International Journal of Mechatronics and Manufacturing Systems (13 papers in press)
Hardware and Software Complex and a Device for Setting Optimal Parameters of the Unit Injector Operation in Diesel Engines
by Ildar Gabitov, Samat Insafuddinov, Nail Yunusbaev, Timur Farhutdinov, Albert Sharafeev, Farid Abdrazakov, Filyus Safin, Elmir Gaysin, Ural Makhiyanov
Abstract: The purpose of this study is to develop a device for setting optimal parameters of a unit injector operation in diesel engines and to justify its design. The other goal is to create a hardware and software complex with a function of modernizing the adjustment rigs. The study analyzes factors that affect the law of fuel supply in the unit injectors. Findings from this analysis base the calculation methods and the regulation parameters of unit injectors. The adjustment parameters of the fuel supply system (cyclic design in particular) are calculated with regard to the injection chamber pressure using a the suggested hardware and software complex.
Keywords: fuel system; unit injector; diesel engine; injection; indication; gas pressure; compression; expansion; simulation of injection.
An Investigation of Acceptance and E-Readiness for the Application of Virtual Reality and Augmented Reality Technologies to Maintenance Training in the Manufacturing Industry
by Helen Scott, David Baglee, Roger O’Brien, Rita Potts
Abstract: Virtual Reality (VR) and Augmented Reality (AR) technologies offer new ways of providing training in manufacturing maintenance. The adoption of modern maintenance training practices has the potential to create efficiencies in terms of cost and time to train, while enhancing the quality of learning and maintenance outputs. However, in order to utilise the potential improvements that VR and AR offer in a manufacturing maintenance context, it is first important to understand the specific factors associated with VR and AR readiness and user requirement. The paper will firstly describe the results from a number of interviews conducted within a range of manufacturing companies in the North East of England to establish the state of e-technology readiness and acceptance, with specific emphasis on VR and AR applications. The results will identify how VR and AR might be utilised, relative to the companys needs. Secondly, a new model for maintenance training utilising VR/AR technologies will be described, based upon the initial findings and analyses combining cognitive behavioural models, real world data, and learning theory.
Keywords: Virtual Reality (VR); Augmented Reality (AR); Manufacturing Maintenance; Maintenance Training; Technology Readiness; Technology Acceptance; Cognitive Behavioural Models.
Robot-assisted Painting System for Bolt-Nut Pairs
by Ran Zhao, Kaiqi Yan, Otto J. Bakker, Svetan M. Ratchev
Abstract: To improve line performance and remove unnecessary low-skilled labour, it is essential automate some of the menial work as well as to have a smart assembly line where human workers can closely collaborate with robots carrying out those tedious tasks. The aim of this paper is to develop an automated bolt-nut pair painting system for a small parts assembly line. Bolt-nut pairs painting of aerostructures, in particular legacy products, relies heavily on the skill or rather craftsmanship of the human operator. This process is time-consuming while automated operations with industrial robots can be a more efficient solution. Spray painting robots have been widely used in industry, however, they are not suitable for painting bolt-nut pairs individually because it will cause a significant waste of materials. Thus, it is essential to develop proper tools and automated methods to replace menial work in order to reduce the cost and improve product quality. In this paper, a low-cost and flexible solution for automated bolt-nut pair painting using a painting dabber and machine vision system is proposed. ASense 2 camera is used to capture the 3D model of the parts, and an ABB industrial robot YuMi is programmed to implement the painting automatically. A specific nozzle for the dabber is designed to apply paint on bolt-nut pairs. The results shows that the location of every bolt-nut pair is found successfully, and the accuracy of the normal vectors is enough for robot-assisted painting work.
Keywords: Automated bolt-nut painting; Machine vision; Robotics.
Special Issue on: From the Members of the Editorial Board
Comparison of Model Free Control Strategies for Chatter Suppression by an Inertial Actuator
by Iker Mancisidor, Alexander Pena-Sevillano, Rafael Barcena, Oier Franco, Jokin Munoa, Luis Norberto Lopez De Lacalle
Abstract: The employment of inertial active damping devices for chatter suppression in machining processes has been widely studied. The main drawback is that machine tools generally offer reduced spaces for the actuator location close to the cutting point and, hence, a reduced volume design is required for this external device. Consequently, the ratio between the force capability and the occupied volume is of major importance. Therefore, the performance of the actuator must be exploited to the fullest, which depends principally on the selected control strategy to determine the force to be exerted. The work presents the comparison of the most used feedback control algorithms and a novel strategy based on the regenerative effect disturbance. Their results are assessed for orthogonal cutting cases, with the aim of optimizing the behavior of the active damping system.
Keywords: active damping; inertial actuator; chatter.
