bluuebunny/crossref_metadata_2025 huggingface dataset:
Obstacle Avoidance by Unmanned Underwater Vehicle
Authors: Zak Andrzej
Published: January 2016

Paper presents method of obstacle avoidance used in the example of unmanned underwater vehicle. The solution of this problem is divided into stage of: obstacle detecting and shape determination, decision making and control signal generation. The process to avoid an obstacle is presented as iterative model of behavior of dynamic system based on an array of discrete transitions between the successive states in accordance with accepted principles. The obstacle shape is determined basis on its histogram both in the horizontal as well as vertical plane of observation. Every stage of process of obstacle avoidance is described in details and both mathematically as well as by figures documented. At the end there are presented chosen results of simulation research which verify proposed solution.
Analysis of Unrepeatability of an SI Engine Based on Measurements of Indicated Pressure
Authors: Kordos Paweł , Nieoczym Aleksander
Published: January 2016

The article presents the results of an empirical study of unrepeatability of the spark-ignition engine BMW N43 B20 AY, which uses a spray-guided gasoline direct injection system to create the fuel mixture. The values of the so-called unrepeatability index of maximum indicated pressure were analyzed for two different engine operating conditions: under maximum load (absolute throttle at 91%) and under partial load (absolute throttle at 33%). The values of the index were calculated on the basis of values of indicated pressure recorded over 100-cycles at five predefined rotational speeds of the engine crankshaft. It was found that the unrepeatability of maximum indicated pressure during operation of the test engine was lower under partial load than under maximum load.
Research and Analysis of Accuracy of Location Estimation in Inertial Navigation System
Authors: Rajchowski Piotr , Cwalina Krzysztof , Sadowski Jarosław
Published: January 2016

In the article the research and analysis of digital signal processing and its influence on accuracy of location estimation in developed inertial navigation system was presented. The purpose of the system is to localize moving people in indoor environment. During research a measuring unit for recording selected movement parameters was made. In the article were also described author’s inertial navigation algorithms.
Computing of Poles of Linear Antennas from Noisy Responses
Authors: Walkowiak Maciej , Witenberg Anna , Jagodzińska Katarzyna
Published: January 2016

This paper deals with the issue of the natural frequencies of simple linear antennas. Analytical and numerical ways of determining such frequencies are discussed. We focused on the calculation of natural frequencies with data disorder and we have shown how this data disorder affects the location correctness of such frequencies. What is more, using SEM model and the poles concept, the boundary value of data disorder necessary to determine the correct location of natural frequencies is given.
Possibility to Use Cameline (Camelina sativa) as an Alternative Raw Material for Production of Biofuels
Authors: Ambrosewicz-Walacik Marta , Tańska Małgorzata , Nitkiewicz Szymon , Walacik Marek
Published: January 2016

The goal of the paper is to determine a possibility to use methyl cameline esters and their mixtures with diesel oil (in ratios of 95:5, 90:10, 85:15, and 80:20) as fuels for compression-ignition engines (diesel engines). The cameline esters obtained in the result of one-step basic transesterification were characterised in respect of kinematic viscosity at 40°C, density at 15°C, acid number, solid impurities content, sulfur content, ignition temperature, temperature of cold filter clogging, and oxidation resistance at 110°C. It was shown that majority of factors of pure cameline esters analysed in the paper, excluding content of impurities and oxidation resistance, met the requirements of the PN-EN 14214, 2012 standard. Whereas, in case of mixtures of diesel oil with varied addition of esters, it was ascertained that 5, 10 and 15% addition of the biocomponent did not affect significantly the physico-chemical properties of the prepared fuel. In turn, the highest, 20% share of a cameline ester caused a slight increase in viscosity, density, content of impurities and ignition temperature of the obtained mixture. However, it is noteworthy that these factors did not exceed the acceptable values according to the standard. In general, it was also ascertained that the only parameter disqualifying use of these samples as a fuel for compression-ignition engines was too high content of impurities.
Advanced Neuro-Fuzzy System in the Task of Position-Force Control of a Manipulator
Authors: Muszyńska Magdalena , Gierlak Piotr
Published: January 2016

The article presents an application of the hybrid neuro-fuzzy system in the task of position-force control of a robotic manipulator. The position-force control is especially important when the interaction force between the manipulator and its environment are large. This control problem relies on simultaneous execution of interacting forces between the manipulator’s tip, environment and the realisation path along the contact surface. Realisation of many robotised processes requires an application of the hybrid position-force control to perform the desired trajectory of the manipulator’s tip. This trajectory is associated with the contact surface geometry, and the desired down-force of the tip. In the article, the advanced neuro-fuzzy control system for the manipulator’s nonlinearities compensation is used.
An Example of a Special Algorithm Application for Control of Aerial Guided Bomb Flight, during Guidance on the Ground Moving Target
Authors: Stefański Konrad
Published: January 2016

