Modern Machinery (MM) Science Journal, November 2019

November 2019

MACHINING OF THIN BLADE USING VIBRATION PREDICTION AND CONTINUOUS SPINDLE SPEED CONTROL

P. Vavruska, M. Sulitka, M. Stejskal, A. Simunek, J. Falta, P. Heinrich, M. Kopal
Keywords: Machining; Optimization; Spindle speed control; Feed-rate control; FEM analysis; Deformation; Quality

The paper focuses on the issue of controlling the cutting conditions in finishing machining of compliant workpieces, such as typically thin blades, in order to eliminate undesirable vibration and achieve high quality machined surfaces while also increasing productivity in machining processes. Workpiece vibration along the toolpath results from excitation of the workpiece by cutting forces. A strategy of (…)

DESIGN OF A MICRO TOOL FOR HIGH-EFFICIENCY MICRO SLOTTING

L. Zhong, D. Peng, Q. Yin
Keywords: Tool design; Micro slotting tool; Novel structure; Micro arrayed slots; High efficiency

Micro structure with arrayed slots has excellent performances, including friction, lubrication and diffraction, because of their arrayed features. Numerous fields are concentrating on this structure, attributed to its excellent properties. In this paper, the conventional micro end milling tool was analyzed, and the drawbacks in micro slot milling were discussed. A micro slotting tool with a novel struct (…)

HIGH SPEED SYNCHRONOUS RELUCTANCE DRIVES FOR MOTOR SPINDLES

M. Weber, M. Weigold
Keywords: High speed machining; Synchronous reluctance drive; Motor spindle

This article presents a new design for setting up high speed synchronous reluctance motors (SynRM) in motor spindle applications for up to 30,000 rpm. The transversal laminated SynRM rotor package is supported by thin steel sheets and a shaft nut to exert a constant axial clamping force. Both, numerical and practical investigations are carried out using FEM-analysis and a test bench for centrifugal forc (…)

MODELLING AND OPTIMIZATION OF THE CUTTING FORCES DURING TI6AL4V MILLING PROCESS USING THE RESPONSE SURFACE METHODOLOGY AND DYNAMOMETER

I. A. Daniyan, I. Tlhabadira, S. N. Phokobye, M. Siviwe, K. Mpofu
Keywords: Cutting speed; Depth of cut; Feed; Piezoelectric sensors; Process parameters

The measurement of cutting forces using highly sensitive piezoelectric force sensors is significant in the optimization of the machining process. In this study, the modelling and optimization of the cutting forces during the milling process of Ti6Al4V was carried out using the Response Surface Methodology (RSM) and the dynamometer. The ranges of the process parameters are: cutting speed (250-280 mm/min (…)

HIGH-RESOLUTION GEOMETRY MEASUREMENT WITH A COLLABORATIVE ROBOT

M. Riedl, R. Danzl, M. Felberbauer, T. Lankmair
Keywords: Focus Variation | Robot | integration | 3D dataset | optical metrology | 3D measurement | automation | collaborative | Inline

The improvements of robust optical 3D metrology and robot systems are opening new possibilities of inline optical geometry measurements. The combination of these two facts allows measurements using the robot as manipulation system to increase the measurement area beyond a single field of view. By examining the sample from different angles using the robot to obtain high-resolution 3D datasets also from (…)

DESIGN AND SIMULATION-BASED ANALYSIS OF A TEST BED FOR TWO-DIMENSIONAL KINEMATICALLY COUPLED FORCE COMPENSATION

S. Ihlenfeldt, J. Müller, M. Merx, C. Peukert
Keywords: Linear Motor; Control; Compensation; Feed Drive; Redundant Axis

To reduce the excitation of structural oscillations machine tools’ feed dynamics are usually limited. Thus, their productivity is restricted, especially for high dynamic processes with negligible process forces. The principle of Kinematically Coupled Force Compensation (KCFC) tries to overcome this issue by combining a redundant axis configuration with the principle of force compensation. In this paper (…)

CHATTER AVOIDANCE IN MILLING BY USING ADVANCED CUTTING TOOLS WITH STRUCTURED FUNCTIONAL SURFACES

J. Baumann, E. Krebs, D. Biermann
Keywords: Cutting tools; Chatter avoidance; Surface structures

The productivity of machining processes is often limited by the occurrence of dynamic effects. The presented approach intends to counteract tool deflections, and thus to damp and disrupt chatter vibrations by using milling tools with defined functional structures on the flank faces at the minor cutting edges. The potential of process stabilization is evaluated by analyzing the operational behavior of th (…)

