Chip Shape Research Articles

Measurement-While-Milling (MWM): An innovative approach for increasing the casing milling efficiency in deep drilling operations

Deep boreholes are secured by steel tubes (casings) which are run in the hole and cemented in place. In most cases, these casings are considered a permanent installation. However, sometimes they have to be removed in order to repair or abandon the well. As the casing is cemented in place, it cannot be pulled, but needs to be milled to small chips which are flushed out of the borehole by the drilling mud. One of the main challenges in casing milling operations is continuous and complete chip removal. If the metal chips are too long, chip nests will grow around the milling string. As a result, this will restrict the annulus flow area and affect the chip removal in boreholes. The obvious solution in such condition is to do round tripping and clean the chip nest which is associated with the risk of injuries, as well as, increasing the none-productive time. In the worst case, the poor cleaning and circulation of chips can even end up with the milling string stucking problem in boreholes, consequently long-time fishing job. According to the available literatures, hardly any study for identifying the chip shapes and accordingly adapting the operation parameters to the casing milling process environment downhole to keep milling within desired generated chip shapes and sizes could be found. This paper presents an encouraging idea to monitor the milling process in real time by utilizing the acoustic emission signals (vibration modes) accompanied with the milling process to identify the desired chip shape and size range. Initial laboratory tests have been carried out to investigate and study the acoustic emission signals accompanying the casing milling process to identify the chip shapes and sizes. The preliminary test results show very good correlation and agreement between the chip length formed during those specific tests and the observed burst events in the measured signals. The study results have demonstrated the functionality of the new concept, and thus confirmed that it is a very promising idea towards developing a practical real time downhole monitoring system for milling operations. Adapting the milling operation parameters downhole in real time to keep the milling process within the desired generated chip shapes and sizes will offer better cleaning and removal of the chips and will prevent the development of chip nest around the drill string and its consequences such as round tripping, risk of drilling crew injury, none-productive time and even milling string stucking problems.

Study on the working performance of CrAlCN coated and uncoated carbide twist drill

A drilling test was carried out for a 6 mm diameter carbide twist drill with CrAlCN coating and an uncoated carbide twist drill to grasp the effect of CrAlCN coating on the tool performance. Drilling and machining tests on ASTM1045 steel workpieces using CrAlCN coated and uncoated tools. Observe the pattern of variation of surface morphology and roughness of holes with the number of drilled holes using SEM and optical microscope. The effect of CrAlCN coating on carbide twist drill on drilling quality was analyzed by comparing the wear, surface roughness and chip shape of twist drill at different periods and parameters of drilling. The study concluded that using CrAlCN coated tools improved the wear resistance of the drill and significantly reduced BUE. Compared to the uncoated bit, the diameter of the drill decreased to 5.91 mm for the coated tool and 5.79 mm for the uncoated tool after 80 holes. The roughness of the coated bit was 3.324 µm at a feed rate of 0.12 mm/r and several holes of 40, which was significantly lower than that of the uncoated bit. Chip analysis showed that the coated tool maintained well-broken and tightly spiraled chips. In contrast, the uncoated tool produces tightly spiraled chips and short ribbon chips at a feed rate of 0.18 mm/rev, and the edges of the chips can appear significantly serrated. The research results improve the understanding of the drilling wear mechanism, provide new technical means to improve the analysis of working tool performance and provide a reference basis for the design of new coating tools.

Simulation analysis of titanium alloy micro-drilling based on thermo-mechanical coupling

With the increasing demand for high precision micro parts in machining field, the development of micro hole drilling technology, especially the finite element simulation technology is rapidly promoted. However, there are many limitations in the simulation of micro-drilling, such as element size, computational efficiency, chip forming, etc. In the present work, a finite element software, Abaqus has been used to simulate the thermal-mechanical coupling micro-drilling process of titanium alloy material, and the key technologies, such as twist bit modeling, material constitutive model, chip separation criterion and element division, were investigated. Through simulation, it was found that with the increase of rotational speed and the decrease of feed speed, chip shape gradually fragmented, in addition, thrust force and torque diminished. Since chip shape, thrust force and torque are important factors affecting drilling quality and tool life, the work could offer important guiding significance for cutting parameter optimization.

