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PROCEEDINGS IN MANUFACTURING SYSTEMS

ISSN 2343–7472

ISSN-L 2067–9238

 

 

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Journal

PROCEEDINGS

IN MANUFACTURING SYSTEMS

 

Volume 8, Issue 4,  2013

 

 

Contents

 

·         Florina CHISCOP, Catalina ENACHE, Marius CHISCOP, Cristian Eugen STOICA,

           Study for zero breakdowns and productivity increase

 

·         Florian LOTTERSBERGER, Norbert HAFNER, Dirk JODIN,

           Efficiency indicators for benchmark and improvement of energy efficiency on automated material flow systems

 

·         Corina CONSTANTIN, George CONSTANTIN

           Empirical model of the cutting forces in milling

 

·         Josef SEDLÁK, Zuzana FIŠEROVÁ, Josef CHLADIL, Oskar ZEMČÍK, Jiří DVOŘÁČEK,

           The influence of lubricants on the durability of roller bearings

 

·         Nicolae BOIAN, Marioara Adriana BOIAN,

           The diagnosis of financial resources of small and midle size enterprises (SME)

 

·         Anişoara CORĂBIERU, Ştefan VELICU, Petrică CORĂBIERU, Dan Dragoş VASILESCU,

           Researches on the superficial layers modified of the vehicles parts and component parts, by combined processing in liquid and solid phase

 

·         Tiberiu DOBRESCU, Nicoleta Elisabeta PASCU, Aurel Florin ARION,

           Improving the slicing process characteristic parameters

 

·         Sorin Mihai CROITORU, Adrian Ion PACIOGA,

           Testing titanium implants             

 

·         Matúš KOŠINÁR, Ivan KURIC, Cristina MOHORA,

           Innovative method for measurement of geometric accuracy of machine tool 

 

·         Emil UDUP, Claudiu-Florinel BÎŞU, Miron ZAPCIU,

           Numerical evaluation of radial deformation of main spindle bearings

 

 

pp. 193-198

 

STUDY FOR ZERO BREAKDOWNS AND PRODUCTIVITY INCREASE

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Florina CHISCOP1,*, Catalina ENACHE2, Marius CHISCOP3, Cristian Eugen STOICA4

1) PhD, Lecturer, Department of Machines and Manufacturing Systems, University “POLITEHNICA” of Bucharest, Romania

2) PhD Student, Assistant, Department of Engineering Graphics and Industrial Design, University “POLITEHNICA” of Bucharest, Romania

3) Student, Department of Machines and Manufacturing Systems, University “POLITEHNICA” of Bucharest, Romania

4) PhD Student, Department of Machines and Manufacturing Systems, University “POLITEHNICA” of Bucharest, Romania

Abstract: Ensuring a rational production structure and design should be a priority for anyone starting a manufacturing architecture. This action can take place in two different periods of time: when designing the manufacturing architecture or when the manufacturing architecture is functional depending on products range, manufacturing technologies, production or labour organization. The main focus of this paper is to optimise an assembly manufacturing architecture with the purpose of productivity increase. The optimisation process is carried out on a vertical refrigerators assembly line from ARCTIC Company. Our case study is based on identifying and eliminating mechanical breakdowns that occur in the assembly line and negatively influence the productivity rates. Another important factor we have to take into consideration is that all sub-components manufacturing architectures must be levelled as their productivity rates generate the assembly line productivity. Prior to optimisation process the entire system was monitored for several months as to determine the location, number and duration of breakdowns. A number of solutions were proposed, implemented and validated in order to reduce the breakdowns number and to achieve the main goal, assembly line productivity increase.

 

Key words: optimisation, assembly line, mechanical breakdowns, productivity, cycle time, redesign.

 

 

pp. 199-204

 

EFFICIENCY INDICATORS FOR BENCHMARK AND IMPROVEMENT

OF ENERGY EFFICIENCY ON AUTOMATED MATERIAL FLOW SYSTEMS

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Florian LOTTERSBERGER1,*, Norbert HAFNER2, Dirk JODIN3

1) DI, PhD candidate, TU Graz, Institute of Logistics Engineering ITL, Graz, Austria

2) Ass.-Prof. DI Dr.techn., workgroup leader, TU Graz, Institute of Logistics Engineering ITL, Graz, Austria

3) Univ.-Prof. Dr.-Ing. habil., head of ITL, TU Graz, Institute of Logistics Engineering ITL, Graz, Austria

