MM Science Journal, November 2021

November 2021

FRAMEWORK FOR COUPLED DIGITAL TWINS IN DIGITAL MACHINING

D. Plakhotnik, A. Curutiu, A. Zhulavskyi, Xavier Beudaert, Jokin Munoa, M. Stautner
Keywords: CAM | digital twin | digital machining | NC verification

This paper presents a further elaboration of the use of the digital twin concept in digital machining. The main goal of the research is an attempt to combine digital representations of different objects involved in the machining process in a holistic manner. Digital twins of the in-process workpiece, cutting tool, clamping, and machine tool along with the process twin are connected in a framework in whi (…)

EXPERIMENTAL STUDY ON TILTING STIFFNESS OF OIL HYDROSTATIC SHALLOW RECESS THRUST BEARINGS

F. A. Tripkewitz, M. Fritz, M. Weigold
Keywords: shallow step | inherently compensated | hydrostatic bearing | angular stiffness | 2D-Reynolds

Circular shallow recess bearings generate a not rotationally symmetrical pressure profile if they are not aligned parallel. The throttling effect of the shallow recess makes this response possible. Furthermore, the generated pressure profile acts against the tilting. As a result, a shallow recess bearing generates a tilting stiffness. This article outlines an experimental approach to characterize the ti (…)

CHARACTERIZATION OF METAL WORKING FLUIDS USING TRIBOLOGICAL TESTING METHODS

N. Ostrowicki, J. Markert, N. Hanenkamp
Keywords: Metal working fluids | Minimum quantity lubrication | Pin-on-Disc | tribology

The objective of this paper is to determine whether it is possible to compare the lubricating properties of different Metal working fluids (MWF) for a defined cutting application using easily reproducible tribological tests. The idea is that this will eventually allow users of MWF to select the most suitable MWF for a specific application without the need to run expensive and time-consuming tests on a m (…)

INSTANTANEOUS PARAMETER IDENTIFICATION FOR MILLING FORCE MODELS USING BAYESIAN OPTIMIZATION

B. Schmucker, M. Busch, T. Semm, M. F. Zaeh
Keywords: machining simulation | parameter identification | optimization | data analytics

The comparison between measured and simulated machining forces enables the evaluation of workpiece quality, process stability, and tool wear condition. To compute the machining forces that occur, mechanistic cutting force models are typically used. The cutting force coefficients (CFCs) of mechanistic force models are directly linked to the mechanics of chip formation and, thus, depend on the tool-workpi (…)

DEPTHS OF CUT IDENTIFICATION IN 3-AXIS MILLING USING CUTTING FORCE SPECTRUM

L. Morelli, N. Grossi, A. Scippa, G. Campatelli
Keywords: end milling | Simulation | frequency | cutting force | monitoring

Cutting forces analysis is one of the most important means of improving machining quality and productivity. In 3-axis milling, the frequency domain analysis of the cutting forces provides information which can be adopted for both predicting and monitoring the cutting process. However, the evaluation of the cutting forces spectra requires the application of specific tools (i.e., Fourier’s Transform) to t (…)

MACHINE LEARNING BASED IDENTIFICATION OF ENERGY EFFICIENCY MEASURES FOR MACHINE TOOLS USING LOAD PROFILES AND MACHINE SPECIFIC META DATA

L. Petruschke, G. Elserafi, B. Ioshchikhes, M. Weigold
Keywords: Machine tool | energy efficiency measures | energy states | expert system

Approaches to detect energy efficiency measures are associated with time consuming analysis requiring expertise. Against this background, this paper presents an expert system to identify potentials for improving the energy efficiency of metal cutting machine tools based on measurement and meta data of 35 machines. For this purpose, it is necessary to determine energy states of machine tools and control (…)

FRICTIONAL FORCE MODELING OF A MACHINE TOOL FEED DRIVE TELESCOPIC COVER

J. Ferkl, L. Novotny, S. Fiala, P. Kolar, M. Rytir
Keywords: Machine Too | Feed Drive | Telescopic Covers | virtual machine tool | Friction Modeling | LuGre Model

