Width Of Cut Research Articles

Improved localized fatigue wear resistance of large forging tools using a combination of multiple coupled bionic models

It is important to solve the partial fatigue wear of large forging dies, where the service life can be short. The purpose of this paper is to use laser remelting biomimetic technology to prepare a coupling biomimetic model combination on the mold surface, strengthen the local fatigue wear resistance of the mold, and extend the service life of the mold. Three types of laser energies were used to prepare the coupling biomimetic elements and analyze the microstructure and phase composition of the specific gravity melting zone. The biomimetic units were combined into a variety of coupling biomimetic models (fringe, mesh, and dense array models with different laser energies), and the number of fatigue cracks and the weight of wear loss of the coupling biomimetic model were compared at different temperatures. The mechanism of the coupling bionic model was analyzed, and the coupling bionic surface with a dense row structure was determined to have strong anti-fatigue wear performance. According to the Range Method, the relationship between wear and fatigue temperature and laser energy of the coupled bionic model was determined. Using DEFORM software to simulate the stress, temperature, and wear conditions of the front axle die surface, different coupling biomimetic model combinations were prepared on the abrasive surface. The die wear and cut edge width of the forgings were reduced after practical production, which proved that the laser bionic local strengthening method can effectively prolong the service life of a die.

Effects on tool performance of cutting edge prepared by pressurized air wet abrasive jet machining (PAWAJM)

Abstract Edge preparation techniques are used to shape a proper edge microgeometry for enhanced tool performance. However, depending on the edge preparation method, the edge properties are also altered. Most of the reported work is limited to the effect of edge micro-geometry. In this paper, cutting edges prepared by pressurized air wet abrasive jet machining (PAWAJM) were evaluated from several aspects including tool edge geometries, tool surface quality and topographies, edge hardness (H) and residual stresses. Furthermore, the influence of the prepared edge on the tool performance of uncoated tungsten carbide cutting inserts with different average cutting edge rounding ( S ¯ ) as well as different form factor (K) were experimentally investigated through the orthogonal turning of AISI 4140 alloy steel. Results show that the performance of the prepared cutting edge depends on the combined effect of the initial state of edge geometry and edge properties For symmetric edges (form factor K = 1), the optimum range for average cutting edge rounding ( S ¯ ) was found to be 20 μm to 30 μm when using cemented carbide tools for dry machining AISI 4140 steel at a feed rate (f) =0.1 mm/rev, width of cut = 3 mm, and cutting speed (vc) = 300 m/min.

Investigation on the Effect of Variation in Cutting Speeds and Angle of Cut During Slant Type Taper Cutting in WEDM of Hastelloy X

Nickel-based superalloys are classified under difficult to machine materials due to its higher affinity to tool materials and low thermal diffusivity. Wire electric discharge machining (WEDM) is a spark eroding technique for precise machining of such superalloys with complex machining geometries. Tapering in WEDM has many disadvantages like wire break, angular inaccuracies and dielectric distribution for better surfaces. In this paper, a unique method was developed and employed to achieve taper surface by tilting the workpiece using a slant type taper fixture for machining of tapered surfaces. Different aspects like cutting thickness, surface roughness, slant angle, surface crack density and width of cut were examined for five distinct cutting speed parameters at different angles, namely 0°, 15°, 30°, 45° and 60°. In the present research work, Hastelloy X was machined using zinc-coated copper wire and cutting speed was ranged between 0.16 and 2.49 mm/min. The slant angle was observed to be independent of cutting speed, and it was influenced by wire vibration, manufacturing imprecisions of slant fixture. It was found that as the cutting speed increases, surface crack density and surface roughness also increase. It was observed that both the parameters increased with the increase in the angle of cut from 0° to 60° although the cutting speed decreased.

