CONTENTS

SPONSORING
Issue No.1, 2019 is sponsored by the Ministry of Science
and Higher Education of Poland - funding for DOI

JOURNAL OF MACHINE ENGINEERING

o article: A New Generation of Production with Cyber-Physical Systems - Enabling the Biological Transformation in Manufacturing (NEUGEBAUER F., IHLENFELDT S., SCHLIEßMANN U., HELLMICH A., NOACK M.), pp. 5-15
o article: Increasing Productivity of Cutting Processes by Real-Time Compensation of Tool Deflection Due to Process Forces( BRECHER Ch., WETZEL A., BERNERS T., EPPLE A.), pp. 16-27
o article: Autonomous Machining - Recent Advances in Process Planning and Control ( DITTRICH M.A., DENKENA B., BOUJNAH H. UHLICH F.), pp. 28-37
o article: Utilisation of IoT and Sensing for Machine Tools ( FUJISHIMA M., MORI M., IRINO N., NARIMATSU K., IRINO N.,), pp. 38-47
o article: Contemporary Challenges in Tool Condition Monitoring (JEMIELNIAK K.), pp. 48-61
o article: Development of Tribo-Testers for Predicting Metal Cutting Friction( GRZESIK W., RECH J.), pp. 62-70
o article: Development of a High-Speed Mirror-Like Finish Polishing Technology for Minute Parts Based on a Linear Motor ( TANABE I., DE SOUSA GAMA V., ISE Y., TAKAHASHI S., ISOBE H.), pp. 71-85
o article: Digital Twins as a Modern Approach to Design of Industrial Processes( RAUCH L., PIETRZYK M.), pp. 86-97
o article: Parameterization of Environmental Influences by Automated Characteristic Diagrams for the Decoupled Fluid and Structural-Mechanical Simulations( GLÄNZEL J., KUMAR,T.S., NAUMANN Ch., PUTZ M.), pp. 98-113
o article: Prediction of the Shape Accuracy of Parts Fabricated by Means of FLM Process Using FEM Simulations( MÖHRING H.Ch., STEHLE T., MAUCHER C., BECKER D., BRAUN S.), pp. 114-127
o article: Digital Twin Based Synchronised Control and Simulation of the Industrial Robotic Cell Using Virtual Reality( KUTS V., OTTO T., TÄHEMAA T., BONDARENKO Y.), pp. 128-144

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© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

A NEW GENERATION OF PRODUCTION WITH CYBER-PHYSICAL SYSTEMS - ENABLING THE BIOLOGICAL TRANSFORMATION IN MANUFACTURING

Reimund NEUGEBAUER¹, Steffen IHLENFELDT², Ursula SCHLIEßMANN³, Arvid HELLMICH², Marian NOACK^2
1Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., München, Germany
²Fraunhofer Institute for Machine Tools and Forming Technology IWU, Dresden, Germany
³Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany

Abstract

Within 200 years since the industrial revolution manufacturing systems have often changed their faces. Emerging nations, new markets, new inventions and the changing needs of the society forced them to adapt. Until today, the arising challenges are immensely diverse: highly individualized products, decreasing manufacturing time, limited resources and critical ecological footprints are only a few of them. Oftentimes solutions for these issues and other future requirements can be found by interrogating nature. Applying knowledge of biological principles to industrial manufacturing processes is recently referred to as "biological transformation of manufacturing systems". Hereby three levels of a biological transformation are introduced, starting from inspiration over integration to the interaction of biological and technical systems. The paper illustrates the idea of biological transformation with specific examples for each level. On the inspiration-level the design of manufacturing systems with elements of natural ecosystems is described. Thus flexibility is increased, material cycles are closed and waste will be reduced. Furthermore the integration-level is illustrated by the use of microorganisms in cutting fluids. Finally, evolutionary computing within an automatic joining cell is shown as an example for the interaction-level.

Author Keywords :

biological transformation, Cyber-Physical Production Systems, future manufacturing systems, machine tools

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

INCREASING PRODUCTIVITY OF CUTTING PROCESSES BY REAL-TIME COMPENSATION OF TOOL DEFLECTION DUE TO PROCESS FORCES

Christian BRECHER¹, Arndt WETZEL¹, Thomas BERNERS¹, Alexander EPPLE^1
1Laboratory of Machine Tools and Production Engineering (WZL), RWTH Aachen University, Aachen, Germany

Abstract

The Internet of Production (IoP) describes a vision in which a broad range of different production data is available in real-time. Based on this data, for example, new control types can be implemented, which improve individual manufacturing processes directly at the machine. A possible application scenario is a tool deflection compensation. Although the problem of tool deflection is well known in the industrial field, a process-parallel compensation is not common in industrial applications. State-of-the-art solutions require time and cost consuming tests to determine necessary cutting parameters. An NC-integrated compensation that adapts the tool path in real-time will make these tests obsolete and furthermore enables higher chip removal rates. In this paper, a control-internal real-time compensation of tool deflection is described, which is based on a process-parallel measurement of process forces. The compensation software is designed as an extension to the NC kernel and thereby integrated into the position control loop of an in-series NC. The compensation movements are generated by manipulating the reference values of the feed axes. The approach is investigated by experiments with linear axis movements. During these tests, a significantly reduction of geometrical machining errors is possible.

Author Keywords :

tool deflection, industry 4.0, process control, milling, productivity increase

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

AUTONOMOUS MACHINING - RECENT ADVANCES IN PROCESS PLANNING AND CONTROL

Marc-André DITTRICH¹, Berend DENKENA¹, Haythem BOUJNA¹, Florian UHLIC^1
1Institute of Production Engineering and Machine Tools, Leibniz Universität Hannover, Hannover, Germany

Abstract

While autonomous driving has come close to reality over the recent years, machining is still characterised by many manual tasks and prone to costly errors. In this article, an overview is given about the potential of autonomous machining and uprising technologies that support this vision. For that purpose, a definition of autonomous machine tools and the required elements is presented. Next, selected elements of an autonomous machine tool, e.g. sensory machine components and control loops, are discussed. Finally, some insights into ongoing research projects regarding the use of machine learning for process planning and control are given.

Author Keywords :

machine tool, process planning, adaptive machining, machine learning

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

UTILISATION OF IOT AND SENSING FOR MACHINE TOOLS

Makoto FUJISHIMA¹, Masahiko MORI¹, Koichiro NARIMATSU¹, Naruhiro IRINO^1
1DMGMORI Co., Ltd., Tokyo, Japan

Abstract

Strong requirements for automation in the production processes using machine tools have been increasing due to lack of high-skilled machining engineers. Automation used to be utilised in mass production, but it is also necessary in medium- to low-volume production recently. Next requirements will be monitoring or sensing functions to make the following possible: prompt service when the machine stops; detection of abnormality before the machine breaks down; and compensation of thermal displacement to ensure machining accuracy. These now need to be performed automatically in place of operators so that abnormality can be detected during machining operation. In this paper core technologies to support automation system will be discussed which are operation monitoring, predictive maintenance, sensing interface and thermal displacement compensation as a sensing application.

