Kerf Angle Research Articles

PERFORMANCE ENHANCEMENT OF BRASS EDM ELECTRODES WITH CRYOGENIC TREATMENT WHILE MACHINING THE COLD WORK STEEL AISI D2

This study investigates the performance of deep cryogenically treated brass (CuZn25Al5) electrodes in the die-sink EDM process. Two different cryogenic treatment durations, 6 h and 12 h, were applied to 8 mm diameter electrodes, and their effects were compared to untreated electrodes. The machining tests were conducted under moderate and aggressive conditions. In the machining tests, the 6-h cryo-treated electrode exhibited a 16.8% increase in material removal rate (MRR) under moderate conditions and a 19.7% increase under aggressive conditions compared to the reference electrode. The 12-h cryo-treated electrode showed similar MRR values to the reference electrode but improved tool wear resistance by 9.4% under moderate conditions. The kerf angle was minimized, indicating better hole verticality, in the 6-h cryo-treated electrode group. The improvement in machining performance was attributed to the enhancement in electrical conductivity of the electrodes, which increased by 28% for the 6-h cryo-treated electrode and 20% for the 12-h cryo-treated electrode. X-ray diffraction (XRD) analysis revealed shifts in peak positions and possible phase transformations due to cryogenic treatment. Surface roughness measurements showed improved surface conditions in the cryo-treated electrodes under aggressive conditions. The results indicate that cryogenic treatment enhances MRR, reduces tool wear, and improves surface quality in die-sink EDM. These improvements are attributed to increased electrical conductivity and changes in the internal structure of the brass electrode.

Enhancing machining accuracy of banana fiber-reinforced composites with ensemble machine learning

Through innovative predictive modeling, this study advances Abrasive Water Jet Machining (AWJM) for banana fiber-reinforced biocomposites. Utilizing Artificial Neural Network (ANN) and Long Short-Term Memory (LSTM) models, hyperparameters are meticulously tuned for predicting Surface Roughness (Ra), Material Removal Rate (MRR), and Kerf Angle (Ka). Optimal configurations are identified, such as 3–6-6–4-1, 3–5-5–4-1, and 3–5–4–4-1 for ANN models, and 250, 100, and 50 units for LSTM models. Beyond individual models, the study explores stacking ensemble models, merging ANN and LSTM strengths with a Linear Regression final estimator, showcasing robust performance validated with high R-squared values. Regression models from Design Expert 13 contribute to understanding process parameter-outcome relationships. Optimized input parameters offer insights into minimizing surface roughness and kerf angle while maximizing MRR. This holistic approach, integrating advanced machine learning and ensemble learning, enhances predictive accuracy for banana-reinforced biocomposites, providing a versatile framework for diverse materials processing applications.

Experimental study of penetration for the analysis of pre-cut free surface parameters in rock materials based on response surface methods

The strength of intact rock material is reduced after it has been cut by techniques such as water jets, based on which the use of disc cutter hobs for rock-breaking by hobbing has good economic results. The kerf is the free surface created by water jet cutting. The kerf depth, kerf spacing, and kerf angle are the main parameters affecting the rock-breaking force of the disc cutter, which can be simplified as the normal penetration load of the indenter. To investigate the effect of prefabricated notch parameters on the penetration load and the sensitivity of the response of penetration load to each factor, response surface tests were carried out on sandstone and granite specimens, and every factor’s impact on the penetration load was examined. The results showed that: (1) The single factor analysis and interactive analysis of the prefabricated kerf parameters for sandstone and granite samples showed that the penetration load was negatively correlated with kerf depth and kerf angle, and positively correlated with kerf spacing within the set range of the test. (2) The difference in rock strength can also affect the penetration load of the samples. In the prefabricated kerf-assisted rock-breaking test, for the high-strength rock samples represented by granite, increasing the prefabricated kerf depth can reduce the penetration load of the samples more effectively.