Metallization of Silver Through Coffee‐Ring Assisted Ribonucleic Acid Scaffolding Technique

AbstractPreferential binding of base pair units with metallic ions within deoxyribonucleic acids (DNA) to form metal‐DNA complexes are well studied and understood. Excitingly, such natural processes have been utilized “artificially” for designing and fabricating nanometallic structures and patterns primarily using double stranded DNA. However, little or no effort has been given to ribonucleic acid or RNA in this aspect. Therefore, in this work we study the scaffolding effect of RNA on metalizing silver (Ag) ions and further the diffusion of majority of the Ag‐RNA complexes towards artificially introduced cut or scribed edges as a result of the coffee‐ring effect. Upon removal of the RNA scaffold, metallic nanostructures remain along the line of the cut corresponding to the micrometre scale length of the cut, exercising some amount of control and manipulation of parameter. Other parameters such as the height and diameter may directly be related to the concentration and diffusion of the Ag‐RNA complexes, while gap size related to the cut width. We anticipate that further in‐depth studies will be required before a comprehensive model could be proposed for highly controllable and flexible nanostructure and nanowire fabrication using nucleic acid scaffolding techniques.

Effects of Double V Cuts in Perforated Twisted Tape Insert: An Experimental Study

The thermal performance of heat exchanger is considerably enhanced by the use of inserts. Twisted tape inserts are known for producing large heat transfer enhancements at the expense of fairly large friction penalty. With the objective to explore the effect of twisted tape with perforations and V cuts, the present study investigates the thermo-hydraulic performance of solid twisted tape, perforated twisted tape, and perforated twisted tape with double V cuts for the Reynolds number range of 2000–25000. During the experiments, the twist ratio of tapes is varied in the range of 2–6, while the depth ratio and width ratio of V cuts for perforated twisted tape with double V cuts are varied in the range of 0.2–0.27. The maximum enhancements in Nusselt number and friction factor were found to be 3.5 and 9.63, respectively, corresponding to the perforated twisted tape with double V cuts having V cut depth ratio and width ratio of 0.27 and twist ratio of 2.

Measurement Method of the Width of the Strands of Cut Tobacco Based on Digital Image Processing

Summary The width of cut tobacco strands is an important indicator for physical parameters as well as for the smoking quality. In some countries, cut width helps to distinguish fine-cut tobacco and pipe tobacco and thus differentiates taxation rate. A new method for rapid measurement of the width of cut tobacco strands was developed based on digital image processing, because the method described in ISO 20193, though easy to implement in factories, proved time consuming and generated high testing costs. The essence of this method is to determine the statistic width of incisions. The straight-line segments represent the width of strands of cut tobacco, from which the determination of the width for randomly placed tobacco strands could be achieved. Five kinds of samples (‘ISO collaborative study samples 0.4 mm, 1.0 mm, 1.6 mm and 3.0 mm’ and ‘Guangdong baked 0.9 mm’) were used to study the comparability of the measurement results between the method presented in this work and the current ISO method. Results show that accuracy and repeatability are comparable. In addition, the testing efficiency of the method presented in this work appears to be higher than the current ISO method, and it is thus a promising alternative method for measuring the width of strands of cut tobacco.

Thermal cutting of thermomechanically rolled S700MC and heat-treated S690QL steels

The article describes the impact of oxygen, HD air plasma and laser beam cutting processes on structural changes and quality of the surface of thermomechanically treated S700MC and heat-treated S690QL steels. Taking into account good quality of obtained cut surface, particular attention shall be attached to the structural and chemical changes due to the impact of the heat cycle. Those modern steels are especially susceptible to a loss of their properties during the heat interaction in thermal cutting processes. The quality of the surfaces after thermal cutting processes were evaluated in accordance to ISO 9013:2017 (bevel angle, surface roughness, rectangularity tolerance). Also, measurements of cut widths and breakthrough holes diameters were accomplished. In the next stage the hardness measurements and metallography examination were performed. The following devices were used for this purpose: metallographic light stereoscopic microscope Olympus SZX9 and Wilson Wolpert 401 MVD for Vickers’s hardness measurements.

