© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2009, Poland

A NEW MULTIDISCIPLINARY APPROACH FOR THREE-DIMENSIONAL FOIL MACHINING

Rachel JAOUEN^1,2, Jean-Pierre MARTINEAU¹, Jean-Yves HASCOET¹ Thomas DAMAY²,br>
¹Institut de Recherche de l'Ecole Navale, BCRM , ENGEP Ecole, Marine nationale, CC 600, 29240 BREST Cedex 9, France, rachel.jaouen@ecole-navale.fr, jean-pierre.martineau@ecole-navale.fr , thomas.damay@ecole-navale.fr
²Institut de Recherche en Communication et Cybernétique de Nantes, 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 03, France, rachel.jaouen@irccyn.ec-nantes.fr, jean-yves.hascoet@irccyn.ec-nantes.fr

Abstract

The context of this paper implies disciplines of mechanical design, machining and hydrodynamics behaviours applied to propellers. Performances of propellers are linked with their shape and their surface texture. To optimise hydrodynamics behaviours, it is demonstrated in this paper that required polishing operation is not essential. To study the influence of an predefined surface texture on the performances of a three-dimensional foil, a comparative analysis is conducted. The presented methodology allows the definition of tool paths, according to the desired surface texture and upstream flow. Three foils are machined, and their performances are compared to each other: the first, considered as the reference, has a surface roughness like mirror, the second features machined peaks parallel to the upstream flow and the third has machined peaks following streamlines obtained by Computational Fluid Dynamics for operating conditions. The validation of this method is experimental: on the one hand by the manufacturing of foils following pre-established trajectories, and on the other hand by the functional test in hydrodynamic tunnel. This paper presents the methodology steps, and the hydrodynamic behaviours that the three different foils show. In a first approach, the different surface textures do not influence the lift coefficient but strongly influence the drag coefficient of a foil. Furthermore several hypotheses educed from the observed tendencies are discussed.

Author Keywords :

adapted tool trajectories, 5 axis machining machining peaks, hydrofoil lspropellers, hydrodynamic

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

HIGH SPEED CUTTING OF SUPERALLOYS

Hans-Werner HOFFMEISTER1¹, Ronald WITTMER¹, Christian SCHNELL¹,
¹TU Braunschweig, Institute of Machine Tools and Production Technology

Abstract

A possibility to improve the productivity in production industry is the implementation of high speed cutting processes. In particular, the high performance machining of superalloys such as titanium- and nickel-based alloys makes high demands on tools and machines. Therefore, it is important to understand the chip formation mechanisms during high speed cutting.This paper describes the effect of different influential variables including the tool chip angle, cutting velocity, chip thickness and the structure of the superalloys Inconel 718 and TiAl6V4 on chip formation and cutting forces. The experiments were accomplished on a a quick-stop experimental rig, which allows to decelerate the workpiece, even for very high cutting speeds, within a distance which is smaller than the chip thickness. The experimental examinations were completed by temperature measurements. The knowledge of the resulting tool, workpiece and chip temperatures from high performance machining of hard machinable alloys at high cutting speeds contributes to understanding of the different chip formation mechanisms and the influence on tool-life.

Author Keywords :

high speed cutting, superalloys, inconel, titanium

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

A NEW STRATEGY OF TOOL PATH PLANNING BASED ON HYDRODYNAMIC DATA TO MACHINE MARINE PROPELLER

Thomas BRETEAU^1,3, Thomas DAMAY¹, Emmanuel DUC², Jean-Yves HASCOËT³,
¹IREnav, Ecole Navale 29 240 Brest Armées (France), {thomas.breteau,thomas.damay}@ecole-navale.fr
²LaMI, Campus de Clermont-ferrand, Les Cézeaux BP 265, 63 275 Aubiere Cedex (France), Emmanuel.duc@ifma.fr
³IRCCyN, 1 rue de la Noë BP 92101, 44 321 Nantes Cedex 3 (France), {thomas.breteau,jean- yves.hascoet}@irccyn.ec-nantes.fr

Abstract

Marine propellers are complex surfaces that are usually machined with a perfect roughness in order not to disturb the theoretical flow. Because this requirement is penalizing from a manufacturing point of view, the global objective of the study is to propose an approach in which the machining parameters are linked to functional properties of the blade in order to remove the polishing phase. To reach this objective, hydrodynamic data are used: streak lines, that are computed during the propeller design phase, characterize the fluid behavior at the close vicinity of the blade. Those lines, which are theoretically continuous at the leading edge, turn out to be discontinuous, due to the computing method. To be consistent with the fluid behavior as much as possible, the idea presented in the paper is to compose a continuous trajectory, especially at the leading edge, to mill the surface. Thus, an algorithm is developed to plan tool paths which are smoothed at leading edge using Bezier curves. Moreover, this algorithm allows to quantify the cusp height at the leading edge to avoid a drop in performance using criteria linked to the dynamical behavior of a five axis machine tool. In this work, a strategy is developed and enables multiaxial milling of a blade surface by using geometric and hydrodynamic data and by respecting the associated constraints.

Author Keywords :

propeller, tool path planning, machining methodology

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

CHATTER IN CUTTING PROCESSES

RAFAL RUSINEK¹, JERZY WARMIŃSKI¹,
¹Lublin University of Technology, Mechanical Faculty, Department of Applied Mechanics Nadbystrzycka 36, 20-618 Lublin, Poland, e-mail: r.rusinek@pollub.pl, j.warminski@pollub.pl

Abstract

Vibrations during a cuttting process are analysed by means of a frictional and a regenerative model. For this purpose a new model which contains a nonlinear friction force, defined by Rayleigh's self-excitation, is developed. Then a one degree of freedom model is examined using analytical and numerical methods. The regenerative model of cutting is separately examined in order to emphasize differences between frictional and regenerative models. Next, a mutual interaction of frictional and regenerative effects is discussed and their influence on process stability is shown. Finally, a two degree of freedom frictional model with an extra centrifugal force is investigated. Various kinds of behaviour, from regular to chaotic are shown.

Author Keywords :

chatter,cutting process dynamics

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

HIGH PERFORMANCE OF NANOWIN^TM GRINDING WHEELS

Czesław NIŻANKOWSKI¹,
¹Ośrodek Badawczo-Rozwojowy Sprzętu Mechanicznego w Tarnowie Sp. z o.o.

Abstract

NanoWin^TM grinding wheels represent the most recent generation of bound abrasive tools. They are characterized by the fact that the nanocrystalline sintered corundum immersed in the matrix of special ceramic glasscrystalline binder has been applied as abradant in them. In this paper, the results of comparative experimental tests of the cutting capacity of classical alundum, submicrocrystalline sintered corundum and NanoWin^TM grinding wheels have been presented. The cutting capacities of the tested grinding wheels were determined with the application of the first McKee-Moor indicator. It was found that the cutting capacity of the tested grinding wheels in the process of hardened steel surface grinding stayed in the proportion of ca. 1 : 3 : 5, respectively.

