Effects of Preheating Temperature at Primary Shear Zone in Laser Assisted Milling Process

2019 ◽  
Vol 825 ◽  
pp. 45-50
Author(s):  
Kamonpong Jamkamon ◽  
Keiji Yamada ◽  
Katsuhiko Sekiya ◽  
Ryutaro Tanaka

In this paper, preheating temperature was investigated for the laser assisted machining (LAM) of Inconel 718 under different conditions for the milling test. The experimental results show that the requirement of laser power for the particularly preheating temperature proportionally increased with the table speed. The resultant cutting force for sufficient shearing work material in LAM was lower than conventional machining (CM) approximately 11, 21 and 28% for the cutting speed of 30, 50 and 75 m/min, respectively. The tool wear in LAM could be improved at relatively high cutting speed of 75 m/min and the hardness of machined surface in LAM was slightly higher than CM.

2015 ◽  
Vol 787 ◽  
pp. 460-464 ◽  
Author(s):  
M. Vignesh ◽  
K. Venkatesan ◽  
R. Ramanujam ◽  
P. Kuppan

Inconel 718, a nickel based alloys, addressed as difficult to cut material because of hard carbide particle, hardness, work hardening and low thermal conductivity. Improving the machinability characteristics of nickel based alloys is a major anxiety in aircraft, space vehicle and other manufacturing fields. This paper presents an experimental investigation in Laser assisted turning of Inconel 718 to determine the effects of laser cutting parameters on cutting temperature and cutting forces. This nickel alloy has a material hardness at 48 HRC and machined with TICN/Al2O3/TiN tool. This is employed for the manufacture of helicopter rotor blades and cryogenic storage tanks. The experiments were conducted at One-Factor-at-a-Time.The effects of laser cutting parameters, namely cutting speed, feed rate, laser power and laser to work piece angle, on the cutting temperature and cutting force components, are critically analysed and the results are compared with unassisted machining of this alloy. The experiments are conducted by varying the cutting speed at three levels (50, 75, 100 m/min), feed rate (0.05, 0.075 0.1 mm/rev), laser power (1.25 kW, 1.5 kW, 1.75 kW) and at two level laser to work piece angle (60, 75°). At the optimal parametric combinationof laser power 1.5 kW with cutting speed of 75m/min, feed rate of 0.075 mm/min and laser to work piece angle 60°, the benefit of LAM was shown by 18%, 25% and 24% decrease in feed force (Fx), thrust force (Fy) and cutting force (Fz) as compared to those of the conventional machining. Examination of the machined surface hardness profiles showed no change under LAM and conventional machining.


Wear ◽  
2017 ◽  
Vol 376-377 ◽  
pp. 125-133 ◽  
Author(s):  
A.H. Musfirah ◽  
J.A. Ghani ◽  
C.H. Che Haron

Author(s):  
Salar Tavakoli ◽  
Helmi Attia ◽  
Raul Vargas ◽  
Vincent Thomson

Generally, superalloys have superior strength and toughness compared to conventional engineering material. However, while applications for such materials are growing, the improvement of their machinability has not been improved in parallel. Of particular interest to the aerospace industry, are nickel-based superalloys. Inconel 718, which is one type of nickel-based superalloy, is considered difficult-to-machine at room temperature due to the fact that it retains much of its strength at high temperatures. Conventional machining methods applied to these materials results in excessive tool wear and poor surface finish. One approach, which is becoming increasingly popular with difficult-to-machine materials, is laser assisted machining (LAM). This study assesses the effect of LAM on the machinability of Inconel 718 using a triple-layer coated carbide tool in terms of cutting forces, tool wear and surface finish. A focused Nd:YAG laser beam was used as a localized heat source to thermally soften the workpiece prior to material removal. Finishing operations were assumed throughout the experiments. Cutting tests were performed over a wide range of cutting speeds (ranging from 100 to 500 m/min) and feeds (ranging from 0.125 to 0.500 mm/rev) to determine the optimum cutting speed and feed for each tool material. Results showed a significant drop in all three components of cutting force when thermal softening caused by the laser power was in effect. A two to three fold improvement was observed in terms of surface finish and tool wear under LAM conditions when compared to conventional machining.