Author Keywords :

sensing, IoT, machine tools, automation

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

CONTEMPORARY CHALLENGES IN TOOL CONDITION MONITORING

Krzysztof JEMIELNIAK^1
1Warsaw University of Technology, Department of Automation and Metal Cutting, Poland

Abstract

Implementation of robust, reliable tool condition monitoring (TCM) systems in one of the preconditions of introducing of Industry 4.0. While there are a huge number of publications on the subject, most of them concern new, sophisticated methods of signal feature extraction and AI based methods of signal feature integration into tool condition information. Some aspects of TCM algorithms, namely signal segmentation, selection of useful signal features, laboratory measured tool wear as reference value of tool condition - are nowadays main obstacles in the broad application of TCM systems in the industry. These aspects are discussed in the paper, and some solutions of the problems are proposed.

Author Keywords :

tool wear monitoring, metal cutting, signal processing, signal feature

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

DEVELOPMENT OF TRIBO-TESTERS FOR PREDICTING METAL CUTTING FRICTION

Wit GRZESIK¹, Joel RECH^2
1Faculty of Mechanical Engineering, Opole University of Technology, Opole, Poland
²University of Lyon - ENISE, Saint-Etienne, France

Abstract

This paper overviews some frequently used apparatus for determination of friction between the elements of tribo-pairs which represent the cutting tool and the workpiece materials. The three methods which utilize different measuring techniques are outlined and some construction details of tribotesters are presented. The main advantages and disadvantages of the closed and open tribosystems along with their practical applications in machining are highlighted.

Author Keywords :

metal cutting, friction, tribometers

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

DEVELOPMENT OF A HIGH-SPEED MIRROR-LIKE FINISH POLISHING TECHNOLOGY FOR MINUTE PARTS BASED ON A LINEAR MOTOR

Ikuo TANABE¹, Valerio DE SOUSA GAMA², Yoshifumi ISE², Satoshi TAKAHASHI¹, Hiromi ISOBE^1
11Faculty of Mechanical Engineering, Opole University of Technology, Opole, Poland
²Nagaoka University of Technology, Graduate School of Mechanical Engineering, Niigata, Japan

Abstract

As high speed, high acceleration and stable drive on machine tools is constantly growing in demand, the use of linear motors in machine tools has increased. On the other hand, in order to achieve a high degree of quality, the need for mirror-like finish surfaces on industrial products has also considerably increased. This research explores the use of linear motors to develop a high-speed fine polishing process that achieves a mirror-like finish surface on small parts. The first stage of this process consisted in developing a polishing device, which was composed of a NC milling machine, a linear motor drive and a polishing head. Specifically, a polishing head attached to a linear motor drive was coupled with the spindle of a NC milling machine. A substitute for a small linear motor drive was obtained from a commercially available shaver, while the polishing head was made of propylene. The polishing head elaboration process, linear motor drive properties, lapping agent and the optimum polishing conditions were investigated in several experiments. The evaluation consisted in the high-speedpolishing of minute areas on flat surfaces using the selected optimum conditions. It is concluded that, (1) the proposed system was able to achieve a mirror-like finish surface, (2) when compared to polishing with an ultrasonic motor, the machining time of the proposed system was reduced by half, (3) the proposed system was able to achieve a mirror-like finish on a 3 mm square sided area.

Author Keywords :

polishing, linear motor, mirror-like surface, high quality

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

DIGITAL TWINS AS A MODERN APPROACH TO DESIGN OF INDUSTRIAL PROCESSES

Lukasz RAUCH¹, Maciej PIETRZYK^1
1AGH University of Science and Technology, Kraków, Poland

Abstract

The objective of the paper was to describe the concept of a virtual, digital equivalent to a physical process. The basic idea of the virtual counterpart for the process called a digital twin is described first. Following this the hybrid computer system dedicated to the design of the optimal manufacturing technology for thin steel strips is presented. The models used in the system and the database are described. Numerical tests showing capabilities of the system recapitulate the work.

Author Keywords :

computer system, hot rolling, optimization

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

PARAMETERIZATION OF ENVIRONMENTAL INFLUENCES BY AUTOMATED CHARACTERISTIC DIAGRAMS FOR THE DECOUPLED FLUID AND STRUCTURAL-MECHANICAL SIMULATIONS

Janine GLÄNZEL¹, Tharun Suresh KUMAR¹, Christian NAUMANN¹, Matthias PUTZ^1
1Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz, Germany

Abstract

Thermo-elastic effects contribute the most to positioning errors in machine tools especially in operations where high precision machining is involved. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behaviour between the machine tool surface and the surrounding air (fluid). Heat transfer coefficient (HTC) values effectively represent this solid-fluid heat transfer and it serves as the boundary data for thermo-elastic simulations. Thereby, deformation results can be obtained. This two-step simulation procedure involving fluid and thermo-structural simulations is highly complex and time-consuming. A suitable alternative for the above process can be obtained by introducing a clustering algorithm (CA) and characteristic diagrams (CDs) in the workflow. CDs are continuous maps of a set of input variables onto a single output variable, which are trained using data from a limited number of CFD simulations which is optimized using the clustering technique involving genetic algorithm (GA) and radial basis function (RBF) interpolation. The parameterized environmental influences are mapped directly onto corresponding HTC values in each CD. Thus, CDs serve as look-up tables which provide boundary data (HTC values along with nodal information) under several load cases (combinations of environmental influences) for thermo-elastic simulations. Ultimately, a decoupled fluid-structural simulation system is obtained where boundary (convection) data for thermo-mechanical simulations can be directly obtained from CDs and would no longer require fluid simulations to be carried out again. Thus, a novel approach for the correction of thermo-elastic deformations on a machine tool is obtained.

Author Keywords :

thermal effects, simulation, machine tool, environment, positioning errors

JOURNAL OF MACHINE ENGINEERING

Vol 19, No. 1, 2019, Page 114-127

ISSN 1895-7595

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

PREDICTION OF THE SHAPE ACCURACY OF PARTS FABRICATED BY MEANS OF FLM PROCESS USING FEM SIMULATIONS

H.-Christian MÖHRING¹, Thomas STEHLE¹, Clemens MAUCHER¹, Dina BECKER¹, Steffen BRAUN^1
1Institute for Machine Tools (IfW), University of Stuttgart, Stuttgart, Germany

Abstract

The prediction of component properties from the Additive manufacturing (AM) process poses a challenge. Therefore, this paper presents the development of a novel machine data (G-Code) based procedure as well as its programming implementation of a process simulation in ANSYS Mechanical for the fused layer modelling (FLM) process. For this purpose, an investigation of additively produced components with varying parameters made of polylactic acid (PLA) is carried out and simulated by means of the developed method. Application of the developed method makes it possible to predict the thermally induced distortion of PLA-Parts based on the machine data from the FLM process before production.