Author Keywords :

nanotechnology, grinding wheels, cutting capacity

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

DEVELOPMENT ON DIAMOND TOOL WITH FORCED COOLING SYSTEM FOR HIGH SPEED CUTTING OF AERONAUTIC AND ASTRONAUTIC PARTS

Ikuo TANABE¹, Thang Binh HOANG1 ¹, Tetsuro IYAMA¹,
¹Nagaoka University of Technology,1603-1 Kamitomioka-machi, Nagaoka, Niigata, 940-2188 Japan

Abstract

Recently titanium alloys and nickel alloys have become eminent for making aeronautic and astronautic parts. Since both nickel alloys and titanium alloys have a very small thermal conductivity, the being used tool will suffer from a huge damage by heat generated during cutting process. Therefore, there is a requirement for a durable tool with excellent cooling capacity. In this research, a new electro-deposited diamond tool for high speed cutting of nickel alloys and titanium alloys was developed and evaluated. The new tool is a cup shaped end mill, its body is made from copper (due to its superior heat conduction characteristics) and the platting layer for bonding the diamond grains #120 is nickel. The cooling system is an advancement of the former used heat pipe. Water is supplied from outside through a thin tube, that is integrated in the tool body. Thereby the effect of water evaporation, featuring a very large cooling capacity, could be applied. The assayed materials were Ti6Al4V and Inconel 718. The cutting conditions were investigated by some pre-experiments. It is concluded from the results that; (1) The cooling capacity of the new tool using water evaporation is very effective to maintain the grinding potential of electro-deposited diamond tools, (2) The new tool is effective for high speed grinding of nickel alloys and titanium alloys (3) The new tool and compulsory cooling system are economical and eco-friendly.

Author Keywords :

high speed cutting, diamond tool, forced cooling Ni alloy, Ti alloy, aeronautic and astronautic parts

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

THE ANALYSIS OF FEEDRATE CORRECTION INFLUENCE ON CORNER RADIUS ERRORS OF WORKPIECES DURING MILLING

Jerzy JÓZWIK¹, Paweł FILIPIAK¹,
¹Scientific Group, Lublin University of Technology, Mechanical Engineering Faculty, Department of Production Engineering, Nadbystrzycka Street 36, 20-618 Lublin, j.jozwik@pollub.pl, phiodor@op.pl

Abstract

Geometrical accuracy of workpieces manufactured in CNC technology is dependent on many different factors, such as the parameters of a cutting process. The most significant are: cutting velocity vc and feed rate vf but also proper cooling and appropriate rigidity of a machine tool. Values of these parameters are dependant on the kind of a workpiece and on the applied tools. Considering shape complexity of a workpiece, dimensional and shape errors can appear, for example deviations of flatness, rectilinearity and radius roundness, etc. To avoid errors connected with geometrical profile, the parameters of machining should be selected in such way to obtain maximal value of quality rating of a product considering its shape and dimension. The aim of this paper is to evaluate the correction of feed rate (vf ) influence on radius errors of a workpiece's corners and to define the relation between technological conditions of cutting process and the actual shape of radius after machining. In theoretical part, the influence of different factors on the accuracy of cutting on CNC machine was included; the main focus was on the accuracy of cuttings the corners with different radii. The practical part consists of corner's radius errors measurements with the usage of coordinate measuring machine and complex analysis of research findings. The findings were presented in the form of diagrams and charts. Because of the fact that the feed rate influences the global time of workpieces' machining, the findings presented in this paper enable the production engineers to choose the optimal value of feed rate during the cutting of corners on CNC machines. It is very important during machining of matrices which construction consists of many corners with given radii that are placed between perpendicular and slant walls.

Author Keywords :

cutting process, correction of feed rate, radius errors, workpiece, CNC machine

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

PRODUCTION OPTIMIZATION BY COGNITIVE TECHNOLOGIES

Robert SCHMITT^1,2, Robert SCHMITT², Mario ISERMANN^2
1Werkzeugmaschinenlabor WZL, RWTH Aachen University, Steinbachstr. 19, 52074 Aachen. Germany
²Fraunhofer Institute for Production Technology IPT, Steinbachstr. 17, 52074 Aachen, Germany

Abstract

Today, value chains are considered fractionally and on the basis of simplified model assumptions. Interactions between processes, materials, means of production and individuals acting in this environment as well as the effect of changes on the product usually are not known exhaustively. In order to take corrective actions towards these deficits, self-optimizing production system technologies can be used. They provide systems that emulate the "human" ability of reaching a decision with technical architectures. The goal of these approaches is to steadily analyze and evaluate the actual status in technological as well as in organisational areas and conduct a system adaptation to alternating objectives. Central questioning in this field of research is how to survey production data in order to detect correlations of production parameters and their influence on product parameters, how to derive decisions from this knowledge and how to learn from the consequences. Application technologies capable of taking on these tasks of self-optimization to emulate intelligent behaviour are analysed. The aim is to identify the competencies of these technologies, in order to build a cognitive system architecture based on applications especially suited for each task that has to be fulfilled to emulate cognitive human decision making processes.

Author Keywords :

cognitive tolerance matching, self-optimization, SOAR, cognition, intelligent production systems

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

MANUFACTURING PROJECTS CASH-FLOW DYNAMICS AND RISK MANAGEMENT

Sergei KRAMARENKO1¹, Eduard SHEVTSHENKO¹, Tatyana KARAULOVA¹, Yan WANG²,
¹Tallinn Technical University, Ehitajate tee 5, 19086, Tallinn, Estonia, eduard.shevtshenko@ttu.ee
²University of Central Florida, Orlando, FL 32816, USA wangyan@mail.ucf.edu

Abstract

A project portfolio is referred to as an optimal combination of specified projects to best achieve defined goals of an enterprise. The goals may imply either economic and business strategies, or technical strategies. This paper presents an idea of project portfolio management in intelligent decision support systems (IDSS), which emphasizes on the problem of resource allocation, in particular cash. A rational way of distributing cash among different projects is modeled. We propose a concept of cash-flow dynamics module, which can be plugged into IDSS. The IDSS allows project managers to make decisions regarding the order of priority for projects' launching times based on risk and profitability of projects. This paper describes how this module can support cash-flow management processes, from budgeting for future periods to tracking real-time cash flow. Based on an analogy between cash-flow processes and physical flow of fluid, a cash-flow dynamics model is introduced. The theory of Bernoulli principle for cash-flow planning and tracking is applied.