Development of a portable stereolithography device for computer numerical control machining centers
by Vasileios Sergis, George-Christopher Vosniakos
Abstract: A low-cost portable stereolithography (SLA) device is designed to cure polymer resin at suitable laser light wavelength. Required motions are imparted by any three-axis CNC machining center exploiting serial communication interface, macro programming and machine data manipulation facilities. The device consists of three subsystems: laser beam, resin handling and micro-controller, making use of several sensors and actuators. For an approximately circular beam spot the G-code is generated by commercially available slicing software and is automatically modified to comply with the CNC machine controllers own automation functions. Alternatively, for line-shaped laser beams G-code can be directly generated from STL files by making use of profiling and hatching library routines. The device has been tested with two different power diode lasers for manufacturing a variety of parts. Curing rate was tested by microhardness measurement. Dimensional accuracy with respect to nominal was recorded using a white-light scanner, proving that acceptable accuracy is reachable.
Keywords: Additive Manufacturing; Stereolithography; photopolymers; CNC; machining center; micro-controller; g-code macros.
Ultrasonic-assisted machining processes: A review
by Uday Shanker Dixit, Pulak Mohan Pandey, Girish Chandra Verma
Abstract: Ultrasonic-assisted machining process is one of the most recently explored hybrid machining processes. In ultrasonic assisted machining process, an oscillating motion (of small amplitude and high frequency) is superimposed on the conventional machining operation. The assistance of ultrasonic vibrations in machining process improves the performance of the process by reducing cutting forces and enhancing surface quality. The effect of ultrasonic vibration has been found very beneficial in different conventional and non-conventional machining processes. This paper reviews the analytical and experimental studies in the area of ultrasonic-assisted turning, milling and drilling, respectively. Additionally, the effect of ultrasonic vibration on non-conventional machining processes is also reviewed. The paper also explains the effect of ultrasonic vibration on the cutting mechanics. The research gaps present in the ultrasonic-assisted machining process domain have also been highlighted in order to drive on the path of future research in this area.
Keywords: ultrasonic-assisted machining process; ultrasonic-assisted turning; ultrasonic-assisted milling; ultrasonic-assisted drilling; hybrid machining; ultrasonic-assisted grinding; cutting force; surface roughness; vibrations; cutting temperature.
Micro textured cutting tool effects on cutting forces, volumetric wear and adhesion in dry turning of titanium alloy
by Tugrul Özel
Abstract: There are several distinct advantages offered by micro-textures applied to cutting tool surfaces to reduce forces, friction, and wear. This study provides investigations on micro-grooves fabricated on the rake face of tungsten carbide inserts (WC/Co) that were used in turning titanium alloy Ti-6Al-4V under dry conditions. Tool inserts included varying micro-groove width (50 ~100 m), depth (10 ~ 30 m) and spacing (15 ~ 100 m). In the experiments, a constant depth of cut and a cutting speed were used. The effect of micro-textured tool surfaces on cutting force and tool wear was found to be significant.
Keywords: Cutting tool; machining; micro-texture.
Data-driven productivity improvement in machinery supply chains
by Rafael Lorenz, Torbjørn H. Netland, Philip Roh, Valentin Holzwarth, Andreas Kunz, Konrad Wegener
Abstract: Modern manufacturing machines are equipped with numerous sensors that collect a large amount of various data. This data can be used to improve the machines productivity. Both the users and suppliers of machines could benefit from such opportunities. However, because machine users risk the loss of intellectual property, they are often reluctant to share their data. This represents a major inhibitor of data sharing in machinery supply chains. This paper proposes a five-step method for initialising data sharing between machine users and their machine suppliers. The method was tested and validated in a case company, and the potential benefits for machine users were quantified.
Keywords: Data sharing; Remote Services; Smart Machining Systems; Product-Service-Systems.
Cutting force investigation in face milling of additively fabricated nickel alloy 625 via powder bed fusion
by Jixiong Fei, Kaushalendra Patel, Guoliang Liu, Tugrul Özel
Abstract: The face milling of additively fabricated nickel alloy 625 produced via laser powder bed fusion is experimentally investigated. Typically, cutting forces are the most important factor affects the process outcome in terms of surface finish and chatter vibrations in milling of difficult-to-cut materials. The additively fabricated materials possess different mechanical properties hence their cutting force performance is usually unknown. For additively fabricated nickel alloy 625, the build direction and scan strategy rotation are known to influence the resultant workpiece structure with columnar grains. The peak milling force is found dependent upon the feed direction as well as the layerwise scan rotation employed in fabricating the workpiece. Feeding the cutter against the build direction resulted in lower peak forces with larger deviations, however feeding along the build direction resulted in higher peak forces with lower deviations. The build direction was also observable on fan shaped chip surfaces.
Keywords: Additive Manufacturing; Milling; Force; Nickel.