Abstract: Rising energy costs as well as ecological goals put energy efficiency on a significant level of interest in most industries. Industrial Logistics operates a huge number of devices and is characterized by high over all energy consumption. Therefore, contemporary industrial applications require solutions, which are (re)designed for high energy efficiency. Currently no general guidelines or standards exist regarding how energy efficiency is represented in relation to logistic output. The paper presents the basis for a benchmark system for energy efficiency of automated in-plant systems. Through the use of Energy Efficiency Indicators (EEI), efficiency is becoming quantifiable. Comparisons and optimization tasks on systems can be worked out and evaluated. The focus here is on conveyor systems for unit loads as they are commonly used for the transportation of goods in typical logistics applications. The common structures and basic operation functions of material flow technology are explained. Starting with a basic definition of energy efficiency, the mathematical derivation of Energy Efficiency Indicators is performed by the use of basic characteristics of conveyor systems. All process steps necessary for determining the energy efficiency indicators are described. Finally, the validity and clarity of the EEIs is verified by an application example.

Key words: energy efficiency, industrial logistics, green logistics, benchmark system, efficiency indicator, material flow system, conveyor system.

 

 

pp. 205-212

 

EMPIRICAL MODEL OF THE CUTTING FORCES IN MILLING

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Corina CONSTANTIN1, George CONSTANTIN2,*

1) Eng., PhD, Metallurgical Enterprise for Aeronautics METAV, Bucharest, Romania

2) PhD, Prof, Machine and Production Systems Department, University “Politehnica“ of Bucharest, Romania

Abstract: The paper deals with some aspects of modeling milling force as approach of the integration of multiple modeling in cutting, trying to bring some original aspects in the empirical approach. Within the experimental researches several experiments were conducted on the following types of materials: steel (OLC 45 improved), aluminium alloy (7178), grey cast iron, and titanium (purity 99%). The experimental research in milling with one tooth on 180ş were made on a vertical machining centre, FIRST MCV 300, with three axes, in the laboratory of Machine Tools of Machines and Manufacturing Systems Department, Engineering and Management of Technological Systems, University “Politechnica” of Bucharest. The main purpose of the work is to obtain functions of two variables (cutting depth ap and feed per tooth fz) for coefficients Kn and Kt (specific forces) by multiple regression. They are integrated in the tangential and normal forces Ft and Fn expressions. The corresponding diagrams of Kn and Kt based on the mathematical model are compared to those determined by experiments for the four materials studied. Some comparison charts for Fx and Fy measured and simulated using the mathematical model established are finally presented, resulting a good approximation. Several conclusions regarding modeling are drawn.

Key words: milling, milling cutter, specific cutting force components, tangential cutting force, normal cutting force, cutting force on axis, measured force, simulated force, comparison.

 

 

pp. 213-220

 

THE INFLUENCE OF LUBRICANTS ON THE DURABILITY OF ROLLER BEARINGS

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Josef SEDLÁK 1,*, Zuzana FIŠEROVÁ2, Josef CHLADIL 3, Oskar ZEMČÍK 4, Jiří DVOŘÁČEK 5

1) Eng., Ph.D., Lecturer, Faculty of Mechanical Engineering, Institute of Manufacturing Technology, Brno, Czech Republic

2) Eng., Ph.D. Student, Faculty of Mechanical Engineering, Institute of Manufacturing Technology, Brno, Czech Republic

3) Eng., PhD., Lecturer, Faculty of Mechanical Engineering, Institute of Manufacturing Technology, Brno, Czech Republic

4) Eng., Ph.D., Lecturer, Faculty of Mechanical Engineering, Institute of Manufacturing Technology, Brno, Czech Republic

5) Eng., Lecturer, Faculty of Mechanical Engineering, Institute of Machine and Industrial Design, Brno, Czech Republic

Abstract: The paper describes the determination of various factors lubricants that affect the durability of rolling bearings or general rolling contact. Their knowledge is a prerequisite for use in calculating the life of roller bearings from two perspectives. Above all, it will be possible to determine more accurately the durability of rolling bearings or rolling contact with all the economic consequences. The deepening of this information will enable purposeful and controlled increase of rolling bearing durability. Developing a reliable calculation of the life and durability of roller bearings or other machine nodes with rolling contact is a long-term global problem that has recently received considerable attention. The need for more accurate calculations with respect to operating conditions and desired reliability of machinery and equipment is enforced by constant rapid pace of development of most industries as well as engineering. In this situation it is necessary to give designers such calculation methods and materials that enable optimal use of the properties of roller bearings in rotating systems of machinery and equipment.

Key words: lubricant, durability, lifetime, reliability, roller bearing.