Telescopic covers are components which can have a potentially large impact on machine tool feed drive capabilities. Generally speaking, frictional force modelling is a well-established field of interest in which many approaches and challenges have been identified. This paper addresses frictional force modelling of machine tool feed drive telescopic covers. A sequential assembly approach and control syst (…)

COMPARISON OF SPRAYABILITY AND SOLUBILITY OF BIO-BASED LUBRICANTS WITH LIQUID CARBON DIOXIDE

T. Meier, D. Gross, N. Hanenkamp
Keywords: CMQL | milling | turning | bio-based oils | carbon dioxide

In recent years, cryogenic minimum quantity lubrication (CMQL) has been established in comparison to pure cryogenic cooling. The used oil has a crucial influence on the success of the technology. The aim of this study is to investigate the influence of oils from renewable resources with regard to their miscibility with carbon dioxide (CO2) and their spraying behavior. Ten different bio-based oils (synth (…)

INFLUENCE OF CONTOUR RADIUS AND FIBER ORIENTATION ON HEAT ACCUMULATION DURING MACHINING OF UNIDIRECTIONAL CFRP

J. Mehnen, W. Hintze, M. Koeppe
Keywords: CFRP | Unidirectional | temperature | FEM

The production of carbon fiber reinforced plastic (CFRP) parts requires edge trimming after primary shaping. Heat accumulates in convex workpiece sections, leading to increased temperatures compared to straight edges, possibly compromising the material. Existing analytical models assume constant thermal conditions and are therefore unable to calculate temperature fields of curved workpiece contours. Ac (…)

UTILIZATION OF MACHINE LEARNING APPROACHES FOR TOOL WEAR DETECTION AND PREDICTION IN THE CIRCULAR SAWING PROCESS OF METALLIC MATERIALS

P. Georgi, S. Eschelbacher, H.-C. Moehring
Keywords: Machine Learning | circular sawing | tool wear detection

Efficiency plays a major role in many areas of the mechanical processing of metals. Especially in basic provision of raw material, for example by cutting components to length during sawing, high penetration and thus efficiency as well as high robustness of the process is required. Here, the saw-ing tool and its durability is the decisive component in the process. In today's state of the art, at least in (…)

SEMI-ANALYTICAL PERIOD-DOUBLING CHATTER ANALYSIS IN THIN WALL MILLING

M. Sanz-Calle, J. Munoa, A. Iglesias, LN. Lopez de Lacalle, Z. Dombovari
Keywords: milling | chatter | period-doubling

During thin-walled part milling, a dominant flexible direction perpendicular to the feed motion is most likely to exist, which allows to formulate the stability problem in the frequency domain in a very simple form. By these means, the existence of optimal engagements under up-milling strategy for achieving a theoretical infinite Hopf stability have already been demonstrated. However, period-doubling ch (…)

USING GAMIFICATION ON THE SHOP FLOOR FOR PROCESS OPTIMIZATION IN MACHINING PRODUCTION

M. Dewald, O. Kohn, Y. Dehorn, H. Howaldt, A. Ebben, N. Kratzke, F. Janssen, M. Weigold
Keywords: Process optimization | Internet of Things | Machine tools | Gamification

The optimization of production processes is even in 2021 still an up-to-date topic, where the use of data is discussed, and the utilization has proven to be effective in specific applications in the last 10 years. Despite increasing access to information directly from the production process and more available computing resources, the data still holds unused potential. Even ongoing digitalization does n (…)

TOOL CONDITION MONITORING AND TOOL DEFECT DETECTION FOR END MILLS BASED ON HIGH-FREQUENCY MACHINE TOOL DATA

Alexander Fertig, Lukas Grau, Marius Altmannsberger, Matthias Weigold
Keywords: Tool Condition Monitoring | Machine Learning | Defect classification | Internal machine tool data