This paper presents the analysis of the variety of methods regarding aerial guided bomb control during the ground attack on a moving target. Based on this method there was an earlier research regarding motion control of the three degrees of freedom gyroscope axis [1,2] during space exploration and discovered target tracking. Positive results obtained during that research led to conclusion that the proposed control method will be accurate to establish a control force for aerial bomb guiding. This method is based on the use of phase trajectories control deviations. Switching of the control forces in the particular phase plane points causes the deviations to decrease to zero and facilitates the proper trajectory of the bomb. This paper presents a switching algorithm, equations of kinematics and dynamics of a bomb flight-path and the variety of examples of a numerical simulations. Obtained results were presented in the graphic form.
An Analytical Literature Review of the Available Techniques for Relieving Transmission Line Bottleneck in Deregulated Power Systems
Authors: Mohd Zin Abdullah Asuhaimi , Moradi Mehdi , Khairuddin Azhar , Moradi Mohammad
Published: January 2016

Relieving power transmission line bottleneck is one of the major tasks performed by system operators (SOs) to ensure the operation of transmission system within operating limits. With the advent of electric power market, the relieving bottleneck becomes extremely important challenge and it can impose a barrier to the electricity trading. In order to deal with the challenge, many researchers have recently proposed various techniques. The purpose of the this study is to provide a comprehensive review of the available techniques for relieving bottleneck that are applied to address power transmission line bottleneck issues in in deregulated power systems. The most up to date relevant options are described and categorized into specific clusters. A comparative analysis is carried out in which the advantages and disadvantages to each technique are assessed. Lastly, after the appraisement of the existing bottleneck management techniques, some conclusions and suggestions are put forward for relieving power transmission line bottleneck in the future.
A Review of Recent Studies on Positive Lightning
Authors: Wooi Chin Leong , Abdul-Malek Zulkurnain , Ahmad Noor Azlinda , Mokhatri Mehrdad , Khavari Amir Hesam
Published: January 2016

Lightning is a natural phenomenon that has much impact on man and man-made systems. Lightning can be generally characterized as either negative return stroke (NRS) or positive return stroke (PRS). PRS have high peak currents and long continuing current that are responsible for more intense damage than negative return strokes. However, PRS are considerably less studied compared to NRS due the complexity and paucity of PRS. This study attempts to provide an overview of the positive lightning characteristic research in recent years. The review is classified into four groups, which are: preliminary breakdown pulse of positive lightning, compact intracloud discharge, positive leader and positive lightning return stroke. In spite of recent progress made in this area, our knowledge on the physics of positive lightning remains considerably poorer than negative lightning. Many questions regarding the characteristic of positive lightning and their properties cannot be answered without further research. It would be of great interest to examine the positive lightning parameters under different meteorological conditions as well.
Transmission Line Using Discrete Wavelet Transform and Back-Propagation Neural Network Based on Clarke’s Transformation
Authors: Saini Makmur , bin Mohd Zin Abdullah Asuhaimi , Bin Mustafa Mohd Wazir , Sultan Ahmad Rizal , Rahimuddin
Published: January 2016

This paper proposes a new technique of using discrete wavelet transform (DWT) and back-propagation neural network (BPNN) based on Clarke’s transformation for fault classification and detection on a single circuit transmission line. Simulation and training process for the neural network are done by using PSCAD / EMTDC and MATLAB. Daubechies4 mother wavelet (DB4) is used to decompose the high frequency components of these signals. The wavelet transform coefficients (WTC) and wavelet energy coefficients (WEC) for classification fault and detect patterns used as input for neural network training back-propagation (BPNN). This information is then fed into a neural network to classify the fault condition. A DWT with quasi optimal performance for preprocessing stage are presented. This study also includes a comparison of the results of training BPPN and DWT with and without Clarke’s transformation, where the results show that using Clarke transformation in training will give in a smaller mean square error (MSE) and mean absolute error (MAE). The simulation also shows that the new algorithm is more reliable and accurate.
Development of Remote Control System for Residential AC Power Supply Based on GSM Technology
Authors: Noh Muhamad Syukri Md , Arief Yanuar Z. , Muhamad Nor Asiah
Published: January 2016

The present study deals with the development of remote control system based on the Global System for Mobile Communication (GSM) technology for switching the low voltage AC power supply system at residential consumer. Function of this system is to disconnect and reconnect the electricity supply to consumers. The introduction of the GSM technology and particularly the use of hand-held mobile phones has brought the innovative distance communication to remote locations. This utilization of this technology for the remote control of systems and appliances will make life easier, safe and quick from anywhere. GSM module was used for receiving short message service (SMS) from user’s mobile phone that automatically enable the controller to take any further action such as to switch on and off the consumer load at the incoming power supply. The system was integrated with microcontroller and GSM network interface using assembly language. AVR Studio 4 software was utilized to accomplish the integration. The system is activated when user sends the SMS to GSM controller circuit at electric meter consumption panel board. Upon receiving the SMS command, the microcontroller unit then automatically controls the incoming power supply by switching on or off the device according to the user command. In other words, the developed system reads message from the mobile phone and responds to control the devices according to the received message. The system can also give feedback to the user to inform the status of switching operation if such command is received.
Effect of Calcination Temperature on Catalyst Surface Area of Ca Supported TiO2 by Sol-Gel Method for Biodiesel Production
Authors: Yahya Noor Yahida , Ngadi Norzita
Published: January 2016