Meshless Single Grain Cutting Simulations on the GPU
by Matthias Röthlin, Hagen Klippel, Mohamadreza Afrasiabi, Konrad Wegener
Abstract: Physically sound prediction of grinding results necessarily starts with the single grain interaction with the material, which is especially important for engineered grinding tools (EGT). The deformations encountered in single grain simulations are severe, especially due to the large negative rake angles. Conventional software tools using FEM suffer from the induced extreme distortions of the grid, necessitating costly remeshing operations. Meshless methods are not limited in the amount of deformation they can reproduce and thus a promising alternative, which also has the potential for extreme parallelization on the graphics co-processor (GPU). With the drastically increased computational speed unprecedented simulation resolutions can be achieved at reasonable computation times allowing parameter studies on different friction and constitutive models with first order complete meshless formulations.
Keywords: Meshless Methods; GPGU Computing; Simulation; Metal Cutting; Grinding; Engineered Grinding Tools; Smoothed Particle Hydrodynamics; Particle Methods; CUDA; Open Source.
Robust Trajectory Control of an Unmanned Aerial Vehicle Using Acceleration Feedback
by Hammad Zaki, Gokhan Alcan, Mustafa Unel
Abstract: In this work, acceleration feedback is utilized in a hierarchical control structure for robust trajectory control of a quadrotor helicopter subject to external disturbances where reference attitude angles are determined through a nonlinear optimization algorithm. Furthermore, an acceleration-based disturbance observer (AbDOB) is designed to estimate disturbances acting on the positional dynamics of the quadrotor. For the attitude control, nested position, velocity, and inner acceleration feedback loops consisting of PID and PI type controllers are developed to provide high stiffness against external disturbances. Reliable angular acceleration is estimated through a cascaded filter structure. Simulation results show that the proposed controllers provide robust trajectory tracking performance when the aerial vehicle is subject to wind gusts generated by the Dryden wind model along with the uncertainties and measurement noise. Results also demonstrate that the reference attitude angles calculated through nonlinear optimization are smooth and within the desired bounds.
Keywords: robust control; acceleration feedback; disturbance observer; quadrotor; hierarchical control; nonlinear optimization.
Development and Application of an Automated Impulse Hammer for Improved Analysis of Five-axis CNC Machine Dynamics and Enhanced Stability Chart Prediction
by Martin Postel, Nicolas Candia, Bircan Bugdayci, Fredy Kuster, Konrad Wegener
Abstract: Imprecise frequency response measurements can be a major problem in the analysis of CNC milling machine dynamics. Errors due to limited human capabilities hamper the precision of conventional impact tests using an impact hammer. Furthermore, impact tests on milling machines can be very time-consuming if dedicated parameter studies are performed, and also hazardous if impacts need to be performed on a rotating structure. To overcome these problems, a modularized and automated impulse hammer is presented in this paper. When using the automated impulse hammer, the variance in amplitude of subsequent impulses reveals to be one order of magnitude lower than when excitation is performed by hand. It is illustrated how the automated device can be used to investigate very distinct dynamic effects on a CNC machine that require a very high measurement precision, and also in which cases it helps to obtain more accurate stability chart predictions.
Keywords: automated impulse hammer; machine dynamics; chatter stability; mechatronics.
Smart Factory equipment integration through standardized OPC UA communication with companion specifications and equipment specific information models
by Fabian Stoop, Gerald Ely, Robert Menna, Greg Charache, Thomas Gittler, Konrad Wegener
Abstract: Industry 4.0 promotes digitalization side of manufacturing organizations into smart factories. Different operations in these organizations need to be upgraded to achieve new connective, remote and smart systems. Communication and connectivity of an operational data collection are the required principal components to enable manufacturing equipment to interact with Manufacturing Execution System (MES). Enabling technologies like OPC Unified Architecture (OPC UA) and standards like ISA95 are key resources to develop automated interfaces between equipment and control systems. The integration on equipment and MES side of these tools is challenging and needs to be realized with a long-term perspective. The main target is to integrate complex equipment in a simple and convenient way through the use of a companion specification, a dynamic address space and a OPC UA client characterization process. Challenges to overcome are the choice or the reconciliation of the right set of programming languages, the integration of generic, domain agnostic, domain specific and equipment specific information models, as well as the ease of maintenance to accommodate changes. This study describes the overall approach in a generic fashion and demonstrates its applicability in a complex manufacturing environment, serving as a blueprint for most other manufacturing environments. The outlined concept is based on C# and LabView source-code developed for semiconductor back-end equipment, which interacts with an MES through the Process Automation Controller (PAC). The proposed system is validated for a final testing unit in the production of kW-class high-power laser diodes.
Keywords: Smart Factory; OPC UA; Companion Specification; Information Model; ISA95; Manufacturing Execution System; Machine Connectivity.