A STUDY OF THE APPLICATION OF VOLUMETRIC COMPENSATION BY DIRECT AND INDIRECT MEASUREMENT METHODS

M. Holub, J. Knobloch, T. Marek
Keywords: Geometric accuracy; Volumetric accuracy; Direct method; Indirect method

The present article deals with the measurement methods based on experimental tests and their impact on the resultant volumetric error of CNC machine tools (MT). Volumetric error compensations represent a promising technology to increase the production accuracy of machine tools. This article studies direct and indirect methods to measure the volumetric accuracy on a MT. The assessed parameters are not on (…)

SURFACE HARDENING AND WEAR CORRELATIONS STUDIES WHEN TURNING INCONEL 718

P. Jeyapandiarajan, M. X. Xavior, N. C. Sasidharan, A. Duchosal
Keywords:   Mg alloy | Inconel 718; Machining; Work hardening; Cutting tool; Tool wear

Machining is one of the stochastic processes, in which, the work specimen is exposed to rigorous plastic deformation which, results in rapid increase in work hardening effect and affects the life of the cutting tool particularly for Inconel 718. The depth and degree at which machined surface harden depends on factors like material properties, tool composition and tool dimensions, tool condition, cutting (…)

MATERIAL REMOVAL MODE IN 3D MICRO USM

Y. Chen, Z. Yu, G. Li, S. Lei, N. Wataru
Keywords: Micromachining; Ultrasonic vibration; Material removal mode; 3D micro cavity; Surface roughness

Ultrasonic machining (USM) is known for its ability of processing brittle and hard materials such as silicon, glass and quartz. Usually, material removal in conventional USM is in brittle mode. The machined surface is covered with sharp tips and edges. In micro USM, the size of machined feature is less than 1 mm. Different from the conventional USM, in micro USM, it was found that the machined surface i (…)

A GENERALIZED FORCE AND CHIP FLOW MODEL FOR OBLIQUE CUTTING AND VARYING UNDEFORMED CHIP CROSSSECTIONS

L. Meier, L. Seeholzer, K. Wegener
Keywords: Cutting forces; Restricted chip motion; Turning; Drilling

Simple cutting force models are well suited for orthogonal cutting. However, industrial processes often use oblique cutting with complicated cutting edge shapes, where simple cutting force models underestimate the forces. The new cutting force model is based on an existing model for restricted chip motion, but generic cutting edge and rake face shapes and arbitrary process kinematics are accepted to cal (…)

ADAPTIVE SCHEDULING THROUGH MACHINE LEARNING-BASED PROCESS PARAMETER PREDICTION

M. Frye, D. Gyulai, J. Bergmann, R. H. Schmitt
Keywords: Artificial intelligence; Machine learning; Data analytics; Adaptive scheduling; Process parameter prediction; Process optimization; Job shop scheduling

Detailed manufacturing process data and sensor signals are typically disregarded in production scheduling. However, they have strong relations since a longer processing time triggers a change in schedule. Although promising approaches already exist for mapping the influence of manufacturing processes on production scheduling, the variability of the production environment, including changing process cond (…)

QUALITY CONTROL OF A MILLING PROCESS USING PROCESS DATA MANAGEMENT IN THE AEROSPACE INDUSTRY

D. Pfirrmann, M. Voit, M. Eckstein
Keywords: Process data management; Milling; Predictive quality; Predictive maintenance; Aerospace industry

Global production is in a state of change, with multiple challenges. One challenge is the digitization of production processes in the aerospace industry, due to the high requirements regarding the reliability of the transportation vehicle. It is a premise to record the manufacturing processes using sensors and to analyze them by means of process data management. Therefore, approaches regarding the predi (…)

THE INFLUENCE OF CUTTING CONDITIONS ON SURFACE INTEGRITY IN HIGH FEED MILLING OF Ti-6Al-4V WITH SUPERCRITICAL CO2 COOLING

P. Litwa, K. K. Wika, A. Zonuzi, C. Hitchens
Keywords: Milling; Ti-6Al-4V; Supercritical carbon dioxide; Surface integrity

