Modern Machinery (MM) Science Journal, November 2018

VIRTUAL LABORATORY FOR STUDY OF CONSTRUCTION OF MACHINE TOOLS

JIRI KROUPA, ZDENEK TUMA, JIRI KOVAR, VLADISLAV SINGULE
Keywords: education | visualization | Machine tools | Virtual Reality | virtual laboratory

Virtual reality is quickly evolving technology which is starting to push not only in entertainment but also in other disciplines like an automotive, machine or aircraft industry. Due to ever higher teaching demands of these problematics virtual reality is one of the ways how to increase teaching efficiency. This paper aims to create a virtual laboratory with an interactive model of a machine tool. Head- (…)

DEVELOPMENT OF A VALVE FOR A BRAKING-TORQUE CONTROL USED ON RAILWAY BRAKES

PATRIK BORDOVSKY, PHILIP AMOS MERKEL, HBERTUS MURRENHOFF, OLIVER REINERTZ, KATHARINA SCHMITZ
Keywords: Simulation | railway application | valve design | hydro-mechanical braking-torque control | spring-applied disc brake

A novel hydraulic disc brake system with a closed-loop control of the braking torque is under development at the Institute for Fluid Power Drives and Systems (ifas) of RWTH Aachen University. During the braking process, the torque on the caliper acts on a supporting rod. It has been found that the resulting supporting force is proportional to the braking torque. Thus, this force is utilized as a feedbac (…)

DIRECT MILLING ON CNC CAROUSEL

KAREL OSICKA, MILAN KALIVODA, MILAN DVORAK
Keywords:   cartesian coordinates | Sinumerik | CNC system | milling | adjustable rotation axis | carousel

The article discusses an application of new possibilities for the older type of machine. This machine is a heavy vertical lathe in the single column design (series carousel SKJ) which after modernization has a new CNC control system. It has a generally wide range of standardized machining cycles, which are determined not only for carousels. When upgrading the system usually not all software on the machi (…)

POLYNOMIAL INTERPOLATION IN 5-AXIS MILLING

PETRA OHNISTOVA, MIROSLAV PISKA, DAVID PRAT
Keywords: milling | control point | control system | spline | polynomial interpolation

This study is an introduction to the five-axis milling using polynomial interpolation approach. Progressive milling technologies using different spline interpolations in the control system Sinumerik 840D were compared for a defined number and distributions of the controls points of a planar curve. A tool trajectory for the five-axis CNC milling of a concave profile was generated as the superposition of (…)

USAGE OF THE FUZZY LOGIC TO PREDICT SURFACE QUALITY OF MACHINED PARTS DURING MILLING OPEARTION

JAN STREJCEK, LIBOR ZAK, JAKUB DVORAK
Keywords: parameter | tool | surface | fuzzy logic | quality

High level of the quality requirements of machined parts is the standard, which is not unique only for automotive industry, but in industry general. The quality of the product surface roughness is key parameter for every machined product, one of the process with the high influence to surface  quality is the milling process. In this article is used fuzzy logic to predict the surface quality by milling op (…)

NON DESTRUCTIVE EVALUATION OF SURFACES AFTER HARD MILLING

MIROSLAV NESLUSAN, MARIA CILLIKOVA, PAVEL KEJZLAR, JURAJ URICEK
Keywords: wear | white layer | surface integrity | milling | Barkhausen noise

Grinding operations are sometimes replaced with hard turning or milling cycles. Mechanism of chip separation during grinding and the corresponding surface integrity remarkably differs from hard turning or milling. For this reason, this paper deals with application of Barkhausen noise for evaluation of surface anisotropy after hard milling. Experiments were carried out on hardened bearing steel 100CrMn6. (…)

LNU-FUZZY NETWORK AS A MATHEMATICAL ADAPTIVE MODEL OF A HYDRAULIC SYSTEM

MARTIN VESELY
Keywords: adaptive model | 4-way proportional valve | neuro-fuzzy network

Model adaptive controllers such as Model Predictive Control or Model Reference Adaptive Control need a precise mathematical model of the controlled system adaptable in real-time. Systems consisting of a hydraulic 4-way proportional valve and a linear motor have non-linear behaviour such as hysteresis of and valve, death zone of a valve spool, time delay of a data transfer and control unit, dependence on (…)

USAGE OF TOPOLOGICAL OPTIMIZATION IN DESIGN OF MECHANICAL FORGING PRESSES

KAREL RAZ, MILAN CECHURA
Keywords: forging | weight | deformation | topological optimization | mechanical press

This article deals with the usage of topological optimization method in the design of mechanical forging press. This area of industry is worldwide without significant development changes for long time. Topological optimization is used here for minimizing weight of forging press and maximizing stiffness of whole machine. Mechanical press with nominal force 80 MNis used as an example.  Frame of press is m (…)

HIGH PRESSURE HYDRAULICS IN DIESEL ENGINE FUEL SYSTEM

VACLAV VONDRACEK, ZDENEK TROJAN, MIROSLAV MALY
Keywords: injector | injection system | fuel distribution

The use of high-pressure fuel injection with ultra-fast actuators provides an opportunity for flexible molding of injection parameters, not only for the corect size of the fuel batch, but also in terms of very precise timing. These are good preconditions for optimizing the combustion process and improving of engine performance parameters

ANALYSIS OF MATERIAL REMOVAL ON RADIAL COMPRESSOR WHEEL OF AIRCRAFT ENGINE AFTER FINISHING PRODUCTION OPERATIONS USING CMM

