In the present paper, experimental study is made to investigate the effect of cutting parameters ... more In the present paper, experimental study is made to investigate the effect of cutting parameters on surface roughness in dry high speed milling of hardened tool steel using two cutting tools (diameter of 20 and 40 mm). The cutting parameters considered include cutting speed and feed per tooth. Experiments are conducted in up-cut and down-cut milling. Based on the experimental data, the effect of tool diameter on the surface roughness is analyzed. The good surface roughness can be achieved in high speed machining of examined steel but rapidly tool wear is observed.
Annals of DAAAM for ... & proceedings of the ... International DAAAM Symposium .., 2019
In this paper, the experimental investigation of effect of overhang tool length, depth of cut and... more In this paper, the experimental investigation of effect of overhang tool length, depth of cut and feed rate on two responses such as tool vibration and surface roughness, by using Taguchi method and main effect plot was performed. C45E steel bars with diameter of 88 mm were machining using different values of overhang tool length, depth of cut and feed rate. Other process parameters were constant. Taguchi method was performed in order to identify the effect of each input process parameters on the analysed responses. The results were shown that the overhang tool length has a primary effect on the tool vibration and the surface roughness. The feed rate has secondary effect on the tool vibration, while the depth of cut has secondary effect on the surface roughness.
This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat a... more This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat affected zone width (HAZ, mm) during high-alloyed steel 1.4828 laser cutting using oxygen as an assistance gas. For the definition of appropriate mathematical models, multiple linear regression analysis is used, with four independent variables that were varied at five levels. Following parameters are varied: cutting speed (V), assist gas pressure (p), focus position (fs) and stand-off (N d). In comparison between the model and the experimental results, it can be concluded that the effects of specified parameters on cut quality, productivity and thus the legitimacy of this technology for cutting high-alloyed steels are well described by the obtained mathematical models.
Original scientific paper Machining system VBS was constructed and built at the Faculty of Mechan... more Original scientific paper Machining system VBS was constructed and built at the Faculty of Mechanical Engineering in Sarajevo, for investigations of the phenomena in high speed milling. Since the requests for high speeds and accelerations of the main spindles and the transmitters for the feed motions require specific design and mechatronic solutions, this paper presents the selection of optimal design variety of components integrated in machining system VBS. The investigation of the effect of the cutting parameters on the cutting forces during high speed face milling (range of cutting speed from 750 m/min to 3000 m/min) was conducted on the machining system VBS. Investigations were carried out on hardened alloy steel EN 10083-3 (41Cr4). The results show that cutting force FR decreases by increasing cutting speed. Also the investigations show that the feed per tooth has significant effect upon the values of cutting forces. This paper further presents the mathematical model for calculating cutting force in high speed cutting. Experimental results are compared with calculation results.
Although transdermal drug delivery systems (DDS) offer numerous benefits for patients, including ... more Although transdermal drug delivery systems (DDS) offer numerous benefits for patients, including the avoidance of both gastric irritation and first-pass metabolism effect, as well as improved patient compliance, only a limited number of active pharmaceutical ingredients (APIs) can be delivered accordingly. Microneedles (MNs) represent one of the most promising concepts for effective transdermal drug delivery that penetrate the protective skin barrier in a minimally invasive and painless manner. The first MNs were produced in the 90s, and since then, this field has been continually evolving. Therefore, different manufacturing methods, not only for MNs but also MN molds, are introduced, which allows for the cost-effective production of MNs for drug and vaccine delivery and even diagnostic/monitoring purposes. The focus of this review is to give a brief overview of MN characteristics, material composition, as well as the production and commercial development of MN-based systems.
This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat a... more This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat affected zone width (HAZ, mm) during high-alloyed steel 1.4828 laser cutting using oxygen as an assistance gas. For the definition of appropriate mathematical models, multiple linear regression analysis is used, with four independent variables that were varied at five levels. Following parameters are varied: cutting speed (V), assist gas pressure (p), focus position (fs) and stand-off (N d). In comparison between the model and the experimental results, it can be concluded that the effects of specified parameters on cut quality, productivity and thus the legitimacy of this technology for cutting high-alloyed steels are well described by the obtained mathematical models.