In the context of increasing digitalization, machine tools have a decisive impact on the manufacturing of technically sophisticated products. The resulting large amount of available data opens up new opportunities for process monitoring and optimization. In this paper, a new in-process tool condition monitoring (TCM) approach for end mills is developed. Besides in-process wear determination, the present (…)

ASSESSMENT OF FINISH MACHINING AND MASS FINISHING AS POST-PROCESSING METHODS FOR PBF-LB/M-MANUFACTURED 316L

C. Fuchs, L. Kick, O. Leprevost, M. F. Zaeh
Keywords: Post-Processing | finishing | Vibratory Finishing | additive manufacturing | Machining Allowance

Additive manufacturing techniques are increasingly used in industry. However, the direct usage of additively manufactured parts is limited due to their relatively low surface quality. Especially to achieve functional surfaces, post-processing has to be carried out. Post-processing methods include traditional mechanical cutting processes as well as electrical and chemical processes. Since previously depo (…)

THE IMPACT OF KEY TEMPERATURE MEASURING POINTS ON THERMAL ERROR COMPENSATION MODEL TRANSFER BETWEEN MILLING CENTERS OF THE SAME PRODUCT LINE

M. Straka, M. Mares, O. Horejs
Keywords: thermal error | Compensation | Machine tool | Key temperature points | Transferability

Machine tool thermal errors are an important element in machined workpiece inaccuracies. In the past few decades, thermal errors have been successfully reduced by software compensation techniques such as multiple linear regression analysis, finite element method, neural network and transfer function (TF). A phenomenological approach based on TFs is used for thermal error compensation in this research. T (…)

INCREASING PERFORMANCE AND ENERGY EFFICENCY OF A MACHINE TOOL THROUGH HYDROSTATIC LINEAR GUIDEWAYS WITH SINGLE DIGIT MICROMETRE FLUID FILM THICKNESS

M. Fritz, M. Groeb
Keywords: hydrostatic | guideway | Machine tool | precision | microgap | Energy Efficiency

Ever increasing requirements to machine tool performance lead to a shift from regular roller bearing towards hydrostatic guideways. These have many advantageous properties, such as non-existent stick and slip, nearly no wear, while increasing dampening and stiffness. Compared to traditional guideways, hydrostatic have a constant energy demand, resulting from pump losses. The pump losses are composed out (…)

BURR FORMATION AT THE INTERFACE DURING BI-MATERIAL ORTHOGONAL CUTTING

C. Poissenot-Arrigoni, G. Fromentin, G. Poulachon, B. Marcon, C. Legrand
Keywords: Burr formation | Bi-material

To reduce the size of exit burrs induced by broaching, it is possible to use a low value martyred part clamped to the functional one on the tool exit side. Thence, this research work deals with an in-situ analysis of the burr formation at a bi-specimens interface in orthogonal cutting configuration. New mechanisms of burr formation at the interface formed by Inconel 718 and cast iron specimens are ident (…)

ROBOT-BASED SURFACE FINISHING OF FORMING DIES CONCERNING DIFFERENT PATH STRATEGIES

S. Bay, P. Bossong, M. Weigold
Keywords: Industrial Robots | Milling; Machining Strategies | Forming Dies

The production of shape accurate forming dies in the toolmaking industry requires a high degree of manual labour. To achieve a higher level of automation, machine-based approaches are necessary. Therefore, robot-based milling experiments of difficult-to-machine cold work steel 1.2379 are carried out. This paper presents an experimental study of different path strategies using an industrial robot to mil (…)

A DEEP LEARNING APPROACH TO ELECTRIC LOAD FORECASTING OF MACHINE TOOLS

B. Dietrich, J. Walther, Y. Chen, M. Weigold
Keywords: Machine Learning | Machine tool | Load forecasting

The ongoing climate change and increasingly strict climate goals of the European Union demand decisive action in all sectors. Especially in manufacturing industry, demand response measures have a high potential to balance the industrial electricity consumption with the increasingly volatile electricity supply from renewable sources. This work aims to develop a method to forecast the electrical energy de (…)