Author Keywords :

intelligent decision support system, project cash flow management

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

ENERGY AND CARBON FOOTPRINT ANALYSIS FOR MACHININGTITANIUM Ti-6Al-4V ALLOY

M. F. RAJEMI¹, P. T. MATIVENGA¹, S. I. JAFFERY¹,
¹E-mail address : Mohamadfarizal.Rajemi@postgrad.manchester.ac.uk

Abstract

Titanium alloys are increasingly being used in manufacturing especially in aerospace industries. The environmental impact of using this material is rarely discussed especially with regards to energy consumption and its contribution to carbon emissions. The poor machinability of titanium leads to lower material removal rate and longer machining time. Coupled with high carbon footprints encountered, in extracting this material from ore, it is clear that the environmental impact of using this material needs to be optimised. In the research reported here, cutting tests were undertaken on a lathe and milling machine using unified cutting conditions. The associated energy and carbon footprints were analysed and discussed with emphasis on high speed machining. The paper clearly shows the impact of process choice and cutting speed on environmental footprints as a key performance measure in sustainable manufacturing.

Author Keywords :

energy and carbon footprint; machining; sustainable manufacturing.

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

AN INTELLIGENT SENSOR BASED SUPERVISION SYSTEM FOR CYLINDRICAL GRINDING PROCESSES

Paweł LAJMERT¹, BOGDAN KRUSZYŃSKI¹, Dariusz WRĄBEL¹,
¹Technical University of Łódź, Institute of machine tools and production engineering, Poland

Abstract

The paper presents a sensor based supervisory control system for cylindrical grinding processes which ensures reliable process monitoring and control in the presence of process disturbances. The system makes use of different processing techniques and process models to reliably detect incipient and abrupt symptoms of undesired process states and tool wear. As a result the supervisory system manages different actions to keep the process within the optimal working region. The system consists of two levels which act in parallel. The objective of the first optimisation level is to maximize the material removal rate, simultaneously satisfying restrictions on surface roughness, out-of-roundness and waviness errors and on grinding temperature. At the same time the second, geometrical control level is responsible for the removal of the initial shape error by stabilising the motion trajectory of the grinding wheel in relation to the part being ground. The concept of the supervision system was evaluated by a preliminary experiments to prove its effectiveness.

Author Keywords :

monitoring, supervision,optimization, cylindrical grinding

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

INCREASING OF RAPID PROTOTYPING PERFORMANCE BY 3D PRINTING TECHNOLOGIES

Birthe MATSI¹, Tauno OTTO¹, Lembit ROOSIMÖLDER¹,
¹University: Tallinn Univercity of Technology, Facutly: Faculty of Mechanical Engineering e-mail: birthe21@hotmail.com, e-mail: kaimo.sonk@mail.ee

Abstract

Rapid prototyping (RP) is being recognised as a significant technology for future product development. One of the most effective RP technologies is 3D printing. A three dimensional object is created by layering and connecting successive cross sections of material. Therefore this new RP methodology is generally faster, more affordable and easier to use than any other additive fabrication technologies. This paper analyses performance of RP methods and compares these based on use-cases. Prototypes of casing type details have been created using different RP technologies. Productivity of product development process and 3D printing has been investigated. A problem in differences between physical prototypes compared to existing computer model (digital prototype) can be diminished by using comparative pre-testing. Case studies of increasing innovation capacity in development of casing type details have been analysed. In addition, suggestions for increasing innovation capacity and performance of rapid manufacturing have been made.

Author Keywords :

rapid prototyping (RP), 3D printing, product development, performance of rapid manufacturing

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

TUNING OF A FUZZY SYSTEM FOR CONTROLLING SEARCHING PROCESS IN MULTI OBJECTIVE SCHEDULING IMMUNE ALGORITHM

Iwona WOSIK¹, Bożena SKOŁUD¹,
¹Institute of Engineering Processes Automation and Integrated Manufacturing Systems University of Technology, Poland

Abstract

In the paper the Multi Objective Immune Algorithm (MOIA) for an open job shop scheduling problem (OJSP) is proposed. The OJSP belongs to most both time consuming and most complicated problems in scope of searching space. In the paper schedules are evaluated by using three criteria: makespan, flowtime and total tardiness. MOIA proposes a schedule, which is best one, selected from a set of achieved solutions. An affinity threshold is a parameter that controls equilibrium between searching space and solutions diversity in MOIA. The affinity threshold is defined by using fuzzy logic system. In the paper fuzzy system is tuned by selecting shape, size of fuzzy sets, and fuzzy decisions of an affinity threshold. If the fuzzy system is used then neither the knowledge about the affinity threshold nor influence over searching processes is not required from a decision-maker. The application of the fuzzy system makes the process of decision-making user friendly. In the paper efficiency of MOIA before and after the fuzzy system tuning is compared and computational results are presented

Author Keywords :

Immune Algorithm, multi objective optimisation, fuzzy system

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2009, Poland

DEVELOPMENT OF HIGH PERFORMANCE MACHINE TOOLS

Jerzy JĘDRZEJEWSKI¹, Wojciech KWAŚNY^1
1Institute of Production Engineering and Automation, Wroclaw University of Technology, Wroclaw, Poland

Abstract

This paper presents a general characteristic of modern cutting machine tools and their role in achieving high machining performance. The determinants of machine tool development, stemming from the constant development of products and their complexity and from market demands, are discussed in detail. Special attention is devoted to the improvement of the machine tool structure and its variations created in response to the continuous and flexible increase in machining efficiency. The importance of developing multitask, hybrid and reconfigurable structures is discussed. The essence of the development of multi-spindle units as the modules having a decisive influence on machining performance, precision and costs is described. Moreover, trends in the development of feed units and distance measuring systems are presented.

Author Keywords :

machine tool, development, precision, performance, intelligence

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

COUPLED MODEL OF THE SPINDLE AND MACHINE TOOL FRAME

Petr KOLAR¹, Matej SULITKA^1
1Research Center for Manufacturing Technology, CTU in Prague, Horska 3, 128 00 Prague 2, Czech Republic

Abstract

Influence of the machine frame on the dynamic properties of spindle and tool is investigated using an example of a real machine tool. Model of the whole mechanical system is created as a coupled system of the tool, spindle and machine frame single submodels. Experimental verification of the model has shown a good match of the system critical frequencies and compliances. It has been proved that properties of the machine frame limit the dynamic properties at the tool tip especially in the case, if a compact tool is used.

