- TITLE: MACHINE VISE WITH ELECTROMECHANICAL CLAMP FOR MILLING MACHINES
- AUTHOR(S): N. Krykun, Y. Kuznietsov
- ABSTRACT: Article is devoted to the development of machine vices with an electromechanical clamp for milling machines. The goal of the work is to create an effective and reliable device that will ensure increased accuracy and speed of processing parts on milling machines. In the course of the work, an analysis of the existing constructions of vices and their clamping technologies was carried out, the main requirements for the developed device were determined. Based on this analysis, a vise design was developed, which includes an electromechanical drive for clamping parts. This solution allows you to automate the clamping process, reduce the complexity of maintenance and increase the accuracy of the positioning of parts. The proposed vices can be used on modern milling machines of various types, which helps to increase production productivity and the quality of processing parts.
- DOI: http://doi.org/10.62853/TQNU7369
- PAGES: 3-5
- DOWNLOAD: Vol71-2025-1-3-5.pdf
- HOW TO CITE THIS ARTICLE: N. Krykun, Y. Kuznietsov. Machine Vise with Electromechanical Clamp for Milling Machines. Journal of the Technical University of Gabrovo. 71 (2025) 3-5.
- TITLE: EFFECT OF THE INFILL ARCHITECTURE ON THE MECHANICAL PROPERTIES OF 3D PRINTED PETG SAMPLES
- AUTHOR(S): N. Petrov, M. Ormanova, I. Jelezarov.
- ABSTRACT: In the present work, polyethylene terephthalate glycol (PETG) tensile and flexural test specimens were fabricated using the fused filament fabrication (FFF) technique. The samples had different infill densities, namely 35% and 100%, and different infill layer architectures – 45° and 90°. Mechanical tests were performed in order to determine the influence of the chosen 3D printing technological conditions on the flexural and tensile strengths of the samples. The results indicated that in all cases increasing the infill density increased the mechanical performance of the specimens. At low infill densities the change in the orientation of the samples had minimal effect on the mechanical capabilities of the samples, however, increasing the infill density to 100% led to a slight increase of the tensile strength and a major increase of the flexural strength.
- DOI: http://doi.org/10.62853/HHVS3786
- PAGES: 6-12
- DOWNLOAD: Vol71-2025-2-6-12.pdf
- HOW TO CITE THIS ARTICLE: N. Petrov, M. Ormanova, I. Jelezarov. Effect of the infill architecture on the mechanical properties of 3D printed PETG samples. Journal of the Technical University of Gabrovo. 71 (2025) 6-12.
- TITLE: DESIGN AND FABRICATION OF DUAL-HEAD 3D PRINTER
- AUTHOR(S): V. Nguen, T. Tung
- ABSTRACT: This study presents the design and fabrication of a dual extruder 3D printer aimed at enhancing multi material and multi color additive manufacturing capabilities. Unlike conventional single head 3D printers, the proposed system integrates two independent extruders, enabling simultaneous deposition of different filaments for increased design flexibility and productivity. The mechanical structure is developed with an aluminum frame, ensuring rigidity and precision. Key subsystems including the X, Y, and Z axes are driven by belt and screw mechanisms, with dynamic analysis conducted to determine operating forces and ensure motion accuracy. Finite Element Method (FEM) simulations verify the structural integrity of the frame under expected loads, showing stress and deformation well within safe limits. The prototype features a working volume of 200×200×250 mm, a maximum printing speed of 55 mm/s, and achieves high dimensional accuracy, demonstrated by a machine bed parallelism deviation of only 0.01 mm. Experimental results validate the effectiveness of the dual head configuration in producing high quality, dual color printed parts, highlighting the printer’s potential in rapid prototyping and customized manufacturing applications.
- DOI: http://doi.org/10.62853/FRAU2101
- PAGES: 13-18
- DOWNLOAD: Vol71-2025-3-13-18.pdf
- HOW TO CITE THIS ARTICLE: V. Nguen, T. Tung. Design and Fabrication of Dual- head 3D printer. Journal of Technical University of Gabrovo. 71 (2025) 13-18.
- TITLE: DESIGN AND ANALYSIS OF A GANTRY ROBOT FOR PICK AND PLACE APPLICATIONS
- AUTHOR(S): T. T. Tung, N. T. Anh, N. X. Quynh, T. V. Minh
- ABSTRACT: This paper presents the design, development, and performance validation of a lightweight XYZ gantry robot optimized for pick and place operations. While the mechanical configuration leverages common components NEMA 17 stepper motors, T8 lead screws, and servo actuated grippers the novelty of this work lies in its system level optimization, task specific mechanical integration, and design for affordability strategy tailored for low force, high repeatability industrial tasks. Unlike of the shelf or DIY variants, this system incorporates analytically derived actuator sizing, load driven gripper force estimation, and workspace driven frame optimization to achieve consistent performance while maintaining a minimal bill of materials. The modular architecture and hybrid manufacturing approach enable rapid deployment in education, research, and SME automation scenarios, filling the gap between low cost prototypes and over engineered commercial solutions. The prototype gantry robot was designed for objects up to 100 g and experimentally validated using a 200 g test payload to assess load-bearing capacity and control stability.
- DOI: http://doi.org/10.62853/DVRH9432
- PAGES: 19-24
- DOWNLOAD: Vol71-2025-4-19-24.pdf
- HOW TO CITE THIS ARTICLE: T. T. Tung, N. T. Anh, N. X. Quynh, T. V. Minh. Design and analysis of a gantry robot for pick and place applications. Journal of the Technical university of Gabrovo. 71 (2025) 19-24.
- TITLE: INVESTIGATION OF A MUFFLER WITH MODIFIED HELMHOLTZ RESONATOR VOLUME UNDER MULTI-LOAD OPERATING MODES
- AUTHOR(S): H. Kuşçu, T. Pektaş
- ABSTRACT: Helmholtz resonators are widely applied in exhaust aftertreatment systems to improve acoustic attenuation, but their performance depends on resonator volume and engine operating conditions. This study examines the effect of enlarging the resonator volume from 30.67 L to 57.83 L on the acoustic behavior of a prototype muffler. The objective was to evaluate transmission loss at multiple load points and provide a basis for future optimization. Acoustic measurements were performed under five operating modes, defined by engine speed and torque, with a microphone placed at the outlet. Results were benchmarked against a reference muffler. The modified design achieved notable improvements in insertion loss for four out of five modes, with relative gains up to 46%. Only at the lowest load condition (Mode 1) was a decrease observed. Back pressure remained within acceptable limits, indicating no major penalty in flow performance. Findings confirm that resonator volume has a strong influence on acoustic characteristics across operating conditions. While the prototype achieved substantial improvements, variations between modes emphasize the need for designs optimized for all load points. This work provides experimental evidence on the relationship between resonator volume and acoustic performance, serving as a foundation for future research in multi-load-point optimization.
- DOI: http://doi.org/10.62853/WRTX8487
- PAGES: 25-27
- DOWNLOAD: Vol71-2025-5-25-27.pdf
- HOW TO CITE THIS ARTICLE: H. Kuşçu, T. Pektaş. Investigation of a muffler with modified helmholtz resonator volume under multi-load operating modes. Journal of the Technical university of Gabrovo. 71 (2025) 25-27.