This study investigates the influence of cutting conditions on surface integrity in the milling of Ti-6Al-4V using various cooling methods: soluble oil coolant; supercritical carbon dioxide; and supercritical carbon dioxide with Minimum Quantity Lubrication. A Design of Experiments approach was used to evaluate a change in direction and interactions between the input factors and the responses. The resul (…)

FREE-FORM TOOLS DESIGN AND FABRICATION FOR FLANK SUPER ABRASIVE MACHINING (FSAM) NON DEVELOPABLE SURFACES

G. Gómez-Escudero, H. González, M. Barton, P. Bo, P. Fernández-Lucio, L. N. López de Lacalle, A. Calleja
Keywords: Free form abrasive tool; Non developable surfaces; Flank Super Abrasive Machining (FSAM)

Manufacturing improvements are becoming a real need in industry. In order to satisfy these industrial requirements, they should be targeted in two different directions: new manufacturing processes and surface optimization through algorithms. On the one hand, Super Abrasive Machining (SAM) is presented as a new manufacturing process combining benefits from milling and grinding technologies. On the other (…)

FREQUENCY RESPONSE PREDICTION FOR ROBOT ASSISTED MACHINING

A. Barrios, S. Mata, A. Fernandez, J. Munoa, C. Sun, E. Ozturk
Keywords: Robot; Dynamics; Frequency response; Receptance coupling; Machining

Robotics is increasing its presence in the machine tool sector. One interesting application for robot assisted machining involves a robot locally increasing the stiffness of a thin walled part to suppress regenerative vibrations and minimize part deformations during machining. Simulating the dynamics improvement achieved when coupling the robot and the part is of high concern, in order to guarantee th (…)

IN-PROCESS MONITORING AND ANALYSIS OF WHIRLING MOTIONS IN BORING AND TREPANNING ASSOCIATION DEEP DRILLING

A. Steininger, F. Bleicher
Keywords: BTA/ STS deep drilling; Monitoring machining process; Short-time Fourier transformation; STFT; Dynamic disturbances

This work presents a holistic approach for monitoring machining processes of an industrial deep drilling machine. For that purpose, a machine tool was equipped with a multi-sensory monitoring system with the objective to detect and assess dynamic disturbances during the machining process. Disturbances are key characteristics of deep drilling processes and are intensified due to the high length to diamet (…)

THE IMPACT OF SIZE REDUCTION ON THE ENERGY EFFICIENCY, DYNAMICS AND MACHINING PERFORMANCES IN MILLING

P. Haas, A. Schorderet, C. Jeannerat, J. Richard, Ch. Balistreri, N. P. Gilani
Keywords: Size reduction; Micro-machine; Milling; Energy; Dynamics; Machining performances; Air consumption; Thermal characteristics; Modal analysis

The Micro5 5-axes milling machine was specifically developed for micro, or mini, technical productions and focused on simplicity and efficiency. It provides functional, qualitative and economical performances. Designed for low cutting forces (HSC technology), it has an excellent dynamics. The first vibration modes and compliances being very high, the machine is insensitive to axes accelerations. It ther (…)

MOBILE MACHINES FOR THE MACHINING OF LARGE DIMENSION PARTS

O. Legoff, M. Ritou, C. Maurin, S. Bonnet, B. Furet
Keywords: Mobile machine; Robotic machining; Large dimension

The machining of large dimension part presents issues of accuracy and of part handling. Machine-tools of large capacity are classically used, but they are very expensive. The paper investigates original solutions with mobile milling machines. A comparative study of a machining robot and of a portable milling machine is performed. Instrumented experiments of face milling operation were carried out and th (…)

EFFECT OF TEMPERATURE AND OXIDATION IN CUTTING ZONE ON WEAR OF CUTTING TOOLS WITH MULTILAYER COMPOSITE NANO-STRUCTURED COATINGS AT HIGH SPEED TURNING

M. Volosova, A. Vereschaka, A. Okunkova, N. Sitnikov, N. Andreev, F. Milovich, J. Bublikov
Keywords: Multilayered nanostructured coatings; Wear; Metal cutting tools; Nanolayer; Diffusion processes; Oxidation

The article discusses the ability of multilayer composite nano-structured coatings based on the Cr-CrN-(Ti,Cr,Al,Si)N system to resist wear factors activated with increasing temperature, such as diffusion and oxidation processes, as well as spinodal decomposition of the coating material. Investigators were carried out in turning C45 steel at the following cutting conditions: f = 0.2 mm/rev, ap = 1.0 mm, (…)

