This paper presents the major cutting knowledge, the opinion data and the results of actual theoretic parameters solutions and the current results, estimated by contemporary needs of hydro abrasive cutting technology. Here is a newly opened and discussed question of current data terminology disunity in the area of metrology topography surfaces of cutting walls created by abrasive waterjet.U radu su prezentirana temeljna znanja, razmišljanja i rezultati teorijskih rješenja vezano uz trenutne procijenjene suvremene potrebe za hidroabrazivnom tehnologijom rezanja. Ovdje je i ponovo otvoreno pitanje trenutne terminologije u području mjeriteljstva topografi je površina dobivenih rezanjem abrazivnim vodenim mlazom

D. Kozak

I. Samardžić

J. Valíček

M. Kušnerová

S. Hloch

HRČAK - Portal of Croatian Scientific and Professional Journals

125METALURGIJA 51 (2012) 1, 125-128S. HLOCH, J. VALÍČEK, I. SAMARDŽIĆ, D. KOZAK, M. KUŠNEROVÁCLASSIFICATION OF TECHNICAL MATERIALS ACCORDING TO CLASSES MACHINABILITY FOR HYDROABRASIVE CUTTING Received – Prispjelo: 2011-01-28Accepted – Prihvaćeno: 2011-04-18Review Paper – Pregledni radISSN 0543-5846METABK 51(1) 125-128 (2012)UDC – UDK 621.96:621.7:620.1.001.3=111This paper presents the major cutting knowledge, the opinion data and the results of actual theoretic parameters solutions and the current results, estimated by contemporary needs of hydro abrasive cutting technology. Here is a newly opened and discussed question of current data terminology disunity in the area of metrology topography surfaces of cutting walls created by abrasive waterjet.Key words: hydroabrasive cutting, machinability, divisibility, classifi cation categories of materialsKlasifi kacija tehničkih materijala prema klasama obradivosti kod hidroabrazivnog rezanja. U radu su prezenti-rana temeljna znanja, razmišljanja i rezultati teorijskih rješenja vezano uz trenutne procijenjene suvremene potrebe za hidroabrazivnom tehnologijom rezanja. Ovdje je i ponovo otvoreno pitanje trenutne terminologije u području mjeriteljstva topografi je površina dobivenih rezanjem abrazivnim vodenim mlazom.Ključne riječi: hidroabrazivno rezanje, obradivost, djeljivost, klasifi kacijske kategorije materijalaINTRODUCTIONAt the present time, requirements on increase of cut-ting materials production by high strongholds and hard-ness (e.g. titanium, nickel, composite materials, etc.) continuously grow. Conventional methods of cutting are not always technically and economically acceptable for cutting these materials, therefore new so - called „unconventional” cutting methods get more popular. These unconventional methods of cutting are imple-mented particularly when classical methods are less ef-fective, or when they totally fail. They benefi t all sorts of physical principles how to shape material (e.g. chem-ical, electrochemical, mechanical, etc.). One of these unconventional methods is also abrasive waterjet cut-ting (AWJ), especially high - speed liquid jet with addi-tive of strong abrasive materials. The high speed of fl owing out waters with additive of abrasive makes it possible to shape intensively, economically and at the same time ecologically wide spectrum of industrial ma-terials from paper, paste - board, wood, plastic, cork, building matters and rocks to metals and their alloys. These are highly actual technologies due to its univer-sality, environmental economy and safety within ma-chining industry. While the technology of a proper cut-ting by AWJ is already hardware also software based, except specifi c cases, there is still a technical issue with the way of a quality verifi cation of a machined surface of continual drive at production. S. Hloch, J. Valíček, M. Kušnerová, Faculty of Manufacturing Technolo-gies TU Košice with a seat in Prešovi, Slovakia,  I. Samardžić, D. Kozak, Mechanical Engineering Faculty J. J. Strossmayer University of Osijek, Slavonski Brod, CroatiaRELATED WORKS The cutting process of technology AWJ is the hy-droabrasive disintegrative process caused by the stren-gth, the tension and the deformation effect of cutting tools on work material. The tool is the high - speed fl ow of water and the abrasive mixture. The result of the process cutting is the dividing cut. The mechanism of outer and inner reactionary physical- mechanical fac-tors is developed by cutting tool that reaches the bal-ance. This balance is displayed by the three-dimension-al topographical function of surface state of cutting walls generated in the cutting level. It is dividing or a cutting tool with somewhat different mechanical fea-tures, than are dividing, cutting, shaping or drilling tools in classical engineering or other spheres. This cutting tool is fl exible not solid, therefore the trajectory of its dividing cutting trace changes quickly in critical mo-ments of interaction with material. The abrasive defor-mation process of AWJ stream is in principle given by the elemental action of abrasive particles. The principle of the strength effect is in impact speed at contact