Currently, the major concern in production of biodiesel is to find a new catalyst which can produce high quality of biodiesel at lower costs. In this study, titania supported CaO catalyst was prepared by a so-gel method. The characterization of catalyst was done using Brunauer-Emmett-Teller (BET) model method to characterize the surface area of the catalyst. Further, the ability of the catalyst for transterification reaction of waste cooking oil (WCO) with methanol was also assessed. The effect of calcination temperature on the catalyst to the transesterification reaction was examined to investigate the relation between catalyst calcination temperature and percentage yield (% yield) of biodiesel production.
Feasibility Analysis of Stand-Alone Renewable Energy Supply for Telecommunication Tower Using Homer
Authors: Mohd Noor Mohamad Shahrizal , Adzis Zuraimy , Arief Yanuar Z. , Muhamad Nor Asiah
Published: January 2016

This paper deals with the importance and need of using solar photovoltaic (PV) system as a stand-alone system instead of diesel generators for electrical energy supply of a communication tower owned by Celcom (Malaysia) Berhad at G0422 Batu 18, Ulu Langat, Selangor, Malaysia. It can be considered as a commercial renewable energy application in Malaysia, addressing the potential and possibility of adopting solar energy resources, particularly for sectors with high energy consumption. The electric power generation system, which consists of solar PV system hybrid with diesel generator, has the ability to provide 24 hours electricity to the load. To optimize the system design, this work compares a wide range of equipment with different constraints and sensitivities. The Hybrid Optimization Model for Electric Renewables (HOMER) was utilized for designing the system in the early phases of planning and decision making in rural electrification projects due to its flexibility. The analysis is based on the technical properties and life cycle cost (LCC) of the system. The initial capital cost, cost of installation and operation costs over the system’s life span is comprised in the LCC. This system offers a better reliability, efficiency, flexibility of planning and environmental benefits compared to the diesel generators systems by saving the environment from the burning of fossil fuels. The proposed system is able to supply 3.5kW of power which is suitable for actual site loading requirement of around 3kW. The economic output from HOMER exhibits that the tower without diesel generator, total net present cost is RM 610,639, the highest compared with a tower with diesel generator; RM 421,244.
Removal of Oil Using Activated Carbon from Textile Sludge Biochars
Authors: Sohaimi Khairunissa Syairah Ahmad , Ngadi Norzita
Published: January 2016

The study of oil pollution is crucial nowadays and considered as one of the critical issues as oil pollution gives bad effects especially to wastewater treatment facilities. For that purpose, this study investigated the potential of activated carbon from biochars of textile sludge precursors for oil removal. The activated carbons were produced from biochar obtained through the pyrolysis of textile sludge waste by chemical activation with 1M of phosphoric acid which denoted as AC-B-H3PO4. Apart from that, the performance of adsorptive properties of the activated carbon was tested using simulated cooking oil waste water in homogeneous form as the targeted adsorbate. The effect of adsorption contact time and initial concentration of simulated oil wastewater towards performances of AC-B-H3PO4 in removal of simulated oil wastewater were studied and compared with biochars700. The equilibrium time in adsorption of the simulated oil wastewater for both biochar700 and AC-B-H3PO4 was obtained in 30min. Meanwhile, the effects of initial concentration of simulated oil wastewater, biochars700 has earlier achieved equilibrium at 300mg/l up to 500 mg/l, while for AC-B-H3PO4, the adsorption capacity still increase at a high initial concentration of simulated oil waste water but in a slow rate. The results obtained showed that AC-B-H3PO4 has more potential for oil spills treatment than biochars due to its ability to treat the high initial concentration of simulated oil wastewater at the equilibrium time. The findings also provide for an alternative for low cost and effective adsorbent for the oil pollution treatment.
New Advancement on Cross-Linked Enzyme Aggregates within Magnetically-Separable Mesoporous Silica
Authors: Sulaiman Nurul Jannah , Rahman Roshanida Abd
Published: January 2016

Magnetically-separable enzyme system has been developed by adsorption, precipitation and cross-linking of enzymes in superparamagnetic hierarchically ordered mesoporous mesocellular silica (M-HMMS). The immobilization of xylanase within M-HMMS were compared between enzyme adsorption (EA), enzyme adsorption and cross-linking (EAC), and enzyme adsorption, precipitation and cross-linking (EAPC). EAPC includes higher enzyme activity immobilized within the matrix in comparison with the other methods. Furthermore, the immobilized enzyme is predicted to be prevented from leaching out of the matrix when exterior blow is being tested on the structure. Thus, the stability of the EAPC of this invention is anticipated to be maintained even after a long time passed since high enzyme activity compared with known method can be supported and immobilized within the matrix. Consequently, it is possible to improve performance of the enzymes by manipulating the preparation and operation condition.
Preparation of Chitosan-Grafted Nanocellulose via Microwave-Initiate Method
Authors: Arsad Nurul Jannah , Ngadi Norzita , Mohamed Razak Siti Fatimah
Published: January 2016

