Cutting Surface Roughness Research Articles

Effect of process parameters on depth of penetration and topography of AZ91 magnesium alloy in abrasive water jet cutting

Abstract In the present study, the influence of dynamic process parameters such as water pressure, traverse speed and abrasive mass flow rate on depth of penetration and surface topography in high strength AZ91 magnesium alloy were investigated using Abrasive Water Jet (AWJ) cutting technology. Process parameters were varied at 3 levels and influences of each parameter on penetration ability were identified using analysis of variance (ANOVA). Contribution of water pressure and traverse speed on jet penetration found higher compared to abrasive mass flow rate. Profile projector was used to measure depth of penetration. Microstructural features and topography of cut surfaces were examined using Scanning Electron Microscopy (SEM). Micro cutting and ploughing were observed on the top and bottom portion of the cut which were similar to that of modes of deformation in other ductile materials like aluminium and steel. Surface roughness of cut surfaces was measured using Taylor Hobson surface roughness tester. Surface roughness found higher at higher traverse speeds and lower at lower traverse speeds. This study also highlights the suitability of AWJ cutting technology for cutting magnesium and its alloys.

The Effect of Selected Technological Parameters of Laser Cutting on the Cut Surface Roughness

The Effect of Selected Technological Parameters of Laser Cutting on the Cut Surface Roughness

Multi-Objective Optimization of Surface Roughness and Cutting Forces in Hard Milling Using Taguchi and Response Surface Methodology

Cutting forces and surface roughness are important output parameters affecting the machining performance and quality of any machined surface in hard milling. In order to obtain the best surface quality and highest productivity, the input-cutting parameters need be considered and chosen properly whenever hard milling is involved. Therefore, in this paper, an attempt is made to conduct the multi-objective optimization of the surface roughness (Ra) and the resultant cutting force (Ft) in hard milling of SKD61 steel by Taguchi method and Response Surface Methodology (RSM). Values of the input parameters for milling tests are chosen through the stability lobe diagram of a machine tool simulated by the use of Cutpro software. The Taguchi method is used for designing all of the milling experiments. The values of Ra and Ft are measured by a Surftest SJ-400 and a dynamometer, respectively, and then analysis of variance is conducted to find out the effect of machining process conditions on Ra and Ft. In order to get the low Ft and Ra, a multi-objective optimization is implemented with the use of the desirability function. The results reveal that the optimized machining conditions for Ra and Ft are a cutting speed of 100 m/min, a feed rate of 0.015 mm/tooth, and a depth of cut of 0.44 mm, with predicted Ra of 0.206 µm and Ft of 66.58 N.

Beam polarization effect on the surface quality during steel cutting by a CO2 laser

The beam polarization effect on the quality of oxygen-assisted laser cutting of low-carbon steel by a CO2 laser is studied experimentally and theoretically. The cut surface roughness is examined as a function of cutting parameters in the case with linear polarization of the laser beam. It is demonstrated that the minimum roughness level is reached if the electric field vector is aligned perpendicular to the cutting velocity vector. The distribution of the absorbed laser power inside a narrow cut channel is computed numerically. It is concluded that the absorbed power distribution exerts a significant effect on the surface quality and it is important to provide radiative heating of the side walls to ensure lower-level roughness. Based on the results obtained, a possible explanation is proposed for the worse quality of the cut surface of metal materials by a fiber laser as compared to a CO2 laser.

Influence of Process Parameters on CNC Turning of Aluminium Hybrid Metal Matrix Composites

An effort has been made in this investigation to find the influence of turning process parameters on the machinability of hybrid metal matrix composite comprising alumina (Al2O3) and molybdenum disulphide (MoS2) particulates dispersed on aluminium casting alloy LM6 in turning process. Design of Experiments approach was used to plan the experiments and the acquired data were analysed using design expert software associated with response surface method (RSM). In this paper work cutting speed, feed and depth of cut were considered as input process parameters and the resultant force of cutting forces in three directions, Specific Cutting Pressure (SCP) and surface roughness Ra were considered as responses. Statistical analyses were carried out to estimate the performance of machining parameters. The influence of input parameters on machining-force, SCP and the surface roughness Ra were analysed using surface response graphs. The experimental study revealed that cutting speed and feed were the most influencing parameter that affects the machining force and SCP.