with surface of cutting front in level of the contact angle. It is about the interaction between the effective AWJ stream fi eld and instantaneously geometric proportions of sur-face interactive stressed spot of material in the cutting level by the AWJ stream fi eld. The reversed reaction of material causes changes in the process of cutting, changes original material parameters and initial param-eters change AWJ stream fi eld. The cutting of material by AWJ technology is specifi ed by a typical curvature and delay of cut trace behind nozzle at its deepening. The physical mechanical and strain-tension characteris-126  METALURGIJA 51 (2012) 1, 125-128S. HLOCH et al.: CLASSIFICATION OF TECHNICAL MATERIALS ACCORDING TO CLASSES MACHINABILITY ...tics of material of workpiece determine the intensity of reactionary forces and characterize, or sort every mate-rial to the group of its hydroabrasive divisibility by AWJ stream. To date a general opinion dominates about the physical- mechanical complication of the cutting proc-ess also its analytical solution, i. e. about complication of a defi nite physical - mathematical description in its simultaneous functions regarding segmentation of the whole set of technical, technological and material pa-rameters that enter the process. Procedural functions of these parameters are mutually blended and they infl u-ence each other. At the same time their partial effects may developed or interfere on the contrary. Apart from that value of the parameters are not constant, but change in different ways in time. From analytical point of view a generally accepted opinion dominates about compli-cacy of analytical solution and especially such solution that would be simply and effectively applicable in prac-tice. This opinion confi rms to date the reality of the in-suffi cient theoretic mastered of cutting disintegration mechanism of material by the forces abrasive effect.PROBLEM DEFINITIONOn the basis of historical study and contemporary development of the technology AWJ in theory, experi-ments and practice we know, agreeable with opinion contemporary authors [1-19], that the problems of the physical- mechanical disintegration materials principle and production of new surface by hydroabrasive cutting stays also today live that is why till this time open. Ac-cording to mechanical properties of divided material it happens only to shift in - depth levels of these zone characterized by identical elements of a topography sur-face. Identical values of ratios introduced of geometric quantities correspond then identical values zoned dis-tributed of mechanical and strain-tension quantities.If it is necessary to study these patterns to disposal the samples that are high e.g. only 8 mm for all investi-gate materials, it is impossible in a simple way to com-pare the results of measurement, because at soft materi-als all over high sample moved in the elastic zone of loading, but on the contrary at solid material it is al-ready moved e.g. from 4 mm depths in the plastic zone. The in-depth limits of transition from the elastic to the plastic zone is e.g . for solid Cor-Ten steel CSN 13 242 with modulus fl exibility in traction Estalemate = 220 GPa naked 5,4 mm, while for clean aluminium Al with modulus fl exibility E = 72 GPa result from this limits by prediction calculation as far as on 52,1 mm depths of cut. It is possible to fi nd on these zonal levels then iden-tical conditions for both materials among geometric also strain-tension parameters. The in-depth position of transition from the elastic to the plastic zones is never-theless infl uenced in given material domineering by choice of technological parameters of support: 1.  analytical encompassment of patterns of values zonal distribution of geometric and strain-tension parameters is a condition for prediction of compu-tational equations, that are important in fi nal con-sequence not only for choice of technology, but also for automated control of the shaping process. The reasons to simultaneous data generally con-fessing insuffi cient level present of knowledge it is possible in fi ne frame to the next points: inade-quate respect of the material physical- mechanical parameters of samples with their uniform of math-ematical formulation absence,2.  inadequate respect of the physical- mechanical parameters of AWJ stream as cutting tool with uniform of mathematical description absence,3.  inadequate respect of the physical - mechanical, respective system tension-deformation integrity: the technological parameters - the tool - the mate-rial - the topography of surface,4.  insuffi cient exploitation – of patterns study of dis-tribution and the zonality geometric parameters of surface by a hydroabrasive process of generated cutting walls,5.  the absence of enough generalized theoretic pre-diction limit reached depths in different materi-als,6.  the total factionalism of results from different ex-perimental workplaces and thereby given to their bad mutual correlate,7.  