Experimental study of penetration of pre-cut free surface rock materials based on orthogonal tests and response surface testing methods

The parameters of the pre-cut kerf as the free surface on rock material have an important influence on the rock-breaking force of the disc cutter of TBM. The rock-breaking force of the disc cutter can be simplified as the normal penetration load of the metal indenter. In order to study the effect of the pre-cut free surface parameters on the penetration load, orthogonal experiments and response surface tests were carried out on sandstone and granite samples, and extreme deviation analysis and analysis of variance (ANOVA) were performed. The results showed that: (1) the order of priority of the factors affecting the penetration load of the disc cutter was Kerf depth > Kerf spacing > Kerf angle. (2) The fitting degree of the regression equation for the predicted values of the penetration loads of the sandstone and granite samples was R2 (Sandstone) = 0.9810 and R2 (Granite) = 0.9995, respectively, indicating that there was a good fit between the measured and predicted values of the penetration load of the two samples.

Evaluating the optimum abrasive water jet machinability for CARALL composites with various fiber orientations

AbstractCarbon Fiber Reinforced Aluminum Laminated (CARALL) composites are widely used in aircraft structures due to their ability to be produced in different shapes with desired properties and their high impact resistance properties. As with other layered composite materials, processing of CARALL composites by conventional manufacturing methods results in many damage mechanisms such as fiber breakage, deformation in the hole region, stress concentration, resin‐fiber separation and microcracks. One of the modern manufacturing methods, Abrasive Water Jet (AWJ), is a processing method in which the material is removed by abrasion and almost any material can be cut without thermal degradation. There are no experimental studies in the literature on the drilling of CARALL composites by modern manufacturing methods. The aim of this study is to investigate the impact of machining parameters on the output variables (kerf taper angle (K), roundness error (Re) and material removal rate (MRR)) as well as the effect of fiber orientation on the drilling of CARALL composites with different fiber orientations on an AWJ machine. PROMETHEE‐GAIA weighted by Entropy Weighting Method were used to ascertain the optimum levels of control factors. CARALL composites with different fiber orientations were drilled with an 8 mm diameter AWJ with three different water pressures, three different nozzle feed rates. With PROMETHEE‐GAIA multi‐criteria optimization method, the optimum levels of the factors that provide both minimum Re and K values and maximum MRR value were obtained with twill woven material, 1680 mm/min feed rate and 1680 bar water pressure.Highlights CARALL composite materials with two different fiber orientations (twill weave and UD) were used. CARALL composite materials were drilled at different machining parameters. Abrasive water jet was used in drilling experiments. Optimum drilling parameters were determined to achieve minimum roundness error, minimum kerf angle and maximum material removal rate. PROMETHEE‐GAIA was used as a multi‐criteria decision‐making method.

Influence of Awj Parameters on Material Removal Rate, Surface Roughness, and Kerf Angle during Machining of Prosopis Juliflora Bark Fibres/Carbon Reinforced Hybrid Polymeric Composites

This study investigates the impact of changing the settings of the Abrasive Water Jet (AWJ) on the material removal rate (MRR), surface roughness, and kerf angle during the machining process of carbon-reinforced hybrid polymeric composites and Prosopis juliflora bark fibres. The hybrid nature of these materials presents unique machining opportunities as well as difficulties. As a result, optimizing the AWJ settings is essential for productive and efficient machining. The findings demonstrate the intricate connections between the AWJ parameters and the machining characteristics of the hybrid composite. To optimize MRR while minimizing surface roughness and controlling the kerf angle, the optimal parameter combinations are identified. The findings provide valuable insights for the manufacturing industry, particularly concerning sustainable materials and hybrid composites.