 

 

pp. 221-226

 

THE DIAGNOSIS OF FINANCIAL RESOURCES OF SMALL AND MIDLE SIZE ENTERPRISES (SME)

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Nicolae BOIAN1,*, Marioara Adriana BOIAN2

1) PhD, Lecturer, department of Engineering Technology and  Industrial Management, University “Transilvania”, Brasov, Romania

2) Head of financial accounting department, Financial Investment Company “Transilvania” SA, Brasov, Romania

Abstract: The paper presents a method of diagnosing financial resources as part of small enterprise resources analysis. Starting from general knowledge regarding financial resources, its diagnose objectives and specific demand for small and middle size enterprises, the paper synthesizes a model to be used in diagnose analysis process. According to this model, we establish a specific method of evaluation for the two criteria: profitability-liquidity and security-risk. For each of these we present the tables with the financial indicators. A scoring evaluation method is associated to this diagnose model in order to facilitate setting the business level in accordance to financial resources criterion. The score function with variables, coefficients and the main coordinates of their choice is also presented. Following the diagnose score, the business level is established and few methods to improve are suggested. Finally, the paper presents a case study of a company in the field of tourism. We assessed the business rate and setting the main conclusions following diagnose. We added the tables containing values of indicators for the two criteria and also the justification for the choice of coefficients significance and the conventional score assigned for each domain of analysis.

The main conclusions regarding the case study are closing the paper.

Key words: financial resources, diagnosis analysis, profitability, liquidity, security, risk.

 

 

pp. 227-232

 

Researches on the superficial layers modified of the vehicles parts and

component parts, by combined processing in liquid and solid phase

 View full text

Anişoara CORĂBIERU 1, Ştefan VELICU 2,*, Petrică CORĂBIERU 3, Dan Dragoş VASILESCU 3

1) Lecturer., PhD, Technical University "Gheorghe Asachi" of Iasi, Romania

2) Prof., PhD, Polytechnic University of Bucharest, Romania

3) Scientific Researcher II, SC Procomimpex of Iasi, Romania

Abstract: The paper presents the technological aspects of processing combined liquid and solid phase. Combined treatment goal is to get parts and automotive components by surface modified. Technological aspects analyzed include: the technological principle, experimental process flow analysis, interpretation of preliminary results. Novelty consists in obtaining superficial hardened layers of the vehicles parts by the implementation of the processing technologies combined liquid and solid having the following main phases: Phase 1 –superficial micro-alloying directly in the liquid phase, achieved by the interaction of the liquid steel with the layers deposited on the mould walls. The successive layers deposited  on the mould walls have been obtained using a paste having as base the hardening mixture with the composition of 40% metallic powders and 60% carburizing powders; Phase 2 –hardening thermal processing id made in an induction heating installation using treatment cycle-diagrams previously established depending on the base material of the vehicle part and on the composition and structure of the superficial layers obtained following the superficial micro-alloying directly in the liquid. Phase 3 – final heat treatment, using a variant depending on the chemical composition of the base material (vehicle part core), composition and structure of the superficial layers and the real stress and service conditions of the vehicle part.

Key words: researches, superficial layers, combined processing.

 

 

pp. 233-238

 

IMPROVING THE SLICING PROCESS CHARACTERISTIC PARAMETERS
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Tiberiu DOBRESCU1,*, Nicoleta Elisabeta PASCU2, Aurel Florin ARION3

1) Assoc. Prof., PhD, Machine and Manufacturing Systems Dpt., University “Politehnica” of Bucharest, Romania

2) Lecturer, PhD, Engineering Graphics and Industrial Design Dpt., University “Politehnica” of Bucharest, Romania

3) Assistant Prof., Engineering Graphics and Industrial Design Dpt., University Politehnica” of Bucharest, Romania

Abstract: Although improvements in wafering techniques have produced great saving in device manufacture, further advances in both wafer productivity and quality can be achieved by a systems approach to the slicing operation. An ID blade is a bonded abrasive grinding wheel whitch cuts a deep, narrow slot in the material. In the case of cutting silicon wafers, the major objective are to make a perfectly stright cut, to remove material fast, and to minimize subsurface wafer damage. With impetus from the semiconductor industry, the I.D. diamond saw blade was developed to reduce kerf losses when slicing these expensive material.  This paper presents experimental results obtained to optimize the characteristic parameters of the slicing process of hard and brittle materials (silicon, germanium, ceramic a.s.o.) used in the electronics industry. Experimental data are used to optimize the slicing process of brittle materials (silicon, germanium, ceramic, a.s.o.) to obtain some wafers of high shape and dimensional accuracy such as the resulting wafers require a shorter processing time through the super- finishing process.

Key words: slicing, I.D. cutting, I.D. diamond wheels, silicon wafer, productivity, quality.