Modeling of the catastrophe of chip flow angle in the turning with double-edged tool with arbitrary rake angle based on catastrophe theory

It has been found experimentally that when planing or turning with double-edged tool with 0° rake angle, the chip flow angle will suddenly change with the continuous change of cutting parameters. This phenomenon, named the catastrophe of chip flow angle, is caused by the nonlinearities in non-free cutting process, but further study has not been conducted. To explore the mechanism of the catastrophe of chip flow angle, in this paper, a mathematical model (cusp catastrophe model) of the catastrophe of chip flow angle in the turning with straight double-edged tool with arbitrary rake angle is established based on catastrophe theory. Applying this model, the main characteristics of the catastrophe of chip flow angle are analyzed, and a set of critical conditions of the catastrophe of chip flow angle is predicted. To verify the predicted critical conditions of this model, a group of experiments on 6061 aluminum alloy with double-edged tool with given rake angle is designed. In this experiment, the continuous change of width of cut is achieved by turning the specially designed tapered end face of 6061 aluminum alloy, and the critical conditions of the catastrophe of chip flow angle are captured by analyzing the chip flow videos and the dynamic cutting forces. The agreement between the critical conditions predicted by the model and the experimental results is satisfactory.

English

A predictive model for the determination of optimum fuel consumption of a tractor during ridging operation has been developed. The model development involved field experimentations to determine the various parameters affecting tractor fuel consumption, like draught, speed, depth of cut, soil moisture content, cone index and width of cut. The field investigations were carried out at the farm of Rivers State Agricultural Development Programme in Port Harcourt, Nigeria. The field experimental design adopted was the Factorial in Randomized Complete Block Design (RCBD). It consisted of 9 experimental treatments with three replications. The experimental land area was 160 m by 32.5 m (5200 m2), which was sub-divided into three blocks of 9 plots each, measuring 50 m by 2.5 m, with an inter-plot spacing of 1 m provided for different treatment options. The experimental fuel consumption was determined from measuring the actual amount of fuel used by the tractor per unit time. The model equation was then formulated using the Buckingham pi theorem. The model showed that tractor fuel consumption during ridging is directly proportional to the draught, ridging speed, height of ridge and moisture content; and inversely proportional to the penetration resistance and width of cut. The model was validated by graphical comparison and with root mean square error and paired t-Test. The results obtained showed that there was no significant difference between the measured and predicted values at 95 and 99% confidence limits; and the model can accurately predict tractor fuel consumption during ridging operations using a disc ridger. Key words: Buckingham pi theorem, disc ridger, fuel consumption, predictive model, ridge height, ridging operation, ridging speed, tractor.

Numerical study on heat transfer enhancement and flow characteristics of double pipe heat exchanger fitted with rectangular cut twisted tape

In the present study, the heat transfer, friction factor and thermal performance factor of rectangular cut twisted tape (RCT) that are inserted in inner tube side of a double pipe heat exchanger (DPHE) are numerically examined. The obtained results have been compared with the performance of heat exchangers, which are equipped/unequipped by typical twisted tape (TT). The RCTs have constant twist ratio (Y = 3.0) and are used in different cut depth ratios (DR = 0.15, 0.24 and 0.33) and cut width ratios (WR = 0.15, 0.24 and 0.33). The investigated Reynolds number range is from 6000 to 18,000 and the working fluid is considered to be water. Hot water with a variable mass flow rate is flowing through the inner pipe but cold water has counter flow through annulus side with constant mass flow rate. For the selection of the turbulence model and validation, the obtained numerical results for plain double pipe heat exchanger (P-DPHE) and heat exchanger with TT are compared with empirical correlations. Then the more accurate model was used to simulate the RCTs cases. Comparing the simulation results for RCTs and TT, it was determined that Nusselt number, friction factor and thermal performance factor will have higher value when using RCTs. This behavior is directly and inversely proportional to the DR and WR respectively. In this study, the highest thermal performance factor is about 1.46 which is obtained for RCTs in DR = 0.33 and WR = 0.15 conditions. In addition, new empirical correlations have been offered for calculating a Nusselt number and friction factor for inserted rectangular cut twisted tape in a tube.