Author Keywords :

spindle dynamic properties, machining productivity,y machine frame and spindle, coupled models, modal decomposition

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

MODELLING SUPPRESSION OF NON-LINEAR MACHINE VIBRATION

JIRÍ VONDRICH¹, EVZEN THÖNDEL¹, Emmanuel DUC², Jean-Yves HASCOËT^3
1Czech Technical University in Prague, Faculty of Electrical Engineering,, Department of Electric Drives and Traction, Technická 2, 166 27 Prague 6, Czech Republic, vondrich@fel.cvut.cz, thondee@fel.cvut.cz

Abstract

In this paper, the coupled non-linear differential equations of the model of machine as non-linear dynamical two degree of freedom vibrating system including cubic non-linearity are solved. The system consists of the main system and the absorber. Consider the non-linearity dynamical vibrating system as a model machine, which is compiled of a driven motor, gearbox and mechanisms with elastic and damping parts and driven parts. The absorber is used to control the main system vibrations when subjected to external excitation force. This system represents many applications in machine tools, ultrasonic cutting process, etc. Optimum working conditions for the absorber are by the same frequencies ω = ω₂ [1] of the action force F =F₀ sinω t and main mass m₁. The effects of different parameters of the system are studied numerically with Matlab.

Author Keywords :

Matlab, non-linearity's, vibration, machine

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

APPROACH FOR THE DEVELOPMENTOF ENERGY-EFFICIENT MACHINE TOOLS

Reimund NEUGEBAUER¹, Uwe FRIEß², Jörg PAETZOLD², Markus WABNER¹, Markus RICHTER^2
1Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz, Prof. R. Neugebauer, Chemnitz, Germany
²Institute for Machine Tools and Production Processes, Prof. R. Neugebauer, University of Technology Chemnitz, Chemnitz, Germany

Abstract

The life cycle costs of machine tools are much higher determined by their energy costs than what is often roughly assessed. The growing demand for consumer goods and especially possibilities of individual mobility in major parts of the developing world - e. g. Asia - will lead to serious problems in meeting the demand for an abundant energy supply and will increase the cost for energy further in the near-term future. Harder efforts are necessary to "reach more with less" - using less energy than today to reach a defined goal in production. The paper deals with a methodology to design machine tools with a high "energy efficiency". Based on the property-driven design methodology by Weber a systematic approach is shown to enhance the design of machine tools. Energy efficiency is a new additional and central property in the design process. To attain these given properties characterisations are determined by the engineer to fulfil these properties. On the developing-path the characterisations are defined in more detail step by step, and after each step it is assured if the accounted properties where met by the defined characteristics. The approach is to first analyse existing machine tools and therefore define prior energy consumers. The identified major consumers are afterwards systematically addressed to reduce their energy consumption. The result is an enhanced machine tool with state-of-the-art energy usage. This addresses the objectives of the EU and takes pressure of the energy supply by reducing the energy demand in production.

Author Keywords :

energy efficiency, machine tool, product development

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

ONE APPROACH TOWARDS ANALYTICAL DETERMINATION OF THE CNC MACHINE TOOL SERVO DRIVES POSITION LOOP GAIN

Zoran PANDILOV¹, Vladimir DUKOVSKI^1
1University "Sv. Kiril i Metodij", Faculty of Mechanical Engineering, Karpos II b.b., P.O.Box 464, MK-1000, Skopje, Republic of MACEDONIA, Tel.: 389 2 3099 259 Fax: 389 2 3099 298 E-mail: panzo@mf.edu.mk

Abstract

One of the most important factors which influences the dynamical behaviour of the servo drives for CNC machine tools is position loop gain or Kv-factor. It directly influences the contouring accuracy of the machine tool. Usually position loop gain is experimentally tuned on the already assembled CNC machine tool. This paper gives one approach towards its analytical calculation. The difference between analytical calculated and experimentally obtained Kv-factor is smaller than 5%, which is completely acceptable.

Author Keywords :

analytical determination, CNC machine tool, servo drives, position loop gain

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

VIRTUAL EVALUATION OF MACHINE TOOL COVER PASSIVE FORCES USING A COVER COMPLEX MODEL

Jan HUDEC¹, Petr KOLAR¹, Matej SULITKA^1
1Research Center for Manufacturing Technology, CTU in Prague, Horska 3, 128 00 Prague 2, Czech Republic

Abstract

The passive forces acting against the drive force are phenomena that influence dynamical properties and precision of linear axes equipped with feed drives. Covers are one of important sources of passive forces in machine tools. The paper describes virtual evaluation of cover passive forces using the cover complex model. The model is able to compute interaction between flexible cover segments and sealing wiper. The result is deformation of cover segments and wipers which is used together with measured friction coefficient for computation of cover total passive force. This resulting passive force is dependent on cover position. Comparison of computational results and measurement on the real cover is presented in the paper.

Author Keywords :

machine tool cover, passive force modelling, passive force compensation

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

SIMULATION TESTING OF THE MACHINE TOOL EQUIPPED WITH THE ACTIVE FEED DRIVE

Jiri SVEDA¹, Michael VALASEK¹, Zbynek SIKA^1
1Department of Mechanics, Biomechanics and Mechatronics, Faculty of Mechanical Engineering, CTU in Prague, Karlovo nám. 13, 121 35 Praha 2, Contact e-mail: Michael.Valasek@fs.cvut.cz

Abstract

The vibration of a machine tool is mainly caused by the dynamic acceleration of a motion axis and by the forces that act on it. All the disturbance forces are transmitted to the machine tool frame through the drive (motor) and its regulation loop and they excite its vibrations. Thus the achievable dynamics and machining quality is negatively influenced. There are several possibilities how to suppress the excited vibrations including the recently introduced "motor on motor" technique which is based on the serial connection of two linear motors. This paper presents new simulation results performed on the simulation model of a real machine tool. The maximal achievable tuning of the regulation loop parameters of the motion axis equipped with the "motor on motor" technique was confronted with the conventional feed drive setting. The "motor on motor" feed drive properties were also tested in the virtual machining operation mode where the real measured cutting force was used. The sensitivity analysis of the reaction force and the middle mass movement of the "motor on motor" feed drive solution to the predicted cutting force introduced to the feed drive control has been investigated. The middle mass is represented by the shared part of both linear motors which absorbs the high frequency part of the reaction force by its movement.

Author Keywords :

machine tool, feed drive, control loop simulation, cutting force, vibration suppression

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

APPLICATION OF UNCONVENTIONAL MATERIALS ON PRIMARY STRUCTURAL PARTS OF MACHINE TOOLS

Jan SMOLIK¹, Viktor KULISEK^1
1Research Center for Manufacturing Technology, CTU in Prague, Horska 3, 128 00 Prague 2, Czech Republic

Abstract

The paper is mainly focused on possible domains of application of composite sandwich materials in the field of machine tools. A theoretical case study analyzing the effect of application of composite sandwich materials on the dynamics of the X-feed-drive axis of the horizontal milling machine is presented. The benefits of composite sandwich materials are discussed and summarized in the context of modern machine tools and their desired static and dynamic properties. Experimental case study is also presented.