Author Keywords :

additive manufacturing, FLM- simulation, shape accuracy

JOURNAL OF MACHINE ENGINEERING

Vol 19, No. 1, 2019, Page 114-144

ISSN 1895-7595

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

DIGITAL TWIN BASED SYNCHRONISED CONTROL AND SIMULATION OF THE INDUSTRIAL ROBOTIC CELL USING VIRTUAL REALITY

Vladimir KUTS¹, Tauno OTTO¹, Toivo TÄHEMAA¹, Yevhen BONDARENKO^1
1Tallinn University of Technology, School of Engineering, Department of Mechanical and Industrial Engineering,

Abstract

During the years common understanding of the possibilities and perspectives of Virtual Reality (VR) usage has been changed. It is thought that VR is mainly used in entertainment purposes, but it is being used already for many years in different industries, and now with easier access to the hardware it became a helpful and accessible tool that could be used and developed in any field of human activities. In manufacturing, immersive technologies are mainly used nowadays for the visualisation of processes and products combining those visuals into the factory Digital Twin (DT) which is possible to view from the inside look. This feature is already being used in several manufacturing simulation tools, which enable to view onto industrial line / robotic cells via Virtual Reality glasses. However, the potential of using simulations with VR in manufacturing is not fully uncovered. The main aim of this, industrial robotics targeted research is to enable besides simulation also universal control algorithms through Virtual Reality experience, produced by game engine Unity3D, which can be easily modified for a wide range of industrial equipment. The primary outcome of this work is the development of the synchro-nisation model of real and virtual industrial robots and experimental testing the developed model in Virtual Reality and shop floor labs

Author Keywords :

digital twins, industrial robots, virtual factory, virtual reality

CONTENTS

SPONSORING
Issue No.2, 2019 is sponsored by the Ministry of Science
and Higher Education of Poland - funding for DOI

o article: Design Approach for High-Dynamic Planar Motion Systems Based on the Principle of Kinematically Coupled Force Compensation (IHLENFELDT S., MÜLLER J., MERX M., PEUKERT Ch. ), pp. 5-17
o article: Influence of Linear Feed Drive Controller Setting in CNC Turning Lathe on the Stability of Machining (GRAU J., SULITKA M., SOUCEK P. ), pp. 18-31
o article: Investigation of Local and Modal Based Active Vibration Control Strategies on the Example of an Elastic System (PEUKERT Ch., PÖHLMANN P., MERX M., MÜLLER J., IHLENFELDT S. ), pp. 32-45
o article: Lightweight Machine Enclosures for Dynamic and Efficient Production Processes (MÖHRING H.Ch., STEHLE T., SCHNEIDER M ), pp. 46-53
o article: Energy-Based Characterization of Precision Hard Machining Using Partially Worn CBN Cutting Tools (GRZESIK W., DENKENA B., ZAK K.), pp. 54-62
o article: End Milling of TI-48AL-2CR-2NB Under High-Feed Conditions (FINKELDEI D., BLEICHER F. ), pp. 63-72
o article: Simulation Tests of Adaptive Control Strategie for CNC Machine Tools (STRYCZEK R., SZCZEPKA W.), pp. 73-82
o article: Paddle Shape Optimization for Hole-Flanging by Paddle Forming Through the Use of a Predefined Strain Path in Finite Element Analysis (BESONG L.I., BUHL J., BAMBACH M. ), pp. 83-98
o article: Experimental Investigations of the Bonding Zone in the Explosive Welding of a Differently Structured Steel-Zirconium Platers (PRAZMOWSKI M., PAUL H. ), pp. 99-110

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© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

DESIGN APPROACH FOR HIGH-DYNAMIC PLANAR MOTION SYSTEMS BASED ON THE PRINCIPLE OF KINEMATICALLY COUPLED FORCE COMPENSATION

Steffen IHLENFELDT^1,2, Jens MÜLLER¹, Marcel MERX¹, Christoph PEUKERT^1
1TU Dresden, Faculty of Mechanical Science and Engineering, Institute of Mechatronic Engineering, Chair of Machine Tools Development and Adaptive Controls, Dresden, Germany
²Fraunhofer Institute for Machine Tools and Forming Technology IWU, Dresden, Germany

Abstract

Machine tools feed' dynamics are usually limited in order to reduce excitation of machine structure oscillations. Consequently, the potential increase in productivity provided by direct drives, e.g. linear motors, cannot be exploited. The novel approach of the Kinematically Coupled Force Compensation (KCFC) applies a redundant axis configuration combined with the principle of force compensation and thus achieves an increase in feed dynamics while drive reaction forces cancel out each other in the machine base. In this paper, the principle of KCFC is introduced briefly. Subsequently, the basics for the realisation of a highly dynamic KCFC motion system with planar motion are derived and discussed. In order to achieve highest acceleration (> 100 m/s2) and jerk (> 100000 m/s3), a mechatronic system with specially designed components for the mechanical, electrical and control system is required. Thus, the design approach presented in this paper applies lightweight slides, a decoupled guide frame and voice coil motors operated at high frequencies for the pulse width modulation and control loops.

Author Keywords :

linear motor, control, feed drive

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

INFLUENCE OF LINEAR FEED DRIVE CONTROLLER SETTING IN CNC TURNING LATHE ON THE STABILITY OF MACHINING

Jan GRAU¹, Matej SULITKA¹, Pavel SOUCEK^1
1CTU - Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Production Machines and Equipment, Prague, Czech Republic

Abstract

The paper deals with the influence of linear feed drive controller setting of a CNC turning lathe on the stability of machining. A coupled simulation model of feed drive control and ball screw drive mechanics with a transmission belt was created and validated by the feed drive diagnostic measurements. The influence of drive control on the overall dynamic compliance at the TCP and the limits of stable depth of cut was examined. Impact of the feed drive actual kinematics configuration on the stability limits was studied as well.

Author Keywords :

chatter, ball-screw, feed-drive

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

INVESTIGATION OF LOCAL AND MODAL BASED ACTIVE VIBRATION CONTROL STRATEGIES ON THE EXAMPLE OF AN ELASTIC SYSTEM

Christoph PEUKERT¹, Patrick PÖHLMANN¹, Marcel MERX¹, Jens MÜLLER¹, Steffen IHLENFELDT^1,2
1Technische Universität Dresden, Faculty of Mechanical Science and Engineering, Institute of Mechatronic Engineering, Chair of Machine Tools Development and Adaptive Controls, Dresden, Germany
²Fraunhofer Institute for Machine Tools and Forming Technology IWU, Dresden, Germany

Abstract

Nowadays, feed axes are often equipped with multiple parallel-acting actuators in order to increase the dynamics of the machine tool. Also, additional actuators for active damping are widely used. Normally, the drives or actuators are controlled independently without consideration for the impact on each other. In contrast, by using the modal space control, the system can be decoupled and the modal control loops can be adjusted independently. This control approach is particularly suitable for motion systems, such as machine tools, which have more drives or actuators than degrees of freedom of movement. This paper deals with the pre-investigation of the modal-based vibration control for machine tools with additional actuators. The object of investigation is an elastic system with a movable saddle. The modal-based control is compared with a local control approach. The results obtained experimentally on the test rig are presented. The modal control is superior since, with the modal approach, each control loop corresponds to a specific vibration mode, and the control law for this loop is designed to provide the desired performance of the control system at the corresponding resonance frequency. The parameterisation of the control loops is simplified by modal control, since the modes can be controlled independently.

