Experimental Investigation of the Tool Wear and Tool Life in Micro Hard Milling

2013 ◽  
Author(s):  
Shreyas Shashidhara ◽  
Xinyu Liu ◽  
Weihang Zhu ◽  
James Curry ◽  
Victor Zaloom
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Abrasive Wear ◽  
Cutting Force ◽  
Tool Life ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Dry Machining ◽  
Edge Chipping ◽  
Edge Radius

The objective of this project is to experimentally investigate the influence of Minimum Quantity Lubrication (MQL) on tool wear and tool life in micro hardmilling. The experiments were performed on stainless steel using uncoated WC micro-mill with the nominal diameter of 508 microns. The tool wear is characterized by the volume of the material loss at the tool tip. In order to reveal the progression of the tool wear, the worn tool was examined periodically under SEM after a fixed amount of workpiece material removal (1.25 mm3 or 5 slots in this study). The tool life was characterized as the amount of material removed, instead of the conventional cutting times. The feedrate and the spindle speed were fixed, and two levels of axial depth of cut (50 and 75 microns) were compared. The higher depth of cut leads to longer tool life. The machining performance under MQL is superior to the dry machining for both process conditions in terms of the tool life. The cutting forces in feed direction and the surface roughness at the bottom of the slots were also examined during the experiments. The magnitude of the machining forces showed cyclic pattern for both MQL and dry machining. The SEM images and the cutting force signals suggested that the dominant mode of the tool wear in micro-milling is edge chipping and abrasive wear at the tool tip. The loss of the micro-grain of WC at the cutting edge leads to edge chipping, which reduces the effective cutting diameter; the abrasive wear enlarge the edge radius, causing the cutting force increase. As the cutting edge radius reaches a certain dimension, the whole edge was stripped off, a new edge formed with a smaller edge radius, and the cycle restarts. Under MQL cutting conditions, three cycles were observed before tool failure, while under dry machining conditions, the tool only experienced two cycles before tool breakage. The surface roughness at the bottom of the slots improved significantly with the application of MQL for all levels of the tool wear. The surface roughness did not increase drastically as the tool wear increased. It reached a plateau after the tool wear went into gradual wear state. Further experiments and theoretical analysis will be pursued in the future to gain a deeper understanding of tool wear mechanism in micro-milling.

scholarly journals Milling Inconel 718 Workpiece With Cryogenically Treated And Untreated Cutting Tools

2021 ◽  
Author(s):  
Hüseyin Gürbüz ◽  
Şehmus Baday
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Abrasive Wear ◽  
Inconel 718 ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Cutting Tool Wear ◽  
Feed Force

Abstract Although Inconel 718 is an important material for modern aircraft and aerospace, it is a kind material, which is known to have low machinability. Especially, while these types of materials are machined, high cutting temperatures, BUE on cutting tool, high cutting forces and work hardening occur. Therefore, in recent years, instead of producing new cutting tools that can withstand these difficult conditions, cryogenic process, which is a heat treatment method to increase the wear resistance and hardness of the cutting tool, has been applied. In this experimental study, feed force, surface roughness, vibration, cutting tool wear, hardness and abrasive wear values that occurred as a result of milling of Inconel 718 material by means of cryogenically treated and untreated cutting tools were investigated. Three different cutting speeds (35-45-55 m/min) and three different feed rates (0.02-0.03-0.04 mm/tooth) at constant depth of cut (0.2 mm) were used as cutting parameters in the experiments. As a result of the experiments, lower feed forces, surface roughness, vibration and cutting tool wear were obtained with cryogenically treated cutting tools. As the feed rate and cutting speed were increased, it was seen that surface roughness, vibration and feed force values increased. At the end of the experiments, it was established that there was a significant relation between vibration and surface roughness. However, there appeared an inverse proportion between abrasive wear and hardness values. While BUE did not occur during cryogenically treated cutting tools, it was observed that BUE occurred in cutting tools which were not cryogenically treated.