Author Keywords :

structural parts of machine tools, machine tools lightweight design, non-conventional materials in machine tool design,feed drive complex model

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

AN EXPERIMENTAL STUDY ON THE DETERMINATION OF OPTIMAL LUBRICATION CONDITIONS IN A HIGH-SPEED SPINDLE

Seong-Jin PARK¹, Young-Kug HWANG¹, Choon-Man LEE^1
1Department of mechanical design and manufacturing, Changwon National University, Korea, e-mail address: cmlee@changwon.ac.kr

Abstract

The heat generation inside spindles becomes a major factor that limits the allowable maximum rotational speed in machine tools and decreases the cutting quality. It is necessary to accurately estimate the temperature distribution in spindles caused by the heat generation in bearings and its heat transfer characteristics in order to perform the high-speed and high-precision in high-speed spindles. In addition, an accurate correction process is required according to the results of the estimation through investigating the thermal deformation error. A commercial program, MINITAB, was used to establish an experiment plan that analyzes the heat generation characteristics of the spindle system according to the operation and lubrication conditions of the spindle. Also, the change in the outer ring temperature of bearings was measured according to the experimental plan. After establishing a response surface model using the results of the experiment, the estimation equation of the quadratic polynomial model was proposed for determining the optimal lubrication condition. A verification experiment was applied to verify the accuracy of the experimental equation determined by the estimated regression model and the experimental value used in the estimation of the regression model.

Author Keywords :

optimal lubrication condition, oil-air lubrication, high speed spindle

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

A STUDY ON THE OPTIMAL DESIGN OF AIR POCKETS IN AN AIR BEARING APPLIED TILTING INDEX TABLE

Mun-Jae LEE¹, Choon-Man LEE^1
1Department of mechanical design and manufacturing, Changwon National University, Korea, e-mail address: cmlee@changwon.ac.kr

Abstract

The tilting index table has attached to CNC machining center with 3axes, it can be improvement of its performance and its machining efficiency. The tilting index table is a key unit in order to manufacture some non-rotational and 3-dimensional parts, using the conventional machining center. The tilting index table is directly connected to a processing object. Regarding the increase in the deflection of the table, it directly affects processing objects and increases errors and that makes impossible to obtain desired processing precision. Thus, this study performed the shape optimization of air pockets in order to minimize the deflection presented in the existing table. In the numerical optimizing method for implementing optimal design, the general full factorial design and response surface method in the design of experiments were used. A finite element analysis was used for computational experiments in which the finite element analysis was performed by using the ANSYS Workbench, which is a type of commercial FEM tool. In addition, the analysis of the results was performed by using the commercial program, Minitab 15. The results show that the optimum design results is better than those of the initial design.

Author Keywords :

optimal design, tilting index table, air bearing, air pocket

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2009, Poland

MACHINE TOOL CONTROL WITH ADDITIONAL MEASUREMENT FOR INCREASING THE CONTROL SYSTEM DYNAMICS

Petr STRAKOŠ¹, Michael VALÁŠEK^1
1Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Mechanics, Biomechanics and Mechatronics, Karlovo nám. 13, Praha 2, Czech Republic, email: Michael.Valasek@fs.cvut.cz

Abstract

As a typical type of controller in the area of machine tools the classical cascade controller is used. It consists of several PI control loops and allows the position control of the machine tool. This type of controller is easy to be implemented and gives satisfactory results but only in the case that the sufficiently stiff machine tool is being controlled. If adverse is true the performance of the controller deteriorates. This is due to the fact, that the controller is limited by the structural properties of the machine tool. The bandwidth of the controller is restricted by the position of the first anti-resonant frequency of the machine tool. The control techniques overcoming this limitation have been extensively researched. As a result the control technique employing the additional measurement of TCP, the model-based predictive control and the Kalman filter is used and delivers the increased control system dynamics. The paper deals with the description of the proposed control concept and the practical methods for additional measurement together with the Kalman filter tuning are described. The evaluation of the proposed control concept is based on the experimentally measured data on the machine tool axis with significant flexibility.

Author Keywords :

machine tool, additional measurement, predictive control, Kalman filter

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

TOTAL INERTIAL TOLERANCING, A NEW WAY TO DRIVE PRODUCTION

Maurice PILLET¹, Dimitri DENIMAL², Eric PAIREL³, Serge SAMPER^3
1Professor, University of Savoie - France
²Doctor, University of Savoie - France
³Associate Professor, University of Savoie - France

Abstract

Inertial tolerancing is a new concept of tolerancing which has done a first standardization in France (NF XP E 04-008 (2009). The paper presents a generalization of the inertial tolerancing: total inertia. The goal of total inertial tolerancing is to use the information include in the numeric description of the product. The Total inertial tolerancing defined "consistent functional subset" and different coordinate systems. For each of these subsets, we defined the maximum variability accepted (maximum inertia) from digital target. Inertia is the mean square deviation of the differences between the actual part and the target, measured in accordance with normal to the surface. Each functional subset will be identified by different colors. The purpose of the production is to produce parts with the least variability compared to the numerical shape. The production problem can be represented by two vectors: The vector of the deviations from the target on all measured points, and the vector of the control factors. Thereof, the question is: What is the value to apply on each corrector to minimize the vector of deviations? A reply is given by the total inertial tolerancing of which the link between the maximum inertia and the production is strong. Thus, the problem consists into compute the pseudo-inverse matrix of the relation between the deviation and impact vectors. This pseudo-inverse matrix allows minimizing the least squares deviation, in other words, minimizing the inertia. In this paper, we will present an example of inertial tolerancing specification of a complex part and we will show how to adjust a production with its new approach.

Author Keywords :

statistical tolerancing, inertial tolerancing, inertial process control, 3D process control, numerical chain integrity

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

CONTOURING ACCURACY OF A MACHINE TOOL: DESIGN OF A PERFORMANCE TEST AND OPTIMIZATION OF THE JERK

Gaetano Massimo PITTALA¹, Michele MONNO^1
1Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, 20156, Milan, Italy

Abstract

With increasing demand of high feed rates the dynamical characterization of a milling center is becoming a strategic aspect. The contouring accuracy at high feed rates and high acceleration is vital in order to preserve the tolerance integrity of parts produced with high speed machining. The dynamic accuracy is influenced by the velocity, acceleration and Jerk. While the cutting speed depends from technological considerations and the maximum velocity and the acceleration depends from the mechanical structure, what value assign to the Jerk is not well defined. The Jerk has an important impact on the execution time of a tool path in a mould/die production, where there are frequent accelerations and decelerations, and a high jerk leads to a deteriorated surface accuracy and an unsmooth machining process. In this paper, experimental test were conducted on various milling centers in order to define the Jerk value. Firstly, some tool path features are introduced in order to consider the effect of the trajectory. Then a tool path, called STAR, is designed and it has been tested by changing the Jerk. A mathematical model able to estimate the execution time it was prepared. A performance test is designed in order to estimate the contouring accuracy in relation with Jerk for all tool paths. The best value of Jerk is the compromise between high accuracy and high productivity. Then an objective function is introduced in order to optimize the Jerk.