2013 ◽  
Vol 773-774 ◽  
pp. 370-376
Author(s):  
Muhammad Adib Shaharun ◽  
Ahmad Razlan Yusoff ◽  
Mohammad S. Reza

Titanium is difficult-to-cut materials due to its poor machinability and thermal conductivity when machining at high cutting speed. To overcome this machining titanium alloy problem, this study in interaction between machining structural system and the cutting process are very important. One of the main problems in the cutting process is chatter vibration. Due to chatter problem, the mechanism to suppress chatter named, process damping is a useful method can be manipulated to improve the limited productivity of titanium machining at low speed machining in milling process. In the present study, experiment are conducted to evaluate and study the process damping mechanism in milling using different types of variable tools geometries. These tools are variable he-lix/uniform pitch, variable pitch/uniform helix and variable helix and pitch and uniform helix/pitch. The result showed that the variable helix and pitch tools is very significantly improve process damping performance in machining titanium alloy compare to traditional of regular tools and other irregular tools.


2021 ◽  
Author(s):  
Hüseyin Gürbüz ◽  
Şehmus Baday

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.


Author(s):  
Keith Bourne ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor

In this paper, a mechanical microscribing process is described that combines AFM probe-based microscribing with a five-axis microscale machine tool motion platform in order to achieve high scribing speeds, a large working volume, and the capability of cutting curvilinear patterns of grooves. An experiment is described that demonstrates groove formation, groove shape, and tool wear when long grooves are formed using multiple tool passes. A second more systematic experiment is described in which short-distance single-pass cutting tests were used to explore the effects of cutting speed, nominal tool load, and AFM probe mounting angle on groove geometry, tool wear, effective rake angle, and chip formation. Lastly, an experiment is described in which a long curvilinear groove is cut. It is shown that the most well-formed grooves were cut and acceptable tool wear was achieved, when using a high cutting speed, high nominal tool load, and low probe mounting angle. The capability of cutting grooves as long at 82 mm but with depths of only a few hundred nanometers, using a single tool pass at cutting speeds as high at 25 mm/min is demonstrated.


Author(s):  
Santosh Kumar Sahu ◽  
Saurav Datta

Inconel 718 is a nickel-based super alloy widely applied in aerospace, automotive, and defense industries. Low thermal conductivity, extreme high temperature strength, strong work-hardening tendency make the alloy difficult-to-cut. In contrast to traditional machining, nonconventional route like electro-discharge machining is relatively more advantageous to machine this alloy. However, low thermal conductivity of Inconel 718 restricts electro-discharge machining from performing well. In order to improve the electro-discharge machining performance of Inconel 718, powder-mixed electro-discharge machining was reported in this paper. It was carried out by adding graphite powder to the dielectric media in consideration with varied peak discharge current. The morphology and topographical features of the machined surface including surface roughness, crack density, white layer thickness, metallurgical aspects (phase transformation, crystallite size, microstrain, and dislocation density), material migration, residual stress, microindentation hardness, etc. were studied and compared with that of the conventional electro-discharge machining. Additionally, effects of peak discharge current were discussed on influencing different performance measures of powder-mixed electro-discharge machining. Material removal efficiency and tool wear rate were also examined. Use of graphite powder-mixed electro-discharge machining was found to be better in performance for improved material removal rate, superior surface finish, reduced tool wear rate, and reduced intensity as well as severity of surface cracking. Lesser extent of carbon migration onto the machined surface as observed in powder-mixed electro-discharge machining in turn reduced the formation of hard carbide layers. As compared to the conventional electro-discharge machining, graphite powder-mixed electro-discharge machining exhibited relatively less microhardness and residual stress at the machined surface.