INVESTIGATION OF THE DYNAMIC BEHAVIOR OF MACHINE TOOLS DURING CUTTING BY OPERATIONAL MODAL ANALYSIS

J. Berthold, M. Kolouch, J. Regel, M. Putz
Keywords: Machine tool; Dynamic; Operational modal analysis; Measurement

A common approach for the experimentally estimation of modal parameters is the Experimental Modal Analysis (EMA). EMA takes place in the standstill of the machine, consequently neglecting effects that only occur during the cutting process. Alternatively the Operational Modal Analysis (OMA) makes possible to investigate structures under operational loads and conditions. In this paper, a machine tool is i (…)

INFLUENCE OF BOTH RAKE AND FLANK FACES METAL WORKING FLUID (MWF) STRATEGIES ON MACHINABILITY OF Ti-6Al-4V ALLOY

A. Kummamkandath, A. Duchosal, A. Morandeau, R. Serra, R. Leroy
Keywords: Cryogenic machining; Rake and flank application; CO2; Ti-6Al-4V; Machinability; Surface integrity; Chip microstructure

This study mainly focuses to investigate the machining performances of variety of metal working fluid (MWF) strategies such as cryogenic (CO2), minimum quantity lubrication (MQL) and emulsion, into rake and flank face application during the face milling of titanium (Ti-6Al-4V grade 5) alloy. Modified CoroMill600 milling cutter with internal channels to inserts rake face and flank face delivery, and PVD (…)

AFFECTATION OF CHIP FORMATION IN SINGLE-LIP DEEP HOLE DRILLING AT SMALL DIAMETERS BY APPLICATION OF LOW-FREQUENCY VIBRATION SUPPORT

M. Reiter, F. Bleicher
Keywords: Deep hole drilling; Long-chipping material; Vibration; Chip formation; Material removal

Deep hole drilling processes are relevant for various applications where bore holes with high length-to-diameter-ratios (L/D) and good surface qualities are necessary, carried out mostly at the end of the (machining) process chain. Therefore, the avoidance of tool breakage and the resulting process stability is mandatory. One of the main causes for the failure of single-lip drills in the machining of lo (…)

VIBRATION ATTENUATION OF BORING BARS WITH NONLINEAR CONTROL FORCE

Z. Iklodi, A. Astarloa, Z. Dombovari
Keywords: Boring bar; Active damper; Nonlinear force; Linear stability

An active method for boring bar vibration attenuation and chatter suppression is presented through the introduction of a nonlinear control force within a tuned mass damper. Its effects on process stability and its control options are discussed in detail. The effectiveness of the active damping system and the optimal control parameters are determined through numerical simulations carried out on a simplif (…)

LONG-TERM THERMAL COMPENSATION OF 5-AXIS MACHINE TOOLS DUE TO THERMAL ADAPTIVE LEARNING CONTROL

P. Blaser, J. Mayr, K. Wegener
Keywords: Thermal behavior; Compensation; Self-optimization; Machine learning

This paper presents a prediction and compensation approach for thermal errors of 5-axis machine tools, based on supervised online machine learning. Process-intermittent probing is used to identify and update a thermal autoregressive with exogenous input (ARX) model. The approach is capable of predicting and compensating thermal displacements of the tool center point based on changes in the environmental (…)

FEED DRIVE CONDITION MONITORING USING MODAL PARAMETERS

J. Ellinger, T. Semm, M. Benker, P. Kapfinger, R. Kleinwort, M. F. Zäh
Keywords: Feed drive; Condition monitoring; Ball screw; Linear guide; Preload loss; Analysis of variance; Machine tool

Ball screws and linear guides are among the key components of machine tools. Abrasive wear causes a loss in stiffness of these components over time affecting the attainable manufacturing precision and, eventually, leads to failures and costly down-time. In order to control these effects, the condition of the crucial feed drive components needs to be monitored. This paper shows, how the feed drive condit (…)

S-CURVE ALGORITHM OF ACCELERATION/DECELERATION WITH SMOOTHLY-LIMITED JERK IN HIGH-SPEED EQUIPMENT CONTROL TASKS

V. Kombarov, V. Sorokin, O. Fojtu, Ye. Aksonov, Ye. Kryzhyvets
Keywords: CNC; S-curve algorithm of acceleration/deceleration; Smoothly-limited jerk; High-speed equipment

