<p> 34th INTERNATIONAL CONFERENCE ON PRODUCTION ENGINEERING 28. - 30. September 2011, Niš, Serbia University of Niš, Faculty of Mechanical Engineering</p><p>APPLICATION OF THE COMPUTER AIDED SELECTION OF OPTIMAL CNC MILLING STRATEGY</p><p>Jozef NOVAK-MARCINCIN, Miroslav JANAK, Ludmila NOVAKOVA-MARCINCINOVA, Veronika FECOVA, Jozef BARNA Faculty of Manufacturing Technologies, Technical University of Kosice, Bayerova 1, Presov, Slovakia [email protected], [email protected], [email protected], [email protected]</p><p>Abstract: Goal of this paper is to describe manufacturing strategies used in 3D milling and possibilities to simplify the choice of manufacturing strategy, especially for inexperienced user. Main attention is directed to creation of simple software tool for optimization of suitable milling strategy selection, functional principles of this program and conditions related to its creation.</p><p>Key words: computer aid, milling strategies, software application, Delphi</p><p>1. INTRODUCTION MasterCAM, PowerMILL, ESPRIT, VX CAD/CAM and other. Currently in the field of CAD/CAM systems there is need of using such systems for improvement of production’s efficiency, production time shortening, simplification of production, saving of energies and materials and that also in implicated form of better exploitation of production devices and lesser tools consumption. This request of productivity improving concerns all the participants from the field of tool, automobile and aero-industry, producers of moulds and different parts of variable shapes in various usage areas. Optimization of suitable manufacturing strategy selection is important matter mainly for new and inexperienced users of CNC technique, for the acquirement of Fig.1. Milling strategies in different CAM systems knowledge about strategies and their importance and utilization of new software tools would present barrier These software systems concern milling in the scope of 2 from economical and time aspect. Simple but helpful – 5 axis machining. They offer section designing for software product should assist in faster decision about roughing, which is machining with goal of cutting as strategy fitness and produce positive impacts of this much material as possible considering additional material decision correctness. Further chapters consist briefing of for further operations. They also offer finishing, which computer aid of manufacturing strategies and creation means the process of removing residual material left on method of software which mitigates the selection of workpiece after some previous technology [1]. milling strategy. To main roughing strategies supported in CAD/CAM systems belongs: 2. CA MANUFACTURING STRATEGIES  raster milling – tool path is parallel with coordinate system axis, tool is moving upright with minimal There are a huge number of products offering computer steps, aid in different production spheres including  contour milling – tool path copies the contour of manufacturing strategies area. Common effort of these machined element, CAM systems is to simplify the work of NC programmer  profiling – tool path copies the contour of machined and to ensure the correctness of his decisions or even to element while keeps moving with defined steps, substitute his own decision by software process and so to  raster and profiling – combination of two previous ensure best possible milling efficiency. To most used strategies. CAD/CAM systems solving the problems of To finishing strategies offered in CAD/CAM systems manufacturing strategies currently belong: EdgeCAM, usually belongs [2]: Pro/ENGINEER, ProTOOLMAKER, CADDS, CAM-  projection milling – means projection of 2D TOOL, Catia, FeatureCAM, SurfCAM, Unigraphics, predefined motion to the model,  constant Z-hight milling – mill moves in certain hight  Output information section – space for quoting the while copying model’s contours, results of computations and final strategy selection.  corner milling – for removing the residual material For comparison, numerical values of results are shown after previous tool or in between two surfaces, for each strategy. Optimal variant will be highlighted.  nib milling – mill moves down the model continuously like a pen,  rotary milling – tool moves linear, workpiece rotates around its axis.</p><p>Radial Raster</p><p>Fig.3. User’s environment of software – a) geometry selection, b) input information, c) graphical information, d) output information section Spiral Box Program for its computation uses mathematical operations Fig.2. Projection strategies of finish cutting summarizing length of tool trajectory. When entering input data into the editable labels, it assigns them to In most software concerning manufacturing strategies NC relevant variables. Numerical dimensions of machined programmer has an option to choose suitable strategy, surface and tool diameter serves as limit borders decisive which would allow surface machining in shortest possible about stopping of tool motion. After pressing the time while preserving requested quality. However only COMPUTATION button program starts the procedures few programs select optimal strategy without choice that calculate the length of tool path for each strategy process of its user. according to input data received from user. Optimal solution presents the variant with lowest value of 3. SOFTWARE FOR OPTIMAL MILLING machining time criteria. STRATEGY SELECTION 4. CONCLUSION For creation of application we use program language Object Pascal and its visual implementation called From programmer point of view, application uses events Delphi. Every application created in Delphi is based on control of particular visual components – panels, edit components. They generate its design and executive fields, labeled edit fields, buttons, images. From the kernel. Most of necessary components are implied with an aspect of computation, main part of program code installation pack of Delphi, other can be created by user consists of cycles, that ensure computing determination in or downloaded from web [3]. case of reaching the borders of machined surface. Final Application should terminate optimal strategy after border contouring of machined element is added to result consideration of certain criteria such as machining time, in order to make the final faces and edges smooth. residual stresses volume and tool wear. To do so it will Slovak Ministry of Education supported this work, compare the output values of computations for each contract VEGA No. 1/0036/09, KEGA No. 047- strategy (length of absolved trajectory, number of 004TUKE-4/2010 and ITMS project code 26220220125. contours, etc). To perform these computations program needs input data given by user corresponding with cutting conditions. That concern tool diameter, feed rate, side motion and sizes of machined surface. User’s environment consists out of 4 main parts:  Geometry selection section – buttons for choice of machined surface type according to its geometrical characteristics.  Input information section – space for writing of cutting parameters related to suitable strategy REFERENCES selection. [1] CHANG, T. CH., WYSK, R. A., WANG, H. P.:  Graphical information section – visual information Computer-Aided Manufacturing. Prentice-Hall, New giving user a view of planned strategy and Yersey, 1998, 748 p. dimensions. [2] LEE, K.: Principles of CAD/CAM/CAE Systems. Addison-Wesley, Reading, 1998. [3] MARCINCIN, J. N., JANAK, M. (2009). Software support for selection of suitable milling strategy. Buletin Stiintific, Vol. 23, p. 119-122. </p>