Mode Machining Research Articles

Выбор материала и геометрических параметров расточного резца для обработки покрытий на основе никеля

Design and development of a technology for machining the parts to be restored in the repair industry includes selection of their machining method and modes, cutting tools, etc., and is a complex task, which solution determines the restored product quality. Machining quality largely depends on the metal machinability, which is understood as the material ability to be cut. The paper considers features of a bush machining after restoration of the worn inner surface, this operation consists of black, clean and fine boring, as well as of honing. Operations of black and clean boring are the most difficult in machining the restored bushes. This happens because hardness of the resulting layers is in the range of HRC 48…55 after induction sintering with subsequent rolling, which complicates the cutters operation in bush boring. The PG-SR2 powder having the Ni-Cr-B-Si alloying system is used in the built-up welding of parts working under wear, corrosion, erosion and elevated temperature conditions. Rolling is eliminating significant waviness and surface roughness resulting from sintering. One of the important issues in machining the coatings applied by centrifugal induction sintering is selection of the cutting tool material for black and clean boring.

Исследование отклонений формы изделий из быстрорежущей стали при точении фрезерованием на станках с ЧПУ

Investigation of form deviations of cylindrical high-speed steel (HSS) products made under turning-milling operation by CNC-controlled lathe machining center (further CNC) with auxiliary drive axle is given. Technological support of high-speed steel products quality made by turning milling operation on a CNC lathe machining center with an auxiliary drive axle takes effect owing to the shape deviation reduction. Planning of experiments was carried out according to the Taguchi method for four factors and three levels. The experiment was conducted on a DMG NEF 400 lathe machining center having an auxiliary drive axle, which allows machining modes to be performed with a rotating tool. Samples of high-speed steel R6M5K5-MP were used. Machining operation was made according to the scheme of orthogonal turning by milling. A core carbide mill CCM 4321 was used as a cutting tool. Out-of-roundness (lobing) was estimated using optical method. All measurements were carried out on the Bruker Contour GT-K1 optical profilometer. Surface micro-dimensions were measured by optical scanning of the surface. Surface optical scanning resulted in a point cloud was obtained that mirrors micro-dimensions of the cylindrical profile of the piece partmeasured section. The obtained data obtained made it possible to measure a lobing that occurs under orthogonal milling turning method. The influence of cutting modes on the shape and size of the maximum peaks of the cut is proved. The smallest facet pattern value is observed for milling width a_e in the range of 3,5...5,5 mm with high feed values for the tooth f_z and low cutting speed v_c. The largest cut height is observed at the average values of a_e, a_p, v_c. It is an optical profilometer that is an effective means of measuring facet patterns or lobings. The results obtained in the work allow predicting form deviations of a blank made of high-speed steel under turning milling operations on CNC machines. The results of the study can be used to improve rotary cutting tools quality in the tool industry.

Machining grade 4 titanium alloy by minimum quantity lubrication for enhanced sustainable manufacturing

AbstractMachining is a widely used class of industrial manufacturing operation, wherein cutting fluids play a vital role in terms of machining accurate dimensional quality objects due to their cooling, lubricant, and chip removal abilities. Although certain advanced cutting fluids have changed the manufacturing industry for the better, there are some environmental concerns associated with some of these fluids. The use and disposal of cutting fluids may be costly and subjected to stringent government laws. Hence, the ever-growing research conducted on environmentally friendly cutting fluids may lead to enhanced sustainable manufacturing. The aim of this investigation is therefore to investigate the viability of minimum quantity lubrication (MQL) during machining of titanium alloys with specific focus on the commercially pure grades (grade 4). A comparative study was conducted in order to establish the effects of different modes of lubrication, i.e., dry, wet, and MQL machining on titanium.