THE EFFECT OF USING RECYCLED CONCRETE ON THE MECHANICAL AND TECHNOLOGICAL PROPERTIES OF CONCRETE IN THE PRODUCTION OF PRECAST

PETR JUNGA, JAROSLAVA HEJDOVA, JURAJ RUZBARSKY
Keywords: Aggregate | concrete | recycled aggregate concrete | precast concrete | compressive strength | modulus of elasticity

The paper deals with the verification of the possibility of replacing natural aggregate with recycled aggregate concrete (RAC) in the production of precast concrete. In the practical experimental part, concrete mixtures with different proportions of recycled concrete are tested. The results shows that the use of recycled concrete as a substitute for aggregates is possible. However, the ratio of replaced (…)

INVESTIGATION OF LUBRICATING OILS FROM RENEWABLE RESOURCES FOR CRYOGENIC MINIMUM QUANTITY LUBRICATION

T. Meier, D. Gross, N. Hanenkamp
Keywords: CMQL | milling | turning | bio-based oils | carbon dioxide

Cryogenic minimum quantity lubrication using liquid carbon dioxide (CO2) has increasingly become the focus of research in recent years. With this cooling strategy it is possible to cool and lubricate the cutting zone individually by regulating the oil and liquid CO2 flow. The oil used has a significant influence on the process stability and performance. The aim of this study is to identify the influence (…)

ANALYSIS OF THE INTEGRATION POSSIBILITY OF THE ELECTRIC VEHICLES ON BATTERY AND FUEL-CELLS BASE IN TRANSPORT SECTOR OF THE SLOVAK REPUBLIC

MIROSLAV RIMAR, OLHA KULIKOVA, ANDRII KULIKOV, MARCEL FEDAK
Keywords: Electric vehicles | fuel-cells | hydrogen | transport

The total world energy consumption is permanently growing during last 30 years. Alternative energy sources are one of the best ways to save the environment polluted by the combustion products of gasoline, diesel fuel, and even methane or propane. The main idea of the article is to analyse the possibility and it influence of integration of the electric vehicles on battery and fuel-cells base in the trans (…)

EXPERIMENTAL ANALYSIS OF THE ETCHING PROCESS FOR VALIDATION OF NON-CONVENTIONAL SLOT MACHINING IN AERO ENGINE COMPONENT MANUFACTURING

C. Baier, M. Weigold
Keywords: Wire EDM | Turbine Discs | Nickel-Based Alloys | Electrolytical Etching

To fulfill service life and integrity requirements when using a non-conventional process in aerospace industry, a comprehensive validation needs to be carried out. According to the state of the art, the characteristically resulting recast layer of wire electrical discharge machining (WEDM) can be reduced to a few microns. To meet existing requirements for eliminating the recast layer, it is essential fo (…)

IDENTIFICATION OF THE ROOT CAUSE OF SURFACE TOPOGRAPHY INACCURACIES BY MEANS OF PROCESS MONITORING: INDUSTRIAL EXAMPLES

M. Gil, X. Beudaert, J. Munoa, D. Barrenetexea, J.A. Sanchez
Keywords: chatter | Defects | surface topography | vibrations

The surfaces of machined workpieces contain the signature of the manufacturing process. Indeed, the surface inaccuracies can be related to process parameters and machine vibrations. This paper aims at using process monitoring to identify the origin of surface topography defects. Thus, vibration and other process parameter measurements are correlated with profile measurements to establish the relationshi (…)

DEMONSTRATION OF A NEW APPROACH FOR MEASURING TOOLS WITH THE IMPINGEMENT SOUND OF AN AIR JET USING MACHINE LEARNING

H. Wuerschinger, D. Gross, M. Muehlbauer, M. Stadler, N. Hanenkamp
Keywords: Tool Condition Monitoring | condition monitoring | Impingement Sound | Jet Impingement | Air Jet; Flow Noise | Airborne Sound | Machine Learning