Experimental Analysis and Investigation of Machining Parameters in Finish Hard Turning of AISI 4340 Steel

Hard-turning is alternative machining process to the cylindrical grinding. It produced surface finish as good as cylindrical grinding with higher material removal rates by keeping small feed and depth of cut. It avails machining process in machining cost, high quality, less down machining time, lower investment, and smaller tooling inventory while get rid of non-value added activities. The optimum selection input parameters results into reduced tool wear and surface roughness and wearing of tool. The present work evaluates effect of input Parameters such as nose radius, cutting speed, feed and depth of cut and output parameter surface roughness on hardened AISI 4340 steel material. Taguchi’s technique is used as experimentation method and multiple regression method is used in order to optimize machining parameter for minimum surface roughness. The results showed that nose radius is more influencing parameter than feed, cutting speed, depth on surface roughness in finish hard turning. A total 9 experimental runs were conducted using an orthogonal array In order to verify result multiple regression analysis has modelled. Optimize cutting parameters which give high surface finish is obtained. Thus, it is possible utilization of machine and decrease production cost in an automated manufacturing environment.

Development of Cuttability Abacuses in Abrasive Waterjet Cutting With Regard to Depth of Cut and Roughness of Cut Surfaces

Abstract The purpose of this study is to develop a cuttability abacus, including traverse speed and pump pressure, with regard to depth of cut and roughness-of-cut surface in the cutting operation using an abrasive waterjet on limestone, commercially named Sivrihisar Light Beige. For this purpose, cuttings were realized with an abrasive waterjet cutting machine at six different traverse speeds (400, 600, 800, 1000, 1500, and 2000 mm/min) and six different pump pressures (90, 120, 180, 230, 300, and 360 MPa) with constant standoff distance, abrasive flow rate, and nozzle diameter depending on the factorial design of the experiment by using Design Expert 7.1. Experimental measurements using a digital caliper for the depth of cut and a Surftest SJ-400 surface roughness tester for roughness, after the cutting operations, were also carried out. As a result, a cuttability abacus for a limestone sample was developed for abrasive waterjet cutting, and is presented in this study. These abacuses could be of help in the natural stone industry with regard to a more efficient usage of the abrasive waterjet cutting machine. By using them, it is easy to specify the depth of cut and roughness values in different operational parameters before starting the cutting operation. These abacuses also can be used in the machining and engraving of marble slabs and tiles for technical and artistic purposes.

Long-pulse quasi-CW laser cutting of metals

Long-pulse quasi-CW laser cutting of metals is well suited to small-scale manufacturing settings where process flexibility is of high value and investment capacity is limited. This process refers to cutting operations performed with millisecond laser pulses obtained through modulation of the pump source to achieve continuous-wave (CW) operation over limited time intervals. The ability to minimize heat conduction losses, comprising the vast majority of absorbed laser power at low velocity, allows processing of relatively thick sections compared to what would be possible at the same average power with a CW laser source. The present study quantifies the reduction in heat conduction losses with pulsed exposure by employing a simple power-balance representation of the heat flow problem. Laser-cutting experiments are performed with inert and active assist gases on 1- and 4-mm thick steel samples, varying peak power (0.3–3 k W), pulse energy (0.3–12 J), repetition rate (25–1000 H z), and velocity (1–40 m m/s). The lowest minimum laser cutting power and highest cutting efficiency are achieved with maximum peak power and lowest permissible pulse overlap for a continuous cut. Under these conditions, heat conduction losses are reduced by more than 60% with nitrogen assist gas compared to CW exposure and more than 50% with oxygen. The calculated average cutting front temperatures are 450–630 ∘C and 620–900 ∘C, respectively, well below the melting temperature of steel. Lowest dross adhesion and cut edge surface roughness are obtained with oxygen assist gas, leading to both the lowest minimum average cutting power and highest cut quality. These results demonstrate an efficient process that improves the feasibility of low velocity laser cutting and therefore the range of industrial applications in which laser technology can employed.