Author Keywords :

modal control, active vibration control, machine tool, inertial actuator

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

LIGHTWEIGHT MACHINE ENCLOSURES FOR DYNAMIC AND EFFICIENT PRODUCTION PROCESSES

H.-Christian MÖHRING¹, Thomas STEHLE¹, Matthias SCHNEIDER^1
1University of Stuttgart, Institute for Machine Tools (IfW), Stuttgart, Germany

Abstract

Usually machining centres for processing wood-based and composite materials have moving partial machine enclosures in the X-axis direction. Because the workpieces to be machined are often large (e.g. aircraft doors), these partial enclosures have prevailed on the market compared to voluminous complete enclosures. Owing to the general trend towards complete machining through process integration, an increasing number of additional units are integrated into machining centres in addition to the main spindle. This leads to an increase of the mass to be moved as well as a larger and thus heavier partial enclosure. This inevitable increase in mass leads to a deterioration of the dynamic properties of the machine. To counteract this increase in mass, the use of lightweight design materials for machine enclosures becomes in the focus of attention. The lightweight materials to be used must comply with the requirements of modern mechanical engineering and legislation: retention in the event of tool breakage, reduction in the noise exposure of the machine environment and cost-effective solutions compared to the materials used nowadays. The sheet steel used today as material for partial enclosures is therefore to be supplemented or replaced with suitable lightweight design materials. Different lightweight materials are qualified for suitability as machine enclosure. Apart from mass reduction, ecological as well as economic aspects of the used materials play an important role. For this purpose, the safety properties (impact resistance in case of tool breakage / collision) of these weight-reduced materials have to be determined. In addition, an improvement in the acoustic behaviour of the machine is achieved by the new lightweight materials since the machine enclosure shields the distinctive sound sources.

Author Keywords :

machine tool, safety, acoustic emission

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

ENERGY-BASED CHARACTERIZATION OF PRECISION HARD MACHINING USING PARTIALLY WORN CBN CUTTING TOOLS

Wit GRZESIK¹, Berend DENKENA², Krzysztof ZAK^1
1Faculty of Mechanical Engineering, Opole University of Technology, Poland
²Gottfried Wilhelm Leibniz Universität Hannover, Germany

Abstract

This paper highlights the performance of precision hard turning with CBN cutting tools from energy point-of-view with additional tool wear effect. For this purpose several wear tests were performed during which the tool nose wear VBC and the corresponding changes of component forces Fc, Ff and Fp were continuously measured. Based on the measured forces and geometrical characteristic of the uncut layer, specific cutting and ploughing energy were determined for several combinations of cutting parameters. Consequently, changes of energy consumption resulting from tool wear evolution for variable feed rate, depth of cut and tool nose radius were presented.

Author Keywords :

hard machining, CBN tool, tool wear, specific energy

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

END MILLING OF TI-48AL-2CR-2NB UNDER HIGH-FEED CONDITIONS

Daniel FINKELDEI¹, Friedrich BLEICHER^1
1TU Wien, Institute of Production Engineering and Photonic Technologies (IFT), Wien, Austria

Abstract

Gamma titanium aluminides are fast developing materials and particularly in use for aerospace and automotive components. Due to the high cutting forces and raised cutting temperatures achieved during milling of this material, tool-wear is a crucial factor. Thus, increasing of the cutting speed leads to a significant rise of the cutting temperature. On the one hand, the implementation of innovative cooling strategies can reduce the heat flux in the cutting tool. On the other hand, analysing of the heat generation during the cutting process can lead to improved machining strategies. Previous research attempts assess microstructural and chip formation, as well as tool-wear in finish milling of this material. However, few have investigated the optimal cutting strategies in roughing and finishing of titanium aluminides. In this study, the milling operation under high feed rate should be investigated and the potential to improve chip removal rate and tool life should be determined.

Author Keywords :

cemented carbide cutting tools, titanium aluminides, specific cutting forces, high feed machining

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

SIMULATION TESTS OF ADAPTIVE CONTROL STRATEGIES FOR CNC MACHINE TOOLS

Roman STRYCZEK¹, Wojciech SZCZEPKA^2
1University of Bielsko-Biala , Faculty of Mechanical Engineering and Computer Science, Bielsko-Biala, Poland
²Siemens sp. z o. o., Industry Automation and Drive Technologies, Katowice, Poland>

Abstract

The issue addressed in the article concerns the current needs and possibilities of computer-aided design of adaptive control strategies in machining processes. A simulative method of selecting the adaptive feed control strategy while rough turning materials difficult to machine, effective and inexpensive in its implementation, based on controlling the load placed on the machine's drives, has been presented. The results of a number of virtual tests of the proposed feed control strategy have been included, while paying particular attention to the stability of the machining process during moments of sudden change in the machining allowance. The obtained results meet the accepted quality indicators of the control algorithm. At the same time, the experiences collected by the author while conducting the tests confirmed the complexity of the issue and the resulting necessity to implement a comprehensive simulation testing program.

Author Keywords :

adaptive control, processing simulation, virtual reality, intelligent machining

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

PADDLE SHAPE OPTIMIZATION FOR HOLE-FLANGING BY PADDLE FORMING THROUGH THE USE OF A PREDEFINED STRAIN PATH IN FINITE ELEMENT ANALYSIS

Lemopi Isidore BESONG¹, Johannes BUHL¹, Markus BAMBACH^1
1Chair of Mechanical Design and Manufacturing, Brandenburg University of Technology Cottbus-Senftenberg, Cottbus, Germany

Abstract

This research investigates a novel hole-flanging process by paddle forming through the use of finite element (FE) simulations. Paddles of different shapes rotating at high speeds were used to deform clamped sheets with pre-drilled holes at their centers. The results of the simulations show that the paddle shape determines the geometry and principal strains of the formed flanges. A convex-shaped paddle forms flanges with predominant strains in the left quadrant of theforming limit diagram (FLD). However, the convex paddle promotes unwanted bulge formation at the clamped end of the flange. A concave paddle forms flanges with no bulge but the principal strains of elements in the middle section of the flange are in the right quadrant of the FLD which indicates an increased probability for crack occurrence. An optimization of the paddle shape was conducted to prevent bulging at the clamped end while avoiding crack occurrence. The paddle shape was optimized by mapping the deformation of some elements along the flange length to a pre-defined strain pathon the FLD while maintaining the bulge height within the desired geometric tolerance. The radii and lengths of the paddle edge were varied to obtain an optimum paddle shape.