Analyses of Tool Wear and Chip Type for Different Coated Carbide Inserts in Turning Hardened 1.6582 Steel

This article deals with the comparative wear of CNMG-coated sintered carbide indexable cutting inserts by several manufacturers when turning 1.6582 steel hardened to 40–44 HRC. The main goal will be to demonstrate the different course of wear by testing seemingly identical inserts for engineering companies, showing the connection between the course of wear and the production of waste in the form of chips. The monitored type of wear was the flank wear VBmax of a cutting tool depending on the length of the machining time. Additionally, the effect of cutting tool wear on chip production, i.e., their quantity, shape and size, was monitored. For the purpose of mutual comparison, uniform cutting conditions were chosen on the basis of previous experiments, ensuring the stability of the given cutting process. For flank wear analysis, optical and electron microscopes were used. Meanwhile, a portable roughness tester was used to analyze the roughness of the machined surface. It was found that the quality of the interconnected coating layers has a perceptible influence on wear rate of the evaluated cutting inserts. The relation between the degree and characteristics of wear on the one hand, and the properties of the produced chips that identify the effect of the difference in the deposition layers using EDX/SEM analysis on the other, foreshadows the importance of choose between products with similarly declared properties was found. The current assessment of cutting tool wear and the evaluation of the chip produced has significant economic potential for manufacturing companies seeking to minimize costs.

Structural Characterization and Mechanical Properties of Ductile Iron - Enhanced Alloyed Ductile Iron

In this study, an attempt has been made to produce ductile iron or spheroidal graphite iron and to study its important properties with a view to reduce the import of machinery parts made of ductile iron. Locally available compressor scrap (i.e. the compressor cylinder) which is made from grey cast iron was used to produce ductile iron using a crucible furnace that is fired by oil. Also, recycling of the grey cast iron to ductile iron was investigated and its effect on the microstructure, chemical composition, mechanical properties and chip shape. The mechanical and structural characteristics of the ductile irons that alloyed by the supplement of Ni, Mo, Mg, and Cr were studied In this study, four kilograms of the scrap were charged into an oil-fired crucible furnace. The scrap was heated to 1400°C with using a temperature controller to monitor the temperature with an inserted thermocouple. For desulphurization, the mixture of 3 wt.% burnt lime with 1 wt.% fluorspar of scrap weight was added to the molten at 1400°C by direct tapping into the molten. Then, 2.75 wt.% nickel element, 0.75 wt.% ferromolybdenum and 0.5wt.% ferromanganese of the scrap weight were added. Also, 1.25 wt.% spheroidizing alloy (FeSiMg9) and 1wt.% inoculant alloy of scrap weight were used to treat the iron melt at 1450°C. The analysis of scrap sample and product sample was done to determine their chemical composition, tensile strength, impact strength, hardness, and microstructure. The scrap and the as-cast product analysis determine its chemical composition, tensile, impact, hardness and microstructure. The microstructures revealed that the scrap contains flake graphite and the as-cast product contains spheroid graphite. An increase of the ultimate tensile stress (537.17 MPa), elongation (10%), hardness value (480.4 HB) and impact value (11.21 J) was observed for the alloyed ductile iron as compared with the mechanical properties of grey cast iron scrap, including (247.75 MPa), (6%), (400.3 HB) and (5.66 J), respectively. One of the important conclusions is the plunge container manufactured, and that was used according to the plunging technique followed in this investigation proved successful

A comparative analysis of chip shape, residual stresses, and surface roughness in minimum-quantity-lubrication turning with various flow rates