A numerical and experimental analysis of CO2 laser micro-milling on PMMA sheet considering a multipass approach for microfluidic devices

Laser-assisted machining is an advanced manufacturing process that provides excellent cutting quality, flexibility, and precision. The current study used a CO2 laser to create microchannels in polymethyl methacrylate (PMMA) sheets using a series of laser passes by varyingparameters such as laser power (30–40 Watt), number of passes (1–4), and cutting speed (20–25 mm/s). A finite element analysis is performed using ABAQUS with subroutines such as Distributed Flux (DFLUX) and User Defined Field (USDFLD) to simulate and predict the upper and lower kerf width, kerf angle, and heat-affected zone (HAZ) during the process. Thermal analysis has been performed by considering the laser beam as body heat flux with a moving heat source. It has been observed that the HAZ tends to reduce with the increase of laser cutting speed. During the laser cutting process, the upper kerf width is found to increase with increasing laser power, as well as with increasing the number of passes at a given laser power and cutting speed. It is also predictedthat when laser cutting speed increases, the kerf width for a given laser power decreases. The experimental and simulation results are in good agreement and the results demonstrated thatthe average percentage error in HAZ, kerf angle,upper kerf, and lower kerf width was 3.21 %, 5.06 %, 7.60 %, and 22.2 %, respectively. The results of this study have significance for the advancement of precise and state-of-the-art manufacturing for application in microfluidic devices.

AN IN-DEPTH INVESTIGATION ON KERF ANGLE IN PIERCED HOLE ON INCONEL-625 SUPERALLOY USING ABRASIVE WATERJET CUTTING PROCESS

This work investigates the piercing of microholes in turbine shroud rings (Inconel-625) using the Abrasive Waterjet Cutting process. The concern with the hole piercing is the kerf angle caused by the attenuation of the jet energy and stand-off distance, which seriously impacts the processing precision of abrasive water jet piercing. The effects of piercing parameters like machining time (40, 60 and 80[Formula: see text]s), abrasive mesh size (80 mesh and 120 mesh), stand-off distance (1, 2, 3 and 4[Formula: see text]mm), abrasive jet pressure (100, 125, 150 and 175[Formula: see text]MPa) are studied to reduce the kerf angle. The kerf angle increased linearly with a stand-off distance increase at different machining times. By piercing for 60[Formula: see text]s and 80[Formula: see text]s, the lowest values of kerf angle are obtained (0.03∘ and 0.02∘). The optimum conditions for making a pierced hole with a minimum kerf angle of 0.02∘ were achieved with a machining time- of 60[Formula: see text]s, abrasive mesh size- of 20 mesh, and abrasive jet pressure- of Scanning electron microscope (SEM) images and visual measuring system (VMS) images are used to identify the surface characteristics in kerf zone. The features, including ploughing, particle embedment, lip impression and wear path due to the ductile mode of erosion caused by high energy impact, is also discussed.

An investigation into cut surface quality of Al6061/Al2O3/B4C composite using hydro-abrasive machining process

The modern era has realized the tremendous potential of metal matrix composites (MMCs) in slowly substituting the traditional materials used in automotive and aerospace industries. Traditional machining of second generation MMCs is quite challenging due to heat generation, tool wear, and low cut surface quality. This work presents an analysis on hydro-abrasive machining (HAM) of the Al6061/Al2O3/B4C composite by using an amalgamated method of gray incidence based response surfaces (GIRS) to produce a good surface quality. The influence of HAM variables [abrasive flow rate (FA), waterjet pressure (PWJ), jet traverse speed (SJT), and stand-off distance (DS)] on various cut surface characteristics [surface roughness (Ra), striation-free zone (SFZ), striation angle (ΘS), and kerf angle (ΘK)] is examined using L27 OA and response surface plots. A hybrid approach of the GIRS method is presented for necessary polynomial modeling and simultaneous optimization. The reduction of response values is primarily influenced by the waterjet pressure and jet traverse speed. An optimal cutting condition resulted in a significant reduction in surface roughness by 19.22% and striation angle by 10.82%. The improvements in striation-free zone and kerf angle were also notable with reductions of 7.89% and 4.74%, respectively. FESEM images of machined surfaces, profile graphs of surface roughness, and images observed using atomic force microscopy were also studied.

