scholarly journals Experimental Studying of the Variations of Surface Roughness and Dimensional Accuracy in Dry Hard Turning Operation

2018 ◽  
Vol 12 (1) ◽  
pp. 175-191 ◽  
Author(s):  
S. Yousefi ◽  
M. Zohoor
Keyword(s):  
Surface Roughness ◽  
Boron Nitride ◽  
Tool Wear ◽  
Feed Rate ◽  
Hard Turning ◽  
Cubic Boron Nitride ◽  
Dimensional Accuracy ◽  
Spindle Speed ◽  
Cutting Depth ◽  
Nose Radius

Objective: Hard turning in dry condition using cubic boron nitride tools, as an alternative of traditional grinding operation, is an advanced machining operation in which hardened steel with the hardness greater than 46 HRc is machined without the use of any coolant. Method: In the hard turning process, due to its hard nature, usually the cutting depth is selected lower than or equal to the nose radius, and the cutting zone is mainly limited within the tool nose area. Thus, unlike the traditional turning, the effect of the nose radius on the surface finish and dimensional accuracy becomes more complicated. Therefore, in this paper, firstly, the effect of processing parameters such as nose radius on the surface roughness and dimensional accuracy is investigated. Then, the relationship between the surface finish and dimensional accuracy variations with vibration, cutting forces, and tool wear is studied experimentally. The results revealed that feed rate is the most important factor influencing the surface roughness, whereas spindle speed and cutting depth are insignificant factors. On the other hand, cutting depth and spindle speed have the greatest effect on the dimensional accuracy, while nose radius has no significant effect. The vibration and wear analysis revealed that compared with the vibration, the tool wear has no considerable effect on the dimensional accuracy. It was also observed that the spindle speed has a contradictory effect on the surface roughness and dimensional accuracy. The best dimensional accuracy is obtained at 500 rpm, while the best surface quality is achieved at 2000 rpm. Result: The obtained results also showed that increasing the feed rate from a particular value not only leads to no significant changes in the surface roughness value but in some cases can also decrease the surface roughness. Conclusion: According to the analysis results, the lowest cutting depth, the moderate feed rate, and the speed lower than 1100 rpm provide the best dimensional accuracy. Compared with carbides and ceramics, cubic boron nitride tools produce a better surface roughness at both higher cutting depth and speed. 0.202 µm is the best surface roughness that was obtained at rε = 1.2 mm, N = 2000 rpm, f = 0.08 mm/rev, d = 0.5 mm which is comparable with the surface quality obtained by the conventional grinding operation.

DEVELOPMENT OF SURFACE ROUGHNESS PREDICTION MODEL FOR HARD TURNING ON AISI D2 STEEL USING CUBIC BORON NITRIDE INSERT

2017 ◽  
Vol 80 (1) ◽  
Author(s):  
Amrifan Saladin Mohruni ◽  
Muhammad Yanis ◽  
Edwin Kurniawan
Keyword(s):  
Surface Roughness ◽  
Boron Nitride ◽  
Feed Rate ◽  
Hard Turning ◽  
Cubic Boron Nitride ◽  
Cutting Speed ◽  
Machining Parameters ◽  
Aisi D2 Steel ◽  
Aisi D2 ◽  
D2 Steel

Hard turning is an alternative to traditional grinding in the manufacturing industry for hardened ferrous alloy material above 45 HRC. Hard turning has advantages such as lower equipment cost, shorter setup time, fewer process steps, greater part geometry flexibility and elimination of cutting fluid. In this study, the effect of cutting speed and feed rate on surface roughness in hard turning was experimentally investigated. AISI D2 steel workpiece (62 HRC) was machined with Cubic Boron Nitride (CBN) insert under dry machining. A 2k-factorial design with 4 centre points as an initial design of experiment (DOE) and a central composite design (CCD) as augmented design were used in developing the empirical mathematical models. They were employed for analysing the significant machining parameters. The results show that the surface roughness value decreased (smoother) with increasing cutting speed. In contrary, surface roughness value increased significantly when the feed rate increased. Optimum cutting speed and feed rate condition in this experiment was 105 m/min and 0.10 mm/rev respectively with surface roughness value was 0.267 µm. Further investigation revealed that the second order model is a valid surface roughness model, while the linear model cannot be used as a predicted model due to its lack of fit significance.

scholarly journals Technics Research on Polycrystalline Cubic Boron Nitride Cutting Tools Dry Turning Ti-6AL-4V Alloy Based on Orthogonal Experimental Design