Ductile Regime Machining of Germanium at Varying Depth of Cut

Diamond turning is widely being used from last two decades for the fabrication of optical surfaces with nano-metric accuracy. However, obtaining ductile regime zone during machining is still challenging. Ductile regime machining helps to obtain a crack-free surface on brittle material i.e. germanium, silicon, silicon carbide. The precision manufacturing of these materials is primarily achieved by diamond turning, which normally make use of diamond tool to shear the material and achieve required surface quality with minimum subsurface deformation. This paper investigates the effect of depth of cut on germanium substrate varying from nanometer range to micrometer range (100 nm, 200 nm, 300 nm, 400 nm, 500 nm and 1000 nm, 2000 nm, 3000 nm, 4000 nm). With varying depth of cut surface morphology, surface roughness and subsurface deformation are analyzed. Interferometry technique and SEM are used for the evaluation of surface roughness and surface morphology. Best surface roughness of 3.39 nm is achieved at depth of cut of 300 nm for the machining of germanium with minimum valley and subsurface deformation.

A novel ultrafiltration grade nickel iron oxide doped hollow fiber mixed matrix membrane: Spinning, characterization and application in heavy metal removal

Abstract Nickel iron oxide nanoparticle incorporated hollow fiber mixed matrix membrane was prepared to achieve high throughput as well as high selectivity for heavy metals. The fibers were characterized in terms of their morphology, permeability, molecular weight cut off, zeta potential, surface roughness and adsorption capacity of various toxic heavy metal species. Scanning electron micrograph images showed that the tear drop-like pores in cross section of the fibers were changed into finger-like macropores on addition of nanoparticles. Porosity and pore size in the fibers increased with nanoparticle concentration. Membrane permeability increased almost twice by addition of 3 wt% nanoparticles compared to pure polysulfone membrane. Similar concentration of nanoparticles made the membrane more hydrophilic reducing its contact angle from 77° to 64° and at the same time, molecular weight cut off of the hollow fibers increased from 17 kDa to 34 kDa. Surface zeta potential of the fibers decreased with pH and the membrane with 3 wt% nanoparticles showed a surface potential about −16 mV at pH 9. The maximum adsorption capacity of membrane with 3 wt% nanoparticles was the highest for lead (52 mg/g) followed by copper (42 mg/g), zinc (35 mg/g) and cadmium (24 mg/g). Nickel (17.5 mg/g) and chromium (18 mg/g) had comparable adsorption capacity. Thus, the mixed matrix membrane developed in this study has significant potential in removal of heavy metals from aqueous solution.

Improved Tool Geometry to Enhance Surface Quality and Integrity in Trimming of CFRP Composite Materials

Experimental trimming tests on unidirectional carbon fibre reinforced polymer composites using a conventional tool and a newly developed V-shaped tool were performed to verify the effect on cut quality and surface integrity. Depth of cut and cutting speed were fixed, whereas the fiber orientation angle θ with respect to the cutting direction was varied in the range 0°-180°. Three parameters were selected to evaluate the cut surface: the depth of the splits at the cut specimen sides, the depth of the splits generated in the internal material volume, and the cut surface roughness, Ra. These parameters revealed a significant improvement when using the V-shaped tool.

Experimental research on tension balance control of reciprocating winding diamond wire saw

In this study, the variation in diamond wire tension during the reciprocating wire-winding machining process is investigated to improve the cutting stability and machining precision of a reciprocating winding diamond wire saw. Furthermore, the main causes of wire tension variation are analyzed, a tension control method using a PI (proportional–integral) regulator is proposed, and a wire tension detection and control mechanism is developed to solve the problem of tension variation during the machining process. The performance of this mechanism is verified through experiments, in which polycrystalline silicon materials are cut. Experimental results show that the designed mechanism can effectively mitigate tension instability during the reciprocating wire-winding machining process, control the wire tension fluctuation within 0.6 N, and significantly improve cutting efficiency, cutting surface roughness, and machining dimension accuracy.