Comparison of drilling of Inconel 625 by AWJM and WEDM

PurposeThis study aims to comparatively analyze the cut parts obtained as a result of cutting the Ni-based Inconel 625 alloy, which is widely used in the aerospace industry, with the wire electro-discharge machining (WEDM) and abrasive water jet machining (AWJM) methods in terms of macro- and microanalyses.Design/methodology/approachIn this study, calipers, Mitutoyo SJ-210, Nikon SMZ 745 T, scanning electron microscope and energy dispersive X-ray were used to determine kerf, surface roughness and macro- and microanalyses.FindingsConsidering the applications in the turbine industry, it has been determined that the WEDM method is suitable to meet the standards for the machinability of Inconel 625 alloy. In contrast, the AWJM method does not meet the standards. Namely, while the kerf angle was formed because the hole entrance diameters of the holes obtained with AWJM were larger than the hole exit diameters, the equalization of the hole entry and exit dimensions, thanks to the perpendicularity and tension sensitivity of the wire electrode used in the holes drilled with WEDM ensured that the kerf angle was not formed.Originality/valueIt is known that the surface roughness of the parts used in the turbine industry is accepted at Ra = 0.8 µm. In this study, the average roughness value obtained from the successful drilling of Inconel 625 alloy with the WEDM method was 0.799 µm, and the kerf angle was obtained as zero. In the cuts made with the AWJM method, thermal effects such as debris, microcracks and melted materials were not observed; an average surface roughness of 2.293 µm and a kerf of 0.976° were obtained.

Integrating response surface methodology and machine learning for analyzing the unconventional machining properties of hybrid fiber‐reinforced composites

AbstractThe aim of this investigation was to delve into the impact of abrasive water jet machining (AWJM) process variables on the surface roughness (Ra) and kerf angle (Ka) of hybrid fiber‐reinforced polyester composites. Utilizing both response surface methodology (RSM) and artificial neural network (ANN) prediction models, the study sought to optimize the input parameters for abrasive water jet machining, specifically in the context of paddy straw and PALF‐reinforced polyester hybrid composites. The process parameters targeted for optimization included the abrasive flow rate, traverse rate, and standoff distance during AWJM. The investigation identified an optimal combination of AWJM parameters that effectively meets the practical requirements for machining hybrid fiber‐reinforced polyester composites. According to the RSM, the suggested optimal values for the process parameters are an abrasive flow rate set at 300 g/min, traverse speed at 110 mm/min, and standoff distance at 1 mm. The ANN exhibited robust predictive capabilities, achieving high R2 scores of 0.932 and 0.962 for surface roughness and kerf angle, respectively. To enhance the performance of abrasive water jet machining and minimize surface roughness and kerf angle, the researchers conducted an optimization of the process parameters. Subsequently, confirmation experiments were executed to validate the predictive model and fine‐tune the set of process parameters for practical application.Highlights Investigated AWJM impact on Ra value and kerf angle of hybrid composites. Used RSM and ANN models for parameter optimization in biocomposite. Optimal AWJM parameters: AFR (300 g/min), TS (110 mm/min), and SOD (1 mm). ANN showed strong predictions: R2 scores 0.932 (Ra) and 0.962 (Ka). Confirmation experiments validated the predictive model for applications.

An experimental assessment and optimisation of hole quality in Al2024-T3 aluminium alloy during abrasive water jet machining

