Modeling of the PC MILL100 machine tool and milling process using DELMIA V5R17.

Anania, Florea Dorel ; Zapciu, Miron ; Mohora, Cristina 等

1. INTRODUCTION

The 3D modeling, simulation and optimization using the computer of the real systems based on the mathematical models, became a very useful research tool in many fields of human activities.

In the field of the mechanical engineering the Computer Aided Design--CAD has become an indispensable tool in the conception phase of the product. (Ghionea & Anania 2002)

Since the age of the Industrial Revolution, the manufacturing process has undergone many dramatic changes. One of the most dramatic of these changes is the introduction of Computer Aided Manufacturing (CAM), a system of using computer technology to assist the manufacturing process.

Through the use of CAM, a factory can become highly automated, through systems such as real-time control and robotics. (Ispas et al., 2006) A CAM system usually seeks to control the production process through varying degrees of automation. Because each of the many manufacturing processes in a CAM system is computer controlled, a high degree of precision can be achieved that is not possible with a human interface.

The CAM system, for example, sets the toolpath and executes precision machine operations based on the imported design.(Ispas et al., 2008)

Computer Aided Manufacturing is commonly linked to Computer Aided Design (CAD) systems. The resulting integrated CAD/CAM system then takes the computer-generated design, and feeds it directly into the manufacturing system;(Ispas et al., 2004) the design is then converted into multiple computer-controlled processes, such as drilling or milling.

2. MILLING PROCESS SIMULATION AND NC FILE GENERATION

The complex CAD/CAM software allow to generate an NC file based on the simulation of the cutting process up to 5 axis CNC.

In Delmia V5R17 the CAM moduls offers some important advantage in order to obtain an optimum NC program. It could operate with tools and tools library (Ispas et al., 2007).

A flexible administration of the programs, based on a simple and intuitive interface, is also one of its main characteristics.

The most important feature is that DELMIA allowed a powerful interaction between tool trajectory, verification and optimization.

We generate a 3 axis milling CAM process in order to generate the NC program for a piece shown in figure 1.

To create a CAM model, the 3D design of the pieces has to be modified according with the manufacturing process demands. (Ispas et al., 2007) There must be created some additional contours, plane and point in order to define all the CAM parameters.

In DELMIA--prismatic machining it has to define the workpieces, the pieces, the references, the tool parameters, the type of the machine tool etc (fig.2).

For each type of opertaion there have to be selected some surfaces or conturs in order to define the machining area and all the machining parameters (ex. Speed, cutting depth, etc).

From the optimisation point of view the main advantage in Delmia V5R17 is the freedom to choose and modifies the tool trajectory (fig.3depending on the cutting process (roughing, finishing etc), the material, and the quality of the surfaces. After all the parameters have been defined the NC file can be generated. For this it has to be assigned in DELMIA the NC postprocessor, specific to the machine tool command (ex. for PC MILL 100 SINUMERIK 810).

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3 MODELING THE PART AND KINEMTICS OF THE PCMILL100 MACHINE TOOL

The next step into complex milling simulation is to define the virtual machine tool with all the characteristics (dimensional and functional).

In DELMIA you must have all the parts of the machine defined as 3D model. It is not necessary to define all the machine tool components (as kinematic chaine or bearings), but these have to be define all the parts (as forms and dimensions) from the workspace and their relative position as accurate as possible. The machine tool functional parameters (domaine of speeds curses on each axis) also have to be highly defined.

The specifications of the PC MILL100 are: dimension of the machine tool: Lxlxh - 1730x875x1892 m; the workspace: X x Y x Z -185x100x100; the main spindel speed--60-5000 rot/min; linear speed 0-3000 mm/min.

Function of this specification the PC MILL100 machine tool has been defined in DELMIA (fig.4) All the structural parts as column, turret head, machine bed and machine table were highly designed. Also the workpiece mount point and the tool mount point were accurately defined.

The kinematics of the linear axis was defined as translation joints of the structural parts, according to the machine workspace.

The clamping device can be modeled as a part of the machine tool or separatly. In practice, the clamping devices are specific to the workpiece and/or pieces which have to be machined. For PC MILL 100 it was designed separately (fig.5).

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4 MILLING PROCESS ON THE VIRTUAL AND REAL PCMILL 100 MACHINE TOOL

In order to obtain a simulation of the real conditions which appear on the machine tools it is necessary to go trough the following steps: upload the necessary elements for machining (machine tool, tool, the clamping device, the workpiece and the part); positioning of the parts on the machine table--the setting in position--figure 6; create or uploading the software already modified by using Post processor software; making necessary adjustments for simulation; setting up the collision detection.

This setting in position has a special importance, if the setting in position is realized with different errors, the machining simulation will be realized incorrectly.

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If the simulation results are satisfying, the CNC program is generated based on the choosen post procesor (fig.7).

The NC code was uploaded on the PCMILL100 and the pieces was machined.(fig.8)

To machine these polymer pieces it was used a two theeth mill with 5mm in diameter. The spindle speed was about 4000rot/min and the linear speed was 800 mm/min.

5. CONCLUSION

By simulation there could be obtained the optimum machining parameters in order to assure the surface quality and decrease the machining time;

Using CAD-CAM techniques an optimum NC file can be obtained for a specific machine tool.

By using a PCMILL100 virtual machine tool in machining simulation there were identified and eliminated all the possible clashes between machine components.

Before start using a virtual machine tool for simulation of the process, the model has to be calibrated in accordance with the real machine tool.

New calibration methods are required.

6. REFERENCES

Ghionea, I., Anania, D.(2002)--"The management of the computer aided design using virtual prototype", Proceedings of the International Conference on Manufacturing Systems ICMaS 2002, Ed. Academiei Romane, p.529 ... 532, ISSN 0035-4074, ISBN 973-270932-4.

Ispas C-tin, Paraschiv, M.D., Laboreau L, Anania F,D.(2008) Research concerning the numerical errors correction for a NACA profile surface on a 5 axis machine tool, Academic Journal of Manufacturing Engineering, p75-81, Ed. Politehnica, volume 6, ISSUE 3/2008, ISSN 1583-7904,

Ispas C-tin, Mohora C., Anania F, D, Paraschiv M,D.(2007) Virtual design methods for the new products., Proceedings of the Inetrnational Conference on Manufacturing Systems, ICMaS, 22 Noiembrie, ISSN 1842-3183

Ispas C-tin, Zapciu M., Mohora C., Anania F,D.(2006), Product development using cad-cam-cae software and internet facilities--The International Conference Of The Carpathian Euro-Region Specialists In Industrial Systems Baia Mare--Romania ISSN 1224-3264

Ispas C-tin, Ghionea I, Anania F.D.,(2004) Computer aided design and manufacturing optimization process for a set of spur gears of a gear6ox..International Meeting of Carpatian Specialist in the Field of Gears, Baia-Mare 2004 ISSN--1224-3264