Annals of DAAAM for ... & proceedings of the ... International DAAAM Symposium .., 2022
The FDM process was primarily developed only for certain types of polymer materials. Due to limit... more The FDM process was primarily developed only for certain types of polymer materials. Due to limited mechanical, thermal and electrical properties, these materials can't be used in industrial applications. By adding different nanoparticles and fibers to pure polymers, the aforementioned properties of pure polymers can be improved. However, optimization of process parameters is crucial to produce parts with optimal properties, such as mechanical strength. In this paper was presented the use of Taguchi method for optimization FDM process parameters (layer thickness, raster angle, wall thickness, printing speed, printing temperature and build plate temperature) to improve flexural strength of carbon fiber reinforced polyamide parts. The ranking of the most influential parameters was carried out using Taguchi analysis, and the statistical significance of the analyzed parameters was checked using ANOVA analysis. Based on the results of the Taguchi analysis and ANOVA analysis, it was concluded that the raster angle has a dominant influence on the flexural strength. Maximum flexural stress increases with the increase of the raster angle and maximum value is at a raster angle of 90º. Taguchi analysis showed that increasing build plate temperature and printing temperature are also important for improving the flexural strength.
A numerical model for the prediction of axisymmetric temperature distribution and the shape of ho... more A numerical model for the prediction of axisymmetric temperature distribution and the shape of hole in tungsten alloy during laser drilling has been developed using a finite volume method (FVM). The energy balance equation in integral form is used for a description of the temperature field. Verification of the application of finite volume method is performed by comparing the results of numerical calculations with experimental data. It was found good agreement of results and shown that the finite volume method can be an effective tool to predict the shape of hole and size of the heat affected zone (HAZ) during the laser drilling.
Proceedings of the 23rd International DAAAM Symposium 2012, 2012
This paper presents an experimental study to evaluate the effect of the cutting parameters on the... more This paper presents an experimental study to evaluate the effect of the cutting parameters on the cut quality during plasma cutting of 5 mm thick low alloy steel sheets. The cutting parameters considered include cutting speed and plasma gas pressure. The CNC portal cutting machine VARCUT L2 by plasma device type D12000 is used in the experiments. Results show that good quality cuts can be produced in plasma cutting of low alloy steel, at the cutting speed from 400 to 700 mm/min and at the plasma gas pressure from 4 to 5 bar.
It is necessary to understand the effect of all relevant parameters on the process productivity a... more It is necessary to understand the effect of all relevant parameters on the process productivity and cut quality for optimal design of processing technologies regarding different types and thickness of materials. In this paper, the experimental results of the influence the process parameters on the characteristics of cut quality in CO 2 Key words: CO laser cutting of alloy steels 1.457 and 1.4828 are presented. Nitrogen and oxygen are used as assist gases. There were significant improvements in material savings by reducing the kerf width and heat affected zone, and in increasing of quality of machined surface.
Fused deposition modelling (FDM) has gained popularity in industry because of its ability to manu... more Fused deposition modelling (FDM) has gained popularity in industry because of its ability to manufacture complex parts. But when it comes to the manufacturing of functional products, the advantages of FDM is not so distinct due to the high number of intervening parameters and complex optimal settings set up. This paper investigates the influence of process parameters on the rheological and dynamic mechanical properties of FDM manufactured parts. In this study, an attempt has been made to establish an empirical relationship between the FDM input parameters and the properties involved using IV-optimal response surface methodology and statistical analysis. Further, optimized process parameters were established to maximize the rheological and dynamic mechanical properties through the graphical optimization. The optimization results show that the parameters with the most significant effect on the rheological and dynamic mechanical properties are the layer thickness, the air gap, the road width and the number of contours. The results also show that by taking into consideration the number of contours, the functionality of manufactured part is improved significantly.
Journal of Maritime & Transportation Science, 2019
This paper investigates the influence of the fuel injector nozzle geometry on the liquid fuel con... more This paper investigates the influence of the fuel injector nozzle geometry on the liquid fuel contraction coefficient and Reynolds number. The main three fuel injector nozzle geometry parameters: nozzle diameter (d), nozzle length (l) and nozzle inlet radius (r) have a strong influence on the liquid fuel contraction coefficient and Reynolds number. The variation of the nozzle geometry variables at different liquid fuel pressures, temperatures and injection rates was analyzed. The liquid fuel contraction coefficient and Reynolds number increase with an increase in the nozzle diameter, regardless of the fuel injection rate. An increase in the r/d ratio causes an increase in the fuel contraction coefficient, but the increase is not significant after r/d = 0.1. A nozzle length increase causes a decrease in the fuel contraction coefficient. Increase in the nozzle length of 0.5 mm causes an approximately similar decrease in the contraction coefficient at any fuel pressure and any nozzle l...