Monitoring the tool condition of machining processes is important but challenging. Several automated tool condition monitoring solutions are available, but often not used due to existing restrictions or disadvantages. A new approach can be the detection and measurement of tool conditions analyzing the sound of an air jet impingement on tools. Due to the availability of compressed air as a working and cl (…)

PRODUCTION OF INDIVIDUALISED MULTI-MATERIAL COMPONENTS USING A ROBOT-BASED PROCESS CHAIN

M. Albergt, M. David, M. Dross, A.-K. Reichler, H.-W. Hoffmeister, K. Droeder
Keywords: flexible manufacturing system | Robot | multi-material manufacturing

The production of individual work pieces in small to medium batch sizes requires an adaptation of the manufacturing strategy. Particularly, the manufacturing of multi-material components out of metal and plastic is characterized by high production costs as well as high production times. To resolve this challenge, a new, modular process chain for the production of these structures in a single manufacturi (…)

FINGERPRINT: MACHINE TOOL CONDITION MONITORING APPROACH FOR ZERO DEFECT MANUFACTURING

M. Armendia, J. San Sebastian, D. Gonzalez, B. Santamaria, J. A. Gonzalez, R. Gonzalez-Velazquez, K. Lopez de Calle
Keywords: Machine tool | Zero Defect Manufacturing | condition monitoring | Health Assessment

Manufacturing process monitoring is showing great advances thanks to increasing sensor availability and the development of edge to cloud IoT systems. However, the application of this technology in industry is slowed down due to cyber security policies, the coexistence of old manufacturing systems, with limited monitoring capabilities, with newer and fully monitored ones, and the lack of application-orie (…)

CONTROL STRATEGIES FOR A GANTRY STAGE EQUIPPED WITH FLEXIBLE JOINTS USING FREQUENCY RESPONSE METHODS

P. Poehlmann, M. Merx, J. Mueller, S. Ihlenfeldt
Keywords: gantry stage | linear direct drive | compliant joints | frequency domain

Gantry stages, consisting of two parallel acting drives, are a well-known example, where a significant interaction between all control systems’ in- and outputs is present due to structural coupling. Stability issues and therefore the limitation of the bandwidth of the position control can be a consequence of this effect. The adjustment of the systems mechanical properties using compliant joints, as well (…)

DPART – A DIGITAL TWIN FRAMEWORK FOR THE MACHINING DOMAIN

P. Ganser, T. Venek, V. Rudel, T. Bergs
Keywords: digitalization | digital twin | Industrial Internet of Things | Machining | milling | turning

Todays’ heterogeneous manufacturing environments and isolated manufacturing elements hinder the realization of a complete and data consistent digital twin. Against this background, an increased connectivity based on the Industrial Internet of Things (IIoT) might be the future key enabler for the digital twin. However, it requires each domain to transfer, rearrange and rethink their individual data solut (…)

METHOD FOR SAFE EXPERIMENTAL TESTING OF MACHINE TOOL USABLE SPINDLE POWER

P. Kolar, M. Janota, J. Sveda, Tomas Kozlok
Keywords: Machine tools | dynamic compliance | chatter | Milling stability | Spindle usable power

The regenerative chatter during milling is a consequence of the machine tool dynamic compliance and the specific setting of the cutting process. The basic request on the machine structure is to enable a stable cut with dominant portion of the installed spindle power. In order to improve the dynamic properties of newly-designed machine tools, the machine tool structures are optimized using various advanc (…)

MULTI-PHASE SIMULATION OF THE LIQUID COOLANT FLOW AROUND ROTATING CUTTING TOOL

L. Topinka, M. Braeunig, J. Regel, M. Putz, M. Dix
Keywords: CFD-Simulation | Multi-phase simulation | Thermal investigation | Machine tools | Tool cooling simulation

The heat generated during the cutting processes significantly influences the manufacturing accuracy. For many machining tasks, the use of cooling lubricant is essential to achieve the necessary cooling and lubricating effect in the cutting zone. A reduction of a coolant supply due to resource-efficient or ecological efforts has an impact on the temperature field in the cutting tool and clamping system, (…)