2017 ◽  
Vol 867 ◽  
pp. 165-170
Author(s):  
Isha Srivastava ◽  
Ajay Batish

The aim of this study were to evaluate the performance of PVD (TiAlN+TiN) and CVD (TiCN+Al2O3+TiN) coated inserts in end milling of EN–31 hardened die steel of 43±1 HRC during dry and MQL (Minimum quantity lubrication) machining. The experiments were conducted at a fixed feed rate, depth of cut and varying cutting speed to measure the effect of cutting speed on cutting force and tool wear of CVD and PVD-coated inserts. The performance of CVD and PVD-coated inserts under dry and MQL condition by measuring the tool wear and cutting force were compared. During cutting operation, it was noticed that PVD inserts provide less cutting force and tool wear as compared to the CVD inserts under both dry as well as the MQL condition because PVD inserts have a thin insert coating and CVD inserts have a thick insert coating, but PVD inserts experience catastrophic failure during cutting operation whereas CVD inserts have a capability for continuous machining under different machining. Tool wear has measured by SEM analysis. The result shows that MQL machining provides the optimum results as compared to the dry condition. MQL machining has the ability to work under high cutting speed. As the cutting speed increases the performance of dry machining was decreased, but in MQL machining, the performance of the inserts was increased with increases of cutting speed. MQL machining generates less cutting force on the cutting zone and reduces the tool wear which further increase the tool life.


Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1338
Author(s):  
Lakshmanan Selvam ◽  
Pradeep Kumar Murugesan ◽  
Dhananchezian Mani ◽  
Yuvaraj Natarajan

Over the past decade, the focus of the metal cutting industry has been on the improvement of tool life for achieving higher productivity and better finish. Researchers are attempting to reduce tool failure in several ways such as modified coating characteristics of a cutting tool, conventional coolant, cryogenic coolant, and cryogenic treated insert. In this study, a single layer coating was made on cutting carbide inserts with newly determined thickness. Coating thickness, presence of coating materials, and coated insert hardness were observed. This investigation also dealt with the effect of machining parameters on the cutting force, surface finish, and tool wear when turning Ti-6Al-4V alloy without coating and Physical Vapor Deposition (PVD)-AlCrN coated carbide cutting inserts under cryogenic conditions. The experimental results showed that AlCrN-based coated tools with cryogenic conditions developed reduced tool wear and surface roughness on the machined surface, and cutting force reductions were observed when a comparison was made with the uncoated carbide insert. The best optimal parameters of a cutting speed (Vc) of 215 m/min, feed rate (f) of 0.102 mm/rev, and depth of cut (doc) of 0.5 mm are recommended for turning titanium alloy using the multi-response TOPSIS technique.


2012 ◽  
Vol 488-489 ◽  
pp. 724-728 ◽  
Author(s):  
Tadahiro Wada

Using polycrystalline cubic boron nitride compact (cBN) tools, which have different cBN contents and cBN particle sizes, the influences of both the cBN content and the cBN particle size on tool wear in turning of hardened steel at various cutting speeds was experimentally investigated. Three types of cBN tools (a cBN content of 45-55% and 75%, and a cBN particle size of 0.5 μm and 5 μm, respectively) were tested. Furthermore, three kinds of chamfered and honed cutting edges were also used. The main results obtained are as follows: (1) In the case of the cBN tools with the same cBN particle size of 5.0 μm, the tool life of the cBN tool with a cBN content of 75% was longer than that of the cBN tool with a cBN content of 45% at low cutting speed. However, at high cutting speed, the tool life of the cBN tool with a cBN content of 75% was shorter. (2) The tool life of the cBN tool with both a cBN content of 55% and a cBN particle size of 0.5 μm was the longest. (3) The tool wear of cBN tools decreased with a decrease in chamfer width.


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