The needs of increase in accuracy, quality and shape complexity of parts manufactured in high-speed equipment is a trend of industry. Problems of ensuring the accuracy at high velocities of machine organs motions are formulated. Machine organs movements accuracy is determined by smoothness of their motions and depends on the smoothness of the trajectory and the law of velocity changing along the traject (…)

INVESTIGATION OF PROCESSES IN HIGH-SPEED EQUIPMENT USING CNC CAPABILITIES

Ye. Aksonov, V. Kombarov, O. Fojtu, V. Sorokin, Ye. Kryzhyvets
Keywords: CNC; High-speed equipment; Parameters recording

Improving the accuracy, reliability and performance of high-speed technological systems is one of the most pressing challenges in modern industry. The process of improvements in machine tools is permanent because of growth in requirements for the parts quality. The HSM process progress may depends on specific characteristics of particular machine. In this connection, there is a need to carry out investi (…)

DEVELOPMENT OF A METHOD TO DETERMINE CUTTING FORCES BASED ON PLANNING AND PROCESS DATA AS CONTRIBUTION FOR THE CREATION OF DIGITAL PROCESS TWINS

A. Hänel, E. Wenkler, T. Schnellhardt, C. Corinth, A. Brosius, A. Fay, A. Nestler
Keywords: Digital process twin; Machine data collection; Cutting forces; Process data; Milling

A digital process twin unifies information from planning and manufacturing of a machining process. Calculation and technological models allow the prediction of further information, which normally is not provided. The work shows the recording of both data sources and creation of a digital process twin for a milling application. Further the usage of technological models is shown at the example of cutting (…)

STRATEGY OF MILLING CENTER THERMAL ERROR COMPENSATION USING A TRANSFER FUNCTION MODEL AND ITS VALIDATION OUTSIDE OF CALIBRATION RANGE

M. Mares, O. Horejs, S. Fiala, Ch. Lee, S. M. Jeong, K. H. Kim
Keywords: Thermal error; Compensation; Accuracy; Machine tool; Cutting process

Achieving high workpiece accuracy is a long-term goal of machine tool designers. There are many causes of workpiece inaccuracy, with thermal errors being the most dominant. Indirect compensation (using predictive models) is a promising strategy to reduce thermal errors without increasing machine tool costs. A modeling approach using thermal transfer functions (a dynamic method with a physical basis) has (…)

INVERSE MATERIAL MODEL PARAMETER IDENTIFICATION FOR METAL CUTTING SIMULATIONS BY OPTIMIZATION STRATEGIES

T. Bergs, M. Hardt, D. Schraknepper
Keywords: Johnson-Cook model; Simulation; Optimization; Inverse identification; Machining

Numerical modeling of machining processes exhibits a high potential for shortening process development times. When modeling the machining process, an accurate material model is essential for the success and reliability of the simulated results. Especially, the simulation results depend largely on the material model and on the material parameters. To identify the parameters for machining conditions, inve (…)

PRODUCTIVITY INCREASE OF HIGH PRECISION MICRO-MILLING BY TRAJECTORY OPTIMIZATION

A. Schorderet, R. Herzog, N. Jacquod, Y. Marchand, Ch. Prongue
Keywords: Milling; Vibrations; Trajectory optimization; Surface quality; CNC

Milling parts for watch, medical, aircraft or molds industries is a compromise between time and precision or surface quality. The latter is very often related to machine vibrations during the process. This paper summarizes results obtained with two approaches aiming at reducing machine vibrations caused by axes accelerations. Both are control model based, taking into account the machine's modal behavior (…)

INVESTIGATIONS ON THE INFLUENCE OF ISOTROPY IMPROVING ALLOY ADDITIVES WHEN MACHINING 38MNSIVS6

T. Bergs, T. Seelbach, D. Schraknepper
Keywords: Micro-alloyed steel; Isotropy; Machinability; Inclusions

Resulfurized steels are commonly used in the industry due to its good machinability, which can be related to the formation of microstructural manganese sulfide (MnS) inclusions. On the downside, MnS inclusions cause a high steel anisotropy due to its elongated form. Within this paper, the effect of a MnS reduction and the influence of different countermeasures on the machinability is investigated. The a (…)

PULSATING HIGH-PRESSURE CUTTING FLUID SUPPLY FOR CHIP CONTROL IN FINISH TURNING OF INCONEL 718

T. Bergs, A. Splettstößer, D. Schraknepper
Keywords: Turning; High-pressure cutting fluid supply; Chip breaking; Chip control; Inconel 718; Nickel-based alloys