Chitosan and cellulose are one of natural flocculants. Natural flocculants are non-toxic and biodegradable. Chitosan was grafted onto nanocellulose from empty fruit bunch (EFB) polymer by a irradiation from microwave initiated method. Effects of ratio chitosan to nanocellulose (0.2:1, 0.4:1, 0.6:1, 0.8:1 and 1:1) and irradiation time (1min, 2min, 3min, and 4min) on grafting were studied. Grafting was confirmed through weigh analysis and element analysis. The synthesis method was found to be both efficient and selective for grafting. Novelty, both of the natural polymers was successfully grafted. The grafting percentage was high for ratio cellulose to chitosan 1:1 with 56% at 2min reaction time.
Statistical Analysis of Breakdown Voltages in Virgin and Aged LDPE Using Johnson SB and Weibull Distribution
Authors: Bani Nurul A. , Abdul-Malek Zulkurnain , Ahmad Hussein
Published: January 2016

Polymeric material such as low density polyethylene (LDPE) has been used for decades as insulating material. Any polymeric material will experience degradation after prolonged application of high electrical stresses. Deeper understanding of the long term electrical degradation of the insulating material is necessary to predict the life of high voltage cable. Electroluminescence method (EL) is used to detect the breakdown voltages of thin film LDPE. This method utilizes a Peltier cooled electron multiplying charge coupled device (EMCCD) camera to detect the breakdown of the sample. Statistical distribution of the AC breakdown voltages of 100μm virgin and aged LDPE has been analysed. Comparison for the best fitted distribution was made for Weibull distribution and Johnson SB distribution using Anderson-Darling (A2) goodness-of-fit and Kolmogorov-Smirnov (D) goodness-of-fit (GOF). Johnson SB is rarely used in high voltage engineering application. The probability density function (PDF) and the cumulative density function (CDF) for both distributions are defined in this article. The statistical parameters used are estimated based on Maximum Likelihood Estimation (MLE) for both distributions. Based on the statistical analysis, it is observed that Johnson SB provide better fitting than Weibull distribution with lower fitting error and that 3-parameter Weibull is much better fitting than 2-parameter Weibull distribution for most cases. It is also found that the median breakdown voltage of LDPE samples decreases with increasing aging temperature.
Assessment of Series Compensator for Ferroresonance Damping in Power System
Authors: Abdul-Malek Zulkurnain , Khavari Amir Hesam , Moradi Mehdi , Wooi Chin Leong
Published: January 2016

Nowadays power quality is a critical issue in power system. Moreover the connection of three-phase transformers through underground cables is growing fast in residential, commercial, industrial and rural applications. Due to this increasing situation, the possibilities of having a series connected capacitance and a non-linear inductance, and hence ferroresonance, become more probable. Ferroresonance can also occur in power transformers or reactors by capacitive coupling from neighbouring phases or lines. It is necessary to have a general idea about what would be the best preventive decisions to take in order to avoid unexpected surprises. It is necessary to have an accurate ferroresonance model so that a device that can smoothen the sharp effects of ferroresonance can be found. In this paper, the FACTS device, namely the static synchronous series compensator (SSSC) had been used to mitigate ferroresonance. Results show that using SSSC dramatically decreases and mitigates the ferroresonance shock as well as the instabilities of the network.
First Order Statistical Features Thermal Images for Surge Arrester Fault Classification
Authors: Novizon  , Abdul-Malek Zulkurnain
Published: January 2016

— Thermal imaging technique is a very convenient, versatile and non-contact method which has been used for fault condition diagnosis of electrical equipment. The fault condition diagnosis is composed with data acquisition, data pre-processing, data analysis and decision making. Some important features contain in thermal image can be extracted for equipment condition monitoring and fault diagnosis. This paper attempts to extract some important features from the zinc oxide (ZnO) surge arrester using first order statistical histogram extraction to classify the fault condition using neural network. The experimental work was carried out to capture thermal image of 120 kV rated ZnO surge arrester. The thermal images were segmented and plotted histogram using dedicated software. Some features such as the maximum, minimum, mean, standard deviation, and variance were extracted using the extraction method, classification of aging was carried out using the neural network based on the leakage current values. The health states consist of normal, defection and faulty. The results show that the thermal image features extracted using the extraction method can be used to classify the fault condition of the ZnO surge arresters
Sintering Fundamentals: Historical Aspects
Authors: Upadhyaya Gopal S.
Published: January 2016