Author Keywords :

paddle forming, paddle shape optimization, incremental hole-flanging, strain path mapping

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

EXPERIMENTAL INVESTIGATIONS OF THE BONDING ZONE IN THE EXPLOSIVE WELDING OF A DIFFERENTLY STRUCTURED STEEL-ZIRCONIUM PLATERS

Mariusz PRAZMOWSKI¹, Henryk PAUL^2
1Opole University of Technology, Faculty of Mechanics, Opole, Poland
²Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Cracow, Poland

Abstract

In this work the results of trials aimed at selecting optimal settings of the explosion welding process of 10 mm thick zirconium (Zr 700 grade) plates with carbon steel (P265GH grade) are presented. A bimetal Zr-steel and trimetal Zr-Ti-steel and Zr-Zr-steel where: 2 mm Ti and 3 mm Zr were used as a technological intermediate layer facilitating the bonding. The research was carried out for as-bonded joints, i.e. immediately following explosion welding. Structural analyses in leyers near the interface were focused on the characteristic of the joint interface. Mechanical properties of the obtained clads were measured with shearing, peel and lateral bending tests. Systematic measurements of microhardness distribution enabled analyzing the strain-hardening of the material resulting from explosion welding both at the bond interface zone and throughout the whole section of the clad. It was established that during explosion welding with 10 mm Zr 700 the application of the 2 mm or 3 mm thick interlayers of Zr70 or Ti grade 1, respectively, allows obtaining a joint with good mechanical properties and optimal characteristic of the interface.

Author Keywords :

explosive welding, zirconium/steel clad, technological interlayer

CONTENTS

SPONSORING
Issue No.3, 2019 is sponsored by the Ministry of Science
and Higher Education of Poland - funding for DOI

o article: Investigation of Noise Transmission of a Machine Tool Enclosure (BLEICHER F., REICHL Ch., LINHARDT F., WIMBERGER P., HABERSOHN Ch., KRALL S.), pp. 5-16
o article: Simulation-Based Investigation for Heat Transfer Behavior of Steel Reinforcements in Concrete Machine Frames and Their Thermal Effects (GLÄNZEL J., GEIST A., GEIST A.), pp. 17-30
o article: Effects of Hot Chips in Dry Cutting Processes on the Temperature Field and Displacement of the Machine Tool Table (ALBRECHT T., THIEM X., PENTER L., IHLENFELDT S.), pp. 31-42
o article: Using Sensory Tool Holder Data for Optimizing Production Processes (SCHÖRGHOFER P., PAUKER F., LEDER N., MANGER J., RAMSAUER Ch., BLEICHER F.), pp. 43-55
o article: Effects of Variation in Measurement Chain on Temperature Measurement Calibration with Resistant Temperature Sensors (DEUTSCH J., RIEDEL M., MÜLLER J., IHLENFELDT S.,), pp. 56-65
o article: Optimization of Johnson-Cook Constitutive Model Parameters (LÖSCHNER P., JAROSZ K., NIESŁONY P.), pp. 66-73
o article: Integrated Strain Gauge Printing in a CFRP Structure (MISCH S., WELZEL F., MÖHRING H-Ch.), pp. 74-81
o article: Fast and Cost Efficient Measuring of Geometry and Temperature for Open-Die Forging (RIEDEL M., WIESE T., HELLMICH A., Steffen IHLENFELDT S.), pp. 81-93
o article: Modeling and Convergence Analysis of Directed Energy Deposition Simulations with Hybrid Implicit / Explicit and Implicit Solution (BUHL J., ISRAR R., BAMBACH M.), pp. 94-107

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© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

INVESTIGATION OF NOISE TRANSMISSION OF A MACHINE TOOL ENCLOSURE

Friedrich BLEICHER¹, Christoph REICHL², Felix LINHARDT³, Peter WIMBERGER², Christoph HABERSOHN¹, Stephan KRALL^1
1Institute of Production Engineering and Laser Technology, TU Wien
²Austrian Institute of Technology, Center for Energy, Sustainable Thermal Engineering, Wien
³Department of Geography, Earth Observation and Modelling, Kiel University, Germany

Abstract

Machine tools are highly integrated mechatronic systems consisting of dedicated mechanic design and integrated electrical equipment - in particular drive systems and the CNC-control - to realize the complex relative motion of tool towards work piece. Beside the process related capabilities, like static and dynamic stiffness as well as accuracy behavior and deviation resistance against thermal influence, safety aspects are of major interest. The machine tool enclosure must fulfill multiple requirements like retention capabilities against the moving parts of broken tools, lose work piecesor clamping components. In regular use, the noise emission have to be inhibited at the greatest possible extent by the machine tool enclosure. Nevertheless, the loading door and the moving parts of the workspace envelope are interfaces where noise transmission is harder to be avoided and therefore local noise emissions increase. The aim of the objective investigation is to analyse the noise emission of machine tools to determine the local noise transmission of a machine tool enclosure by using arrays of microphones. By the use of this measuring method, outer surfaces at the front, the side and on the top of the enclosure have been scanned. The local transient acoustic pressures have been recorded using a standard noise source placed on the machine table. In addition, an exemplary manufacturing process has been performed to analyse the frequency dependent location resolved sound emissions.

Author Keywords :

sound pressure level, machine enclosure, noise transmission, acoustic grid

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

SIMULATION-BASED INVESTIGATION FOR HEAT TRANSFER BEHAVIOR OF STEEL REINFORCEMENTS IN CONCRETE MACHINE FRAMES AND THEIR THERMAL EFFECTS

Janine GLÄNZEL¹, Alexander GEIST¹, Steffen IHLENFELDT^1,2
1Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz, Germany
²Dresden University of Technology TUD, Dresden, Germany

Abstract

The determination of the thermal-elastic behavior is one of the main aspects in the design phase of new machine frames. Prototypically simulation models are used for preliminary investigations, which are based on finite element approaches and usually work with simplified material laws. By the manufacturing of machine frames of concrete steel reinforcements are used to ensure the operation reliability due to the high sensitivity of concrete to tensile stresses. Because of different thermal conductivity and specific heat capacity of steel and concrete the reinforcement has a not negligible influence on the total thermal behavior of the system, which cannot be covered with conventional material laws, e.g. from material libraries. Preliminary investigations show, that a volume fraction more than 1 % of the reinforcement of the total volume can cause a relative error up to ten percent in the temperature field. To reflect the real behavior of reinforced concrete for a machine bed,the influence should be exanimated for two different approaches. Next to the real illustration of the geometry of the reinforcement in the FE-model, decoupled simulation approaches are used on reduced models, which should approach numerically the material behavior of the reinforcement.

Author Keywords :

finite-element-method, reinforced concrete,thermal solid simulation, temperature field

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

EFFECTS OF HOT CHIPS IN DRY CUTTING PROCESSES ON THE TEMPERATURE FIELD AND DISPLACEMENT OF THE MACHINE TOOL TABLE

Tom ALBRECHT¹, Xaver THIEM¹, Lars PENTER^1,2, Steffen IHLENFELDT^1,2
1Institute of Mechatronic Engineering Dresden (IMD), TU Dresden, Germany
²Fraunhofer Institute for Machine Tools and Forming Technology (IWU), Germany

Abstract

In machining up to 75% of the geometrical variations of work piece, features are caused by thermally induced deformations of machine components [1]. Since in dry cutting up to 80% of the thermal energy is stored in the chips [2], we expected a significant effect of these process-dependent heat sources on the machine accuracy. Based on preliminary simulation results, we systematically applied determined quantities of heated chips to a machine table to understand their impact on the temperature field. Temperature sensors where used to measure the temperature change on the tables surface and in the structure. Length measuring probes measured the corresponding deformations at 24 points distributed over the table. The measurements show a temperature change of 4 K at the surface and 3 K in the structure near the heat source after 6 minutes of exposure to 500°C chips. In this case, the impact on the temperature field is local but causes the bending of the table. We recorded 8 micron of thermo-elastic deformations. The results suggest that high-accuracy processes with large energy input, such as hard turning, require the heat induced into the machine structure by hot chips to be implemented into compensation methods and correction algorithms.

