Automatic Obtaining of Engine Block in AutoCAD Environment

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Automatic Obtaining of Engine Block in AutoCAD Environment Sever Alexandru HABA, Gheorghe OANCEA Department of Manufacturing Engineering Transilvania University of Brasov B-dul Eroilor, No.29, Brasov ROMANIA [email protected]; [email protected] Abstract: This paper presents a software application used for block generating of an internal combustion engine based on a set of constructive parameters. The application runs in the AutoCAD environment and for the programming process it has been used OpenDCL and VisualLISP environments. After the process of generating the 3D model of the engine block in AutoCAD file is obtained. The software also can export the engine block model in a STL file that is a file format recognized by Rapid Prototyping machines. Key-Words: Engine block, 3D modelling, AutoCAD solids, Internal combustion engine, Rapid prototyping

1 Introduction The engine block is the basic structural element in an internal combustion engines. These types of engines are fitted to the motor vehicles such as cars, tractors, propelled technological equipment, mopeds, motorcycle, A.T.V., snowmobiles, etc. In terms of design, engine block and carcasses are treated as intended to take over the forces and moments which are generated during operation all powertrain[6]. The need to develop a software application like the one presented in this paper, is founded by current manufacturing methods that require real time implementing on production, in the shortest time, at reasonable prices, is a way of gaining market by industrial companies. This application is designed for a 4-stroke, single cylinder, air cooled engine block made from lightweight aluminium alloy that provides a good thermal regime and a considerable decrease in overall weight [3]. In the field of industrial graphics are commonly used CAD processors to ensure besides the accessible user interface, data processing to realize geometric phase of 3D product and manufacturing technology development for a family of parts [4].

2 Software presentation The software application named GENgine (Generate ENgine block) is written in AutoLISP programming language, and graphical user interface is obtained using GUI technique based on the dialog system boxes and on the buttons that trigger events with all options in front of user eyes. It is built in open dialog control language named OpenDCL [8] to carry out an easy dialogue in AutoCAD design environment. It was used VisualLISP and AutoLISP programming language, these, as part of

ISSN: 1792-4294

AutoCAD [7], allow developing sub-systems and functions that are used in graphical applications running under AutoCAD [5]. The application runs in versions of AutoCAD 2008, 2009 and 2010 in optimal conditions, based on the 3D core modelling commands of solids and a set of subroutines that pursues the optimization calculation for determining the contour generators and defining specific points for technological areas of the engine block. It can save the engine block model in files that can be used by Rapid Prototyping machines [1, 2].

2.1 The application block scheme The GENgine application is structured into four interconnected functional modules presented in the block scheme from figure 1. The INPUT DATA module ensures the introduction of geometrical and functional parameters and reads data from files memorised in *.TXT database (LOAD DATA FROM FILE option). ERROR CHECKING module verifies and removes the erroneous data, in case of error detection it shows the wrong parameter in a window. After checking the data set and saving it into the current AutoCAD drawing, the module can write data files on external data support. GRAPHIC PROCESSOR module performs 3D modelling of engine block. OUTPUT DATA module allows AutoCAD files saving (*.DWG files) and files writing for Rapid Prototyping machines (*. STL files).

2.2 GENgine dialog The user interaction is made via cascade dialog boxes that allow a quick entry and an easy modifying of input data.

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Latest Trends on Engineering Mechanics, Structures, Engineering Geology

Figure 2 presents the first window of application that contains the engine block in four spatial configurations.

INPUT DATA Top view - external parameters; - holes parameter; - main body parameters. Section view - main body parameters Air cooling fins parameters - geometrical tolerance; - roughness.

ERROR CHECKING

LOAD DATA FROM FILE (*.TXT files)

Pressing ENTER VALUES button, placed in the bottom of the window, displays the second window (see figure 3) that allows the introduction of geometrical parameters in parallel with an adequate engine block visualization (TOP VIEW). The user choosing LOAD DATA FROM FILE button can upload values for geometrical and quality parameters from a file previously saved. Pressing SHOW THE DIMENSION IN THE DRAW button the values from the fields are read and they are updated on dimensions in the preview drawing. In this way is made an easy visual inspection of entered data by the user. VALIDATE PARAMETERS button is used to run the error checking procedure for data entered. The data entry fields are not accessible at this time. In case of detection of an error, a message is displayed that informs the user on error occurred and error correction is allowed (input new data).