In this research, an experimental investigation was carried out to investigate the interaction between various turning parameters and different minimum quantity lubrication (MQL) flow rates and compare their effects on chip shape and surface integrity characteristics in low speed turning and high speed turning of AA6061-T6. The turning parameters included cutting speed, feed rate, and depth of cut. The flow rates comprised 3.5 $$\mathrm{ml}/\mathrm{min}$$ , 10 $$\mathrm{ml}/\mathrm{min}$$ , and 15 $$\mathrm{ml}/\mathrm{min}$$ , and the surface integrity characteristics consisted of average arithmetic surface roughness, height peak from the valley, and axial and hoop surface residual stresses. The results showed that cutting conditions including cutting speed, feed rate, and depth of cut affected chip shape, while MQL flow rate had no impact on chip shape. The lowest values of cutting speed, feed rate, and depth of cut, equal to 145 $$\mathrm{m}/\mathrm{min}$$ , 0.07 $$\mathrm{mm}/\mathrm{rev}$$ , and 0.66 $$\mathrm{mm}$$ , respectively, resulted in the smallest residual stresses for all the flow rates. Moreover, the smallest surface roughness parameters were obtained at the lowest feed rate (0.07 $$\mathrm{mm}/\mathrm{rev}$$ ) for all the flow rates, whereas there were high interaction effects between cutting speed and flow rate and depth of cut and flow rate. Finally, turning with the minimum quantity lubrications of 3.5 $$\mathrm{ml}/\mathrm{min}$$ and 10 $$\mathrm{ml}/\mathrm{min}$$ , respectively, is suggested to obtain the best overall surface integrity characteristics. These lower values of flow rate are suitable to reduce machining costs, protect the environment, and preserve the machinist’s health. Since most of the previous research studies focused on the comparison of the turning environments including dry, MQL, wet, and cryogenic and only a few research works on the comparative analysis of MQL turning with different flow rates were carried out, the results of the present research can be utilized as a reference for future works in this field.

Research, Modelling and Prediction of the Influence of Technological Parameters on the Selected 3D Roughness Parameters, as Well as Temperature, Shape and Geometry of Chips in Milling AZ91D Alloy.

The main purpose of the study was to define the machining conditions that ensure the best quality of the machined surface, low chip temperature in the cutting zone and favourable geometric features of chips when using monolithic two-teeth cutters made of HSS Co steel by PRECITOOL. As the subject of the research, samples with a predetermined geometry, made of AZ91D alloy, were selected. The rough milling process was performed on a DMU 65 MonoBlock vertical milling centre. The machinability of AZ91D magnesium alloy was analysed by determining machinability indices such as: 3D roughness parameters, chip temperature, chip shape and geometry. An increase in the feed per tooth fz and depth of cut ap parameters in most cases resulted in an increase in the values of the 3D surface roughness parameters. Increasing the analysed machining parameters did not significantly increase the instantaneous chip temperature. Chip ignition was not observed for the current cutting conditions. The conducted research proved that for the adopted conditions of machining, the chip temperature did not exceed the auto-ignition temperature. Modelling of cause-and-effect relationships between the variable technological parameters of machining fz and ap and the temperature in the cutting zone T, the spatial geometric structure of the 3D surface “Sa” and kurtosis “Sku” was performed with the use of artificial neural network modelling. During the simulation, MLP and RBF networks, various functions of neuron activation and various learning algorithms were used. The analysis of the obtained modelling results and the selection of the most appropriate network were performed on the basis of the quality of the learning and validation, as well as learning and validation error indices. It was shown that in the case of the analysed 3D roughness parameters (Sa and Sku), a better result was obtained for the MLP network, and in the case of maximum temperature, for the RBF network.