Author Keywords :

accuracy, thermal error,deformation

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

USING SENSORY TOOL HOLDER DATA FOR OPTIMIZING PRODUCTION PROCESSES

Paul SCHÖRGHOFER¹, Florian PAUKER², Norbert LEDER¹, Jürgen MANGLER², Christoph RAMSAUER¹, Friedrich BLEICHER¹,
¹IFT - Institute for Production Engineering and Laser Technology, TU Wien, Austria
¹Austrian Center for Digital Production GmbH, Wien, Austria

Abstract

Today's highly automated manufacturing specifies the service time of a tool in a way that the tooling costs are balanced against the potential costs of a tool failure. However, the potential cost induced by a tool malfunctioning are rather high. Therefore, the current state-of-the art tackles this issue by replacing the tools prematurely at fixed intervals. To tap into the potential of under-utilized tool runtime this work purposes the use of sensory-tool holders and an interfering feedback loop to the machine tool control system. Besides its real-time closed loop control, to avoid tool failure, it also provides data in the context of (a) the work order, (b) the produced part, (c) the NC-block and command line, on (d) specific machines. Based on this data an ex-post analysis to optimize tool-life and productivity scenarios becomes possible, e.g. custom NC-programs for certain work-orders, configurations and machines. Furthermore, downstreamed work steps can be changed e.g. only to measure produced workpieces if abnormal vibrations are reported by in-process-monitoring.

Author Keywords :

adaptive control, condition monitoring, orchestration platform

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

EFFECTS OF VARIATION IN MEASUREMENT CHAIN ON TEMPERATURE MEASUREMENT CALIBRATION WITH RESISTANT TEMPERATURE SENSORS

Jessica DEUTSCH¹, Mirko RIEDEL², Jens MÜLLER¹, Steffen IHLENFELDT^1,2,
¹Chair of Machine Tools and Control Engineering (IMD), Dresden, Germany
²Fraunhofer Institute for Machine Tools and Forming Technology (IWU), Dresden, Germany

Abstract

Temperature is one of the most important key parameter to consider in measurement and mechanical engineering, because every measurement has to be conducted with reference to standard temperature conditions (20°C, ISO 1). Strictly speaking, almost every measurement depends on the accuracy of the temperature measurement, which requires proper calibration. Therefore, standards list detailed criteria to fulfil temperature calibration with high precision. In fact, any calibration is only valid, if the whole measurement chain is taken into account. This would make recalibration necessary with each variation of the components in the measuring set-up (varying cable length, different measurement channel etc.), which is time-consuming or even impossible in practice. For that reason, this paper presents a practicable calibration strategy, which specifies each component individually and later combines the calibration results according to the composition of the measurement chain. This provides a fast and useful way to achieve the required accuracy of temperature measurement. The examined, exemplary measurement chain consists of an industrial platinum resistance thermometer (IPRT), cables with different lengths, an electrical amplifier and a reference temperature calibrator.

Author Keywords :

temperature measurement, calibration, PRT sensor

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

OPTIMIZATION OF JOHNSON-COOK CONSTITUTIVE MODEL PARAMETERS

Piotr LÖSCHNER¹, Krzysztof JAROSZ¹,Piotr NIESLONY¹,
¹Opole University of Technology, Faculty of Mechanical Engineering, Department of Manufacturing Engineering and Automation, Opole, Poland

Abstract

In modern machining industry, the concept of process optimization has gained widespread recognition. FEM simulations are commonly used for the optimization of machining operations, allowing for a proper choice of tool geometry and process parameters to obtain results that are in accordance with end user criteria. However, one has to be wary that a good agreement of experimental and simulation results is mandatory if the simulation is to be used as a basis for optimization of a real-life process. Therefore, a proper choice of constitutive model parameters is vital. Those parameter values are dependent on many variables. Constitutive model parameter values are determined experimentally - therefore, they are accurate only for the conditions (temperature, strain rate etc.) under which the experiment was performed. The alteration, or optimization of model parameters is necessary if cutting and experiment conditions differ, if one wishes to obtain applicable results. In this work, the authors aim to present a method of optimizing the Johnson-Cook constitutive model parameters to obtain a better fit with experimental data.

Author Keywords :

optimization, Johnson-Cook model, titanium alloy

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

INTEGRATED STRAIN GAUGE PRINTING IN A CFRP STRUCTURE

Sandra MISCH¹, Florian WELZEL¹, Hans-Christian MÖHRING^2
1Institute of Manufacturing Technology and Quality Management (IFQ), Otto von Guericke University Magdeburg, Germany
²Institute of Machine Tools (IfW), University Stuttgart, Germany

Abstract

Our approach is to integrate printed strain gauges into a structure of laminated carbon fibre reinforced plastics (CFRP). This can provide minimizing disturbances caused by an additional sensor weight. Another point is to reduce the occurrence of pre-damage, as a printed structure is integrated directly into the CFRP. Due to the printing, no additional masses are applied to the CFRP by cables. To this end, the boundary conditions for the print are first explained. Subsequently, the strain gages were printed. For this purpose, studies were carried out regarding the orientation of the strain gage printing direction, the influence of repeated printing, the overlapping during printing andthe subsequent lamination in CFRP plates. The sensors are to be used in the structure of the CFRP plate in a machine tool.

Author Keywords :

strain gauge, CFRP, inkjet printing, machine tools

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

FAST AND COST EFFICIENT MEASURING OF GEOMETRY AND TEMPERATURE FOR OPEN-DIE FORGING

Mirko RIEDEL¹, Torben WIESE¹, Arvid HELLMICH¹, Steffen IHLENFELDT^2
1Fraunhofer Institute for Machine Tools and Forming Technology (IWU), Dresden, Germany
²Institute of machine Tools and Control Engineering (IMD), Dresden, Germany

Abstract

In open-die forging it is state of the art to use simulation tools for creating forging plans and setpoint values for the forging press and the automated part manipulator. These forging plans define required positions and forces. Therefore, the process can be fully automated. However, even small variations of not considered influence parameters lead to different forging results and thus to a discontinuous process. Influencing factors are, e.g. material parameter deviations, uncertainties in force measurements or variations in the part temperature due to varying environmental conditions. This paper presents an approach for a fully automatic open-die forging process with respect to actual conditions, based on a parallel measurement of the workpiece geometry and temperature and a "process-real-time" adaptation on the controller system. The focus of this work is the development of a measuring strategy and an according sensor setup for the combined temperature and geometry measurement of the workpiece. In addition, the structure, the characteristic features of the components and the beam path of the sensors scanning units are shown. Furthermore, first experimental results for the alignment of the beam path are presented. In the outline, the setup and calibration strategy of the measurement system are stated.