Numerical and experimental investigations into microchannel formation in glass substrate using electrochemical discharge machining

Microchannels formed in non-conductive substrates like fused silica, glass and quartz, etc, have wide applications in the field of micro-fluidic and lab-on-chip applications due to their optical transparency, chemical inertness, and biocompatible nature. Electrochemical discharge machining (ECDM) has emerged as a potential low-cost fabrication method to fabricate microfeatures in these materials, compared to conventional laser etching techniques. In this paper, numerical simulation and experimental fabrication of microchannels in a glass substrate using the ECDM based micromilling technique is demonstrated. Stainless steel needle as tool electrode is used in alkaline electrolyte medium. The effects of process parameters viz. tool feed rate, pulse frequency and machining voltage on material removal rate (MRR) and surface roughness (SR) of the microchannels were analysed. The experimental results showed that the MRR and SR increases with an increase in machining voltage and tool feed rate but reduces with an increase in the pulse frequency. Simulations using FEM-based model showed similar trends in MRR with that of experiments. A comparison between the cross-section profiles obtained by the experimental work and predicted profile by the numerical simulation showed some deviation between them due to the Gaussian heat flux assumption in the numerical model. Optical images showed that KOH performance is comparatively better than NaOH with respect to thermal damage and width of cut. Further, multi-objective optimization was performed using utility theory coupled with Taguchi’s method to optimize the process parameters. Moreover, the capability of the ECDM process was demonstrated in fabricating various other micro-features such as sinusoidal channel, letter engraving, etc in a glass substrate, which can be extended to other brittle materials like quartz, fused silica, ceramic, etc.

An experimental investigation of changing cut mark cross-sectional size during butchery: Implications for interpreting tool-assisted carcass processing from cut mark samples

Butchery occurs at the intersection between technology, carcass processing behavior, and animal anatomy, and records traces on fragmentary specimens including cut marks. The causal factors and contexts that generate bone surface modifications have been well-studied in experimental archaeology but the ways in which cut mark size or morphology change with time during butchery in response to tool edge dulling or carcass desiccation is currently unknown. This study examines cut mark cross-sectional width and depth change during a sequence of experimental butchery trials that control for the effects of animal size, bone portion density, tool weight, and flake versus core tool type. Mark size is measured from vinyl molds under low-power magnification (40×) and compared to more precise 3d measurement techniques. Tool type and the order of carcass segment defleshing was systematically varied across the experiment, and a linear mixed effect regression model was used to explore the impact of these fixed factors and consider random variability introduced by potential differences in the four cows butchered by eight tools. Mark width and depth samples were negatively related to the density of the portion where marks occur, tool weight had a weak, but significant influence on mark size, and marks incised at different stages in the sequence of defleshing events were similar in width and depth. With current measurement techniques and the large variability in mark size produced during butchery, it is not impossible to infer the timing of mark creation during a tool's use life or its place in a sequence of butchery events, but methodological advancement may overturn this pessimistic conclusion.

Characterizing the local oxidation nanolithography on highly oriented pyrolytic graphite

Here, we characterize the patterns obtained through local oxidation nanolithography (LON) on highly oriented pyrolytic graphite as the write bias, speed, and force were varied. Different types of patterns—bumps, cracked bumps, and trenches—were obtained and characterized using four shape descriptors—pattern width, pattern height, cut width and cut depth. With an increase in write bias the obtained pattern type varied from bumps to cracked bumps to trenches. The use of a bias above 7.25 V resulted in trenches with increased variability in shape descriptor values. Similarly, an increase in write speed demonstrated a transition from trenches to cracked bumps to bumps. An increase in write force from 75 to 150 nN showed a shift in the threshold voltage from 4.25 V to just under 3.75 V and formed cracked bumps instead of bumps. These findings help solve the mystery of why bumps were not reported at threshold voltages before 2008. We believe these findings will be enable uniform reproduction and report of LON pattern.

Effect of Cutting Parameters on Machining Induced Distortion in Thin Wall Thin Floor Parts

This paper presents experimental study on the effect of machining parameters viz., feed, speed, width of cut and depth of cut on machining induced distortion. Machining experiments were done using Response Surface Methodology. Optimization of machining parameters for minimum machining induced distortion was also carried. Four factor, three level Box-Behnken method with analysis of variance is used in dry machining aluminium alloy 2014 T651 with two flute solid carbide Ø 10 mm milling tool. Machining simulation experiments were also carried out using Deform 3D software to know the effects of these parameters on forces and temperature generated for correlation with machining induced distortion. Results show that feed, width of cut and depth of cut have significant effect on machining induced distortion. It is observed that, there is an increase in machining induced distortion due to increase in cutting forces in Z – direction and temperature with increase in feed, depth of cut and width of cut during milling thin-wall thin-floor components. The optimal combination of cutting parameters arrived with target values of distortion and twist less than 0.09 mm is feed 0.18 to 0.2 mm/tooth, speed 180 to 210 m/min., width of cut 5.6 mm and depth of cut 0.4 mm.