Understandings the tribological mechanism of Inconel 718 alloy machined under different cooling/lubrication conditions

Machining of Ni-based superalloys is a challenging issue, and it may lead to tool deterioration, poor surface quality, and other structural defects. Therefore, the main theme of this study is to examine the effect of different sustainable cooling/lubrication conditions on the machining performance, surface integrity, and accompanying tribological aspects of Inconel 718 superalloy. In this context, the milling experiment variables were selected as two feed rates, two cutting speeds, and four cutting environments: dry, air, synthetic oil-based MQL, and LN2-assisted Cryo. Tool wear mechanisms, surface roughness/profile/topography, cutting performance (tool-chip interface temperature and energy consumption), chip shapes, microstructures, and micro-Vickers hardness of the machined surfaces were thoroughly analyzed to assess experimental observations. The Cryo medium reduces tool wear, surface roughness, cutting temperature, and cutting energy by 67 %, 61 %, 85 %, and 33 % in comparison with a dry environment, respectively. Abrasion, adhesion, and diffusion mechanisms were supposed to be the most dominant wear types following SEM observations. Besides, the Cryo environment concluded a reduction of grain size to ⁓ 4 µm in concomitant with an increase of micro-hardness ⁓ % 15. The whole observed outcomes agreed to a great extent with each other, asserting the effectiveness of the LN2 cooling protocol in improving machining characteristics of Inconel 718 superalloy.

Drilling process of Cf/SiC ceramic matrix composites: Cutting force modeling, machining quality and PCD tool wear analysis

Cf/SiC composites are continuous fiber-reinforced ceramic matrix composites with excellent properties, such as high-temperature resistance, high specific strength, and low coefficient of thermal expansion. However, Cf/SiC composites often cause severe tool wear and quality problems. In this paper, tool wear is studied during the machining of Cf/SiC materials. The cutting force model is applied to understand the correlation between cutting force and tool wear. Polycrystalline Diamond (PCD) tools with various point and clearance angles are designed to carry out drilling experiments on Cf/SiC composites with different machining parameters. During experimental investigations, force and acoustic emission signals are analyzed, and PCD tool wear and material machining quality are observed using scanning electron microscopy. Results indicate that PCD tools with a point angle of 140° and a clearance angle of 20° demonstrate the lowest tool wear during machining. Moreover, low-speed and feed machining parameters can effectively reduce tool wear and prolong its life. By observing fracture patterns of hole wall fibers and chip shapes at different stages of tool wear, and combined with the frequency domain distribution of AE signal, the effects of tool wear on the material removal mechanism are summarized. Before tool wear, fiber fracture is flatter, the matrix is mainly removed via crushing. After tool wear, although fiber fracture is more uneven, the matrix is changed from crushing to friction removal, leading to lower surface roughness of the hole wall.

Deformation Analysis of Continuous Milling of Inconel718 Nickel-Based Superalloy.

As a difficult-to-process material, Inconel718 nickel-based superalloy is more and more widely used in aerospace, ocean navigation, and large-scale machinery manufacturing. Based on ABAQUS simulation software, this paper takes the milling force and temperature in the milling process of the nickel-based superalloy as the research object, and establishes the empirical formula for the prediction model of cutting force and cutting temperature based on the method of multiple linear regression. The significance of the prediction model was verified by the residual analysis method. Through data analysis, it is obtained: within a certain experimental range, the influence degrees of each milling parameter on the cutting force and cutting temperature are and , respectively. The actual orthogonal cutting test was carried out on the machine tool, and the reliability and accuracy of the prediction model of cutting force, cutting temperature and tool wear amount were verified. The model formulas of the shear velocity field, shear strain field and shear strain rate field of the main shear deformation zone are constructed by using mathematical analysis methods. The influence law of cutting speed and tool rake angle on the variables of main shear zone is calculated and analyzed. Through the combination of theory and experiment, the relationship between cutting force, chip shape and machined surface quality in milling process was analyzed. Finally, with the increase in the cutting force, the serration of the chip becomes more and more serious, and the roughness of the machined surface becomes greater and greater.