the low level of results generalization reached on different workplaces,8.  till this time it is not to elaborate some uniform nomenclature of technological and metrology conceptions,9.  serious absence is the absence of uniform material technological classifi cation according to their di-visibility of hydroabrasive technology.MATERIAL MACHINABILITY At solution of material deformability and instanta-neous state of the cutting wall in cut on principle it is possible to go out from the integrity of system: the tech-nological parameters - the tool - the material - the sur-face topography and from determine parameters of geo-metric elements, that are measurable on surface of fi nal wall of dividing cut. In dividing cuts realized by hydroabrasive tool the loading and disintegration conditions are essentially different comparing to the stress on material in labora-tory conditions. Laboratory and analytical investigation and description of a deformational process in dividing, or cutting trace, or slot requires development and utili-zation specifi c progress. The principle is a deduction and formulation of technological and mechanical pa-rameters of materials, which are physically what tightly fi xed to specifi cation of desintegrative mechanism of the process itself. Subsequently then to analytically dis-close and describe patterns by which physical - me-chanical alterations of these parameters are adhered 127METALURGIJA 51 (2012) 1, 125-128S. HLOCH et al.: CLASSIFICATION OF TECHNICAL MATERIALS ACCORDING TO CLASSES MACHINABILITY ...whether by deepening of hydroabrasive cut, or by changes of some of the main technological parameters.While laboratory measurement of basic mechanical and also technological parameters of technical materials is provided in line with strict norms in order to match results and reproducibility, the normative for an AWJ technology is likewise late. Therefore it is possible only with diffi culties though to compare and generalize the results published by various laboratories. For personal experimentation it is therefore necessary to choose a referential technology, namely for hydroabrasive divid-ing, as well as for measurement and evaluation of sur-face geometry dividing walls. In order to statistically analyse likewise resulting values to deposit and process in the form of data bank data [18], there has not yet been provided any technological classifi cation of technical materials by categories of divisibility by hydroabrasive tool and thus it is still a serious issue. Therefore within this study, it can be suggested, the technological classi-fi cation of materials to the divisibility categories Tcut, whereas Tcut is decimal logarithm of Young‘s modulus of material fl exibility. Numeric value of hydroabrasive machine ability Tcut = log (Emat) divides whole spec-trum of technical materials on Tcut 1 – Tcut 6 classifi ca-tory class. The hydroabrasive divisibility is therefore likely to be defi ned as technological nature of a material expressing a level of its resistance against desintegra-tive forces generated in cut by high - speed streaming of AWJ according to decade logarithm modulus of fl exi-bility material in traction Emat (Figure 1). The materi-als with biggest resistance against abrasive cutting forc-es developed by a stream of AWJ are classifi ed within categories Tcut 5,5 as far as Tcut 6 (diamond, technical ceramics, sailcloth). By contrast materials with the smallest resistance are classifi ed within the classes Tcut 1 as far as Tcut 2 (elastomers, polymers, cork). Because of extremely high values of modulus fl exibility, strong-holds and hardness of materials from the class Tcut 5,5 to Tcut 6, it is possible to talk about divisibility of these materials by the help of AWJ only theoretically, because their mechanical parameters already exceed the values by mechanical parameters of industrial abrasive used nowadays. Garnet and olivine are ranged at the level of steel to the categories from Tcut 5 to Tcut 5,5. Classifi -cation chart on fi gure 1 is useful for schematic view of sorting the materials into groups to the divisibility cat-egories. For a practical use by a technologist it is pos-sible to provide a detailed classifi cation of technical materials in a table format, whereas every category in the table can classify other technological properties, which are important and characteristic for the specifi c category considering a projection.CONCLUSIONSIn this study there were analysed piece of knowl-edge about production of a dividing cut, opinion data and results of present theoretic solution parameters of cut to the critical estimation of current levels of results from the contemporary needs of hydroabrasive dividing technology point of view. A question of current data ter-minology division in the area of metrology of surfaces topography cutting walls created by abrasive water jet is discussed here as well. Proposing a category of mate-rials divisibility is a very important technological indi-cator. A defi nition of classifi cation categories