scholarly journals Experimental Investigation on Surface Roughness and Tool Wear in Dry Machining of TiC Reinforced Aluminium LM6 Composite

2013 ◽  
Vol 773-774 ◽  
pp. 339-347 ◽  
Author(s):  
Muhammad Yusuf ◽  
M.K.A. Ariffin ◽  
N. Ismail ◽  
S. Sulaiman
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Feed Rate ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Depth Of Cut ◽  
Carbide Tool ◽  
Dry Machining ◽  
Workpiece Surface ◽  
High Cutting Speed

With increasing quantities of applications of Metal Matrix Composites (MMCs), the machinablity of these materials has become important for investigation. This paper presents an investigation of surface roughness and tool wear in dry machining of aluminium LM6-TiC composite using uncoated carbide tool. The experiments carried out consisted of different cutting models based on combination of cutting speed, feed rate and depth of cut as the parameters of cutting process. The cutting models designed based on the Design of Experiment Response Surface Methodology. The objective of this research is finding the optimum cutting parameters based on workpiece surface roughness and cutting tool wear. The results indicated that the optimum workpiece surface roughness was found at high cutting speed of 250 m min-1 with various feed rate within range of 0.05 to 0.2 mm rev-1, and depth of cut within range of 0.5 to 1.5 mm. Turning operation at high cutting speed of 250 m min-1 produced faster tool wear as compared to low cutting speed of 175 m min-1 and 100 m min-1. The wear minimum (VB = 42 μm ) was found at cutting speed of 100 m min-1, feet rate of 0.2 mm rev-1, and depth of cut of 1.0 mm until the length of cut reached 4050 mm. Based on the results of the workpiece surface roughness and the tool flank wear, recommended that turning of LM6 aluminium with 2 wt % TiC composite using uncoated carbide tool should be carried out at cutting speed higher than 175 m min-1 but at feed rate of less than 0.05 mm rev-1 and depth of cut less than 1.0 mm.

An Experimental Study on Finish Dry Milling of AISI 321 Stainless Steel

2016 ◽  
Vol 861 ◽  
pp. 26-31 ◽  
Author(s):  
Peng Guo ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Jun Wang ◽  
Han Lian Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Tool Wear ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Dry Milling ◽  
Aisi 321 ◽  
Coated Cemented Carbide

The milling of AISI 321 stainless steel which has wide engineering applications particularly in automobile, aerospace and medicine is of great importance especially in the conditions where high surface quality is required. In this paper, L16 orthogonal array design of experiments was adopted to evaluate the machinability of AISI 321 stainless steel with coated cemented carbide tools under finish dry milling conditions, and the influence of cutting speed ( V ), feed rate ( f ) and depth of cut ( ap ) on cutting force, surface roughness and tool wear was analysed. The experimental results revealed that the cutting force decreased with an increase in the cutting speed and increased with an increase in the feed rate or the depth of cut. The tool wear was affected significantly by the cutting speed and the depth of cut, while the effect of the feed rate on the tool wear was insignificant. With the cutting speed increased up to 160 m/min, a decreasing tendency in the surface roughness was observed, but when the cutting speed was further increased, the surface roughness increased. The effect of the feed rate and the depth of cut on the surface roughness was slight.

Effect of Tool Wear on Tri-Phase CVD Coated Carbide Tools Life while Turning Al6061

2012 ◽  
Vol 488-489 ◽  
pp. 457-461 ◽  
Author(s):  
Ali Davoudinejad ◽  
Sina Alizadeh Ashrafi ◽  
Abdolkarim Niazi
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Tool Life ◽  
Wear Mechanisms ◽  
Orthogonal Cutting ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Tool Edge ◽  
Product Surface ◽  
Coated Carbide