Owing to its outstanding properties such as corrosion resistance, low density, relatively low cost, and stiffness, Al2024-T3 aluminium alloy has been widely applied in aircraft manufacturing. To perfectly assemble an aircraft, numerous high-quality holes are drilled into its structures employing conventional drilling processes. Conventional drilling poses some challenges such as thermal distortions, burr formations, and tool wear. Alternatively, abrasive water jet drilling (AWJD) is a thermal-free machining process that can be employed as an alternative to conventional drilling of aeronautical structures. Hence, in this work, the effect of abrasive water jet parameters, namely stand-off distance, water jet pressure, and abrasive mass flow rate, on hole-quality parameters was evaluated at traverse speed = 10 mm/min. Three parameters were stand-off distance = 1, 2, and 3 mm, abrasive mass flow rate = 200, 250, and 300 g/min, and water jet pressure = 1800, 2100, and 2600 bar. Using a 6 mm circular-movement diameter of the nozzle tip, optimal stand-off distance, water jet pressure, and abrasive mass flow rate obtained by multi-objective optimization were 2 mm, 250 g/min, and 2600 bar, respectively. The corresponding hole-quality parameters were Diameter = 6.232 mm, Kerf angle = 0.018°, Cylindricity = 0.051 mm, Perpendicularity = 0.033 mm, Circularity = 0.0041 mm and Surface roughness Ra = 2.909 µm. The results showed that water jet pressure had the greatest influence on Perpendicularity, Circularity; stand-off distance had the highest effect on Kerf angle; and abrasive mass flow rate has the largest influence on Hole diameter, Cylindricity and Surface roughness Ra, and Rz at the given value of traverse speed. The adopted optimization process for abrasive water jet of Al2024-T3 aluminium alloy was successfully verified through confirmation runs, clearly illustrating its benefits.

OPTIMIZATION OF CUT QUALITY FOR AWJ PROCESSING OF A STEEL ALLOY

Abrasive water jet (AWJ) has gained an important place among the machining technologies due to its capacity to cut complex shapes in various materials without thermal effects and with low cutting forces, but it also has a reduced environmental impact. A key element for the quality of the cut is the amount of energy contained in the abrasive jet. The dissipaton of energy leads to kerf taper, high values of surface roughness, surface striations, the deviation of the water jet (jet drag), and even insufficient penetration. The current paper investigates the influence of process parameters on the quality of the cut for a S235 steel alloy. The quality of the cut was assessed by four parameters: entrance width of cut (Li), exit width of cut (Le), perpendicularity (u) and kerf angle (α). The experiments were organized according to a D-optimal Response Surface Method. Analysis of variance (ANOVA) was used for the development of a mathematical model that correlates the influence of process parameters on the quality of the cut. Finally, an optimization of the process parameters was proposed.

Hole quality evaluation for abrasive water jet drilling of GF/Al mesh reinforced epoxy hybrid composites

AbstractIn this study, neat glass (NG) fiber and hybrid GF/Al‐wire mesh composites with two different aluminum configurations (AG: with Al in the outer surface, and GA [Glass fiber/Al‐mesh]: with Al in the core) were fabricated using hand‐layup technique and then drilled via an abrasive water jet (AWJ) machine. The impact of the drilling parameters on the hole qualities; delamination , kerf angle (), and circularity error () of the holes were studied. Using Taguchi L9 orthogonal array, drilling operations were conducted. The following AWJ drilling parameters were chosen; water pressure (P), stand‐off distance (S), and traverse speed (V) with three levels each. A single‐objective optimization using Taguchi method was performed to minimize the drilling responses for the least outcome. In addition, gray relational analysis (GRA) was used as a multi‐decision technique. Analysis of variance (ANOVA) was carried out to identify the impacts of AWJ drilling parameters. The results indicated that for AG specimen, was reduced by 5.3%–10.96% and its by 10.4%–29.65%. GA had the lowest kerf angle. The most effective parameters on delamination for NG, AG, and GA were P, followed by S and V. Validation tests showed small variations between experimental and predicted values.Highlights A new GF/Al Wire Mesh Reinforced Epoxy Hybrid Composites were manufactured. AWJ drilling of the manufactured Composites was conducted. Hole quality was improved by adding Al to the outer layers (AG specimen). AWJ parameters were Controlled and optimized to reduce , , and . Process optimization was performed by single and multi‐objective optimization.