Investigation of surface topology in ball nose end milling process of Inconel 718

Inconel 718 known as hard-to-cut material due to its superior mechanical properties; high creep resistance, high fatigue strength, and able to withstand at elevated temperature which remains as challenge to possesses a lower surface roughness (Ra) during machining. The surface topology indicates the integrity of the machined parts. The quality of the Inconel 718 surface during end milling process was investigated. The experiments involved the use of PVD coated with TiAlN/ AlCrN ball nose tungsten carbide with varying of cutting speeds (Vc) ranging between 100 and 140 m/min, a feed rate (fz) of 0.1–0.2 mm/tooth, and an axial depth of cut (DoC) of 0.5–1.0 mm. The effects of the width of cut (WoC) between 0.2 and 1.8 mm were carried out. Due to the profile of the milled surface is complex; some variations in gap distance on the spiral profile were detected. The cutting path area to be found that, the new cut is overlapped which generate a new surface roughness by eliminating the previous cut thus the non-uniform feed marks being created on the machined surface. The surface roughness measured in feed direction was found to be lowered than pick a direction. Furthermore it was found that the WoC are causes the variation in Ra. During machining at low feed rates, the phenomenon of carbide particles was observed which results third body abrasion of machined surface. The particles are then trapped between the fragments and tear surface of the workpiece, thus increases the surface roughness. Based on the interaction effect of WoC and fz, it can be concluded that the feed rate effects on the quality of machined surface whilst WoC controls Ra variation.

Experimental and Parametric Study on the Pull-Out Resistance of a Notched Perfobond Shear Connector

To ease the installation of perforating rebars through multi-holes, an alternative notched perfobond shear connector was proposed by cutting out the hole edge. This paper presents the test results of six pull-out specimens with conventional and notched perfobond shear connectors. The objective was to compare the failure modes and pull-out behaviors of perfobond shear connectors using circular holes and notched holes. Furthermore, the explicit finite element method was introduced and validated to generate parametric results for pull-out tests of notched perfobond shear connectors. A total of 33 parametric simulations were performed to further study the influences of several variables, including the hole diameter, the cut width, the perfobond thickness, the concrete strength, the diameter and strength of the rebar, and the strength of the structural steel. The experimental and numerical results were used to evaluate the previous equations for perfobond shear connectors. Finally, an alternative equation was proposed to estimate the pull-out resistance of notched perfobond shear connectors.

Multi-Objective Optimization of Energy Consumption and Surface Quality in Nanofluid SQCL Assisted Face Milling

Considering the significance of improving the energy efficiency, surface quality and material removal quantity of machining processes, the present study is conducted in the form of an experimental investigation and a multi-objective optimization. The experiments were conducted by face milling AISI 1045 steel on a Computer Numerical Controlled (CNC) milling machine using a carbide cutting tool. The Cu-nano-fluid, dispersed in distilled water, was impinged in small quantity cooling lubrication (SQCL) spray applied to the cutting zone. The data of surface roughness and active cutting energy were measured while the material removal rate was calculated. A multi-objective optimization was performed by the integration of the Taguchi method, Grey Relational Analysis (GRA), and the Non-Dominated Sorting Genetic Algorithm (NSGA-II). The optimum results calculated were a cutting speed of 1200 rev/min, a feed rate of 320 mm/min, a depth of cut of 0.5 mm, and a width of cut of 15 mm. It was also endowed with a 20.7% reduction in energy consumption. Furthermore, the use of SQCL promoted sustainable manufacturing. The novelty of the work is in reducing energy consumption under nano fluid assisted machining while paying adequate attention to material removal quantity and the product’s surface quality.