Author Keywords :

open-die forging, automation, measuring instrument, coordinate and temperature measuring

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

MODELING AND CONVERGENCE ANALYSIS OF DIRECTED ENERGY DEPOSITION SIMULATIONS WITH HYBRID IMPLICIT / EXPLICIT AND IMPLICIT SOLUTIONS

Johannes BUHL¹, Rameez ISRAR¹, Markus BAMBACH^1
1Brandenburg University of Technology Cottbus-Senftenberg, Dept. of Mechanical Design and Manufacturing, Cottbus, Germany

Abstract

Conventional metal manufacturing techniques are suitable for mass production. However, cheaper and faster alternatives are preferred for small batch sizes and individualized components. Directed energy deposition (DED) processes allow depositing metallic material in almost arbitrary shapes. They are characterized by cyclic heat input, hence heating and cooling every point in the workpiece several times. This temperature history leads to distribution of mechanical properties, distortions, residual stresses or even fatigue properties in the part. To avoid experimental trial-and-error optimization, different methods are available to simulate DED processes. Currently, the wire arc additive manufacturing (WAAM) is the most competitive DED process. In this work, a simulation method for the WAAM process is established and validated, which should be capable to calculate global effects (e.g. distortions, residual stresses) of real WAAM-processes with duration of hours and thousands of weld beads. The addition of beads and layers is simulated by the element birth and death technique. The elements are activated according to the movements of the heat source (arc). In this paper, the influence of the time step, the mesh size and the material properties of the inactive elements in hybrid implicit / explicit and fully implicit solutions are evaluated with respect to the computation time and stability. This investigation concludes several recommendations for AM-modelling. For example, a low Young's modulus (100 N/mm2) for the inactive elements show nearly no influences on the welding simulation, but introduces numerical instabilities in case of multiple welding beads. The Young's modulus should be increased to 1.000 N/mm2 for small mesh-sizes, small step-sizes and many beads,even when it introduces unwanted stresses.

Author Keywords :

additive manufacturing, steel,implicit/explicit, thermal cycles

CONTENTS

SPONSORING
Issue No.4, 2019 is sponsored by the Ministry of Science
and Higher Education of Poland - funding for DOI

o article: En Route to Intelligent Wood Machining - Current Situation and Future Perspectives (MÖHRING H.-Ch., ESCHELBACHER S., GÜZEL K., KIMMELMANN M., SCHNEIDER M., ZIZELMANN Ch.,HÄUSLER A., MENZE Ch.), pp. 5-26
o article: Ball Screw Unit Precise Modelling with Dynamics of Loads and Moving Heat Sources Taken into Account (JEDRZEJEWSKI J., KOWAL Z., Wojciech KWASNY W., WINIARSKI Z.), pp. 27-41
o article: A New Multigrid Based Method for Characteristic Diagram Based Correction of Thermo-Elastic Deformations in Machine Tools (NAUMANN Ch., PUTZ M.), pp. 42-57
o article: Development of FEM Model of An Angular Contact Ball Bearing with Its Experimental Verification (TUREK P., SKOCZYNSKI W., STEMBALSKI M.), pp. 58-69
o article: CNC Machine Tool Error Compensation System Implementation Strategies and Their Constraints (MEDYK P., JEDRZEJEWSKI J., KASPRZAK M.), pp. 70-81
o article: Methods of Comparison of Surface Texture Based on Fractal Dimension and Hotelling's T² Test (GOGOLEWSKI D.), pp. 82-90
o article: General Directions in Contact Modelling Development (MACIOLKA P., JEDRZEJEWSKI J.), pp. 91-109
o article: Experimental Model on the Wire Wear for WEDM of Hard to Machine Materials (POROS D., ZABORSKI S., WISNIEWSKA M.), pp. 110-121
o article: Investigations of Applications of Smart Materials and Methods in Fluid Valves and Drives (MILECKI A., RYBARCZYK D.), pp. 122-135

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© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

EN ROUTE TO INTELLIGENT WOOD MACHINING - CURRENT SITUATION AND FUTURE PERSPECTIVES

H.-Christian MÖHRING¹, Sarah ESCHELBACHER¹, Kamil GÜZEL¹, Martin KIMMELMANN¹, Matthias SCHNEIDER¹, Christoph ZIZELMANN¹, Andreas HÄUSLER¹, Christian MENZE^1
1University of Stuttgart, Institute for Machine Tools (IfW), Stuttgart, Germany

Abstract

Wood materials are an important part of our daily life. Besides furniture, doors and window elements, parquet floors, veneering, ply wood, chip- and fibreboards, also structural elements for buildings are typical products. Due to the specific properties, variety and complexity of natural wood, wood materials and wood composites, the machining of parts made out of these materials exhibits specific challenges. In order to further improve productivity, quality and efficiency in wood machining, innovative solutions with respect to tool technology, process planning, machinery, process monitoring and intelligent control are necessary. This keynote paper reviews and summarizes scientific developments in wood machining in recent years. Furthermore, exemplary current an ongoing research activities are introduced. Finally, the paper presents and discusses future potentials regarding new approaches for intelligent process control in wood machining.

Author Keywords :

Ball Screw Unit Precise Modelling with Dynamics of Loads and Moving Heat Sources Taken into Account

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

BALL SCREW UNIT PRECISE MODELLING WITH DYNAMICS OF LOADS AND MOVING HEAT SOURCES TAKEN INTO ACCOUNT

Jerzy JEDRZEJEWSKI¹, Zbigniew KOWAL¹, Wojciech KWASNY¹, Zdzislaw WINIARSKI^1
1Wroclaw University of Science and Technology, Department of Machine Tools and Mechanical Technologies, Wroclaw, Poland

Abstract

This paper deals with the precision modelling of the ball screw unit's thermal behaviour in the turning centre and its impact on the tool head positioning error. The error components along controllable axes X and Z are described in detail using an FE model integrating the changes in thermal and force loads and deformations occurring during the motion of the nut as a heat source. The impact of the nut work cycle on the thermal deformations of the ball screw and the displacements of the slideways and the screw points along both the axes and on carriage positioning precision is demonstrated.

Author Keywords :

ball screw, feed drive, machine tool, modelling

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

A NEW MULTIGRID BASED METHOD FOR CHARACTERISTIC DIAGRAM BASED CORRECTION OF THERMO-ELASTIC DEFORMATIONS IN MACHINE TOOLS

Christian NAUMANN¹, Matthias PUTZ^1
1Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz, Germany

Abstract

It is a well-known problem of milling machines, that waste heat from motors, friction effects on guides, environmental variations and the milling process itself greatly affect positioning accuracy and thus production quality. An economic and energy-efficient method of correcting this thermo-elastic positioning error is to gather sensor data (temperatures, axis positions, etc.) from the machine tool and the process and to use that information to predict and correct the resulting tool center point displacement using high dimensional characteristic diagrams. The computation of these characteristic diagrams leads to very large sparse linear systems of equations which require a vast memory and computation time to solve. This is particularly problematic for complex machines and varying production conditions which require characteristic diagrams with many input variables. To solve this issue, a new multigrid based method for the computation of characteristic diagramswill be presented, tested and compared to the previously used smoothed grid regression method.