Quantifying eroding head cut detachment through flume experiments and hydraulic thresholds analysis

Gully erosion is known as one of the most important environmental earth hazards in the world and especially in Iran where it is controlled by both environmental and human factors. This research has attempted to assess the effects of land use (LU) on gully hydraulic flow condition of head cut initiation under similar soil conditions through an experimental field base plot (15 × 0.4 m). Results reveal that critical shear stresses (τ cr) for head cut initiation in abandoned, dry farming and rangeland, land are 174, 43 and 192 dyne/cm2, respectively, the remarkable differences being the consequence of soil surface condition (e.g., vegetation cover and micro-relief). Moreover, the flow turbulence and response of soil to an increase in flow condition (rate and depth) indicated a complicated behavior which can be addressed to the influences of surface micro-relief features and LU effects. Although a simple linear equation between τ cr and K c can be used to estimate the parameter, significant differences of regression coefficients decrease the general equation for whole data sets. The main explanation for dramatic (3–4 times) variations of τ cr is the vegetation cover and soil surface conditions. In fact, the significant decrease in τ cr under dry farming can be linked to the effect of tillage operation on aggregate strength and soil susceptibility. Findings showed that a boundary shear stress of 35 dyne/cm2 used in some physically based models for predicting erosion is subjected to high uncertainty and not appropriate for estimation of gully development. In addition, the duration of land abandonment has a crucial influence on soil erodibility, a factor given little consideration in erosion models. For the prediction of gully erosion rate, it is recommended that a single erodibility parameter is created from the functional relationship between τ cr and K c. Due to the interaction of slope, flow regime, shear stress and type of ground cover, the relationship between head cut initiation and surface roughness varies. In addition, the Reynolds number is not a reliable parameter for estimation of surface roughness during head cut initiation. Therefore, for gully erosion modeling other hydraulic parameters should be used to produce a reliable model. For prediction of gully erosion rates a single erodibility parameter from the functional relationship between τ cr and K c could be used.

Effect of Water Flow Direction on Cut Features in the Laser Milling of Titanium Alloy under a Water Layer

Laser ablation under a flowing water layer can reduce thermal damage in work material and also provide a better machining performance than processing in ambient air. However, there is still a lack of insight into a more complicated process like laser milling operation in water. Besides the laser parameters, the roles of water flow direction on the cut geometries need to be elucidated to realize the viability and reliability of the laser milling process in water. This study is for the first time to reveal the effects of water flow direction on the cavity dimensions and cut surface roughness in the laser milling process performed under a flowing water layer. Titanium alloy was used as a work sample in this study. The experimental results indicated that the laser beam should travel in the same direction of water flow to provide a uniform cavity depth and smooth milled surface.

Surface Morphology of Silicon Induced by Laser Ablation in Flowing Water

Underwater laser machining process has a high potential over the typical laser ablation to remove materials with less thermal damage occurring along the cut. However, the formations of vapor bubble and cut debris in water can substantially disturb the incident laser beam, thereby reducing the ablation performance. Instead of performing the ablation in still water, the flowing water technique was applied to flush away the cut debris and bubble generated. In this study, the effects of laser pulse energy, traverse speed and water flow rate on the cut surface roughness and heat-affected zone in the laser grooving of silicon were experimentally investigated and analyzed. The findings revealed that the cut surface roughness decreased with the increases in laser pulse energy and laser traverse speed. Though a higher water flow rate resulted in a rougher cut surface, the heat-affected zone can be minimized when the increased flow rate was applied.