Sintering as a technology has been followed from ancient times. However, as science it emerged in 1940s with the seminal work of Frenkel, Huettig, Kuczynski, Lenel, Kingery and Hausner. The present paper covers the historical aspects of sintering fundamentals , right from solid state sintering to liquid phase sintering, activated sintering, electronic theory of sintering, sintering with external pressure, constrain sintering etc. Various mechanisms of sintering with their microstructural relationships have been highlighted. A generalized approach to sintering is called for, which may to great extent bridge the gap between sintering theory and practice.
Study on the Machinability Characteristics of Ti2AlNb Based Alloy in Turning with Coated Cemented Carbide Tools
Authors: Bai Bing , Su Hong Hua , He Lin Jiang , Liao Ling Ji , Ren Jing Gang
Published: January 2016

As a new type of material, Ti2AlNb based alloy has a broad application prospects in aerospace field due to its excellent properties such as low density, high specific strength at elevated temperature, excellent oxide and creep resistance. Many studies involving its material composition and structural properties have been published. However, there are relatively few literatures available on the machinability of Ti2AlNb based alloy. In this work, the turning experiment of Ti2AlNb based alloy was carried out with coated cemented carbide tools. The machinability of Ti2AlNb based alloy was investigated through the cutting force, cutting temperature, tool wear and surface roughness. The result shows that the cutting force is lower and surface quality is better under condition of higher cutting velocity, lower feed rate and smaller depth of cut. The life of tool is longer when they were cutting under the high cutting velocity, low feed rate and small depth of cut. The research could provide some instructive information and basic data for the turning process parameters optimization of Ti2AlNb based alloy.
Friction Modeling and Experimental Research of Tool-Chip in Turning Titanium Alloy Ti6Al4V
Authors: Li Zhen , Liu Er Liang , Wang Teng Da , Zhao Na , Min Ling Chen
Published: January 2016

Cutting force, cutting heat and tool wear are closely related to the friction characteristics of tool-chip interface in the process of metal cutting. The variation of the cutting speed and temperature have been analyzed by the distribution of stress and strain in the primary and the secondary shear zone. A new friction model has been established to analyze the contact length between cutting tool and chip and local friction coefficient at the sliding zone. Cutting experiments have been performed in the process of carbide tools cutting the titaniumTi6Al4V, the contact length of sticking zone and sliding zone and friction coefficient have been analyzed by measured cutting force. The simulation of cutting process has been carried out based on Deform software, then the simulation results have been compared with the test ones, which verifies the accuracy of the established model.
The Influence of the Grinding Wheel Parameters on the Spiral Groove Parameters of the End Mill
Authors: Zhao Xian Feng , Shi Hong Yan , He Lin
Published: January 2016

Inorder to analyze the influence of the grinding wheel parameters on the spiralgroove parameters in the grinding process of spiral groove, this paper analyses indetail the influence of grinding wheel radius, fillet radius and grinding wheelcone angle on the rake angle and the opening angle of the spiral groove basedon the spiral groove mathematical model of the end mill. And two polynomial werefitted between the grinding wheel fillet and the rake angle of spiral groove. Studieshave shown that: when the wheel attitude angle remains unchanged, the fillet ofgrinding wheel influence the rake angleand opening angle of spiral groove significantly; the cone angle of grindingwheel affects the opening angle largely; the radius and cone angle of grindingwheel have the weak influence on the rake angle of spiral groove.
Process Optimization for Milling Deformation Control of Titanium Alloy Thin-Walled Web
Authors: Ding Xu , Chen Ting Ting , Yang Yin Fei , Li Liang
Published: January 2016

The titanium alloy thin-walled structure has been widely used in aircraft construction as one of the main load-bearing components. However, it is difficult to ensure the machining accuracy because of the machining difficulties of materials and structures. This paper takes titanium alloy (Ti6Al4V) thin-walled web as the research object and analyzes the factors of milling deformation. Based on the analysis, the milling process of the titanium alloy thin-walled structure is optimized, including the decrease of cutting force and the increase of processing system rigidity. Furthermore, a reasonable milling scheme is put forward.
Influence of Drill Geometry Parameters on Helical Point Micro Drilling Performance
Authors: Zhang Su Yan , Liang Zhi Qiang , Wang Xi Bin , Zhou Tian Feng , Yan Pei , Xue Si Yi
Published: January 2016

Helical point micro-drill is characterized by a continuous helical flank instead of the piecewise planar flank, and its improved drilling performance is validated compared with planar drill point by some researchers. In this study, to analyze the effect of geometry parameters of helical point drill on the drilling performance, the micro-drills with different point angles, web thicknesses and helix angles of the flute are fabricated on a 6-axis CNC tool grinder, and a serial of micro-drilling experiments involving these drills on 1Cr18Ni9Ti austenitic stainless steel are carried out. In experiments, the drilling forces are measured and exit burrs are observed. Within a certain range of geometry parameters, thrust force increases with the increase of point angle and web thickness, and the decrease of the helix angle of the flute. The point angle is the main contributory factor for the thrust force followed by web thickness, while helix angle has a moderate effect on the force. Furthermore, poisson burr and rollover burr are generated with different point angles. Based on the results, a good selection of the helical point drill geometry parameters with small point angle, big helix angle and small web thickness are proposed to improve the micro-drilling performance.
Experimental Investigation of Mechanical-Thermal Characteristics in High Efficiency Turning Titanium Alloy Ti6Al4V
Authors: Shi Li Min , Yang Cheng , Li Qi Jun
Published: January 2016