PERFORMANCE EVALUATION OF (ALCRN) PVD COATED CBN INSERTS ON MACHINING OF INCONEL 718

P. Jeyapandiarajan, M. Anthony Xavior, Arivazhagan Anbalagan
Keywords: Inconel 718 | Machining | cBN | AlCrN PVD Coating | wear | surface roughness

This research work focuses on the experimental investigations conducted using uncoated cBN tool and (AlCrN) PVD Coated cBN tool for turning Inconel 718. Two different sets of experiments – one with uncoated cBN and another with coated cBN inserts were conducted considering three different levels of cutting speeds, feed rates and depth of cuts. The performance of the coated cBN over the uncoated inserts (…)

INFLUENCE OF MICRO-HOLES ON RAKE FACE OF THE CARBIDE INSERT ON MACHINING PERFORMANCE

P. Jeyapandiarajan, M. Anthony Xavior, P. Sasidharan, Arnaud Duchosal
Keywords: Inconel 718 | Machining | Textured Insert | wear

The performance of the PVD coated carbide insert with micro-holes is experimentally compared with that of the conventional inserts while machining Inconel 718 under Dry and MQL condition (Canola Oil, 0.25% Gr with Canola Oil). The machining performance of textured tool is found to be relatively good when compared to untextured tool in terms of the cutting force, surface roughness, flank wear and crater (…)

MACHINE DATA-BASED PREDICTION OF BLISK BLADE GEOMETRY CHARACTERISTICS

A. Ernst, M. Weigold
Keywords: quality | Machine Learning | milling | Aviation Industry

The increasing availability of data recording solutions in the field of machining in combination with major developments in Machine Learning and Artificial Intelligence enable new approaches towards optimization in the industrial environment. In the aviation industry, critical components must fulfil extremely high quality standards. This requires a stable and error-free manufacturing process, as well as (…)

HIGH-RESOLUTION SURFACE TEXTURE MEASUREMENTS USING A COLLABORATIVE PICK-AND-PLACE ROBOT

M. Riedl, R. Danzl, T. Lankmair, F. Millonig
Keywords: Inline | collaborative | automation | 3D measurement | optical metrology | 3D dataset | integration | Focus Variation | surface texture

The ongoing trend of robotics, automation, quality control and its combination are leading to new possibilities in the field of metrology. The improvements, especially in the handling and accuracy of collaborative robotics, are enabling new applications for automated high-resolution optical 3D measurements. This is the basis for the implementation of a pick-and-place solution for automatic surface textu (…)

WELDABILITY OF COBALT ALLOYS BY HYBRID METHODS

TOMAS HERCIK, MARIAN SIGMUND, PETR HRUBY
Keywords: Cobalt | cobalt alloys | Stellite | unconventional welding | conventional welding

The article presents the current state of the use of cobalt in various industries and its possible elimination in the field of welding. In this area, it is used in the form of cobalt alloys which are affected by various mechanical and chemical influences. These alloys are produced by the secondary metallurgical area. The primary area is the chemical industry which reserves all the use of cobalt for the (…)

DIAGNOSTICS OF ACTUATORS OF MACHINE TOOLS DRIVES ACCORDING TO THE IDENTIFIABILITY CRITERION BY THE STATE SPACE

SERGEI TREFILOV, PAVOL BOZEK, YURY NIKITIN, JOZEF MARTINOVIC , JOZEF PETERKA
Keywords: identification | CNC machine | robot drives | DC motor | state space | discrete model | diagnostics

Currently, in view of the fact that almost all the tasks of the practice of controlling CNC machine and robot drives cannot be accurately represented by linear models, and there is no solution to non-linear models in the general case, a very important task is to develop control algorithms based on discrete models. Discrete models of nonlinear systems assume variable state, control, and measurement matri (…)