Peningkatan Kualitas Keripik Jamur Tiram Produksi Kelompok Tani Pesona Jamur dengan Mesin Spinner


 Pesona Jamur farmer groups primarily focus on producing baglog and cultivating oyster mushrooms. Currently, they are doing business development by making a food product called oyster mushroom chips. This program aims at improving the quality of processed oyster mushroom chips by applying the appropriate technology of a spinner machine equipped with a magnetic contactor. The method used were practical training and assistance in processing oyster mushroom chips then dissemination of applied technology a spinner machine to the partners. The result of this program indicated that the oyster mushroom chip product processed by the Pesona Mushroom Farmers Group has a light brown color and the shape of the mushroom chips is not crushed. Oyster mushroom chip products are of higher quality than before the training activities because they had used the correct processing technique. The taste of the chips is also more savory, coupled with the complete form of chips, which are expected to attract consumers and increase product value. The correct chip processing technique and a spinner machine can minimize the oil content in oyster mushroom chips and expired dates. The product's expiration has increased from one month to four months without preservatives.

Undeformed chip width non-uniformity modeling and surface roughness prediction in wafer self-rotational grinding process

Silicon wafers are commonly thinned employing an ultra-precision grinding machine based on a workpiece self-rotational principle. The diamond grains, stochastically located on the grinding wheel surface, remove the workpiece material and generate a difference in the size and shape of undeformed chips. However, an in-depth understanding of the grain-workpiece interaction randomness in wafer thinning process and its link with surface roughness has not been revealed yet. In this paper, a new index, i.e., undeformed chip width, is first proposed to analyze and describe the stochastic characteristics in material removal process as well as predict the surface roughness of ground wafer. The grinding wheel morphology is constructed by the random operation for grain size and position. Then, a 2D topography generation model is established to calculate the undeformed chip width. The non-uniform distribution characteristics of undeformed chip width under different grinding conditions are further analyzed. Finally, the relation between undeformed chip width and surface roughness of ground wafer is presented. The correctness of developed models is verified using a series of grinding experiments.

Investigation on the cutting mechanism of SiCp/Al composites in ultrasonic elliptical vibration machining

Aluminum (Al)-based silicon carbide (SiC) material composites are considered as difficult-to-machine materials because of the presence of hard reinforced SiC particles, which results in a greater cutting force and poor surface integrity during the machining process. This paper established micro-anisotropic material mechanical models of SiCp/Al composites with a 10vol% SiC particles, and studied the difference in the machining mechanism between ultrasonic elliptical vibration cutting (UEVC) and ordinary cutting (OC) about SiCp/Al. Moreover, this paper mainly focuses on the influence of UEVC on cutting force, von Mises stress distribution, surface integrity, and chip formation. The models are validated by comparing cutting force, chip shapes, and machined surface features in OC machining SiCp/Al experience from the literature. Simulation results indicate that the cutting mechanism of SiCp/Al on UEVC is different from that of OC and has several good properties. At the same cutting parameters, high-frequency vibration makes the cutting force of UEVC exhibit variable periodicity and reduces average cutting force. The instantaneous impact of tool and fast separation results in a more concentrated von Mises stress distribution, thereby resulting in the particles having a greater break degree than that obtained with OC. A comparison of the surface roughness values from the simulation result shows that UEVC obtains better surface integrity than OC does.

Measurement and analysis of sustainable indicators in machining of Armox 500T armor steel

Armox 500T is a special type of armor steel possessing superior mechanical properties suitable for use in vehicles and buildings need for first priority protection. Since these products are large-scale, a welding groove needs to be created before joining which can be done by milling operations. This study aims to address this point by questioning the impact of clean environments, namely, dry, minimum quantity lubrication (MQL), and LN2-based cryogenic cooling on the machining performance measures during milling. The novelty of this paper is the investigation of the effects of different cutting environments on the milling performance of Armox 500T armor steel. The results from this study showed that cryogenic medium has an impressive impact on controlling the temperatures at tool-chip interface which directly reduces flank wear development. In addition, cryogenic and MQL-assisted machining is much better than dry environment in achieving improved surface properties, chip shape, and energy consumptions. Cryogenic cooling seems as the best option for hard milling pursued by MQL and dry environments, respectively, from the sustainability and machinability point of view.

