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21.12.2024

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Optimisation methods for programming CNC machine tools

Wit Grzesik

Recognition of geometrical features of the workpiece (mold base) in NX CAM program [6]

Recognition of geometrical features of the workpiece (mold base) in NX CAM program [6]

This paper presents some important methods of optimisation of CNC programming which covers algorithms of feed changes along the path of tool movement, the concept of feature-based recognition machining (FBM), numerical simulation (FEM/FEA), advanced virtual modelling of machining systems, real-time process simulations with the use of digital twins (DTs) and intelligent control strategies based on the STEP-NC standards. Selected examples of practical industrial applications are overviewed and future development trends are discussed.

KEYWORDS: CNC machine tool, control program, feed optimization, numerical simulation, virtual simulation, STEP-NC interface

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Development of techniques improving functional and programming abilities of intelligent CNC machine tools

Krzysztof Jarosz, Wit Grzesik

An example of a closed-loop self-learning STEP-NC machining system [2, 10]

An example of a closed-loop self-learning STEP-NC machining system [2, 10]

This paper covers the areas of importance in the development of intelligent machine tools (IMTs), including information/knowledge-based computing, advanced virtual modelling of machining systems, real-time process simulations with the use of digital twins (DTs) and intelligent control strategies based on the STEP-NC standards. Select examples of current industrial implementations are discussed, along with prognosing of future development trends. Moreover, the importance of human-machine interaction (HMI) and considering operator behavior and skill levels in the development of HMI is signified.

KEYWORDS: intelligent machine tool, information exchange, virtual simulation, STEP-NC interface

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Progress in modelling and simulation of the machining process – part II: Mesh-free modeling and simulation

Wit Grzesik

The result of chip formation simulation using SPH method for the workpiece and FEM for the tool: a) 3D view and b) contours of effective plastic strain in the cutting zone [10]

The result of chip formation simulation using SPH method for the workpiece and FEM for the tool: a) 3D view and b) contours of effective plastic strain in the cutting zone [10]

In this paper some rules of mesh-free/meshless modeling and numerical simulations of fundamental physical phenomena associated with the machining process, including mechanisms of plastic deformation, chip formation and interfacial friction are overviewed. Some representative examples of the mesh-free modeling application to material removal processes at different scales, i.e. machining processes, water-jet assisted processes, additive machining processes and simulation of micromachining processes using commonly used SPH (smoothed particle hydrodynamics) method are given.


KEYWORDS: mesh-free modeling, numerical simulations, machining process

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Reducing of process model uncertainty towards smart machining systems

Neven Trajchevski, Mikolaj Kuzinovski, Mite Tomov, Piotr Cichosz

Smart machining system architecture [3]

Smart machining system architecture [3]

This paper presents an approach of empirical modeling of cutting process physical phenomena with measurement uncertainty parameters accompanied to the model exponents/ /coefficients. The approach is presented trough an example of creating a power mathematical model for average cutting temperature in turning with details about the uncertainty contributions from different experimental plans. The approach is proposed to be implemented as usual practice during empirical modeling, in order the resulting models to fit with the needs of the smart machining systems and the needs of interoperability between researchers.

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Checking the accuracy of selected methods of probe radius correction

Marek Magdziak, Marcin Krawczyk, Andrzej Kawalec, Jerzy Sładek

Algorithm for assessment of the accuracy of two selected methods of probe radius correction

Algorithm for assessment of the accuracy of two selected methods of probe radius correction

The paper concerns the analysis of accuracy of two methods of probe radius correction which are based on Bézier curves. Those methods can be applied in the case of measurements of free-form surfaces. The analysis of accuracy of selected methods was done in relation to reference corrected measured points.

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Supporting the decision during inter-operational inspection of the electrodes based on the ensemble of neural networks

Halina Nieciąg, Rafał Kudelski, Krzysztof Zagórski

The system consists of CNC electro discharge machine (Roboform 350 Sp GF Agie Charmilles) to manufacture the workpieces, 3R robot for loading workpieces and tools in and out of the machine and for using the identification cycles (Work Master robot) and CMM (DEA Global Performance, with measuring range 500×700×500 mm, resolution 1 µm)

The system consists of CNC electro discharge machine (Roboform 350 Sp GF Agie Charmilles) to manufacture the workpieces, 3R robot for loading workpieces and tools in and out of the machine and for using the identification cycles (Work Master robot) and CMM (DEA Global Performance, with measuring range 500×700×500 mm, resolution 1 µm)

In this paper the method based on the ensemble of artificial neural networks is presented for prediction of the geometrical quality of workpieces after electro-discharge machining (EDM). The complexity and random nature of physical phenomena accompanying the EDM process excluded the theoretical ways. The working electrodes were measured using CMM in flexible manufacturing system. The data obtained from inter-operational measurements were used for the neural networks training. Commonly used measures to express the tool wear turn out to be useless due to their large uncertainty. The tool monitoring and the ensemble method provided more stable diagnosis of the condition of the tool.

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