Aluminum 6061 is a common alloy which is widely used in aerospace and yacht construction industry. Generally machining of aluminum alloys inherently generates high chip sticking on tool face and changes the tool edge geometry, which not only reduces tool life but also impairs the product surface quality. This study investigated the tool life and tool wear mechanisms besides evaluating surface roughness in various cutting conditions to attain finest possible surface with minimum tool wear. Turning experiments performed under dry orthogonal cutting of Al6061 using carbide CVD tri-phase coated inserts with constant depth of cut, various cutting speeds and feed rates. Insert’s flank and rake faces analyzed to assess wear mechanisms. Additionally Scanning electron microscope (SEM) employed to clarify different types of wear. Surface integrity and effect of built up edge in deviating surface roughness were studied in each cutting condition. Additionally results of experiments demonstrated that built up edge took over cutting edge and with sacrificing surface roughness, tool life increased by decreasing pace of abrasive wear propagation on flank face. According to these experiments the main reasons of flank wear were abrasive and adhesion of aluminum on tool face.

scholarly journals An Improved Cutting Force Model in Micro-milling Considering the Comprehensive Effect of Tool Runout, Size Effect and Tool Wear

2021 ◽  
Author(s):  
Tongshun Liu ◽  
Yayun Liu ◽  
Kedong Zhang
Keyword(s):  
Tool Wear ◽  
Size Effect ◽  
Cutting Force ◽  
Cutting Edge ◽  
Micro Milling ◽  
Force Model ◽  
Force Coefficient ◽  
Tool Runout ◽  
Cutting Edge Radius ◽  
Edge Radius

Abstract Tool runout, cutting edge radius-size effect and tool wear have significant impacts on the cutting force of micro-milling. In order to predict the micro-milling force and the machining performance related to the cutting force, it is necessary to establish a cutting force model including tool runout, cutting edge radius and tool wear. In this study, an instantaneous uncut thickness (IUCT) model considering tool runout, a nonlinear shear/ploughing coefficient model including cutting-edge radius and a friction force coefficient model embedded with flank wear width, are constructed respectively. By integrating the IUCT, the nonlinear shear/ploughing coefficient and the friction force coefficient, a comprehensive micromilling force model including the tool runout, size effect and tool wear is derived. Experiment results show that the proposed comprehensive model is efficient to predict the micro milling force.

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.  

Finish Cutting of Carbide Mold with Thermally Affected Layer by Diamond Tool

2012 ◽  
Vol 565 ◽  
pp. 382-387
Author(s):  
Kazuki Imazato ◽  
Koichi Okuda ◽  
Hiroo Shizuka ◽  
Masayuki Nunobiki
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Force ◽  
Diamond Tool ◽  
Depth Of Cut ◽  
Good Surface ◽  
Finish Cutting ◽  
Ultra Precision ◽  
Cutting Experiments ◽  
Edm Process

This paper deals with finish cutting of thermally affected layer on cemented carbide by a diamond tool in order to machine efficiently the carbide mold with high accuracy and good surface without a polishing. The microstructure of thermally affected layer left by EDM process was observed and analyzed by EPMA. Its hardness and thickness were measured. Subsequently, the cutting experiments were carried out by using a PCD tool and an ultra-precision cutting machine. The effects of the thermally affected layer on the surface roughness, the cutting force and the tool wear were investigated. As a result, it was confirmed that the cutting force decreased with an increase in the depth of cut. Furthermore, it was found that the tool wear and the surface roughness obtained by cutting the thermally affected layer were greater than those of the original workpiece.

Investigation on Cutting Forces and Surface Finish in Mechanical Micro Milling of Zr-Based Bulk Metallic Glass

2019 ◽  
Vol 18 (01) ◽  
pp. 113-132
Author(s):  
Debajyoti Ray ◽  
Asit Baran Puri ◽  
Nagahanumaiah
Keyword(s):  
Surface Roughness ◽  
Metallic Glass ◽  
Cutting Force ◽  
Bulk Metallic Glass ◽  
Cutting Parameters ◽  
Milling Process ◽  
Spindle Speed ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Axial Depth