High-pressure cutting fluid supply is widely used in rough turning of difficult-to-cut materials to ensure chip breaking. The acting force of the cutting fluid jet on the back of the chip causes chip breaking. The broken chips are accelerated by this force and can damage the workpiece surface on impact. Consequently, high-pressure cutting fluid supply is not suitable for finish turning mostly, especiall (…)

SENSORS AS AN ENABLER FOR SELF-OPTIMIZING GRINDING MACHINES

M. Maier, T. Gittler, L. Weiss, C. Bobst , S. Scholze , K. Wegener
Keywords: Sensor fusion; Self-optimizing machines; Cost calculation; Process boundary; Grinding burn; Gas sensor; Temperature sensor; Surface roughness

Today, an operator performs experiments to adaptively select grinding process parameters using observations, expert knowledge, and rules of thumb. Self-optimizing grinding machines cannot use operator observations and must, therefore, extract enough information out of the grinding process. In this study, a holistic sensor set-up as foundation for self-optimizing machines are presented exemplarily for cu (…)

CONTROL OF HYBRID ELECTRIC-HYDRAULIC DRIVE FOR VERTICAL FEED AXES OF MACHINE TOOLS

S. Fiala, A. Bubak, L. Novotny
Keywords: Research Center of Manufacturing Technology | 1Czech Technical University in Prague

This paper deals with methods to reduce the influence of gravitational force on machine tool vertical feed axes. It provides an overview of existing counterbalancing mechanisms that are used in industrial applications. The main focus is on an existing solution that uses a rotary piston hydromotor, which has a number of advantageous properties. However, its significant torque ripple limits the practical (…)

OPERATIONAL METHOD FOR IDENTIFICATION OF SPECIFIC CUTTING FORCE DURING MILLING

M. janota, P. Kolar, M. Sulitka
Keywords: Specific cutting force; Mechanistic approach; Chatter; Frequency response function

Specific cutting force is a key parameter that is important for estimating cutting forces that occur during machining. This information is important for various applications. The most important application is estimation of the stability limit valid for the specific configuration of the machine tool, tool and workpiece. There are a number of procedures used to predict the specific cutting force through v (…)

A NOVEL METHOD FOR THE CHARACTERIZATION OF DIAMOND WIRE TOPOGRAPHY AND ABRASIVE GRAIN GEOMETRIES

U. Pala, K. Wegener
Keywords: Diamond wire; Wire sawing; Diamond wire topography; Abrasive grain characterization; Grain geometry

Diamond wire is a relatively new abrasive tool technology used in wire sawing of hard and brittle materials i.e. Si, SiC, sapphire or ceramics in general. Process characteristics such as the undeformed chip thickness, abrasive wear and material removal regime heavily depend on the wire properties. However, manufacturers only provide data on the abrasive grain size range, relative grain density and core (…)

NUMERICAL AND EXPERIMENTAL ANALYSIS OF CHIP FORMATION AT ULTRAHIGH CUTTING SPEED

M. Storchak1, H.-C. Möhring
Keywords: Cutting; High-speed machining; Chip formation; Finite element simulation

The tendency of substantially increasing the cutting speeds in the cutting processes of metallic materials leads to an increase in the productivity of the machining processes. In order to ensure such increase, the regularities of the cutting characteristics at the high cutting speeds should be examined more closely. For the analysis of chip formation at high cutting speed, cutting simulations were used (…)

FINISH MILLING STUDY OF Ti-6Al-4V PRODUCED BY LASER METAL DEPOSITION (LMD)

A. Kallel, A. Duchosal, G. Altmeyer, A. Morandeau, H. Hamdi, R. Leroy, S. Méo
Keywords: Laser Metal Deposition (LMD); Milling; Ti-6Al-4V; Heat treatment; Surface integrity

Components produced and repaired by the Laser Metal Deposition (LMD) process require finish-machining steps in order to improve the poor geometrical tolerance of the functional surfaces. In this work, the LMD process was conducted to build up samples from Ti-6Al-4V powders. The effect of the face milling process on surface roughness of the Ti-6Al-4V parts was studied in different build directions. The e (…)

SURFACE INTEGRITY IN TURNING OF FE17CR2NI0.2C IRON BASED THERMALLY SPRAYED COATINGS WITH SPECIAL RESPECT TO THE INFLUENCE OF THE FEED