PETR MIKES, LIBOR BERANEK, ZDENEK PITRMUC
Keywords: finishing technology | compressor wheel | coordinate measuring machine

This paper deals with the dimensional analysis of the turboprop aircraft engine radial compressor wheel. The radial compressor wheel is very complex component. This part is manufactured by turning and five-axis milling technology. Due to the high stress of this part in service life, the residual stress in the surface layer is important. Desirable are the compressive stress levels to prevent cracks. For (…)

INVESTIGATION OF THE INFLUENCE OF PVD COATINGS FOR DRY GROOVE MILLING

ALES JAROS, JOSEF SEDLAK, JIRI VONDRA
Keywords: flank wear | force loading | PVD coatings | groove milling | high-speed steel

This paper deals with the benefits of PVD coatings applied to HSS three edges end milling cutter. Three types of PVD coatings ((Al,Ti)N, (Al,Ti,Cr)N and nanocomposite nACo) were used to extend the tool life. The coatings were synthesized by a cathodic-arc deposition process. Machining was carried out on the vertical milling machine FB 32V without using process liquid. Set up cutting conditions were cons (…)

EXPERIMENTAL TESTING OF STEEL WIRE ROPES

MARIANNA TOMASKOVA
Keywords: competence coefficient | mechanical tests | steel wire rope

The construction of the steel rope is a complex set which characteristic features, functional ability and life are based on the co-ordination of the separate elements from which the rope is made - steel wires. The paper is focused on fatigue testing of steel ropes. After the fatigue tests, the properties of the wire material, rope erasure and wire strength were determined. Steel ropes were subjected to (…)

MACHINE TOOL VIBRATION REDUCTION USING HYDROSTATIC GUIDEWAY

TOMAS LAZAK, MATEJ SULITKA, EDUARD STACH
Keywords: Machine tool | vibration attenuation | squeeze damping | hydrostatic guideway

Utility properties of the machine tools, such as machining accuracy, surface quality, and productivity are affected by many factors that also include guideway properties. Guideways enable machine tool parts to move. It is generally understood that hydrostatic guideways exhibit better damping properties than linear guideways with rolling elements. However, quantitative expressions of better damping appea (…)

RESIDUAL STRESS WHEN FACE MILLING ALUMINIUM ALLOYS

JOSEF SEDLAK, PETR OSICKA, JOSEF CHLADIL, ALES JAROS, ALES POLZER
Keywords: hole-drilling method | Aluminium Alloys | face milling | internal tension | residual stress

The contribution analyzes the causes of the residual stress in the material during face milling. It focuses on characteristics of internal tension in materials (causes of occurrence, consequences), influence of cutting conditions, machining strategy and possibilities of removal / elimination of internal tension. The experimental section of this article deals with the measurement of internal stresses dur (…)

PRODUCTION QUALITY IMPROVEMENT BASED ON 1D DIGITAL TWIN

JOZEF MICIETA, PETR CHLEBANA, MICHAL MASNY, PETER KRISSAK
Keywords: leakage | digital twin | Simulation | sensitivity analysis | hydrostatic control

One of key component of hydrostatic close circuit pump or motor is hydrostatic control. The control influences their performance and behavior. That is the reason to pay high attention on the qualitative aspects. One of them is the First Pass Yield (FPY) indicator.The aim of the paper is to show simulation deployment into the problem solving of leakage issue. High leakages caused low FPY indicator at pro (…)

COMPARING THE PERFORMANCE OF MICRO-END MILLS WHEN MICRO-MILLING OF ADDITIVE MANUFACTURED TI-6AL-4V TITANIUM ALLOY

ZDENKA RYSAVA, STEFANIA BRUSCHI, MIROSLAV PISKA, JAN ZIDEK
Keywords: micro-end mills | surface integrity | additive manufacturing | micro-milling

The objective of this work is to compare the performance of uncoated micro-end-mills and their effect on micro-milling of the Ti6Al4V titanium alloy that had been manufactured in the technology of Additive Manufacturing (AM). In this work, two different geometries of square-end micro-mills with two and fourcutting fluteshave been used. The effective tool geometry at the real micro-machining is rather pr (…)

INFLUENCE OF END MILL VARIABLE PITCH ON SURFACE QUALITY OF ALUMINIUM THIN-WALLED PARTS

IVAN BURANSKY, MATEJ BRACIK, VLADIMIR SIMNA, TOMAS VOPAT
Keywords: flatness | colour deviation map | 3D scanning | aluminium thin-walled parts | irregular pitch end mills | milling

In this paper the effect of the end mill variable pitch on the flatness and surface quality of aluminium (EN AW 6082) thin-walled partswas studied. Tests were performed using the HSC 105 linear CNC machine and following cutting parameters: cutting speeds (800, 100, 1200 and 1400 m.min-1), feed per tooth (0.12 mm), cutting depth (for roughing 10 mm and for finishing 5 mm). Three teethsolid end millsof 12 (…)

SHOULDER END MILLS WITH PCD INSERTS SHARPENED BY DIFFERENT ELECTRICAL TECHNOLOGIES

TOMAS TRCKA, ALES POLZER, JOSEF SEDLAK
Keywords: tool geometry | temperature measurement | force loading | electrical technologies | PCD

Diamond materials are increasingly used in machining processes as a cutting material, due to their specific properties. Nowadays, is a natural diamond successively replaced by an man-made - synthetic diamond, what also increases their availability. The most used diamond material for milling operations is a synthetic polycrystalline diamond (PCD) produced by HPHT (high-pressure high-temperature) process, (…)