2018 ◽  
Vol 142 ◽  
pp. 03002
Author(s):  
Yunhai Jia ◽  
Lixin Zhu
Keyword(s):  
Surface Roughness ◽  
Experimental Design ◽  
Boron Nitride ◽  
Feed Rate ◽  
Flank Wear ◽  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Orthogonal Experimental Design ◽  
Polycrystalline Cubic Boron Nitride

Ti-6Al-4V components are the most widely used titanium alloy products not only in the aerospace industry, but also for bio-medical applications. The machine-ability of titanium alloys is impaired by their high temperature chemical reactivity, low thermal conductivity and low modulus of elasticity. Polycrystalline cubic boron nitride represents a substitute tool material for turning titanium alloys due to its high hardness, wear resistance, thermal stability and hot red hardness. For determination of suitable cutting parameters in dry turning Ti-6AL-4V alloy by Polycrystalline cubic boron nitride cutting tools, the samples, 300mm in length and 100mm in diameter, were dry machined in a lathe. The turning suitable parameters, such as cutting speed, feed rate and cut depth were determined according to workpieces surface roughness and tools flank wear based on orthogonal experimental design. The experiment showed that the cutting speed in the range of 160~180 m/min, the feed rate is 0.15 mm/rev and the depth of cut is 0.20mm, ideal workpiece surface roughness and little cutting tools flank wear can be obtained.

INVESTIGATION OF WIPER INSERTS EFFECTS IN TURNING AND MILLING PROCESSES

2021 ◽  
pp. 2150111
Author(s):  
MURAT KIYAK
Keyword(s):  
Surface Roughness ◽  
Cost Saving ◽  
Tool Wear ◽  
Feed Rate ◽  
Turning Process ◽  
Nose Radius ◽  
Turning Operations ◽  
Effective Factors ◽  
Milling Operations ◽  
The Many

The surface roughness is a crucial factor in machining methods. The most effective factors on surface roughness are feed rate and tool nose radius. Due to the many advantages of wiper (multi-nose radius) inserts, their importance and use has been increasing recently. The purpose of this paper is to investigate the effect of wiper inserts on surface roughness and tool wear. In this study, conventional inserts and wiper inserts were experimentally compared separately in milling and turning operations. Compared to conventional inserts, the surface roughness values obtained using wiper inserts improved by 33% in turning operations and approximately 40% in milling operations. It was observed that the production time in the turning process was reduced by about 25% in the case of using wiper inserts compared to the use of conventional inserts. In milling, this ratio was determined to be approximately 43% due to the fact that it has multiple cutting edge. It has been observed that the use of wiper inserts in machining methods creates a significant time and cost saving advantage.

Study on the Cutting Properties about Magnesium Alloy when Dry Turning with Kentanium Cutting Tools

2010 ◽  
Vol 102-104 ◽  
pp. 653-657 ◽  
Author(s):  
Xu Hong Guo ◽  
Li Jun Teng ◽  
Wei Wang ◽  
Ting Ting Chen
Keyword(s):  
Surface Roughness ◽  
Magnesium Alloy ◽  
Tool Wear ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Depth ◽  
Dry Turning ◽  
Main Influence

In recent years, the machinability of magnesium alloy is concerned more and more by the public. In this paper, a study on the cutting properties of magnesium alloy AZ91D when dry turning with kentanium cutting tools is presented. It shows the cutting force measured by a data acquisition system which is made up of Kistler9257B piezoelectric crystal sensor dynamometer, Kistler5070A10100 charge amplifier and computer. The effect of cutting parameters on cutting force was studied, and the experimental formula was built. The tool wear and chip characteristics were observed with KYKY-EM3200 electron scanning microscope and EDAX PV9900 alpha ray spectrometer, while the surface roughness of the workpiece was measured with 2205 profilometer. Results showed that the cutting depth was the main influence factor on cutting force, followed by feed rate and cutting speed . The main form of tool wear showed to be diffusive wear and adhesive wear. The feed rate had the main influence on chip form and the workpiece surface roughness, cutting speed was less effective, the cutting depth was the least.

scholarly journals Optimization of Grinding Parameters for Minimum Grinding Time When Grinding Tablet Punches by CBN Wheel on CNC Milling Machine

2019 ◽  
Vol 9 (5) ◽  
pp. 957 ◽  
Author(s):  
Ngoc-Pi Vu ◽  
Quoc-Tuan Nguyen ◽  
Thi-Hong Tran ◽  
Hong-Ky Le ◽  
Anh-Tuan Nguyen ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Feed Rate ◽  
Cubic Boron Nitride ◽  
Cutting Parameters ◽  
Wheel Speed ◽  
Milling Machine ◽  
Cnc Milling ◽  
Cutting Depth ◽  
Cnc Milling Machine ◽  
Grinding Time