Precision micro-component fabrication demands suitable manufacturing processes that ensure making of parts with good form and finish. Mechanical micro milling represents a flexible and powerful process that exhibits enhanced capability to create micro features. Bulk metallic glass (BMG) represents a young class of amorphous alloy material with superior mechanical and physical properties and finds appreciable micro scale applications like biomedical devices and implants, micro parts for sport items and various other micro- components. In the present work, an attempt has been made to analyze the influence of the cutting parameters like spindle speed, feed per tooth and axial depth of cut on the machinability of BMG, in mechanical micro-milling process. The micro-milling process performances have been evaluated concerning to cutting forces and surface roughness generated, by making full slots on the workpiece with solid carbide end mill cutters. The paper presents micro-machining results for bulk metallic glass machined with commercial micro-milling tool at low cutting velocity regime. Response surface methodology (RSM) has been employed for process modeling and subsequent analysis to study the influence of the combination of cutting parameters on responses within the selected domain of cutting parameters. It has been found that the effect of axial depth of cut on the cutting force components is remarkably significant. Cutting force components increases with the increase in axial depth of cut and decreases with increase in spindle speed. At low feed rate, cutting force in the feed direction (Fx, i.e., cutting force along x-direction) increases with a decrease in feed rate. This increase of force could be due to the possible ploughing effect. A similar pattern of variation has been observed with cutting force component in cross-feed direction (Fy) also. It has been found that effect of feed per tooth on the roughness parameter Ra is remarkably significant. Surface roughness increases with feed per tooth. Axial depth of cut does not contribute much to the surface roughness. Surface roughness decrease with the increase of spindle speed.

Minimal quantity cooling lubrication in turning of Ti6Al4V: Influence on surface roughness, cutting force and tool wear

2015 ◽  
Vol 231 (9) ◽  
pp. 1542-1558 ◽  
Author(s):  
Salman Pervaiz ◽  
Ibrahim Deiab ◽  
Amir Rashid ◽  
Mihai Nicolescu
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Cutting Force ◽  
Tool Life ◽  
Heat Dissipation ◽  
Elevated Temperatures ◽  
Chemical Reactivity ◽  
Machining Performance ◽  
Minimal Quantity

Titanium alloys generally show low machinability ratings. They are referred as difficult-to-cut materials due to their inherent properties such as low thermal conductivity, high chemical reactivity and high strength at elevated temperatures. Cooling strategies play an important role to improve the machining performance of the cutting process. In order to facilitate the heat dissipation from the cutting zone, generous amount of coolant is used when machining highly reactive metals such as titanium alloys. Generally, cutting coolants are nominated as pollutants due to their non-biodegradable nature. This article presents experimental evaluation of a minimal quantity cooling lubrication system. The study investigates a combination of sub-zero-temperature air and vegetable oil–based mist as possible environmentally benign alternative to conventional cooling methods. The results are compared with the dry and flood cutting environments as well. Machinability was evaluated experimentally by considering the surface finish, cutting forces, tool life and their associated tool wear mechanisms. It was concluded from the results obtained from the surface roughness, cutting force and tool life investigation that minimal quantity cooling lubrication (internal) cooling strategy has encouraging potential to replace the conventional flood cooling method.

scholarly journals Analysis of Influence of Spindle Speed and Feeding Speed to Tool Wear and Surface Roughness

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
D.L Zariatin
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Tool Life ◽  
Metal Cutting ◽  
Close Relation ◽  
Spindle Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Feeding Speed ◽  
Machining Parameter

One of the problem in metal cutting is tool wear. Its close relation to the expected tool life and quality of product, make tool wear become object of investigation. Eventough tool manufacturers always give recommendation on machining parameter, but they don't share the information on tool wear estimation. Some theory on tool wear has been proposed, but still need verification thru experimental works to determine parameters and constants of tool life typical to machine tool condition and machining process. In this research, experimental work and analysis of the influence of spindle speed (n, rpm), feeding speed (Vf, mm/min) and depth of cut (ap, mm)to surface roughness and tool wear on milling process using carbide ballnose with diameter of 10 mm on Al-7075 had been conducted. From the experiment, it can be concluded that tool wear has influence on surface roughness of product. Tool wear could be minimized by choosing optimum spindle speed and feeding speed.

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