 

 

pp. 239-244

 

TESTING TITANIUM IMPLANTS

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Sorin Mihai CROITORU1,*, Adrian Ion PACIOGA2

1) Assoc. Prof., PhD, Machines and Manufacturing Systems Dept., University “Politehnica” of Bucharest, Romania

1) Senior Researcher, National Institute for Research and Development in Mechatronics and Measurement Technique of Bucharest, Romania

Abstract: Dental and orthopaedic implants are supposed to be tested from medical and/or engineering points of view. This paper presents some engineering experimental research the authors made, related to titanium implants produced by the Romanian manufacturer of dental implants, Tehnomed Impex Co S.A. and the National Institute for Research and Development in Mechatronics and Measurement Technique of Bucharest (orthopaedic implants). Part of the experimental research was performed in the framework of a research contract financed by Romanian Ministry of Research and Education. The tests related to torsion resistance after chemical treatment of the implant were performed in order to see if the implant has the same (or at least enough) resistance even if its wall thickness is diminished after chemical treatment and its surface’s micro geometry is modified. In this case the implants have enough resistance compared to the non treated implants, but the micro geometry has lower quality because of the chemical attack. Tests related to the crystallographic structure of the implant’s material compared the methods of obtaining the implant: rolled bar and rapid prototyping laser sintered bar. In this case the rapid prototyping laser sintered implant has a more compact crystallographic structure, but the cost is greater.

Key words: titanium implant, torsion, crystallographic structure, rolled bar, rapid prototyping.

 

 

pp. 245-250

 

INNOVATIVE METHOD FOR MEASUREMENT OF GEOMETRIC ACCURACY OF MACHINE TOOL
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Matúš KOŠINÁR1,*, Ivan KURIC2, Cristina MOHORA3

1) Eng., PhD Researcher, Department of Automation and Production Systems, University of Žilina, Žilina, Slovak Republic

2) Prof., PhD, Head of department, Department of Automation and Production Systems, University of Žilina, Žilina, Slovak Republic

3) Prof., PhD,  Department Machines and Production Systems, University “Politehnica” of Bucharest, Bucharest, Romania

Abstract: The paper presents an innovative method of data processing with the measurement device – Ballbar QC20W. The program for data transformation was created in Visual Basic.NET and it uses Fourier transformation for spectral analysis of measured profile. The paper presents the measuring method of CNC machine tools using Ballbar QC20W. There is a strong connection between the qualitative parameters of machine tools and the qualitative ones of the products (tolerances, roughness, etc.). It is very important to hold the stability of qualitative parameters of products as a key factor of production quality. The accuracy machine tools evaluation and prediction are of high interest and therefore is also importance to evaluate the accuracy of machine tools and make prediction of possible accuracy. How to detect the accuracy of CNC machine tools, various industries are becoming the user acceptance and maintenance of CNC machine tools much attention to problems. The paper deals about aspects of diagnostic accuracies CNC machine tool as well as with the possibilities of measuring methods and CNC machine tools using multi-parametric diagnostics. Main part evaluates possibility the geometric accuracy of CNC machine tool by specialize developed software’s for compared with a direct (Ballbar QC20) and indirect (Talyrond73) method of measurements.

Key words: Ballbar QC20-W, geometric accuracy, data transformation, direct measurement method.

 

 

pp. 251-256

 

NUMERICAL EVALUATION OF RADIAL DEFORMATION OF MAIN SPINDLE BEARINGS

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Emil UDUP1, Claudiu-Florinel BÎŞU2,*, Miron ZAPCIU2

1)Institute National of Physics and Nuclear Engineering - Horia Hulubei, Magurele, Ilfov, Romania

2)Lecturer,  PhD, Machines and Systems of Production Department, University Politehnica of Bucharest, Bucharest, Romania

3)  Professor,  PhD, Machines and Systems of Production Department, University Politehnica of Bucharest, Bucharest, Romania

Abstract: The paper presents a study on the heat generated by the bearings of a certain type of main spindle assembly, along with the influence of the generated temperature on the Z-Y radial deformations employing numerical simulations as per the finite element method. Moreover, the mentioned numerical simulations have also been subsequently extended to the spindle assembly outfitted with a cooling system on the ball bearing location under the housing. The maximum temperature recorded by numerical simulations on the rear bearing was 51.2 şC while the temperature on the front bearing was 48.7 şC. After having inserted the cooling system, the on the rear bearing temperature decreased to 20.4şC and on the front bearing the temperature decreased to 23.4 şC. Besides, the radial deformation caused by the increase of temperature was 3 µm at a maximum temperature of 23.4 şC, and on the rear bearings it was 3.4 µm at a maximum temperature of 20.4 0C.

Key words: spindle, bearings, thermal distribution, radial deformation, radial clearance.

 

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