Cutting regime parameters play an important role in determining the efficiency of the grinding process and the quality of the ground parts. In this study, the influences of the cutting parameters, including the cutting depth (ae), the feed rate (Fe) and the wheel speed (RPM) on the grinding time when grinding tablet shape punches by a cubic boron nitride (CBN) wheel on a CNC (Computerized Numerical Control) milling machine are investigated. The Taguchi technique based on orthogonal array and analysis of variance (ANOVA) was then applied to design the number of experiments and evaluate the influence of cutting depth, feed rate and wheel speed on the grinding time. The results show that among the three cutting parameters, the most influential parameter on the grinding time is the cutting depth. The second influential parameter on the grinding time is the feed rate. The least influential parameter on grinding time is the wheel speed. In addition, the optimal condition of cutting parameters obtained for grinding tablet shape punches by cubic boron nitride wheels on a CNC milling machine are a cutting depth of 0.03 mm, wheel speed of 5000 rpm and feed rate of 3500 mm/min. This optimum cutting parameters ensure the least grinding time.

Influence of Machining Parameters on Surface Topography of Cubic Boron Nitride at Rotary Ultrasonic Machining

2016 ◽  
Vol 686 ◽  
pp. 180-185 ◽  
Author(s):  
Marcel Kuruc ◽  
Martin Kusý ◽  
Vladimír Šimna ◽  
Jozef Peterka
Keyword(s):  
Surface Roughness ◽  
Boron Nitride ◽  
Feed Rate ◽  
Cubic Boron Nitride ◽  
Cutting Speed ◽  
Machining Parameters ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Hard And Brittle Materials ◽  
Advanced Machining

Poly-crystalline cubic boron nitride (PCBN) is one of the hardest known material. Therefore only advanced methods are able to treat such material. Advanced machining methods, proper for machining of hard and brittle materials (such as glass and ceramics) include rotary ultrasonic machining (RUM). This method should achieve high precision and low surface roughness (at least during machining of materials such as ceramics). Achievable roughness is affected by machined material and machining parameters. This contribution investigates influence of machining parameters, such as cutting speed and feed rate, on resultant surface roughness during machining of PCBN by rotary ultrasonic machining.

Modeling of Cutting Forces Under Hard Turning Conditions Considering Tool Wear Effect

2005 ◽  
Vol 127 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Yong Huang ◽  
Steven Y. Liang
Keyword(s):  
Tool Wear ◽  
Feed Rate ◽  
Cutting Forces ◽  
Hard Turning ◽  
Flank Wear ◽  
Depth Of Cut ◽  
Process Conditions ◽  
Force Model ◽  
Nose Radius ◽  
Small Depth

Quantitative understanding of cutting forces under hard turning conditions is important for thermal modeling, tool life estimation, chatter prediction, and tool condition monitoring purposes. Although significant research has been documented on the modeling of forces in the turning operation in general, turning of hardened materials involves several distinctive process conditions, including negative tool rake angle, large tool nose radius, and rapid tool wear. These process conditions warrant specific treatment in the analysis of cutting forces. This paper first addresses these issues by formulating an oblique chip formation force model through the extension of a two-dimensional (2D) mechanistic force model while considering the effect of tool geometry complexities. The coefficients of the mechanistic force model are estimated by applying a genetic algorithm in overcoming the lack of explicit normal equations. Then the forces occurring due to flank wear are modeled by extending a 2D worn tool force modeling approach into a three-dimensional analysis to accommodate the effect of low feed rate, small depth of cut, and relatively large tool nose radius in hard turning. The total cutting forces are the linear summation of forces due to chip formation and forces due to flank wear. The model-predicted forces match well with experimental results in the turning of hardened 52100 bearing steel under practical cutting conditions (low feed rate, small depth of cut, and gentle cutting speed) using cubic boron nitride (CBN) tools under the progressive tool flank wear conditions.

scholarly journals An Investigation on Effect of Depth of Cut, Feed Rate and Tool Nose Radius on Induced Vibration and Surface Roughness during Hard Turning of 41Cr4 Alloy Steel Using Response Surface Methodology