H. Liborius, A. Nestler, G. Paczkowski, A. Schubert, T. Grund , T. Lampke
Keywords: Surface integrity; Thermally sprayed coatings; Turning

Cylinder linings of lightweight combustion engine blocks made from aluminium cast alloys are typically coated with thermally sprayed layers to enhance the chemical resistance. Finish machining of the cylinder linings is currently done by honing. A substitution of this process by machining with geometrically defined cutting edges would have significant advantages, especially concerning ecological aspects (…)

NICKEL-BASED ALLOY DRY MILLING FORCE AND TEMPERATURE BY USING MONOLITHIC CERAMIC END MILL TOOL

Z. Yuan, J. Zha, J. Liang, Y. Li, Y. Chen
Keywords: Nickel-based alloy; Monolithic ceramic end mill; High speed milling; Material removal rate

Nickel-based alloys are known to be difficult to cut material, which can cause high cutting forces and temperature rise which always leads to excessive tool wear. Traditional views hold the opinion that cutting temperature rise could lead to negative effects. However, milling under high temperature, cutting material can get a thermal softening effect. In this research, the monolithic ceramic end mill wa (…)

METHODOLOGY FOR A MODEL-BASED CONTROL OF THE BOUNDARY ZONE PROPERTIES DURING MILLING OF TI-6AL-4V

M. Wimmer, P. Rinck, R. Kleinwort, M. F. Zäh
Keywords: Milling; Boundary zone properties; Internal stress states; Titanium; sensor tool holder; In-process measurement

A significant influencing factor that determines the strength, lifetime and reliability of a component after machining is the residual stress state in the boundary zone. A reliable adjustment of this condition during machining is currently not possible. It is desired to control the milling process using a model-based approach in order to generate defined geometries and residual stresses in titanium comp (…)

ANALYSIS OF CONTOUR ACCURACY AND PROCESS FORCES USING A CHAMBER-BORING-SYSTEM

R. Schmidt, J. F. Gerken, M. Fuß, D. Biermann
Keywords: Deep hole drilling; Manufacturing process; Chamber boring; Contour measurement; Non-circular profiles; Experimental approaches in machining

Deep hole drilling is a metal cutting method for producing primary cylindrical deep bores with a length-to-diameter ratio larger than l/D = 10. Due to the increasing interest of different branches of the industry in inner contoured workpieces, the Institute of Machining Technology (ISF) and the BGTB GmbH developed a chamber boring system, which allows to contour boreholes in axial and radial directions. (…)

ESTIMATION OF ENGAGEMENT CONDITIONS USING AN ANN PATTERN RECOGNITION SYSTEM ON THE BASE OF A SENSORY TOOL HOLDER

T. Bergs, D. Scharknepper, S. Goetz
Keywords: Process monitoring; milling; Industry 4.0; ANN

Knowledge of the tool wear state in machining has become an important issue in research and industrial application. Current systems use the spindle power or cutting force as measured variable and refer it to a taught set point. However, this method lacks the ability to adapt to new work piece geometries. This new approach focusses on the tool instead of the workpiece, and uses a sensory tool holder with (…)

ANALYSIS OF SURFACE POST-PROCESSING TECHNIQUES FOR IMPROVEMENT OF ADDITIVE MANUFACTURED PARTS IN AEROSPACE

M. O. Oyesola, K. Mpofu, N. Mathe, S. Hoosian, I. Tlhabadira
Keywords: Additive manufacturing; Post-processing; Aerospace

Additive manufacturing (AM) is a fast growing innovative technology with attractiveness to transform the manufacturing segment of the aerospace industries due to its ability to produce final usable parts. However, the surface finish of AM produced parts usually fall short of desires when compared to the conventional manufacturing method. Therefore, post-processing is often required for surface finishing (…)

MACHINABILITY THE AISI 316 STAINLESS STEEL AFTER PROCESSING BY VARIOUS METHODS OF 3D PRINTING

p. mASEK, T. Fornusek, P. Zeman, M. Bucko, J. Smolik, P. Heinrich
Keywords: Hybrid manufacturing; Machining; Machinability; Stainless steel

The importance of the 3D metal printing parts still increases in many branches of production not only for prototyping. The metal prints need machining very often to obtain specific shape, accurate dimensions as well as superior surface roughness. Internal structure of 3D metal prints differs from workpiece made by conventional processes like a rolling process. That leads to different mechanical properti (…)