An integrated model based on deep kernel extreme learning machine and variational mode decomposition for day-ahead electricity load forecasting

An integrated model based on deep kernel extreme learning machine and variational mode decomposition for day-ahead electricity load forecasting

Based on the Engineering Practice of Selection of the Dual Mode (TBM - EPB) and Adaptive Effect Evaluation Analysis

The subway tunnels built in some coastal cities often cross the soft and hard alternating strata, which makes the shield construction more difficult. The single shield mode cannot meet the needs of efficient construction and environmental protection, while the dual mode (TBM-EPB) shield can better adapt to the complex geological conditions of soft and hard alternating, effectively improve the tunneling efficiency of the shield machine, and ensure the safety and timeliness of project construction. Based on the construction practice of the tunnel between Liuxiandong Station and Bai mang Station of Shenzhen Metro Line 13 passing through long distance soft and hard alternating strata, this paper studies the shield machine mode used in the construction of this section, establishes the use of dual mode (TBM-EPB) shield, and conducts the development of a series of key technologies in the construction process such as dual mode conversion, pressure replacement screw conveyor, etc, The adaptability of double mode (TBM-EPB) shield to the long-distance soft and hard alternating strata between Liuxiandong Station and Baimang Station of Shenzhen Metro Line 13 is evaluated. At present, the project has been successfully completed, and its practical experience provides a reference for the promotion and application of TBM-EPB shield in tunnel construction under similar geological conditions.

The effect of dentin surface pretreatment using dimethyl sulfoxide on the bond strength of a universal bonding agent to dentin

BackgroundThis study aimed to evaluate the effect of dentin pretreatment by Dimethyl Sulfoxide (DMSO) on the bond strength and microleakage of a universal bonding agent to dentin.MethodsFifty-six dentinal discs (thickness = 2 mm) were obtained from the crowns of the human third molars. The disks were assigned into 4 groups and treated as follows; self-etch-control group: G-Premio universal adhesive was used in self-etch mode, total-etch-control: G-Premio universal adhesive was used in total-etch mode, self-etch-DMSO: Water-based DMSO (50% volume) was applied on the samples for 60 s followed by application of G-Premio universal adhesive in self-etch mode, and Total-etch-DMSO: The samples were etched, and then, water-based DMSO was applied on them for 60 s followed by the application of G-Premio universal adhesive in total-etch mode. Afterward, resin composite was placed on all samples and light-cured. The samples were kept in distilled water and subjected to 5000 thermal cycles. Microshear bond strength was measured using the universal testing machine and failure modes were analyzed using a stereomicroscope. Forty-eight human third molars were used for microleakage evaluation and a standardized class five cavity was prepared on the buccal surface of each tooth. The teeth were assigned into 4 groups and received aforementioned surface treatment and the cavities were filled with resin composite. After storing in water for 24 h, the samples were subjected to 5000 cycles of thermocycling and the microleakage level of the samples was evaluated using silver nitrate uptake at the bonded interface. Two-way ANOVA test was used to analyze the effect of bonding technique (self-etch/ total-etch) and DMSO pretreatment on the microshear bond strength and microleakage of G-Premio adhesive to dentin.ResultsBonding technique had no effect on the bond strength values (p = 0.17) while DMSO pretreatment significantly decreased the microshear bond strength of the samples (p = 0.001). DMSO application increased microleakage significantly in total-etch (P-value = 0.02) while it had no effect in self-etch mode (P-value = 0.44).ConclusionsPretreatment of dentin using 50% DMSO significantly reduced the bond strength of G-Premio Bond in both self-etch and total-etch modes. DMSO effect on microleakage depended on the etching technique; DMSO increased the microleakage level when the adhesive was used in total-etch mode while did not affect the microleakage in self-etch mode.

An Influence of Spatial Harmonics on an Electromagnetic Torque of a Symmetrical Six-Phase Induction Machine

The analyses of the influence of spatial harmonics on the electromagnetic torque of the multi-phase induction machine and reducing this influence are important tasks to ensure the high efficiency of the induction machine. Designing the machine to consider the influence of spatial harmonics is essential to ensure the desired mechanical and energy characteristics. In the case of the sinusoidal winding supply of the induction machine, the magnetomotive force has high spatial harmonics, which are caused by the machine-winding design. The interaction between the 5th, 7th, 11th and 13th spatial harmonics of the winding function and the first time-harmonic of the winding supply causes the appearance of the 6th and 12th harmonics in the electromagnetic torque of the machine. A prototype of the symmetrical six-phase induction machine and the experimental study for the influence of spatial harmonics on the harmonic content of the stator currents in different machine modes are given in this paper. The mathematical model of the six-phase induction machine has been developed using the average voltages in integration step method. The introduction of the harmonic components into the magnetization inductance in the mathematical model of the six-phase induction machine for taking into account the spatial harmonics of the machine-winding function is proposed in this paper. The adequacy of the mathematical model was confirmed by comparing the simulation and experimental results. The harmonic content of the electromagnetic torque, which is caused by spatial harmonic influence, is analyzed.