Author Keywords :

contouring accuracy, jerk, productivity, milling center

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

ON BOARD CONDITION MONITORING OF FEED AXES BY SIGNAL DECOMPOSITION FOR MACHINES WITH BALL SCREW DRIVES

Detlef MAIER¹, Zheng SUN^2
1Academic staff of the Institut fuer Werkzeugmaschinen (IfW), Universaet Stuttgart, Germany (Corresponding Author), (Sponsor: Prof. U. Heisel)
²Graduand at the same Institute, ministered by Dipl.-Ing. Detlef Maier

Abstract

In order to establish a condition monitoring system to detect wear of the mechanical components of feed drives with ball screws a measuring and data evaluation method has been established. In order to keep the costs down, boundary condition is to use the machines own functionalities only (On Board Diagnosis). At present, most of wear detecting methods use vibration analysis. Here, a signal analysis method is presented that may well complement established methods of vibration analysis. The publication presents a method to exploit positioning data to detect wear of a ball screw drive exemplarily that is run under real conditions. The presented method is partially derived from wear detection methods of roller bearings and may also be adapted for other parts such as linear guides.

Author Keywords :

signal analysis, feed drive, wear

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

CONDITION-BASED PREVENTIVE MAINTENANCE OF MACHINE TOOLS

Reimund NEUGEBAUER¹, Jochen FISCHER^1
1Fraunhofer Institute for Machine Tools and Forming Technology, Chemnitz, Germany

Abstract

Machine tools are expected to be highly available. Unintended failure incurs high costs for repairs and through production losses. Maintenance is a major cost factor and is still mostly reactive today, as a result of failures. Maintenance plans by manufacturers that require preventive maintenance based on running hours are often not implemented consistently. It would be ideal to perform condition-dependent preventive maintenance of the most critical and cost-intensive assemblies of a machine tool. This would make it possible to move repair times into non-productive periods and to procure any spare parts at the right time. Eventually, this would lead to cost savings. This article describes the design of a condition monitoring system for machine tools and shows ways of monitoring the most critical machine tool assemblies.

Author Keywords :

condition monitoring at machine tools, diagnostic parameters, main spindle, axis drives, hydraulic and pneumatic components

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

MEASUREMENT AND CALIBRATION OF MACHINE TOOLS IN 6 DOFs IN LARGE WORKSPACE

Petr BENES¹, Michael VALASEK¹, Jiri SVEDA^1
1Department of Mechanics, Biomechanics and Mechatronics, Faculty of Mechanical Engineering, Czech Technical University in Prague, Karlovo namesti 13, 121 35 Praha 2, Czech Republic Contact e-mail: Petr.Benes@fs.cvut.cz, Michael.Valasek@fs.cvut.cz

Abstract

The measurement and calibration of machine tools in the large workspace (for example 10x20x3m) and in all 6 DOFs (3 cartesian translations and 3 rotations) is not an easy task. A new device called RedCaM (Redundant Calibration and Measurement Machine) has been developed that enables simultaneously to measure all 6 DOFs in the workspace. The RedCaM machine was designed with redundant number of sensors and therefore as a parallel kinematical structure. Thus it profits from the fact that the sensor errors are not chaining. It is equipped only with the sensors and it is operated by the drives of the measured machine tool after the attachment of the platform into the machine tool spindle. The redundancy of sensors provides better accuracy, self-calibration property and very good ratio between the errors of particular sensors and the resulting error of the end effector position. This has been optimized and has proven the improved (minimized) transfer of the errors between the sensors and the position in space in 6 DOFs. In particular the used redundancy of sensors (9 sensors for 6 DOFs) enables the self-calibration (all kinematical parameters are calibrated during the first motions in the workspace) and the minimized transfer of errors between the sensors and the 6 DOFs of the platform that has been experimentally proven to be 1:1. The paper deals with the description of the modification of RedCaM for the usage in the large workspace of machine tools that are in principle unlimited.

Author Keywords :

measurement and calibration, machine tool, 6 DOFs, workspace

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

MODELLING THE COMPENSATION OF MECHANICAL AND NON-MECHANICAL DISTURBANCES IN MECHATRONIC SYSTEMS

Miroslaw GROCHOWSKI¹, Adam BUKOWSKI^1
1Institute of Production Engineering and Automation, ul. Łukasiewicza 5, 50-371 Wrocław, Poland, e-mail: miroslaw.grochowski@pwr.edu.pl, adam.bukowski@pwr.edu.pl

Abstract

In this paper a technique of modelling mechatronic systems is investigated. Such technique is developed in order to build an integrated model of workpiece-fixture system additionally equipped with active deformation compensation system. The analysed type of workpieces is flexible, thin-walled parts under mechanical and non-mechanical loads. The model has been implemented in ABAQUS/Standard FEM code where the behaviour of actuator drives and a control system has been emulated with user subroutines. Model simulation data is confronted against data from experimenta investigations and theoretical calculations. Additional multi-domain simulations with the use of temperature-displacement calculation scheme, utilising the analogous deformation compensation method are described. Finally, results are discussed and conclusions are drawn.

Author Keywords :

compensation, regulation mechatronic system, FEM model

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

THE DEVELOPMENT OF MECHANISM WITH HYBRID KINEMATIC STRUCTURE PROTOTYPE

Viera POPPEOVÁ¹, Juraj URÍČEK¹, Vladimír BULEJ¹, Peter ŠINDLER^2
1University of Žilina, Faculty of Mechanical Engineering, Department of Automation and Production Systems. Univerzitná 1, 010 26 Žilina, Slovakia. Phone: ++421 41 513 2809, e-mail: viera.poppeova@fstroj.uniza.s
²University of Žilina, Faculty of Electrical Engineering, Department of Mechatronics and Electronics. Univerzitná 1, 010 26 Žilina, Slovakia. Phone: ++421 41 513 1626, e-mail: peter.sindler@fel.uniza.sk

Abstract

This paper deals with the development of mechanism with hybrid kinematic structure called trivariant and its subsystems. Hybrid machines are characterized by connecting advantages of both type mechanisms together - high dynamics of parallel mechanisms for positioning and high flexibility and high mobility range of serial mechanisms for orientation. At our department was built the small-scale mechanism prototype used for testing, functional verification, for education and training. There was created the simulation software and control system based on standard PC for this prototype. Our prototype can be applied like small CNC milling machine but it is possible to modify it also for the manipulation with objects like robot device.