Author Keywords :

thermal effects, algorithm, machine tool, measurement

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

DEVELOPMENT OF FEM MODEL OF AN ANGULAR CONTACT BALL BEARING WITH ITS EXPERIMENTAL VERIFICATION

Paweł TUREK¹, Waclaw SKOCZYNSK¹, Marek STEMBALSKI^1
1Wroclaw University of Science and Technology, Department of Machine Tools and Mechanical Technologies, Wroclaw, Poland

Abstract

The article presents FEM model of an angular contact ball bearing used in spindle systems with active preload control. A two-dimensional replacement model for a single rolling element was developed. Its elastic characteristics were determined and the stress distribution was presented for the FEM 2D model. Based on the elastic characteristics for a single rolling element, a complete 3D bearing was modelled. The substitute model of a bearing developed in this way was used to model the spindle system. The elasticity curve of this spindle was determined. The last stage of the work involved the experimental verification of the FEM model using a custom-built test bench, in which piezoelectric elements were used to tension the bearings.

Author Keywords :

preload, angular-contact bearings, machine tool

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

CNC MACHINE TOOL ERROR COMPENSATION SYSTEM IMPLEMENTATION STRATEGIES AND THEIR CONSTRAINTS

Pawel MEDYK¹, Jerzy JEDRZEJEWSKI¹, Marcin KASPRZAK^1
1Wroclaw University of Science and Technology, Department of Machine Tools and Mechanical Technologies, Wroclaw, Poland

Abstract

This paper deals with the constraints imposed on error compensation systems by their implementation strategies. Constraints stemming from the structure of the control system with an NCK architecture of the ADCBI type are presented. Practical realizations of compensation and potential solutions offered by contemporary commercial CNC controllers are discussed.

Author Keywords :

machine tool error, compensation, control system

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

METHODS OF COMPARISON OF SURFACE TEXTURE BASED ON FRACTAL DIMENSION AND HOTELLING'S T² TEST

Damian GOGOLEWSKI^1
1Kielce University of Technology, Department of Mechanical Engineering and Metrology, Kielce, Poland

Abstract

Comparative analysis of the surface texture of machine parts can be successfully carried out using statistical tests. The paper presents a methodology of method used to compare the surface texture by applying Hotelling's T² test as well as a method used to evaluate surface topography by applying fractal dimension. The tests were carried out on samples produced with the use of face milling process for four types of materials. The following types of steel were used: 40HM, C45, NC6 and WCL. For each type of material, four areas were machined with the same machining parameters. Based on these results a decision was made whether the surfaces, despite the same machining conditions, were significantly different from each other. Furthermore, the analysis indicated that the fractal dimension enabled to characterise signal irregularities in quantitative and qualitative way.

Author Keywords :

face milling, fractal dimension,surface roughness, test

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

GENERAL DIRECTIONS IN CONTACT MODELLING DEVELOPMENT

Pawel MACIOLKA¹, Jerzy JEDRZEJEWSKI^1
1Wroclaw University of Science and Technology, Department of Machine Tools and Mechanical Technologies, Wroclaw, Poland

Abstract

This paper presents a survey of works, selected from the period of the last twenty years, on deformations in the contact between rough surfaces. All the selected works use FEM. They deal with the modelling of individual contact asperities or the use of experiment to verify contact models. First, research directions connected with the modelling of single asperities, whose shape is usually approximated with that of a hemisphere or a half cylinder, are presented. Section 3 discusses research directions concerning models which include the layer under asperities, and models for small contact surfaces (about 1 mm2). Section 4 reviews directions in contact modelling which takes into account neighbouring asperities and laterally loaded asperities. Section 5 discusses directions in the development of models and experiments used or suitable for verifying models. Finally, conclusions concerning accurate contact deformation modelling are presented.

Author Keywords :

flat surfaces, contact, asperity, FE model

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

EXPERIMENTAL MODEL ON THE WIRE WEAR FOR WEDM OF HARD TO MACHINE MATERIALS

Dariusz POROS¹, Stanislaw ZABORSKI¹, Magdalena WISNIEWSKA^1
1Wroclaw University of Science and Technology, Department of Machine Tools and Mechanical Technologies, Wroclaw, Poland

Abstract

In this study, the wear of wire electrodes was investigated experimentally in wire electrical discharge machining. Naked brass wire, 0.25 mm diameter, zinc oxide coated brass wire and brass CuZn20 coated with brass CuZn50 wire were applied in the conducted research. The wire wear ratio of WEDM of titanium alloy Ti6Al4V and cemented carbide B40 was described. As important WEDM parameters, the following variables were chosen: discharge time ton, average working voltage U. The following properties of machined materials, such as: melting point Tt, electrical conductivity ?, thermal conductivity K, thermal expansion coefficient k, density ?, heat capacity cp, were also selected to develop the semi - empirical model of the wear of wire electrodes. The variation of the wire wear with cutting different materials by applying three different wire electrodes and process parameters was modelled semi - empirically by employing dimensional analysis.

Author Keywords :

WEDM, wire electrodes wear, dimensional analysis

© Copyright by, Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, Wroclaw 2019 Poland

INVESTIGATIONS OF APPLICATIONS OF SMART MATERIALS AND METHODS IN FLUID VALVES AND DRIVES

Andrzej MILECKI¹, Dominik RYBARCZYK^1
1Institute of Mechanical Technology, Poznan University of Technology, Poznan

I would like to kindly inform that in the result of an oversight in the article: Andrzej MILECKI, Dominik RYBARCZYK, INVESTIGATIONS OF APPLICATIONS OF SMART MATERIALS AND METHODS IN FLUID VALVES AND DRIVES the citation is omitted of the PhD dissertation: Frederika Stefańskiego pt: Badania wzmacniacza elektropneumatycznego typu dysze - przesłona z przetwornikiem piezoelektrycznym, Politechnika Poznańska, Wydział Budowy Maszyn i Zarządzania, Poznań 2017, with reference to content on pages 126 to 129 and the drawings contained therein.
I apologize to Mr. Frederik Stefański for this situation.
Andrzej Milecki

Abstract

In the paper the investigations performed at the Division of Mechtronic Devices at Poznan University of Technology in the area of application of both: smart materials in electro-hydraulic and electro-pneumatic valves, and new methods to control of hydraulic servo drives, are presented. In a first part the piezo bender actuator is shortly described and its application in servo valve is proposed. This actuator replaced the torque motor in the available on the market servo valve. The new valve simulation model is proposed. The simulation and investigations results of the servo valve with the piezo bending actuator are included. In the next part of the paper the application of piezo tube actuator in flapper-nozzle pneumatic valve is described. The test stand and investigations results are presented. Later, in the article, the Model Following Control (MFC) and Fractional order Control (FoC) methods are described. Their application in control of electrohydraulic servo drive is proposed. Some investigations results are included in the paper, showing the advantages of those control methods.

Author Keywords :

Institute of Mechanical Technology, Poznan University of Technology, Poznan