Development of ways to saving energy when operating winding machines

Energy efficiency or energy saving is the practical implementation of scientific, technical, economic and industrial measures aimed at the efficient use of energy resources. Therefore, one of the challenges facing the textile industry is energy saving in technological processes in the production of products. To solve this problem, it is proposed to introduce into production advanced technological processes with low energy costs, the use of technological equipment equipped with electric motors with high rates of consumed electrical energy. This problem is also inherent in winders and similar machines equipped with a bobbin changer. Since most of the time of operation of these devices is wasted and, accordingly, electricity is also wasted. However, to date, these issues have not been given due attention, and studies on this subject have not been conducted. In this work, the operation of the apparatus for changing bobbins in winding and similar machines has been studied in order to reduce power consumption. As a result of the study, a mathematical model of the relationship between the operating mode and technological parameters of machines and apparatuses was obtained, which makes it possible to identify ways to eliminate shortcomings in their work. Discontinuous, on signal and sectional methods of operation of the apparatus for changing bobbins have been developed, which make it possible to reduce power consumption on winding machines by 2.8–4.2 times compared to the existing method of operation. And the autonomous method of operation of the device, proposed in the work, completely eliminates the consumption of electricity consumed by the device for changing bobbins. The results of the study can be used in spinning and weaving mills.

Design of Intelligent AGV Transport Car

Unmanned Guided Vehicle (AGV) is a new type of mobile robot that was applied in various fields. Aiming at the design of dedicated AGV transport vehicle for complex road conditions, this AGV transport vehicle is composed of chassis, traveling mechanism, lifting device, and removable components. By designing and analyzing the mechanical structure of the AGV transport vehicle, and it’s combined with statics theory, and the feasibility of the trolley structure is designed and discussed. The three-dimensional model of AGV transport vehicle is established by Solid Works software, and the cloud diagram of the stress and deformation of the wheel system structure is analyzed by Solid Works Smillation, and the traveling mechanism of the trolley is analyzed by statics. The rationality of the wheel system structure is verified by the deformation cloud diagram of the AGV transport vehicle under various working conditions. Based on the mathematical model optimization of variable density method, the car body frame is optimized and designed to these materials of car body. The design of the track tensioning structure and frame is obtained according to the four general engineering parameters of TRIZ theory. Finally, the modeling design of intelligent AGV transportation car is carried out by using the principles such as division, color change, and dimension change, etc. In order to facilitate the take-off and landing loading and unloading of goods for AGV transportation lifting device, and it is changed to the traditional handling mode of manpower-operated machines.

An explainable AI (XAI) model for landslide susceptibility modeling

Landslides are among the most devastating natural hazards, severely impacting human lives and damaging property and infrastructure. Landslide susceptibility maps, which help to identify which regions in a given area are at greater risk of a landslide occurring, are a key tool for effective mitigation. Research in this field has grown immensely, ranging from quantitative to deterministic approaches, with a recent surge in machine learning (ML)-based computational models. The development of ML models, in particular, has undergone a meteoritic rise in the last decade, contributing to the successful development of accurate susceptibility maps. However, despite their success, these models are rarely used by stakeholders owing to their “black box” nature. Hence, it is crucial to explain the results, thus providing greater transparency for the use of such models. To address this gap, the present work introduces the use of an ML-based explainable algorithm, SHapley Additive exPlanations (SHAP), for landslide susceptibility modeling. A convolutional neural network model was used conducted in the CheongJu region in South Korea. A total of 519 landslide locations were examined with 16 landslide-affected variables, of which 70% was used for training and 30% for testing, and the model achieved an accuracy of 89%. Further, the comparison was performed using Support Vector Machine mode, which achieved an accuracy of 84%. The SHAP plots showed variations in feature interactions for both landslide and non-landslide locations, thus providing more clarity as to how the model achieves a specific result. The SHAP dependence plots explained the relationship between altitude and slope, showing a negative relationship with altitude and a positive relationship with slope. This is the first use of an explainable ML model in landslide susceptibility modeling, and we argue that future works should include aspects of explainability to open up the possibility of developing a transferable artificial intelligence model.