INVESTIGATION OF THE COOLANT FLUID FLOW DISTRIBUTION IN THE GRINDING GAP

C. Baumgart, K. Wegener
Keywords: Grinding; Coolant supply; Coolant nozzles; Grinding fluid flows; Grinding gap; Metal working fluids

In grinding the use of coolants is inevitable to achieve high precision surface properties under the need of high process performance and under reasonable material removal rates. In conventional grinding typically a significant share of the total production energy refers to the delivery and conditioning of the coolants due to the use of flood cooling, which contributes a significant portion to the produ (…)

SURFACE ROUGHNESS AND ITS PREDICTION IN HIGH SPEED MILLING OF ALUMINUM ALLOYS WITH PCD AND CEMENTED CARBIDE TOOLS

U. Teicher, S. Pirl, A. Nestler, A. Hellmich, S. Ihlenfeldt
Keywords: quality prediction | surface quality | milling | PCD | aluminum | High speed machining

Milling structural components from aluminum under enormous requirements of productivity and quality from the aerospace perspective is still the subject of extensive research. The assessment strategies of the surface quality are a big challenge for the surface measurement technique, since only a fraction of the manifesting surface topography can be described with the help of two-dimensional measured va (…)

ADAPTIVE TOOLPATH FOR 3-AXIS MILLING OF THIN WALLED PARTS

N. Grossi, A. Scippa, L. Croppi, L. Morelli, G. Campatelli
Keywords: Toolpath; Milling; Thin-wall workpiece

In this paper a technique to compute the 3-axis toolpath for a thin-wall component is presented aiming at maximizing the engagement conditions, keeping the geometry in tolerance. The toolpath generation is based on the static deflection of the component, predicted by coupling a mechanistic model of the cutting forces with a FE model of the workpiece, including, at each machining step, material removal m (…)

INVESTIGATION ON THE PRODUCTIVITY OF MILLING TI6AL4V WITH CRYOGENIC MINIMUM QUANTITY LUBRICATION

D. Gross, M. Appis, N. Hanenkamp
Keywords: Carbon dioxide; Cryogenic; CMQL; Ti6Al4V; Milling; Spray test

Because of its unique material properties, Ti6Al4V is used for components in the aerospace industry which are subject to high mechanical and thermal loads. Due to that, this material is considered as difficult to cut from a machining point of view. In order to improve productivity in machining Ti6Al4V the use of an effective cooling and lubrication strategy is necessary. This challenge can be managed wi (…)

MODAL-SPACE CONTROL OF A LINEAR MOTOR-DRIVEN GANTRY SYSTEM

C. Peukert, P. Pöhlmann, M. Merx, J. Müller, S. Ihlenfeldt
Keywords: Modal control; Active vibration control; Machine tool; Cascaded control; Linear motor; Inertial actuator

This paper presents the modal control applied to motion systems, in particular for machine tools. This control approach is particularly suitable for over-actuated systems that have more actuators than degrees of freedom. By using the modal approach, the parameterisation of the control loops is simplified since each control loop corresponds to a specific eigenmode. A four-variable modal control of a lin (…)

HIGH SPEED MACHINING OF BRASS ROD ALLOYS

G. Adinamis, F. Gorsler, A. Estelle
Keywords: Brass; Machinability; High speed machining; Turning; Drilling; Milling; Cutting speed; Tool life; Surface roughness; Chip formation; CNC; Throughput; Productivity; Profitability; Steel; Stainless steel

Brass is known for excellent machinability, but its ultimate productivity potential with high speed machining requires further study. An extensive testing program was conducted in laboratory and production settings on representative brass rod alloys using modern machine tools. Machinability data collected for turning, drilling and milling offers new insights on the effects of increasing speed, feed rate (…)

RESOURCE CONSUMPTION CLASSES OF MACHINE TOOLS

M. Putz, H. J. Koriath, A. P. Kuznetsov
Keywords: Machine tool; Energy; Resource; Efficiency; Costs

From the point of view manufacturer, machine tools fulfill technological requirements of manufacturing processes for part geometrical dimensions, shaping, and material property change. Main machine tool functions are axis motions with sufficient power reserve drives to technological process loads, consuming energy. The participation of manufacturing systems and processes for sustainable life in industri (…)