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Configuring and analysis of a class of generalized reconfigurable 2-axis parallel kinematic machine
Goran Vasilic,Sasa Zivanovic,Branko Kokotovic,Zoran Dimic 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7
The paper describes the configuring and analysis of a class of generalized reconfigurable 2-axis parallel kinematic machine (R2PKM). A generalized model which is used for solving inverse and direct kinematic problem is presented. Generalized equations that present the solutions of kinematic problems are derived and they are valid for any configuration of R2PKM. Characteristic configurations of the mechanism are given as an example of the concept realization. For selected configurations, workspaces are defined and possible singular positions of the mechanism are analyzed. Optimization of the mechanism legs length was performed using the condition number. Determination of optimal legs length has been shown for several different configurations of the parallel mechanism. Control and programming system is configured and experimental prototype of R2PKM is realized. Verification of the configured machine, configured control and programming system was performed on the virtual machine and also on the prototype of the machine by drawing several different contours.
The possibilities for application of STEP-NC in actual production conditions
Dejan Lukic,Sasa Zivanovic,Jovan Vukman,Mijodrag Milosevic,Stevo Borojevic,Aco Antic 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7
With the rapid advancement of internet technologies (IT) and computer numerical control (CNC) technologies, the production environment has significantly changed in the last two decades. The International Organization for Standardization (ISO) standard 6983 (Gcode), which is still being used as a link between computer aided design/computer aided process planning/computer aided manufacturing (CAD/CAPP/CAM) and CNC system, represents an obstacle for the full integration of design and manufacturing. The result of efforts to eliminate these obstacles and shortcomings of developed standards for data exchange and sharing is the development of (STEP-ISO 10303) standard, as well as its extension to numerical control STEP-NC. This paper shows the current possibility of implementing STEPNC in integration of computer aided technologies CAx and CNC systems in actual production conditions. Two scenarios represent a new approach to programming CNC machine tools using the STEP-NC protocol, which is explained in detail with IDEF0 diagrams, with defining necessary equipment and software. Implementation of the STEP-NC protocol described by the integration definition for function modeling (IDEF0) methodology was experimentally verified on specific examples for both scenarios, with the application of available CAD/CAM systems and the STEP-NC machine software, as well as appropriate virtual and physical CNC machine tools.
An additive manufacturing benchmark artifact and deviation measurement method
Nikola Vorkapic,Milos Pjevic,Mihajlo Popovic,Nikola Slavkovic,Sasa Zivanovic 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7
Additive manufacturing (AM) is established as a new class for fabricating 3D physical prototypes layer by layer. Given that a large number of different 3D printers (AM machines) are present now (as a product of renowned manufacturers or custom-made products), the design of a benchmark artifact for evaluation of the AM processes is very important. This implies quality evaluation of the capabilities and limitations of each AM process and also the geometrical testing of the 3D printers. The paper proposes a benchmark artifact, according to the criteria for modeling of the benchmark artifact, with a large number of basic features for its geometrical evaluation. Although there are a large number of commercial software packages, this paper also proposes a low-cost developed measurement method of geometrical deviation that could be also adjustable for requirements in an easy way. Verification of the proposed deviation measurement method has been done by several experiments. The experiments include fabrication of the proposed benchmark artifact on available 3D printers by an FFF (fused filament fabrication) process also known as FDM (fused deposition modeling), and after that its scanning. Verification is done by comparing quality evaluation of each fabricated part by developed method and commercial software.