Short-Term Solar Power Forecasting Based on CEEMDAN and Kernel Extreme Learning Machine

The use of renewable energy sources contributes to environmental awareness and sustainable development policy. The inexhaustible and nonpolluting nature of solar energy has attracted worldwide attention. Accurate forecasting of solar power is vital for the reliability and stability of power systems. However, the effect of the intermittency nature of solar radiation makes the development of accurate prediction models challenging. This paper presents a hybrid model based on Kernel Extreme Learning Machine (Kernel-ELM) and Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) for short-term solar power forecasting. The decomposition technique increases the number of stable, stationary, and regular patterns of the original signals. Each decomposed signal is fed into Kernel-ELM. To validate the performance of the hybrid model, solar power data from the BSEU Renewable Energy Laboratory, measured at 5-minute intervals, are used. To validate the proposed model, its performance is compared to some state-of-the-art forecasting models with seasonal data. The results highlight the good performance of the proposed hybrid model compared to other classical algorithms according to the metrics.

Operational characteristics of active rotating-type contactless superconducting field exciter for high-temperature superconducting synchronous machines

The operational characteristics of a contactless superconducting field exciter (CSFE) for operating rare-earth barium copper oxide (REBCO) field windings in high-temperature superconducting (HTS) synchronous machines are investigated, and its performance is evaluated. The CSFE based on permanent magnets (PMs) is a promising candidate as a direct-current power supply for energizing superconducting coils in a noncontact manner, which can enhance the thermal stability, system efficiency, and operational reliability for superconducting applications by significantly reducing the thermal loads of cryogenic cooling systems. However, the limited or passive control performances in our previous demonstration of a 1-kW-class HTS synchronous generator, which depend only on the rotational speed of the HTS synchronous machine, make it difficult to control the field winding during the operation of the HTS synchronous machine. Therefore, in this study, we develop an improved CSFE that is operated independently using active rotating-type PMs to improve the controllability of the field winding operated by the CSFE. Thus, an active rotating-type CSFE is developed to excite and control a 15-kW-class HTS motor, and no-insulation REBCO field magnets are fabricated to utilize the charging loads. Through hardware implementations, we experimentally analyze the operational characteristics of contactless excitation in various operation modes of the HTS synchronous machine, such as initial field excitation at rotor stop, current increase/decrease control, current holding control (i.e., permanent current control), and current control corresponding to the rotation speed and direction of the rotor. The current to the four-pole REBCO field winding is charged to 143.74 A in a noncontact manner, which is 2.87 times the rated field current and close to the critical currents of the REBCO field windings. The qualitative effects of the new function on the active control of noncontact charging current are experimentally verified, and these results can facilitate the application of CSFEs in electric propulsion systems using superconducting motors.

Cleaning the canals of reclaim systems with the help machines with various types of interchangeable working equipment

Relevance. The article describes zones with one or another predominant type of melioration depending on the territorial location of the reclaimed lands, a brief classification of channels is given according to design features, cross-sectional shape, throughput capacity and technical and operational characteristics. Channels are the main elements of reclamation systems. Ensuring high-quality operation of channels with the required bandwidth guarantees the efficient operation of the entire reclamation system. Characteristic canal deformations that occur during operation are given, as well as factors affecting the throughput of canals, such as the appearance of sediment, silting and grass vegetation, the growth of shrubs and small trees. The article presents sewer cleaning machines used on canals of reclamation systems during cleaning and restoration work, describes their design features for cleaning canals of various types and cross sections. Canal cleaners are described, which, according to the mode of operation, are both intermittent and continuous machines, which most effectively and efficiently clean the bottom and slopes of channels of various reclamation systems. The article also provides an explanation of the increase in the efficiency of canal cleaning and the subsequent high-quality work of the reclamation system in the case of using various complexes of sewer cleaning machines, including a variety of machines with different working bodies, sizes and quantities. The choice of the number of machines is directly related to technical and economic indicators: the use of a large number of machines may not be economically feasible, and the use of a minimum number of machines will not provide the re-quired cleaning. Thus, it is important to choose the optimal number of machines of various sizes that form a separate complex.

