a turning operation with CNC or to measure the workpiece dimensions have direct influence on production. The premature removal of the cutting tool results in high cost of machining, since the parcel relating to the cost of the cutting tool increases. On the other hand the late exchange of cutting tool also increases the cost of production because getting parts out of the preset tolerances may require rework for its use, when it does not cause bigger problems such as breaking of cutting tools or the loss of the part. Therefore, the right time to exchange the tool should be well defined when wanted to minimize production costs. When the flank wear is the limiting tool life, the time predetermination that a cutting tool must be used for the machining occurs within the limits of tolerance can be done without difficulty. This paper aims to show how the life of the cutting tool can be calculated taking into account the cutting parameters (cutting speed, feed and depth of cut), workpiece material, power of the machine, the dimensional tolerance of the part, the finishing surface, the geometry of the cutting tool and operating conditions of the machine tool, once known the parameters of Taylor algebraic structure. These parameters were raised for the ABNT 1038 steel machined with cutting tools of hard metal.

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