Spilled ink blots the mind: A reply to Merrit et al. (2018) on subjectivity and bone surface modifications

Categorical variables identifying microscopic features of cut marks produce high accuracy in discrimination of bone surface modifications, but are vulnerable to variable degrees of inter-analyst subjectivity. Metric analyses of cut mark width and depth are presented by Merritt et al. (2018) as a more objective method of identifying cut marks. However, this uni(bi)variate method has shown very high rates of mark classification error when structurally similar marks are compared. Furthermore, within-sample comparison carried out via subsampling shows that different datasets of metric values, obtained with the same type of tool and raw material, are subject to such a high degree of variability that significant differences of homogeneous subsamples are repeatedly obtained, thus preventing any useful analogs to be made. Additionally, this much higher stochastic variability depends on limited knowledge of the contextual processes that intervene in cut mark metric properties, as well as on a mismatch between theoretical premises on the immanent-configurational process-trace dynamics and their confusion during experimental praxis. The selection of specific contextual variables and disregard of others, in addition to the combination of different tool types and raw materials, distorts the resulting cut mark properties. This indicates that even when attempting to use exclusively metric numeric variables, subjectivity is a conditioning factor in analyzing and interpreting cut marks.

Don't cry over spilled ink: Missing context prevents replication and creates the Rorschach effect in bone surface modification studies

The scientific replicability crisis has recently focused on bone surface modification (BSM) analysis, which underlies zooarchaeological and anthropological conclusions about the ecology and evolution of tool-assisted carcass consumption behavior. We review a recent blind test of inter-analyst correspondence in morphometric analysis of experimentally generated butchery marks that advocates algorithmic methods for diagnosing and measuring BSM in an effort to standardize methodology and minimize inter-analyst error (Domínguez-Rodrigo et al., 2017. Use and abuse of cut mark analyses: The Rorschach effect. Journal of Archaeological Science, 86, 14–23. https://doi.org/10.1016/j.jas.2017.08.001). This study overstates concern about the inaccuracy of BSM measurement and interpretation, concluding that BSM analysis is a subjective, non-scientific endeavor. Based on a minimally described sample of cut marks, it measures variables that involve inherent inaccuracy and subjectivity and overlooks how the contexts of experimental sample generation – particularly the difference between immanent and configurational processes – differentially affect cut mark morphometrics. We illustrate this discussion with experimental taphonomic examples focused on analytical context including sample construction and control over factors that affect cut mark cross-sectional size. Our analysis suggests the relationship between tool attributes and cut mark morphology is not generalizable to all experimental and archaeological butchery contexts. We show that our experimental samples capture metric variability observed in archaeological cut marks, but that intentionally incised marks and realistic defleshing marks differ in width and depth. Further, when controlling for factors that impact cut mark size including animal size class, tool type, butcher experience, and density across bone portions, overlapping cut mark widths and depths produced by phonolite and ignimbrite flakes lead to poor classification of marks according to causal flake material, which casts doubt on the ability to discriminate cut marks made by different materials. We build datasets that include diverse experimental contexts and suggest that meta-analysis can disentangle how multiple configurational factors contribute to cut mark morphometric attributes. Ultimately, progress in BSM analysis rests on inter-analyst replicability, which must be preceded by clear discussion of all parts of the inferential loop – from the design of experiments that generate actualistic analogues, to their use in supporting archaeological arguments. Otherwise, problematic expert knowledge traditions may mask arguments from authority in sophisticated methodological language and under-reported experimental context.

Influence of cutting parameters on surface roughness and strain hardening during milling NiTi shape memory alloy

Nitinol is well known as one difficult-to-machine alloy due to its poor machinability, which requires a large amount of cutting force and cutting temperature, resulting in poor surface roughness and strain hardening. The influence of the milling parameters on the surface roughness and strain hardening with orthogonal experiment is studied in this paper. It is found that cutting speed and feed rate have important influence on the surface roughness and strain hardening. When the cutting speed becomes larger, the surface roughness decreases, while the work hardening decreases first and then gets bigger. The surface roughness and work hardening increase gradually when the feed rate increases. However, the width of cut has little effect on the above surface roughness and strain hardening. The research shows that the medium range of cutting speed selection is better for the milling of NiTi shape memory alloy as used as medical implant materials that can achieve the minimal work hardening and smaller surface roughness.