CRYOGENIC MILLING OF METASTABLE AUSTENITIC STAINLESS STEEL AISI 347

K. Gutzeit, S. Basten, B. Kirsch, J.C. Aurich
Keywords: Cryogenic milling | Surface morphology | Deformation induced phase transformation

The metastable austenitic stainless steel AISI 347 offers the possibility to induce a phase transformation from γ-austenite to ε- and α’-martensite when machining. This knowledge is well understood during cryogenic turning and was already applied to improve the surface morphology of metastable austenitic steel. However, the potential of this in-process hardening method is so far limited to rotationally (…)

FUNDAMENTAL INVESTIGATIONS ON THE MACHINABILITY OF ADDITIVELY MANUFACTURED MULTI-MATERIALS

T. Kelliger, D. Schraknepper, T. Bergs
Keywords: machinability | additive manufacturing | Multi-material | Porous Material | Laser Powder Bed Fusion | Laser Metal Deposition | 316L | 1.4404 | Inconel 718 | Chip Formation | cutting force

Additively manufactured multi-materials promise unique combinations of different material properties. However, the machining behavior of these materials is widely unknown. In this study, fundamental investigations on chip formation and morphology, cutting force, workpiece temperature after cutting and surface quality were conducted in orthogonal cutting experiments. Additively manufactured test specime (…)

DEVELOPMENT OF A DECISION BOX OF DIAGNOSTIC SYSTEM FOR ELECTRIC DRIVES

PAVEL STEPANOV, PAVOL BOZEK, STANISLAV LAGUTKIN, YURY NIKITIN
Keywords: Current | vibration | neural network | diagnostics | electric drive

The paper describes a diagnostic system for electromechanical equipment with a decision-making block based on a neural network. An asynchronous gear drive was used as a control object. Decision making was carried out on the basis of a comprehensive analysis of vibration data (from the gear drive) and the current consumption of the induction motor. Vibration velocity, vibration acceleration and current i (…)

CHATTER DETECTION BASED ON A CONTACT SENSOR IN MILLING OPERATIONS

D. Hajdu, D. Bachrathy
Keywords: milling | Contact sensor | Chatter detection

Chatter vibrations during machining operations are large-amplitude self-excited vibrations, which result in the loss of physical contact between the workpiece and the tool. This paper presents an electric contact sensor, which is used to detect the cutting and noncutting periods during the operation. The spectrum of the signal of the electric contact sensor is free from environmental noise and can be us (…)

DEVELOPMENT OF A MEASURING AND CONTROL UNIT FOR AN INTELLIGENT ADJUSTMENT OF PROCESS PARAMETERS IN SAWING

F. Schreiner, B. Thorenz, J. Schmidt, M. Friedrich, F. Doepper
Keywords: Intelligent manufacturing | circular sawing | Cutting conditions and their optimization | Machining of difficult-to-cut materials

Sawing frozen wood differs significantly from sawing unfrozen wood. Temperatures below zero degrees result in an increasing hardness of wood, rising cutting forces and a progression of tool wear. Currently, the adaption of process parameters due to different wood temperatures is based on operator experience, leading to overloaded saw blades, hence causing considerable economic damage by increasing produ (…)

NUMERICAL METHODS FOR THE SIMULATION OF SEGMENTED CHIPS AND EXPERIMENTAL VALIDATION IN MACHINING OF TI-6AL-4V

C. Menze, R. Wegert, T. Reeber, F. Erhardt, H.-C. Moehring, J. Stegmann, S. Kabelac
Keywords: Machining | FEM | orthogonal cutting | element deletion | remeshing | ALE | CEL

The simulation of machining processes holds the opportunity for process improvement on many levels. Possible benefits that can be derived from accurate representations of the real processes on the tool from simulations include a prediction of tool wear, the shape of the chips produced, the forces, frictions and temperatures that arise and the residual stresses in the workpiece. These predictions can be (…)