Titanium alloy Ti6Al4V has poor machinability, which leads to high unit cutting force and cutting temperature, rapid tool failure. In this study, the effect of the cutting speed, feed rate and cooling condition on cutting force and cutting temperature is critically analysed by turning experiment. At the same time, the relationship is established among tool wear, cutting force and cutting temperature. This investigation has shown that cutting speed is the decisive factor which increasing cutting force and cutting temperature. In the process of turning, tool wear results in high amounts of heat and mechanical stress, which leads to serious tool wear. The Minimal Quantity Lubrication reduces the frictional condition at the chip-tool, decreases cutting force and cutting temperature, and delays the tool failure.
A Novel Evaluation Method on the Precision of Linear Motor Feed System in High-Speed Machine Tools
Authors: Yang Xiao Jun , Li Yan , Ma Cheng Fang , Lv Dun , Zhang Jun , Zhao Wan Hua
Published: January 2016

The linear motor feed system can realize high-precision motion with high-speed and high-acceleration, which has a broad application in high-speed machine tools. In its unique zero transmission structure, the motor is connected directly with the mechanical system. The thrust harmonics and other disturbances act on the motor mover directly, which makes the tracking fluctuation more prominent. The traditional accuracy and repeatability of positioning cannot reflect the precision of the linear motor feed system in the process of high-speed movement. In this paper, a novel precision evaluation method which takes the dynamic precision as the index is proposed for the linear motor feed system in high-speed machine tools. The performance and precision of linear motor feed system are evaluated by the transient error, steady-state follow error and tracking fluctuation, respectively. Then the servo control model is established oriented to dynamic precision. The influences of NC instructions, servo system and mechanical system on the dynamic precision are discussed. It can be obtained that this new evaluation method on the precision can evaluate systematically the performance of the linear motor feed system in high-speed machine tools. Meanwhile it can reveal efficiently main factors which lead to the decline of dynamic precision and propose effective improvement methods.
Microstructures and Mechanical Properties of CrN Coatings Deposited by HIPIMS
Authors: Fu Long Sheng , Dai Wei , Wang Qi Min , Zeng Kun
Published: January 2016

CrN coatings have been widely used in many industrial fields, such as cutting tools, moulds, mechanical components. In this work, CrN coatings were deposited using a high power impulse magnetron sputtering (HIPIMS) with various negative bias voltages. The composition, microstructure, and mechanical properties of the coatings were studied using X-ray diffractometer, scanning electron microscope (SEM) and nanoindenter. The cutting performance of the micro drills coated in CrN was also investigated by high speeding dry drilling printed circuit board (PCB). The results show that the bias voltage has significant influences on the microstructure and properties of the as-deposited films. Increasing negative bias voltages resulted in the microstructures refining of the CrN coatings with columnar grains. Further increasing the negative bias voltage caused the formation of defects in CrN. With optimization of the negative bias voltage, the micro-drills with CrN deposited by HIPIMS exhibited an excellent tool life comparing with the uncoated one.
Tool Material Selection Based on Analytic Hierarchy Process Method in Machining Al-Si Piston Alloy
Authors: Li An Hai , Wu Yi Min , Zhao Jun , Gong Zhao Chao
Published: January 2016

Cutting tool is the executor and core element of machining, and tool material is of decisive significance for the development of high-speed machining technology. For a particular workpiece material, to select the appropriate tool material is an important prerequisite to increase the machining productivity and to improve the machined surface quality.In this paper, a weighting method of subjective judgment was utilized to conduct criteria weighting in the tool materials selection when machining Al-Si piston alloy. The analytic hierarchy process (AHP) method was used to subjectively judge the significance of the material properties and determine their criteria weight. The hierarchical structure model, with the objective layer, the criterion layer, and the alternative layer, was established. The performance of tool materials was set as the objective layer. Seven property indexes, such as density, Young's modulus, hardness, fracture toughness, thermal stability, thermal conductivity, thermal expansion coefficient, were chosen as the criterion layer in comparative judgment of the alternatives and criteria. And five kinds of tool materials, YG6X Cemented carbide, YG8 Cemented carbide, PCD, CBN, and Ceramic were chosen as the alternative layer. Then the pairwise comparison matrix of the material property index was constructed to compare a set of criteria pairwise according to their relative importance weight. The comparative weights were derived by finding the largest eigenvector with respective of the matrix. Finally, the consistency index and consistency ratio were calculated to ensure the consistency of the subjective perception and the accuracy of comparative weights. Then the weights of the material properties were determined, and the synthesis scores of the different tool material candidates were obtained.Results revealed that PCD was found as best materials for Al-Si piston alloy machining, and YG8 is slightly more suitable than YG6X for machining Al-Si piston alloy. In short, the qualitative problems in tool material selection were realized systematically and hierarchically by quantitatively calculation and analysis. This provides a new thinking in tool materials selection for high efficiency machining of difficult-to-machine materials.
Next Generation Insert for Forced Coolant Application in Machining of Inconel 718
Authors: Tamil Alagan Nageswaran , Beno Tomas , Wretland Anders
Published: January 2016

Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process.Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at vc 105 m/min, f 0.3 mm/rev and ap 1 mm where the regular insert had a catastrophic failure at vc 90 m/min, f 0.1 mm/rev and ap 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.
Optimal Design Analysis of the Thickness of Shrink-Fit Holder
Authors: Zhou Hou Ming , Liu Bo , Luo Wen Yi , Zhang Gao Feng , Zhou You Hang , Peng Rui Tao
Published: January 2016

A calculation scheme to gain the relationship between the thickness of shrink-fit holder and thermodynamic properties. Based on the theoretical analysis of fitting molder between shrink-fit holder and tool, then the thermodynamic properties of the shrink-fit holder and cutting tool such as contact pressure, equivalent stress and deformation are analyzed at different thickness of shrink-fit holder in static, under cutting force and inducting heating by using the finite element software ANSYS. The results show that the total contact pressure and maximum equivalent stress increased and the minimum thermal displacement difference decreased with the increase of holder thickness. Under the action of cutting force, the contact stress on the tool holder no longer uniformed and the maximum contact stress significantly increased, cutting tool also deformed. Finally a method to determine the reasonable holder thickness is given and it has a practical guiding significance for the design and selection of the shrink-fit tool holder.
Increasing Productivity and Process Stability in Turning of Aerospace Materials with High Pressure Lubricoolant Supply
Authors: Klocke Fritz , Cayli Tolga , Veselovac Dražen
Published: January 2016

In the field of machining difficult-to-cut materials like titanium or nickel-based alloys, the use of a high-pressure lubricoolant supply may result in a significant increase of productivity and process stability. Due to enhanced cooling and lubrication of the cutting zone and thus reduced thermal tool load, tool wear can be decreased which allows higher applicable cutting speeds. Furthermore, the process stability can be increased as a result of effective chip breaking and chip evacuation. Since energy efficiency is very crucial, pressure and flow rate have to be adjusted carefully and in accordance with the cutting parameters to guarantee best results with less energy. For this purpose, experimental investigations were carried out under variation of the flow rate in order to find the minimum required value for a certain machining task with the overall aim to prevent waste of the media used. To maximize the positive effect of high pressure lubricoolant supply strategy on productivity and process stability, specially designed lubricoolant jet guidance geometry on the rake face was also investigated and compared to conventional turning inserts. To study the effect of high-pressure lubricoolant supply on tool temperature, reference tests also carried out using conventional overflood cooling (CoC). The results suggest that the tool temperature can be significantly decreased compared to CoC by applying the high pressure lubricoolant supply and using specially designed jet guidance geometry in turning the investigated aerospace materials TiAl6V4 and Inconel 718.
Research on the High Temperature Constitutive Model of 300M Ultrahigh Strength Steel
Authors: Zhang Hui Ping , Zhao Na , Shi Xu , Zhang Xiao Lei , Ren Yi
Published: January 2016

300M ultrahigh strength steel has good mechanical properties. It has been widely used in the force bearing components of aircraft. In this paper, By using Gleeble1-500D thermal simulator, we studied the change regularity of stress-strain curve of 300M steel using hot compression deformation when temperature is from 800°C to1100°C, strain rate is from 0.001 S-1to 1 S-1 and the strain is 0.7.The experimental results showed that when the strain rate is constant, the flow stress and the peak stress decrease with the increase of deformation temperature. When the deformation temperature is constant, the flow stress and peak stress increase with the increase of strain rate. From the test, we got the true stress-strain curve, calculated the thermal deformation constants such as the deformation activation energy of 300M ultrahigh strength steel. Eventually, we built the thermal deformation constitutive model in hyperbolic sine form of 300M steel.
Dynamic Characteristic Analysis of CNC Turret Punch Servo Beam
Authors: Guo Yan Jun
Published: January 2016

This paper resolved CNC turret punch cause vibration phenomenon in the course of processing sheet,analysis of its dynamic characteristics of the beam servo feed mechanism, using the method of constrained modal analysis.Through the establishment of finite element model exactly for the servo beam and setting the boundary elastic restraint stiffness, solving the natural frequencies and mode shapes of the servo beam under boundary constraints and loading conditions. Constraints modal analysis results are consistent with experimental monitoring results of CNC turret punch servo beam. This modeling methodology and results of the analysis has a high practical value for CNC turret punch dynamic characteristics analysis and structural optimization design.
Instantaneous Dynamics of Multi-Axis Milling Thin-Walled Workpiece with Complex Curved Surface
Authors: Ju Gang Gang , Song Qing Hua , Liu Zhan Qiang , Shi Jia Hao , Wan Yi , Ai Xing
Published: January 2016