Author Keywords :

parallel kinematic structures, hybrid kinematic structures, parallel kinematic machines, parallel kinematic robots

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2009, Poland

HIGH PERFORMANCE MANUFACTURING DEVELOPMENT STRATEGIES IN AVIATION INDUSTRY

Włodzimierz ADAMSKI^1
1Polskie Zakłady Lotnicze, "A Sikorsky Company" 39-300 Mielec

Abstract

Foresight. as modern planning tool. "Clean Sky" project will effect in creating new technologies, which usage in aviation will improve fast progress of technique. The paper indicates the newest technologies or technologies which will develop in about 25 years. Aircraft industry future technologies for Polish conditions have been discussed. List of perspective technologies for aviation and engineering industry has been described. These technologies may be developed in Poland to increase economy competitiveness. New revolutionary materials for aviation industry have been presented. Machine tool technologies, especially Computer Numerical Control (CNC), High Speed Machining (HSM) have emerged as effective mechanisms in the aerospace, automotive, and die and mould industries. These new technologies are attractive for competitive manufacturing because of their technical advantages, i.e. a significant reduction in lead-time, high product accuracy, and good surface finish. However, HSM not only stimulates advancements in cutting tools and materials, it also demands increasingly sophisticated CAD/CAM software, and powerful CNC controllers that require more supportive technologies. This paper describes the computational requirement and cutting parameters of HSM, look ahead programming and simulation

Author Keywords :

perspective technologies, manufacturing, simulation, High Speed Machining

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

ENHANCING CNC MANUFACTURING INTEROPERABILITY WITH STEP-NC

Matthieu RAUCH¹, Raphael LAGUIONIE¹, Jean-Yves HASCOET¹, Xun XU^2
1Institut Recherche Communications et Cybernetique Nantes (IRCCyN), UMR CNRS 6597, 1 rue de la Noe, BP 92101, 44321 Nantes, France, firstname.name@irccyn.ec-nantes.fr
²Department of Mechanical Engineering, University of Auckland, Private Bag 92019, Auckland, New Zealand, x.xu@auckland.ac.nz

Abstract

Despite substantial improvements CNC manufacturing is still based on dated practices and habits. This is mostly due to the use of ISO 6983 standard (G-codes) combined with vendor specific formats to exchange CAD/CAM/ CNC information. The manufacturing sector is consequently made of a collection of disconnected elements that are difficult to make communicate together. On the contrary STEP-NC approach offers many opportunities to overtake the current situation and rethink CAD/CAM/CNC numerical chains. However, the actual integration of STEP-NC in industrial concerns is quite limited. It is essential to couple this innovative approach with existing equipments. This paper shows how STEP-NC can be an efficient way to reconcile today's interoperability and efficiency demands by introducing the association of two manufacturing platforms: SPAIM, developed at IRCCyN (France), and which controls current industrial machine tools directly from STEP-NC files and IIMP from the University of Auckland (New Zealand), which realizes data portability between heterogeneous proprietary formats, process interoperability. As a result, both approaches lead to improved supervision and integration of the machining systems.

Author Keywords :

STEP-NC, advanced CNC, programming CAD/CAM/CNC data interoperability

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

SYSTEM FOR FLEXIBLE MODELLING OF PRODUCTION CYCLES BASED ON FLAT ROLLING

Lukasz RAUCH¹, Lukasz MADEJ¹, Rafal GOLAB¹, Maciej PIETRZYK^1
1Akademia Gorniczo-Hutnicza, al. Mickiewicza 30, 30-059 Krakow

Abstract

The paper presents design and implementation of computer system dedicated to simulation of production cycles based on the rolling processes. The main functionality of the computer system, i.e. support and facilitation of flat rolling technology design, is obtained through flexible interface combined with the modular architecture of numerical library and optimization procedures. Each production cycle (e.g. heating, rolling, cooling, coiling) is prepared to be calculated separately and finally integrated into the sophisticated production cycle. The architecture of designed software as well as models used for numerical calculations are described in details.The system was tested for various configurations of rolling mills. Three of them together with obtained results are presented in the paper: complex production cycle (roughing and finishing rolling), finishing rolling composed of seven passes and laboratory case study.

Author Keywords :

separated modelling, integrated modelling, technology design, rolling, optimization

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

PROBLEMS OF MODERN METHODS IMPLEMENTATION OF STOCK OF TECHNOLOGICAL MACHINES MANAGEMENT

Barbara CIECIŃSKA¹, Katarzyna ANTOSZ^1
1Both Authors: Rzeszow University of Technology, The Faculty of Mechanical Engineering and Aeronautics, Dept. of Manufacturing Processes and Production Organization, Powstancow Warszawy 8, Ave., 35-959 Rzeszow, Manufacturing Processes and Production Organization, Powstancow Warszawy 8, Ave., 35-959 Rzeszow, POLAND

Abstract

Productive management of possessed infrastructure is one of the factors that determine competitiveness specific efficiency and production ability. In fact, the proper operating of devices in the enterprise is a very important element of system of machine operation management. Proper operating demands specific actions due to having certain production demands, priorities and supervision. Issues connected with traditional and modern stock of machine tools management were presented in this paper. Methods of technical infrastructure management of enterprise and their advantages and drawbacks were discussed too. Special importance is given to TPM - an innovative approach towards machine operation, the reduction of stoppages and elimination of sources of wastage. Key aspects of TPM implementation process which requires eg. systemic everyday work (5S), were presented. Beside technical and personal problems, the area of fulfilling the rules of safe work with machining devices was discussed. Stages of searching for incompatibilities, generating of necessary documents and establishing essential areas of technical condition of machines conditions were showed.