Characterization and optimization of abrasive water jet machining parameters of aluminium/silicon carbide composites

Due to the complexity of high temperature and cutting tool wear, most machined components are still facing problems in terms of harder functional fillers that reinforce aluminium matrix composites. Conversely, abrasive water jet machining (AWJM) incredibly useful for the cutting of anisotropic and non-homogeneous metal matrix composites. In this research article, silicon carbide (SiC) particulates were utilized as reinforcement in the AA6026 matrix material (AA6026/SiC) and machined using AWJM under different process parameters namely SiC loading, traverse speed and stand-off distance. Two different compositions of SiC (4, and 8 wt%) were considered to fabricate AA6026 composites using the stir casting. In addition, outputs have been examined, e.g., surface roughness, material removal rate, and kerf angle. An optical microscope, scanning electron microscope, Brinell hardness tester and universal testing machine have been used to characterize the matrix material AA6026 and its composites. Microstructural analysis revealed that the inclusion of SiC particulates in AA6026 affects the very fine grain size of the composite. Furthermore, the 8 wt% composite exhibits the evolution of the Al-Si eutectic phase during solidification. Processing of these composites was performed using the L27 orthogonal geometry, successfully improving the parameters of the abrasive water jet process. The output response shows that reducing the SiC load improves the surface roughness under the key parameters of traverse speed and stand-off distance. However, increasing the SiC loading increases the material removal rate and kerf angle under the key parameters, namely traverse speed, and stand-off distance.

Modelling the Kerf Angle, Roughness and Waviness of the Surface of Inconel 718 in an Abrasive Water Jet Cutting Process.

An experimental study of the abrasive water jet cutting process of Inconel 718 alloy samples with varying values of cutting speed, abrasive flow rate and cutting material height was carried out. Surface roughness and waviness were measured at different cutting depths, and the variation of the kerf angle was studied. It was shown that the depth of cut has the greatest effect on roughness and waviness. The height of the sample has no impact on the roughness and waviness at a particular depth of cut. As the depth of cut increases, in most cases, roughness and waviness increase as well. It has been proven that the cutting speed has a negligible effect on surface roughness, but it has a significant effect on surface waviness. The waviness, on the other hand, depends only slightly on the abrasive flow. It has been proven that the kerf angle does not depend on the abrasive flow. The kerf angle depends mainly on the height of the sample. The models were developed for the parameters of roughness Ra and Rz, waviness Wa and Wz and kerf angle. All models were calculated without separating the surface into smooth and rough cutting regions.

Effect of Abrasive Water Jet Parameters on the Drilling of Aluminum Foam Sandwiched with Glass Fiber Polymer Composites

To attain good geometric shape and size, machining of high-strength metal Fiber laminate becomes inevitable in the field of automotive industries. In this research, aluminum foam sandwiched with glass fiber reinforced polymer (GFRP) composites fabricated using a hand layup process. The glass Fiber composite was fabricated using aluminum foam with a thickness of 1 mm. The effect of abrasive water jet parameters such as pressure (P), stand-off distance (L), and nozzle diameter (D) on material removal rate (MRR) and Kerf angle (Ka) and Surface roughness were investigated. The results were compared without aluminum foam composites. Glass fiber composites with aluminum foam reduced the kerf angle by 44.18 %, and surface roughness (Ra) by 41.77 % as compared with glass fiber composites without aluminum foam. From the investigation, it was noticed that maximum pressure (220 Bar) and minimum stand-off distance (1mm) were optimum parameters for reducing the kerf angle and surface roughness. Also, Optical images of the hole were analyzed for surface quality.