Study on the mechanism and performance of longitudinal-torsional ultrasonic vibration assisted drilling CFRP/Ti stack

The CFRP/Ti stack structure composed of Carbon fiber-reinforced polymer (CFRP) and Titanium alloy (Ti) is intensively used in the assembly manufacturing of aircraft key structures. The difference in physical properties between CFRP and Ti leads to the poor cutting matching performance of the two materials during the one-time drilling of CFRP/Ti stack. Longitudinal-torsional ultrasonic vibration assisted drilling (LTUVD) technology is considered to have excellent application prospects due to its excellent processing characteristics when machining difficult-to-machine materials. In this research, longitudinal-torsional ultrasonic vibration was applied to the drilling of CFRP/Ti stack structure. This research contributes to understand the machining mode mechanism of CFRP/Ti stack processed by LTUVD. Based on the thrust force, entrance morphology, exit morphology, interface morphology and hole wall morphology obtained by LTUVD and CD experiments, the action mechanism and drilling performance of longitudinal-torsional composite ultrasonic vibration in stack drilling were further expounded. The existence of longitudinal-torsional ultrasonic vibration makes the maximum thrust force of CFRP and Ti lower than that of CD by 39.6 % and 24.1 % respectively. The damage degree of CFRP entrance, Ti exit and interface obtained by CD machining was more serious than that of LTUVD. Among them, the entrance damage factor and interface damage factor of CFRP processed by CD were 10.21 % and 15.36 % higher than those of LTUVD, respectively. The morphology of CFRP hole wall formed by CD was slightly worse than that of LTUVD, and has higher surface roughness.

Effects of roughing, finishing, and aggressive machining conditions on the milling performance of AISI 1045 steel using TiAlN coated inserts

The objective of the present study is to develop a better understanding of machining performance of TiAlN coated tools during face milling of AISI 1045 medium carbon steel. The influences of three different cutting conditions (roughing, finishing, and aggressive conditions) were investigated on cutting forces, chip temperature, tool wear, surface roughness, and chip characteristics. The highest cutting forces were obtained under roughing condition, while, aggressive mode of machining (high values of cutting speed, feed, and depth of cuts) resulted in the highest chip temperature, crater, and flank wear. Material adhesion and coating delamination were predominant under roughing condition. On the other hand, aggressive condition exhibited diffusion wear causing large depth of crater and severe thermal cracks leading to fracture of the cutting edge. Attrition and abrasion wear were also evident. The results of cutting forces, chip temperature, surface roughness, and chip characteristics were correlated with those of tool wear. Results were found to be beneficial in recommending appropriate criteria for choosing different cutting conditions in face milling of AISI 1045 steel using TiAlN coated insert.

FACE RECOGNITION SYSTEM FOR AUTOMATIC DOOR ACCESS CONTROL

A face recognition system for automatic door access control has been developed in this work with a view to providing a relatively more robust and foolproof access control which can provide better security and reduce human errors inherent in other conventional methods. The system was designed with machine learning and artificial intelligence to capture faces, train faces with machine mode, and run trained faces to grant access to the user. The system uses the RaspberryPi module, camera module, servo motor and the GSM module which were all incorporated into the fabricated building to make up the prototype developed to provide access control by means of facial biometrics. In order to grant access to registered users, various photos of the users were taken in different positions and expressions with proper illumination. The user’s face is been captured by the camera module and saved in the database with the help of Raspberry Pi Module. Good lighting condition and other favorable conditions helps the camera module to recognize faces and sends signal to the Raspberry Pi which processes these images and opens the door with the help of the servo motor. The developed prototype was used to train fifty (50) users. It granted access to all fifty (50) users when there was proper illumination and pose but five (5) and nine (9) users respectively were denied access due to challenges of poor illumination and pose variation.

Influence of Microstructure and Alloy Composition on the Machinability of α/β Titanium Alloys.