Research on Vibration and Surface Roughness in Hard Cutting Process of Hardened Steel

Vibration of cutting process is an important factor to influence the surface roughness. By Orthogonal design, take hard cutting surface roughness test for bearing steel GCr15 with 62~64HRC, analyzing the law of the variation of cutting parameters effect the amount of vibration and the surface roughness value. And it establishes the formula about vibration and surface roughness. The amount of vibration and the surface roughness increases first and then decreases while the cutting speed increases in a specific area, meanwhile its vibration will reduce and its surface roughness will enlarge while the feed increases. The cutting depth has a little influence to surface roughness and vibration, and the cutting depth is first decreased and then increased accompanied by the tool nose radius increases with the increase of vibration and the surface roughness. The research can provide reference for improving the surface quality.

The Utmost Thickness of the Cut Sheet for the Qualitative Oxygen-assisted Laser Cutting of Low-carbon Steel

The peculiarity of the laser cutting is its high speed combined with the high quality of the cut surface. The issues, how the cutting speed and cut roughness change with the sheet thickness, and what is the utmost thickness at which the quality is acceptable, are of practical importance. Theoretical models of the laser cutting developed today do not permit answering these questions. In the present work, the task is solved experimentally for the oxygen-assisted laser cutting of low-carbon steel. Under study was the dependence of the cut surface roughness on the cutting speed within the wide range of cut sheet thicknesses. The experiments were carried out with the CO2 laser. The empirical dependencies of the optimal cutting speed (at which the cut surface roughness is minimal) on the sheet thickness are found. It is demonstrated that there is the utmost thickness of 40...50 mm, and above it the qualitative cutting is impossible. The obtained results are compared to the similar ones obtained for the fiber laser.

An investigation on co-axial water-jet assisted fiber laser cutting of metal sheets

Water assisted laser cutting has received significant attention in recent times with assurance of many advantages than conventional gas assisted laser cutting. A comparative study between co-axial water-jet and gas-jet assisted laser cutting of thin sheets of mild steel (MS) and titanium (Ti) by fiber laser is presented. Fiber laser (1.07µm wavelength) was utilised because of its low absorption in water. The cut quality was evaluated in terms of average kerf, projected dross height, heat affected zone (HAZ) and cut surface roughness. It was observed that a broad range process parameter could produce consistent cut quality in MS. However, oxygen assisted cutting could produce better quality only with optimised parameters at high laser power and high cutting speed. In Ti cutting the water-jet assisted laser cutting performed better over the entire range of process parameters compared with gas assisted cutting. The specific energy, defined as the amount of laser energy required to remove unit volume of material was found more in case of water-jet assisted laser cutting process. It is mainly due to various losses associated with water assisted laser processing such as absorption of laser energy in water and scattering at the interaction zone.

CNC선반가공에서 노오즈 반경과 냉각방법에 따른 알루미늄7075의 표면 거칠기에 관한 연구

Current world aircraft industry studies on the precision of the product are in active progress. Particularly in terms of improving the quality of processed products in terms of the surface roughness of the dimensional accuracy, fatigue strength, and corrosion resistance, which affect a lot of research on surface roughness, has been investigated. In this study of aluminum alloy, 7075 aircraft aluminum is used in a cutting CNC lathe machine for the cutting speed and feed rate according to the cutting experiments that were conducted. Additionally, the machine tool of the cooling method soluble cutting oil, insoluble cutting oil by cooling, and cooling the workpiece by cutting surface roughness will be investigated. Through the method and soluble cutting oil coolant cooled by the cutting speed increases, the value of surface roughness showed a regular result. Tool nose radius of 0.8 mm than 0.4 mm picture of when approximately 50 of the surface roughness values were less.

Mechanical characteristics of high-quality laser cutting of steel by fiber and CO2 lasers

The quality of cutting of low-carbon and stainless steel by beams of fiber and CO2 lasers with oxygen or nitrogen being used as a process gas is compared. The cut surface roughness for sheets from 3 to 10 mm thick is determined. Domains of optimal (in terms of the minimum roughness criterion) application of lasers of various types in the space of dimensionless parameters (Peclet number and dimensionless power) are found. It is demonstrated that the CO2 laser is more effective for laser-oxygen cutting, while the fiber laser is more beneficial for cutting with the use of a neutral gas.