Development of hybrid composite with natural fillers for mechanical property and machinability study

The urge to build a more environmentally friendly future has motivated researchers to examine composites outside of synthetic fiber and continue to consider natural fibre polymer composite. This present research, the hybrid bio composite was developed by bio fillers and natural fibres. The preliminary investigation was done to examine the possibility of using natural fillers (palm and coconut shell) in natural fibre (hemp and basalt) reinforced polymer (NFRP) composite for manufacturing application. In that way initially mechanical (tensile and flexural) properties testing were done on four different combinations of NFRP by using palm and coconut shell particles, to their influence on mechanical properties (tensile stress 278 MPa and flexural stress 330 MPa). It was found that 5% wt. palm + coco shell fillers combination hybrid composite presented good results in mechanical properties. Then 5% wt. palm + coco fillers was added in the matrix phase of NFRP composite was developed and study the machinability properties by using Abrasive Water Jet Machining (AWJM). NFRP machining in the relationships of material removal rate (MRR), kerf angle and surface roughness has been experimentally examined for various process parameters (nozzle pressure, distance stand and transverse speed). The research values for quality properties (MRR, Kt and Ra) were analysis-based on the trimming factors by developing the Taguchi method. The influence of optimized input process parameters on quality features were examined by utilizing experiential models. From this study, it is noticeable that, filler material in natural fiber composites reduces the kerf angle and the low and very high traverse speed leads the wide disparity in kerf inclination. For obtaining the good surface roughness and material removal rate medium traverse speed and medium stand of distance is the significant parameter respectively and moreover impact of jet pressure on surface finish is 3 times lower than the impact supplied to the surface finish by traverse speed

Kerf Geometry and Surface Roughness Optimization in CO2 Laser Processing of FFF Plates Utilizing Neural Networks and Genetic Algorithms Approaches

This work deals with the experimental investigation and multi-objective optimization of mean kerf angle (A) and mean surface roughness (Ra) in laser cutting (LC) fused filament fabrication (FFF) 3D-printed (3DP), 4 mm-thick polylactic acid (PLA) plates by considering laser feed (F) and power (P) as the independent control parameters. A CO2 laser apparatus was employed to conduct machining experiments on 27 rectangular workpieces. An experimental design approach was adopted to establish the runs according to full-combinatorial design with three repetitions, resulting in 27 independent experiments. A customized response surface experiment was formulated to proceed with regression equations to predict the responses and examine the solution domain continuously. After examining the impact of F and P on mean A and mean Ra, two reliable prediction models were generated to model the process. Furthermore, since LC is a highly intricate, non-conventional machining process and its control variables affect the responses in a nonlinear manner, A and Ra were also predicted using an artificial neural network (NN), while its resulting performance was compared to the predictive regression models. Finally, the regression models served as objective functions for optimizing the responses with an intelligent algorithm adopted from the literature.

A comparative study on drillability of Inconel 625 alloy fabricated by wire arc additive manufacturing

In recent years, the cost-effective wire arc additive manufacturing (WAAM) method is increasingly replacing traditional production methods for Ni-based superalloys. However, the effect of high heat input and elemental segregation in the WAAM method on machinability has not yet been adequately investigated. For this purpose, drilling of wrought and WAAM Inconel 625 samples with thermal (i.e., die-sinking micro-EDM and micro-EDM) and mechanical drilling techniques (i.e., orbital and conventional drilling) was investigated in this study. It was observed that thermal drilling methods formed a white layer with a thickness of 20-25 μm and 35-50 μm in the cross-section of wrought and WAAM specimens, respectively, while no white layer was formed in the mechanical methods. The average surface roughness of the inside hole, Ra, obtained in the conventional drilling process has improved by 46.15 %, 94.62 %, and 92.82 %, compared to the orbital, die-sinking, and micro-EDM methods, respectively. Because the drill cutting form and helix angle used in this method facilitated chip evacuation. The best surface roughness was obtained respectively by conventional (0.27–029), orbital (0.51–0.53), die-sinking (4.54–5.88), and micro-EDM drilling (3.54–4.25) methods. In addition, a larger kerf angle is obtained in the WAAM sample compared to the wrought one due to higher residual stress and higher dislocation density in the WAAM alloy. On the other hand, the higher hardness value of WAAM samples provided better surface quality in mechanical drilling methods than wrought material. An increase in surface hardness values up to 25 μm from the surface was detected due to the recast layer formed in thermal drilling methods and the strain hardening occurring on the surface in mechanical drilling methods.