A comparative study was conducted for the machining of two α/β titanium alloys, namely Ti-6Al-4V (Ti64) and Ti-6Al-7Nb (Ti67), using wire electric discharge machining (WEDM). The influence of cutting speed and cutting mode on the machined surfaces in terms of surface roughness (Ra), recast layer (RL), and micro-hardness have been evaluated. Rough cut (RC) mode at a cutting speed of 50 µm/s resulted in thermal damage; Ra was equal to 5.68 ± 0.44 and 4.52 ± 0.35 µm for Ti64 and Ti67, respectively. Trim-cut mode using seven cuts (TRC-VII) at the same speed decreased the Ra to 1.02 ± 0.20 µm for Ti64 and 0.92 ± 0.10 µm for Ti67. At 100 µm/s, Ra reduced from 2.34 ± 0.28 µm to 0.88 ± 0.12 µm (Ti64), and from 1.42 ± 0.15 µm to 0.90 ± 0.08µm (Ti67) upon changing from TRC-III to TRC-VII. Furthermore, a thick recast layer of 30 ± 0.93 µm for Ti64 and 14 ± 0.68 µm for Ti67 was produced using the rough mode, while TRC-III and TRC-VII modes produced layers of 12 ± 1.31 µm and 5 ± 0.72 µm for Ti64 and Ti67, respectively. Moreover, rough cut and trim cut modes of WEDM played a significant role in promoting the surface hardness of Ti64 and Ti67. By employing the Response Surface Methodology, it was found that the machining mode followed by cutting speed and the interaction between them are the most influential parameters on surface roughness. Finally, mathematical models correlating machining parameters to surface roughness were successfully developed. The results strongly promote the trim-cut mode of WEDM as a promising machining route for two-phase titanium alloys.

Selecting the operating mode of roller machines

A dependence of the distance between the rolls on the radis of the roll, the thickness of the processed material, and the coefficient (angle) of friction of the processed material on the surface of the roll coating were theoretically studied. An experimental study revealed the dependence of the distance between the rolls on the intensity of the load, the radius of the roll, and the thickness of the material being processed. It was found that with an increase in the roll radius and load intensity, and with a decrease in the thickness of the material being processed, the distance between the rolls decreases.

Prediction of erosion rate by a novel method and parametric optimization of edm of novel sic insulated ceramic reinforced with carbon nano tube

In this study, a mathematical model for the multi-optimization of Silicon carbide [SiC] reinforced by Carbon Nano tube [CNT] machined by Electrical discharge machining[EDM] has been done. SiC has an excellent mechanical properties owing to its large use as heat exchangers, sensors and automotive brake discs, etc. All of these applications need a highly precise machined hole with reasonable surface clarity. But due to its high hardness it is impossible to be machined by Conventional mode of machining. As SiC is a highly nonconductive ceramic CNT reinforcement make it possible to machine it by EDM and also increases its mechanical properties. For this study-three different proportion of CNT [2%, 4%, 6%] by Volume has been considered as reinforced material. For selecting the optimal process parameter L9 Taguchi Orthogonal array has been designed for this study by considering different output parameters [i.e CNT Proportion, Current, Voltage & Pulse-On time]. Material removal rate [MRR] and Surface roughness [SR/Ra] has been calculated by conducting the experimentation. The best setting of Process parameters has been predicted by Taguchi Coupled with GREY method. At the optimal condition the deviation in between the experimental result and the predicted result is 4.3% for MRR and 4% for SR respectively. The regression model has been done with R2 and R2adj showing above 90%. ANOVA analysis has been also shows 4% CNT reinforced SiC ceramic can be considered for used in automobile, sensor industries.

Design of a reference part for the comparison of tools in plastic milling operations

In milling operations, the comparison between conventional and innovative tools is of great importance, both in tool development and in setting up processes. Reference parts should represent occurring geometric features of machined parts and applied machining modes of the tools as realistically as possible. However, existing reference parts often cover these inadequately and were mainly developed in the context of metal milling operations. The transfer to the application case of plastic milling operations is only possible to a limited extent, since geometric features and applied machining modes differ significantly from those in metal milling operations. This paper describes the design of a reference part, which is based on selected cross-industry components from plastic milling operations and thus comprehensively reflects their special geometric and machining features. The design of the reference part is based on the feature method following the DIN 14649 and VDI 2218 standards according to which the selected components are decomposed into their individual geometric features and the design of the reference component is derived from them. Based on the newly designed reference part, tools can be systematically and representatively compared within the framework of plastic milling operations with regard to energy efficiency, surface quality and tool life.