The first step to predict the milling stability is to identify the dynamic characteristics of cutting process. And the mass loading effects of removal material play an important role on the dynamic characteristics of milling process for thin-walled parts, such as impeller, turbine blades and automobile components, which is changing with cutting time or tool position. Therefore, how to identify the instantaneous dynamic characteristics of milling process is one of the most significant problems. In the paper, a structural dynamic modification method with variable mass to predict the instantaneous dynamic characteristics of multi-axis milling thin-walled workpiece with complex curved surface is proposed. The proposed method takes into account the variations of dynamics characteristics of workpiece with the tool position and material removal. And the material cutting process is regarded as the structural dynamic modifications of cutting system, the instantaneous dynamic characteristics of which can be estimated by the extended Sherman-Morrison-Woodbury formula to obtain the corrected frequency response function (FRF). Experiments were carried out to obtain the instantaneous dynamics of a thin-walled workpiece and the results were verified by finite element method (FEM).
Design of Typical Aviation Titanium Alloy Benchmark
Authors: Ma Peng Fei , Wang Sheng Zhang , Zhao Wei
Published: January 2016

As technology develops, the aviation structures become more and more complex and consist of more difficult-to-machine features. In order to evaluate the cutting tool performance, it is necessary to design a testing thin-walled benchmark with some typical difficult-to-machine features which are extracted from complex integrated components used in aviation. Firstly, the models with different typical features were designed and optimized using UG NX. Then, based on the analysis of process of typical features, the specific processing strategies of testing benchmarks were proposed. Finally, the process was analog simulated with CAM to evaluate whether it was qualified for machining. The results would make preparations for the evaluation of different cutting tool performance.
The Adaptive Machining of the Leading and Trailing Edges of Precision Forging Blades Based on the On-Machine Measurement
Authors: Gao Jian , Wu Bao Hai , Zhang Ying
Published: January 2016

Blades are important components of aviation-engine, with complex shape and high precision machining. The radius of curvature of the leading and trailing edges of the precision forging blades is small and the curvature changes fast. In this paper, the adaptive machining scheme about the leading/trailing edge of the precision forging blade is proposed. Firstly, the measurement model based on theoretical model of the blade is established. Secondly, according to the measurement model, the measurement path planning is proposed. Thirdly, measurement data processing and registration, then blade model reconstructed to generate the new NC code for machining.
Cutting Parameters Optimization Based on Cutting Force Spectrum when Ball Milling A880 Gas Turbine Blade Profiles
Authors: He Xu Dong , Wang Cheng Dong , Wang Zi Kai , Chen Ming
Published: January 2016

In this paper, experiment investigation is conducted on the machinability when ball milling A880 gas turbine blade profile. Cutting force spectrum acquired online is used to optimize the cutting parameters. The results indicate that cutting force signal in time domain and frequency domain can reveal the cutting stability, which provides an experimental guideline for gas turbine blades manufacturing.
Measurement of Micro-Drill Breakage during PCB Drilling
Authors: Huang Xin , Chen Zhi Shun , Wang Cheng Yong , Zheng Li Juan , Song Yue Xian
Published: January 2016

Due to the weak rigidity of micro-drills and impulse effects, the micro-drill breakage is a common problem in printed circuit board micro-drilling. Traditional micro-drill breakage detection methods and principles, including vacuum-type, laser-type, and contact-type detection, were reviewed in this paper. The comparison of three detection methods showed that the contact-type detection can more satisfy the performance of CNC drilling machine. Three effective contact-detection circuits, including no transformer and rectifier circuit pulse-type, active-type, and trigger-type detection circuit, were introduced. And as a conclusion, differences of these detection methods were compared. Based on the characteristic of three effective micro-drill breakage contact detection circuits, the development trends and designs of innovative detection circuit were proposed to meet the challenges in micro-drill breakage measurement during PCB drilling.
The Machinability Evaluation of Hardened Steel 7CrSiMnMoV
Authors: Feng Xin Min , Zhang S.M. , Hu J.S. , Song X. , Liu F.
Published: January 2016

Based on the cutting performance parameter of hardened steel 7CrSiMnMoV and the application of fuzzy synthetic evaluation principle, the essay establishes a two-level fuzzy synthetic evaluation model of the machinability of 7CrSiMnMoV. Choosing cutting force, cutting temperature and surface roughness of the workpiece produced during machining process as the evaluation index, data are measured through experiment and a synthetic evaluation of the machinability of hardened steel 7CrSiMnMoV is conducted. The result shows that it is reasonable to use cutting force, cutting temperature and surface roughness of the workpiece as evaluation index to evaluate the material machinability. And it also provides guidance to the selection of tools and the technological parameters during the process of cutting 7CrSiMnMoV.