2016 ◽  
Vol 7 ◽  
pp. 32-46
Author(s):  
Christopher Okechukwu Izelu ◽  
Samuel Chike Eze
Keyword(s):  
Surface Roughness ◽  
Response Surface Methodology ◽  
Feed Rate ◽  
Hard Turning ◽  
Cutting Tool ◽  
Depth Of Cut ◽  
Work Piece ◽  
Dominant Effect ◽  
Nose Radius ◽  
Tool Nose Radius

This paper describes an aspect of a set of turning experiments performed in attempt to model, predict and optimize the machining induced vibration and surface roughness as functions of the machining, tool and work-piece variables during hard turning of 41Cr4 alloy special steel, with standard cutting tool, on a conventional lathe. Amongst others, the input variables of interest include the depth of cut, feed rate and tool nose radius. The response surface methodology, based on central composite design of experiment, was adopted, with analysis performed in Design Expert 9 software environment. Quadratic regression models were suggested, and proved significant by an analysis of variance, for the machining induced vibration of the cutting tool and surface roughness of the work-piece. They also have capability of being used for prediction within limits. Analysis of variance also showed the depth of cut, feed rate and tool nose radius have significant effect on the machining induced vibration and surface roughness. Whereas the depth of cut has dominant effect on the machining induced vibration, the tool nose radius has dominant effect on the surface roughness. The optimum setting of the depth of cut of 1.33095 mm, feed rate of 0.168695 mm/rev, and the tool nose radius of 1.71718 mm is required to minimize the machining induced vibration at 0.08 mm/s2 and surface roughness at 6.056 μmm with a desirability of 0.830.

scholarly journals Machinability of Zirconia Toughened Mica Glass Ceramics for Dental Restorations

2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Sivaranjani Gali ◽  
Suresh Chiru
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Feed Rate ◽  
Cutting Forces ◽  
Glass Ceramics ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Dental Ceramics ◽  
Edge Chipping ◽  
Dental Restorations

Objective: For a dental material to be machinable for CAD/CAM technology, it must offer convenient machining, under a given set of cutting conditions. Quantitative evaluation of machinability has been assessed in literature through various parameters such as tool wear, penetration rates, surface roughness, cutting force and power. A machinable ceramic will typically demonstrate a higher tool penetration rate with signs of reduced diamond tool wear and edge chipping. The purpose of this in vitro study was to evaluate the feasibility of machining an experimental ceramic, 20 wt.% zirconia reinforced mica glass ceramics (G20Z) for indirect dental restorations and compare the tool penetration rates of G20Z to commercially available dental ceramics, Presintered Zirconia (PSZ) and IPS emax CAD. Material and Methods:  Precursors of base glass (SiO2 -Al2O3 -K2O -MgO-B2O3 -F) were melted at 15000C for 2 h in a platinum crucible and quenched in deionised water. The glass frit was ball milled with 20 wt. % YSZ (G20Z) and subject to two stage heat treatment in a muffle furnace. Specimens of G20Z (12 X 2 mm) were evaluated for their feasibility of machining under varying spindle speed, depth of cut, and feed rates. Influence of depth of cut, spindle speed and feed rate (vc=8000-16000 rpm, d=0.4-0.8 mm, f=0.1- 0.3 mm/tooth) on cutting forces, material response, surface roughness and tool wear were investigated. Tool penetration rates, tool wear and margin chipping were also evaluated and compared with Pre-sintered Zirconia (PSZ)  and e.max CAD in a custom dental milling surveyor at 30,000 rpm with a load of 0.98 N under water lubrication for 6 min. Tool penetration rates were calculated as the ratio of length of cut and milling time with a measuring microscope and scanning electron microscope was used for tool wear and edge chipping. ANOVA and Tukey Kramer tests were used for statistically comparing the means of each group. Results: Spindle speed and feed rate play a significant role in influencing surface roughness, thrust force, cutting forces and tool wear. Penetration rates of G20Z (0.32 ±0.12 mm/min) was significantly greater than PSZ (0.26 ±0.06 mm/min) and IPS e.max CAD (0.21 ±0.05 mm/min). SEM observations reveal tool abrasion and edge chipping regardless of the ceramic type. Conclusion: High spindle speeds delivers low cutting forces with an average surface roughness of 1.61 µm, with abrasive wear of the tool insert and brittle fracture of zirconia mica glass ceramic composites. G20Z with its machinable nature demonstrates greater tool penetration rates than PSZ and IPS e.max CAD. Tool wear and edge chipping is seen in all the investigated ceramics.   Keywords Machinability, Dental Ceramics, Mica Glass-Ceramics, Dental Zirconia, Tool penetration rates.  

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