Evaluation and mitigation of the influence of pseudorange biases on GNSS satellite clock offset estimation

The pseudorange bias inconsistencies are notably originating primarily from the individual chip shape distortions in the ranging signals, these distortions cause different shifts of the correlator’s tracking point for receivers, as a result giving rise to a different pseudorange bias for each pseudorange observation. The different bias should be properly dealt with in the process of satellite clock offset estimation when receivers of mixed types are used. In this work, using observations from 140 international global navigation satellite system (GNSS) service stations, the pseudorange bias was calculated, and the effect of inconsistent biases on satellite clock offset estimation from different receiver networks was investigated. The inconsistencies between the GPS satellites were ranging from −6 ns to 4 ns. For GALILEO and BDS, the biases are significant, ranging from −20 ns to 40 ns and −60 ns to 40 ns, respectively. The biases of the individual satellites are receiver-related and statistically stable from day to day. The influence of pseudorange bias was strikingly noticeable, and can improve the accuracy of the estimated clock offset by several ps for GPS; and by more than 15 ps for GALILEO and BDS after considering bias inconsistencies. Furthermore, owing to the pseudorange bias correction, the convergence and positioning performance have improved significantly, with an improvement of more than 12 % for the static precise point position (PPP), and more than 10 % for the kinematic PPP.

Study about the chip formation in the turning process using the finite element analysis

At this time, there is a significant interest in the chip shape and formation at the international level, an issue studied based on mathematical calculations, experiments, and finite element analysis. The analysis of the chip formation process showed that the thickness of the undetached chip also varies according to the rake angle of the cutting tool, and using 3D models to analyze the chip formation process demonstrates this fact. Following the research, a study was conducted in which an analysis of the chip morphology is presented. Using Deform 2D application, a finite element simulation - a comparative analysis of the chip formation was performed when the value of the clearance angle varies. The increasing variety of cutting radius values has an influence on the way the chips are formed in terms of thickness, which generate differences in its shape. Following the study, a series of conclusions and own findings emerged that with the increase of the cutting-edge radius, the stress distribution is radial over a greater area of the part, reason for which the deformation of the chip is smaller. Arguments have also been made on distribution of the temperature, which is directly influenced by the shape of the tool, influencing the temperature of the generated chip. The results also show that with the increase of the cutting-edge radius of the tool, there is a tendency for the detached chip to settle.

A combined experimental and numerical approach that eliminates the non-uniqueness associated with the Johnson-Cook parameters obtained using inverse methods

Johnson-Cook constitutive model is a commonly used material model for machining simulations. The model includes five parameters that capture the initial yield stress, strain-hardening, strain-rate hardening, and thermal softening behavior of the material. These parameters are difficult to determine using experiments since the conditions observed during machining (such as high strain-rates of the order of 10^5/sec - 10^6/sec) are challenging to recreate in the laboratory. To address this problem, several researchers have recently proposed inverse approaches where a combination of experiments and analytical models are used to predict the Johnson-Cook parameters. The errors between the measured cutting forces, chip thicknesses and temperatures and those predicted by analytical models are minimized and the parameters are determined. In this work, it is shown that only two of the five Johnson-Cook parameters can be determined uniquely using inverse approaches. Two different algorithms, namely, Adaptive Memory Programming for Global Optimization (AMPGO) and Particle Swarm Optimization (PSO), are used for this purpose. The extended Oxley’s model is used as the analytical tool for optimization. For determining a parameter’s value, a large range for each parameter is provided as an input to the algorithms. The algorithms converge to several different sets of values for the five Johnson-Cook parameters when all the five parameters are considered as unknown in the optimization algorithm. All of these sets, however, yield the same chip shape and cutting forces in FEM simulations. Further analyses show that only the strain-rate and thermal softening parameters can be determined uniquely and the three parameters present in the strain-hardening term of the Johnson-Cook model cannot be determined uniquely using the inverse method. A combined experimental and numerical approach is proposed to eliminate this determine all parameters uniquely.