EFFECTS OF CONSTITUTIVE MODEL PARAMETERS ON FINITE ELEMENT SIMULATION PROCESS FOR HARD MILLING OF AISI H13 STEEL

S. Zhang , B. Li , J. Li, J. Man
Keywords: Constitutive model parameters | FE simulation proces | Hard milling | AISI H13 steel

During the metal cutting process, finite element (FE) simulation has been acknowledged as an efficient way to provide designers more in-depth understanding. Furthermore, constitutive model parameters of the experimental material play a crucial role in determining the accuracy of FE simulation results. In this study, three different sets of Johnson-Cook (J-C) constitutive model parameters (A, B, n, c, an (…)

MODELLING OF PROCESS FORCES FOR COMPLEX MULTIAXIAL TURNING PROCESSES

B. Denkena, A. Kroedel, L. Ellersiek, F. Zender
Keywords: process forces | turning | dexel model | material removal simulation

Increasing demands regarding productivity and component quality are a major challenge in turning. To meet these demands, complex multiaxial turning processes like enhanced variants of the trochoidal turning processes are increasingly used. For these processes, the tool path is optimized to achieve advantageous cutting conditions and thus higher productivity. However, the process forces and their relatio (…)

INFLUENCE OF LPBF PROCESS PARAMETERS ON MILLING OF A MARAGING TOOL STEEL

M. Neuenfeldt, F. Zanger, V. Schulze
Keywords: additive manufacturing | milling | Laser Powder Bed Fusion | maraging steel

As the process parameters in the LPBF-process influence the microstructure, density and hardness of the produced parts, their influence on the milling process is suspected. For this reason the new maraging tool steel alloy Specialis® has been investigated on its machinability depending on the built parameters. The influence of the energy density, laser power and scan speed in the LPBF-process on the mil (…)

DYNAMIC CHARACTERIZATION OF MILLING BASED ON INTERRUPTED FEED MOTION

Adam K. Kiss, D. Bachrathy
Keywords: milling | stability | Chatter detection | Floquet multiplier

This study presents an experimental method for detecting and avoiding chatter vibrations that occur during general milling processes. The main idea is to capture the so-called dominant spectral properties from the transient vibrations of the milling process, which gives a good approximation for its dynamical behavior and provides a quantitative measure of stability. To induce transient vibration, the ma (…)

RAPID UNCERTAINTY QUANTIFICATION OF THE STABILITY ANALYSIS USING A PROBABILISTIC ESTIMATION OF THE PROCESS FORCE PARAMETERS

M. Busch, B. Schmucker, M. F. Zaeh
Keywords: Uncertainty quantification | probabilistic parameter estimation | machining simulation | stability analysis

In the course of the digitization of modern production systems, a reliable parameterization of the digital twin of machining processes is essential. For example, the digital representation of milling operations enables the process parameter selection without time-consuming and expensive test series by using stability lobe diagrams (SLD). However, the parameterization of the underlying process force mode (…)

CAD-BASED PATH PLANNING FOR LINE LASER SCANNING OF CURVED SURFACE

W. Guo, Z. Zhao, D. Ding, Y. Fu
Keywords: Laser-based on-machine measurement | Scan path planning | Conformal mapping | 5-axis machine tool

On-machine measurement by a line laser scanner has a great potential in machining large complex components in aerospace and automation applications. This paper proposes a novel approach for path planning of measuring curved surfaces in a 5-axis machine tool, which takes scanning overlap, visual angle, and working distance into consideration. A conformal mapping algorithm is employed to transform a three (…)

PERFORMANCE OF DIFFERENT DIAMOND CUTTING TOOLS IN FACE MILLING OF CEMENTED CARBIDE

A. Nestler, A. Schubert
Keywords: cemented carbide | Diamond; Milling | Surface properties | tool wear

More and more forming and punching tools as well as wear parts are made from cemented carbide. The large variety and the geometry of these components are often reasons for finish machining by milling, but the tool wear is very high. For the investigations, end mills with different diamond material tips or coatings are used. The cemented carbide specimens exhibit an average tungsten carbide particle size (…)