ERROR FORM (data are reinputted )

All input data are verified in this step. SAVE DATA TO FILE (*.TXT file)

GRAPHIC PROCESSOR In this step are generated the following entities: -external shape; -internal shape; -air cooling fins; -holes.

Fig. 2 First window of GENgine application

OUTPUT DATA

*.DWG files (AutoCAD)

3D model is processed *.STLfile (R.P.)

Fig. 1 Application block scheme

ISSN: 1792-4294

MODIFY PARAMETERS button is used for fields emptying in order to modify data entered by the user. Accessing the NEXT PAGE button allows moving to the next page, it is also possible the return of previous page (see figure 3) without losing the data entered in the current page. The parameters of engine block section in the third dialog box from the figure 4 are entered. They are: general and geometrical dimensions, tolerances, surface roughness and upper and lower deviations for each dimension.

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Fig. 3 Dialog box for top view

Fig. 4 Dialog box for section view

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VALIDATE PARAMETERS button launches the check routine to find out the erroneous data. These data are display into the dialog box from figure 5 and the user has the possibility to correct them.

Fig. 5 Dialog box for error checking

Fig. 7 Engine block generated with GENgine application

4 Conclusion The GENgine application is the core of a complex software system that will be used to manufacture engine blocks, applying part family concepts according to current trends in digital manufacturing. Future developments aim to achieve some other modules that will be included in the software system to design and manufacture parts from this family. Fig. 6 Dialog box for files saving SAVE DATA TO FILE button allows to create an AutoCAD file that contains the 3D engine block model into a location specified by the user. The file can be used later in the manufacturing design process of the engine block. GENERATE 3D SOLID button generates the 3D model associated to engine block, in three-dimensional AutoCAD space, using maximum precision that is required to generate from AutoCAD the STL file. The figure 6 presents the dialog box that is used to save the engine block model in DWG and STL format. STL format is used by Rapid Prototyping machines to manufacture the prototype of part.

3 Case study Using a data set existing in the construction of engine block 4-stroke engine single cylinder air cooled 550 cm3, and running the GENgine application, the result as 3D engine block model in the figure 7 is presented. Based on data entered into the fields of dialog boxes, using SAVE DATA TO FILE option a data file is created on disk. These data can be used later in the manufacturing process. It was also generated a STL file used for the prototype manufacturing on a Rapid Prototyping machine.

ISSN: 1792-4294

References: [1] Berce P., Chezan H., Rapid Manufacturing of Prototypes, Tehnical Press, Bucharest, Romania, 2000. [2] Grote, K.H., Beyer, C., Birke, C., Tenbusch, A., Advances in Integrating Rapid Prototyping and Three – Dimensional Digitizing into Design Methodology and Product Development Processes, Journal of Integrated Design and Process Science, Vol.5, No.2, 2001, pp 13-22. [3] Hieu, N., Manufacturing Processes and Engineering Materials used in Automotive Engine Blocks, http://claymore.engineer.gvsu.edu/~nguyen/egr250 (accessed on 21.04.2010). [4] Ivan M.C., Computer Aided Industrial Graphics, Transilvania University Press, Brasov, Romania, 2007. [5] Oancea, Gh., Computer Aided Parametrical design. VisualLISP/AutoLISP Presentation and Applications, Transilvania University Press, Brasov, Romania, 2003. [6] Pana C., Negurescu N., Popa M.G., Spark Ignition Engines-Process, Matrix Press Rom, Bucharest, Romania, 1995. [7] Yarwood, A., Introduction to AutoCAD2009, 2D and 3D Design, Elsevier, Oxford, UK, 2008. [8]***, Open DCL, http://www.opendcl.com/wordpress, (accessed on 04.05.2010).

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