Tcut is based on the relation to the one of the most important mechanical parameters of materials of Young‘s modu-lus fl exibility Emat, therefore the classifi cation material class is functionally fi xed to the values of cutting resist-ances, cutting speed and to characteristics of reduction. Classifi cation of technical materials in line with catego-ries of hydroabrasive divisibility Tcut has therefore a great meaning practically for the fi rst orientation of the technologist within choosing the main technological parameters of working regime.REFERENCES[1] Hashish, M.: Modeling Study of Metal Cutting with Abra-sive Waterjets. Trans. of the ASME, Journal of Eng. Mat&Tech, 106(1984)1, 88-100[2] Hashish, M.: Pressure Effect in Abrasive – Waterjet (AWJ) Machining. Trans. of the ASME, Journal of Eng. Mat&Tech., 111(1989)7, 221-228[3] Guo, N. S.: Schneidprozess und Schnittqualität beim Was-serabrasiusstrahl – schneiden. VDI Verlag, 1994[4] Zeng, J., Kim, T. J.: A study of brittle erosion mechanism appleid to abrasive waterjet processes. Proc. 10th Int. Symp. on Jet Cutting Technology, BHRA, England, 1990[5] Vašek, J., Martinec, P., Foldyna, J., Sitek, L., Ščučka,J.: Abrasives for AWJ cutting. Academy of Sciences, Ostrava, 2002[6] Blickwedel, H., Guo, N.S., Haferkamp, H., Louis, H.: Pre-diction of abrasive jet cutting ffeciency and quality. Proc. 10th Int. Symp. on Jet Cutting Technology, BHRA, Fluid Engineering Centre, Cranfi eld, UK, 1990[7] Lebar, A., Junkar, M. Surface evaluation methods for ad-vanced AWJ cutting techniques. In. Manufacturing sys-tems (Aachen), 31(2001)2, 101-103. log (Young`s modulus), log(Emat) / MPaDivisibility categories of materials, Tcut / -65432101 2 3 4 5 6elastomerscork+polymeric foampolymerswood softwood hardfibreglassesporous ceramicscements+betons rock+mineralssteelsgarnets+olivinesglasssandwich.folderalloys and castTechnical ceramicsdiamondFigure 1  Distribution of technical materials to the divisibility categories Tcut.128  METALURGIJA 51 (2012) 1, 125-128S. HLOCH et al.: CLASSIFICATION OF TECHNICAL MATERIALS ACCORDING TO CLASSES MACHINABILITY ...[8] Brandt, S., Maros, Z., Monno, M.: AWJ parameters selec-tion – a technical and economical evaluation. Jetting Tech-nology, BHR Group, 2000[9] Burnham, C. D., Kim, T. J.: Statistical characterization of surface fi nish produced by a  high pressure abrasive wate-rjet. Proc. 5th American Water Jet Conference, Toronto, Canada, 1989[10] Singh, J.P., Khen, W.L., Munoz, J.: Comprehensive Eva-luation, of Abrasive Waterjet Cut Surface Quality. Proc. 6th American Water Jet Conference, Houston, Texas, WTJA, 1991[11] Agus, M., Bortolussi, A., Careddu, N., Ciccu, R., Grosso, B.: Optimization of abrasive – workpiece machinig. Jet-ting Technology, BHR Group, 2000[12] Yong, Z., Kovacevic, R.: Modeling of 3D abrasive waterjet machining part 4 - simulation of machining. Jetting tech-nology, BHR Group, 1996[13] Barenbrock, D., Louis, H., Tschimmel, J.: Novel three – dimensional parameters for description of modifi cations of sheet metal surfaces during forming processes. ICM88, Victoria, Canada, May 1999[14] Valíček, J., Hloch, S., Držík, M., Ohlídal, M., Mádr, V., Lupták, M., Radvanská, A.: An investigation of surfaces generated by abrasive waterjet using optical detection. In. Strojniški vestnik - Journal of Mechanical Engineering. 0039-2480: 53, 2007. 224 - 323. ISSN 0039-2480.[15] Valíček J, Hloch S. Optical measurement of surface and topographical parameters investigation created by abrasive waterjet. In: International Journal of Surface Science and Engineering. 3(2009)4, 360-373. [16] Valíček J, Hloch S. Using the acoustic sound pressure level for quality prediction of surfaces created by abrasive wate-rjet. In: The International Journal of Advanced Manufactu-ring Technology. 48(2010)1-4, 193-203.[17] Valíček J, Hloch S, Kozak D. Surface geometric parame-ters proposal for the advanced control of abrasive waterjet technology. In: The International Journal of Advanced Ma-nufacturing Technology. 41(2009)3-4, 323-328. [18] Hloch S et al. Experimental study of surface topography created by abrasive waterjet cutting. In: Strojarstvo. 49(2008)4, 303-309.[19] Hloch S., Valíček J., Simkulet, V. Estimation of the smooth zone maximal depth at surfaces created by Abrasive Wate-rjet. International Journal of Surface Science and Enginee-ring. 3(2009)4, 347 - 359. AcknowledgementsThe work has been supported by projects GA ČR No. 101/09/0650, SGS No. SP/2011/78, MŠMT No. MSM6198910016, RMTVC No. CZ.1.05/2.1.00/01.0040. Thanks also to the Moravian-Silesian Region for fi nan-cial support and VEGA 1/0972/11. Note:  Responsible translator: Željka Rosandić, Faculty of Mechanical Engineering in Slavonski Brod, University of Osijek, Slavonski Brod, Croatia 

Klasifikacija tehničkih materijala prema klasama obradivosti kod hidroabrazivnog rezanja

Abstract

Similar works

Full text

Available Versions

HRČAK - Portal of Croatian Scientific and Professional Journals

Hrčak - Portal of scientific journals of Croatia