In the present paper, experimental study is made to investigate the effect of cutting parameters ... more In the present paper, experimental study is made to investigate the effect of cutting parameters on surface roughness in dry high speed milling of hardened tool steel using two cutting tools (diameter of 20 and 40 mm). The cutting parameters considered include cutting speed and feed per tooth. Experiments are conducted in up-cut and down-cut milling. Based on the experimental data, the effect of tool diameter on the surface roughness is analyzed. The good surface roughness can be achieved in high speed machining of examined steel but rapidly tool wear is observed.
Annals of DAAAM for ... & proceedings of the ... International DAAAM Symposium .., 2019
In this paper, the experimental investigation of effect of overhang tool length, depth of cut and... more In this paper, the experimental investigation of effect of overhang tool length, depth of cut and feed rate on two responses such as tool vibration and surface roughness, by using Taguchi method and main effect plot was performed. C45E steel bars with diameter of 88 mm were machining using different values of overhang tool length, depth of cut and feed rate. Other process parameters were constant. Taguchi method was performed in order to identify the effect of each input process parameters on the analysed responses. The results were shown that the overhang tool length has a primary effect on the tool vibration and the surface roughness. The feed rate has secondary effect on the tool vibration, while the depth of cut has secondary effect on the surface roughness.
This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat a... more This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat affected zone width (HAZ, mm) during high-alloyed steel 1.4828 laser cutting using oxygen as an assistance gas. For the definition of appropriate mathematical models, multiple linear regression analysis is used, with four independent variables that were varied at five levels. Following parameters are varied: cutting speed (V), assist gas pressure (p), focus position (fs) and stand-off (N d). In comparison between the model and the experimental results, it can be concluded that the effects of specified parameters on cut quality, productivity and thus the legitimacy of this technology for cutting high-alloyed steels are well described by the obtained mathematical models.
Original scientific paper Machining system VBS was constructed and built at the Faculty of Mechan... more Original scientific paper Machining system VBS was constructed and built at the Faculty of Mechanical Engineering in Sarajevo, for investigations of the phenomena in high speed milling. Since the requests for high speeds and accelerations of the main spindles and the transmitters for the feed motions require specific design and mechatronic solutions, this paper presents the selection of optimal design variety of components integrated in machining system VBS. The investigation of the effect of the cutting parameters on the cutting forces during high speed face milling (range of cutting speed from 750 m/min to 3000 m/min) was conducted on the machining system VBS. Investigations were carried out on hardened alloy steel EN 10083-3 (41Cr4). The results show that cutting force FR decreases by increasing cutting speed. Also the investigations show that the feed per tooth has significant effect upon the values of cutting forces. This paper further presents the mathematical model for calculating cutting force in high speed cutting. Experimental results are compared with calculation results.
Although transdermal drug delivery systems (DDS) offer numerous benefits for patients, including ... more Although transdermal drug delivery systems (DDS) offer numerous benefits for patients, including the avoidance of both gastric irritation and first-pass metabolism effect, as well as improved patient compliance, only a limited number of active pharmaceutical ingredients (APIs) can be delivered accordingly. Microneedles (MNs) represent one of the most promising concepts for effective transdermal drug delivery that penetrate the protective skin barrier in a minimally invasive and painless manner. The first MNs were produced in the 90s, and since then, this field has been continually evolving. Therefore, different manufacturing methods, not only for MNs but also MN molds, are introduced, which allows for the cost-effective production of MNs for drug and vaccine delivery and even diagnostic/monitoring purposes. The focus of this review is to give a brief overview of MN characteristics, material composition, as well as the production and commercial development of MN-based systems.
This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat a... more This paper defines mathematical models of value changes for surface roughness (Ra, μm) and heat affected zone width (HAZ, mm) during high-alloyed steel 1.4828 laser cutting using oxygen as an assistance gas. For the definition of appropriate mathematical models, multiple linear regression analysis is used, with four independent variables that were varied at five levels. Following parameters are varied: cutting speed (V), assist gas pressure (p), focus position (fs) and stand-off (N d). In comparison between the model and the experimental results, it can be concluded that the effects of specified parameters on cut quality, productivity and thus the legitimacy of this technology for cutting high-alloyed steels are well described by the obtained mathematical models.