Study on the cutting mechanism of randomly deflected truncated cone shape single abrasive grain

Based on the random distribution characteristic of abrasive grains for the grinding wheel circumferential surface during the manufacturing process, considering the grinding parameters and deflection parameters comprehensively, a randomly deflected truncated cone shape single abrasive grain cutting simulation model was established. Then, studying its cutting mechanism, i.e., the trajectory length value by numerical method and formula method was compared, the consequence indicates that the error is extremely small; this demonstrates the accuracy of the numerical method. The calculation and analysis of the workpiece cutting surface topography and the undeformed chip shape were carried out; it shows that the cutting surface topography and the undeformed chip shape are coincident. And the calculation results of the model were compared to verify. The influence laws of each grinding process parameter on the material removal volume (MRV) and material removal rate (MRR) were investigated; the results display that the grinding method affects the changing pattern of MRV and MRR; when the grinding method was up-grinding, a high wheel speed or a small wheel diameter is able to enhance the MRR; the MRV and MRR are increments with the increasing workpiece feed speed or abrasive grain cutting depth; and the MRV and MRR decrease with the raising of the absolute value of single abrasive grain deflection angle. The situation is a similar or opposite trend in down grinding. This work can provide a theoretical reference for the selection and optimization of parameters and further lay a foundation for the research in the grinding mechanism of the grinding wheel.

Effect of Intermetallics and Drill Materials on the Machinability of Al-Si Cast Alloys.

The present study was conducted on the machinability of 396 alloy (containing approximately 11% Si) and B319.2 alloy mainly to emphasize the effects of Fe-intermetallics, i.e., α-Fe, β-Fe, and sludge. The results demonstrate that the presence of sludge in the form of hard spots has a significant effect on cutting forces and tool life, in that it decreases drill life by 50% compared to the base alloy. The formation of the α-Fe phase in the M1 base alloy has a beneficial effect on tool life in that this alloy produces the highest number of holes drilled compared to alloys containing sludge or β-Fe; this result may be explained by the fact that the formation of the α-Fe intermetallic, with its rounded Chinese script morphology and its presence within α-Al dendrites, is expected to improve matrix homogeneity via hardening of the soft α-Al dendrites. Increasing the Fe-content from 0.5% to 1% in the 396-T6 alloy containing 0.5% Mn produces a distinct improvement in alloy machinability in terms of cutting force and tool life. The addition of Fe and/or Mn appears to have no discernible effect on the build-up edge area (BUE) and chip shape.

Improving machining stability of AISI-4140 with magnetic field

Several methods have been developed in order to improve the traditional machining processes and machining outputs. In this study, the effect of the magnetic field on the turning process was investigated. AISI-4140 was machined with different cutting speeds and magnetic flux density magnitudes. The magnetic field was generated with neodymium magnets. Machining stability, surface roughness, and maximum cutting temperature were measured. Additionally, chip shapes were examined. The machining stability was determined by measuring the vibration amplitude and other vibrational parameters (natural frequency, stiffness, and damping coefficients). Conventional turning and magnetic assisted turning were performed under the same cutting parameters consecutively, and the results were compared. According to the results, it was observed that neodymium magnets attached to the cutting tool improve machining stability and damping properties. Surface roughness was decreased between 6%–10% in magnetic assisted turning. Furthermore, it has been observed that the maximum cutting temperatures have been increased between 10%–45% in the magnetic assisted machining. Besides, it can be said that magnets contribute to improving chip control by collecting the chips on them while machining AISI-4140 steel.