Author Keywords :

stock maintenance, workstation organization

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

A NOVEL APPROACH FOR THE ASSEMBLY OF FABRICATED AERO-ENGINE COMPONENTS

Nirosh JAYAWEERA¹, Phil WEBB², Craig JOHNSON^3
1Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, UK
²Department of Systems Engineering and Human Factors, University of Cranfield, UK
³Rolls-Royce plc, Derby, UK

Abstract

Currently the manufacturing of aero-engine intercase is primarily a single piece titanium casting and has slightly deteriorated material properties as compared to sheet metal parts and has long manufacturing lead time. As an alternative solution to above problems, the VITAL (Environmentally Friendly Aero Engines) project aims to design, manufacture and test the critical technologies required to develop new type of clean and low noise aero engines by developing innovative technical solutions to reduce the engine's weight, thereby reducing both fuel consumption and CO2 emission. This requires the fabrication of small and weight optimised parts which will be automatically manipulated, welded, assembled and inspected in a flexible fabrication cell. The paper introduces a novel techniques for compensating the deformation that occur in aero-engine fabricated components and potential component handling errors using standard industrial robots, an advanced end-effector, mathematical processing, non-contact metrology systems and cell control system. The system described in this paper uses in-process measurement sensors to determine the component's exact location prior to the assembly operation. The core of the system is a set of algorithms capable of best fitting measurement data to find optimal assembly of components.

Author Keywords :

robotic assembly, best-fit algorithm, aero-engine components

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

COGNITIVE OPTIMIZATION OF AN AUTOMOTIVE REAR-AXLE DRIVE PRODUCTION PROCESS

Robert SCHMITT¹, Mario ISERMANN², Carsten WAGELS¹, Nico MATUSCHEK^3
1Laboratory for Machine Tools and Production Engineering, RWTH Aachen University, Germany
²Fraunhofer Institute for Production Technology IPT, Aachen, Germany
³BMW Group, Dingolfing, Germany

Abstract

While optimizing tolerances in tolerance chains only single characteristics or objectives of single process steps are considered, there is no information exchange across all processes. Interdependencies between processes, materials, means of production and individuals acting in this environment as well as their effect on product variations are usually not fully understood. In order to face a dynamisation of process specification, interdependencies have to be identified and integrated in future production. The holistic consideration of the process chain focused on the allocation of tolerances allows detection of correlations and interdependencies in the production process itself. By this, process chain information is traced back to conduct the right optimizations at the right place in the process chain. But therefore intelligent controlling mechanisms are needed to analyze and optimize even complex production systems with multi-level interdependencies. Such a cognitive system is able to form the core of self-optimizing production system. Using this cognitive system, the production process of an automotive rear-axle drive is optimized in order to minimize disturbances created by structure-borne sound emissions. Therefore several cognitive technologies have been evaluated to fulfil specific tasks in process optimization.

Author Keywords :

cognitive tolerance matching cognition, self-optimization, rear-axle-drive

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

FRACTAL MANAGEMENT APPROACH FOR THE MANUFACTURING PROJECTS IN THE COLLABORATIVE NETWORKS OF SME-S

Igor POLYANTCHIKOV¹, Eduard SHEVTSHENKO², Sergei KRAMARENKO^3
1Tallinn Technical University, Ehitajate tee 5, 19086, Tallinn, Estonia, Poljantsikov.igor@gmail.com
²Georgia Institute of Technology, Atlanta, Georgia, 30332, USA eduard.sevtsenko@hotmail.com
³Tallinn Technical University, Ehitajate tee 5, 19086, Tallinn, Estonia, sergei.kramarenko@ttu.ee

Abstract

Nowadays an increasing number of enterprises realize the importance of competitiveness improvement through collaboration. It is obvious that the collaborative network is becoming an effective tool that enables small and medium sized enterprises (SMEs) to survive under the global crisis pressure. It enforces enterprises to focus resources and means on the main activities, and to rebuild the architecture for manufacturing system in effective ways. Therefore, we decided to continue working on research topic of collaborative manufacturing projects management. In this paper we introduce the novel framework for the further development of the existing collaborative network concept in which we combined multiple project management methodology and fractal model of collaborative network of enterprises. The proposed framework enables SME-s to use resources more efficiently, reduce manufacturing costs, rapidly respond to customer demand changes, increase the productivity, reduce total lead time of collaborative projects, improve the products quality, improve the practice of collaboration in multi-project management, improve stability, share the expensive costs and equipment, reduce inventory, raise the accuracy of the forecast, reduce the data entry time, and improve the performance of delivery. In this paper, we will present the project-based fractal collaborative network framework, multiple project management and fractal model framework. We will introduce our vision of information and communication processes in the novel collaborative network, tasks and relationships of collaborative enterprises project managers, external and internal relationships of project managers.

Author Keywords :

collaborative network, project management fractal enterprise model

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

GREEN MANUFACTURING IN MACHINERY INDUSTRY

Viktoria BASHKITE¹, Vadim MOSEICHUK¹, Tatyana KARAULOVA^1
1Tallinn Technical University, Ehitajate tee 5, 19086, Tallinn, Estonia, tatjana.karaulova@ttu.ee

Abstract

Green manufacturing cuts across every aspect of manufacturing including product development, process technologies, energy consumption and material flow. Becoming green can be viewed as a process where we start using more eco-friendly manufacturing resources that have low embedded energy and come from renewable resources. Green Manufacturing covers the whole life cycle of product, from requirements specification, design, manufacturing, and maintenance to final discarding. Green design is the most significant part of product's life cycle. Term "green" means that design should consider the product's impact on the environment and causes minimal pollution. This term includes such important approaches as design for the environment (DFE), design for disassembly (DFD), and design for recycling (DFR). Manufacturers can think about the end-of-life approaches across a wide range of products they use in production processes, for example, different machines, machine-tools, material handling equipment, cranes, etc. The analysis of current end-of-life practices identifies significant improvements to product design that reduce the impact of manufactured goods on the environment as whole. The scope of this paper is to describe possible product's end-of-life strategies on the basis of material handling equipment case study.

Author Keywords :

green manufacturing, green design, remanufacturing, material handling equipment

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2010, Poland

KNOWLEDGE MANAGEMENT BASED PROCESS PLANNING SYSTEM

Valentina GECEVSKA¹, Franc CUS^2
1Faculty of Mechanical Engineering, University Ss. Cyril and Methodius, Skopje, Macedonia
²Faculty of Mechanical Engineering, University of Maribor, Maribor,

Abstract

Process planning knowledge (PPK) is one of the most important knowledge in production manufacturing enterprise. The traditional method of organizing data into knowledge relies on manual analysis and interpretation. This paper analyzes the source and composing of process planning knowledge and state of arts on process planning discovery in production manufacturing enterprise. On the basis of the application of computer aided process planning (CAPP) system in mechanical manufacturing enterprise, the concept of process planning information model (PPIM) is proposed based on process planning databases. This paper provides a CAPP database developed in own research, clarifying how PPK and PPIM in CAPP database are related both to each other and to related fields, the technology database of process planning knowledge discovery is modeled based on object-oriented model-driven technology, and the process planning knowledge discovery script is designed.

Author Keywords :

process planning, knowledge management, manufacturing enterprise