Annals of DAAAM for ... & proceedings of the ... International DAAAM Symposium .., 2022
The FDM process was primarily developed only for certain types of polymer materials. Due to limit... more The FDM process was primarily developed only for certain types of polymer materials. Due to limited mechanical, thermal and electrical properties, these materials can't be used in industrial applications. By adding different nanoparticles and fibers to pure polymers, the aforementioned properties of pure polymers can be improved. However, optimization of process parameters is crucial to produce parts with optimal properties, such as mechanical strength. In this paper was presented the use of Taguchi method for optimization FDM process parameters (layer thickness, raster angle, wall thickness, printing speed, printing temperature and build plate temperature) to improve flexural strength of carbon fiber reinforced polyamide parts. The ranking of the most influential parameters was carried out using Taguchi analysis, and the statistical significance of the analyzed parameters was checked using ANOVA analysis. Based on the results of the Taguchi analysis and ANOVA analysis, it was concluded that the raster angle has a dominant influence on the flexural strength. Maximum flexural stress increases with the increase of the raster angle and maximum value is at a raster angle of 90º. Taguchi analysis showed that increasing build plate temperature and printing temperature are also important for improving the flexural strength.
A numerical model for the prediction of axisymmetric temperature distribution and the shape of ho... more A numerical model for the prediction of axisymmetric temperature distribution and the shape of hole in tungsten alloy during laser drilling has been developed using a finite volume method (FVM). The energy balance equation in integral form is used for a description of the temperature field. Verification of the application of finite volume method is performed by comparing the results of numerical calculations with experimental data. It was found good agreement of results and shown that the finite volume method can be an effective tool to predict the shape of hole and size of the heat affected zone (HAZ) during the laser drilling.
Proceedings of the 23rd International DAAAM Symposium 2012, 2012
This paper presents an experimental study to evaluate the effect of the cutting parameters on the... more This paper presents an experimental study to evaluate the effect of the cutting parameters on the cut quality during plasma cutting of 5 mm thick low alloy steel sheets. The cutting parameters considered include cutting speed and plasma gas pressure. The CNC portal cutting machine VARCUT L2 by plasma device type D12000 is used in the experiments. Results show that good quality cuts can be produced in plasma cutting of low alloy steel, at the cutting speed from 400 to 700 mm/min and at the plasma gas pressure from 4 to 5 bar.
It is necessary to understand the effect of all relevant parameters on the process productivity a... more It is necessary to understand the effect of all relevant parameters on the process productivity and cut quality for optimal design of processing technologies regarding different types and thickness of materials. In this paper, the experimental results of the influence the process parameters on the characteristics of cut quality in CO 2 Key words: CO laser cutting of alloy steels 1.457 and 1.4828 are presented. Nitrogen and oxygen are used as assist gases. There were significant improvements in material savings by reducing the kerf width and heat affected zone, and in increasing of quality of machined surface.
Fused deposition modelling (FDM) has gained popularity in industry because of its ability to manu... more Fused deposition modelling (FDM) has gained popularity in industry because of its ability to manufacture complex parts. But when it comes to the manufacturing of functional products, the advantages of FDM is not so distinct due to the high number of intervening parameters and complex optimal settings set up. This paper investigates the influence of process parameters on the rheological and dynamic mechanical properties of FDM manufactured parts. In this study, an attempt has been made to establish an empirical relationship between the FDM input parameters and the properties involved using IV-optimal response surface methodology and statistical analysis. Further, optimized process parameters were established to maximize the rheological and dynamic mechanical properties through the graphical optimization. The optimization results show that the parameters with the most significant effect on the rheological and dynamic mechanical properties are the layer thickness, the air gap, the road width and the number of contours. The results also show that by taking into consideration the number of contours, the functionality of manufactured part is improved significantly.
Journal of Maritime & Transportation Science, 2019
This paper investigates the influence of the fuel injector nozzle geometry on the liquid fuel con... more This paper investigates the influence of the fuel injector nozzle geometry on the liquid fuel contraction coefficient and Reynolds number. The main three fuel injector nozzle geometry parameters: nozzle diameter (d), nozzle length (l) and nozzle inlet radius (r) have a strong influence on the liquid fuel contraction coefficient and Reynolds number. The variation of the nozzle geometry variables at different liquid fuel pressures, temperatures and injection rates was analyzed. The liquid fuel contraction coefficient and Reynolds number increase with an increase in the nozzle diameter, regardless of the fuel injection rate. An increase in the r/d ratio causes an increase in the fuel contraction coefficient, but the increase is not significant after r/d = 0.1. A nozzle length increase causes a decrease in the fuel contraction coefficient. Increase in the nozzle length of 0.5 mm causes an approximately similar decrease in the contraction coefficient at any fuel pressure and any nozzle l...
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