Influence of single and dual cryogenic jets on machinability characteristics in turning of Ti-6Al-4V

Author(s):  
Mozammel Mia ◽  
Nikhil Ranjan Dhar

Based on the necessity of a solid study on the orientation of liquid nitrogen jets in turning, this study investigates the specific cutting energy, surface roughness, chip morphology, chip–tool interface temperature, tool life, and wear of coated carbide tool under the single and duplex jets liquid nitrogen for congenial turning of a hard-to-cut superalloy (Ti-6Al-4V). The single jet was aimed at rake face, whereas the duplex jets were impinged at rake and flank surfaces, simultaneously. Results showed that the later coolant employment method ensured the most favorable machining characteristics, which can be accredited to the extreme cooling by liquid nitrogen jets, in terms of reduced specific cutting energy, temperature, roughness, and admittedly, an increased life of tools. The duplex liquid nitrogen jets prolonged tool life by 60% and 30% compared to dry and single jet assistance, respectively. However, no visible difference in chip formation has been noticed. In recapitulation, the duplex liquid nitrogen jets are established as sustainability promoter as—tool life is increased thus tool cost is reduced, required energy is lessened, temperature is pacified, surface quality is improved, and above all, favorable machinability of Ti-6Al-4V superalloy is attained.

Author(s):  
Anshuman Das ◽  
Miyaz Kamal ◽  
Sudhansu Ranjan Das ◽  
Saroj Kumar Patel ◽  
Asutosh Panda ◽  
...  

AISI D6 (hardness 65 HRC) is one of the hard-to-cut steel alloys and commonly used in mould and die making industries. In general, CBN and PCBN tools are used for machining hardened steel but its higher cost makes the use for limited applications. However, the usefulness of carbide tool with selective coatings is the best substitute having comparable tool life, and in terms of cost is approximately one-tenth of CBN tool. The present study highlights a detailed analysis on machinability investigation of hardened AISI D6 alloy die steel using newly developed SPPP-AlTiSiN coated carbide tools in finish dry turning operation. In addition, a comparative assessment has been performed based on the effectiveness of cutting tool performance of nanocomposite coating of AlTiN deposited by hyperlox PVD technique and a coating of AlTiSiN deposited by scalable pulsed power plasma (SPPP) technique. The required number of machining trials under varied cutting conditions (speed, depth of cut, feed) were based on L16 orthogonal array design which investigated the crater wear, flank wear, surface roughness, chip morphology, and cutting force in hard turning. Out of the two cutting tools, newly-developed nanocomposite (SPPP-AlTiSiN) coated carbide tool promises an improved surface finish, minimum cutting force, longer tool life due to lower value of crater & flank wears, and considerable improvement in tool life (i.e., by 47.83%). At higher cutting speeds, the crater wear length and flank wear increases whereas the surface roughness, crater wear width and cutting force decreases. Chip morphology confirmed the formation of serrated type saw tooth chips.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2799
Author(s):  
Mohammad Shariful Islam Chowdhury ◽  
Bipasha Bose ◽  
German Fox-Rabinovich ◽  
Stephen Clarence Veldhuis

The machining of Ti6Al4V alloy, especially at low cutting speeds, is associated with strong Built-Up Edge (BUE) formation. The PVD coatings applied on cutting tools to machine such materials must have the necessary combination of properties to address such an underlying wear mechanism. The present work investigates and shows that TiB2 PVD coating can be designed to have certain mechanical properties and tribological characteristics that improve machining in cases where BUE formation is observed. Three TiB2 coatings were studied: one low hardness coating and two high hardness coatings with varied coating thicknesses. Wear performances for the various TiB2 coated carbide tools were evaluated while rough turning Ti6Al4V. Tool wear characteristics were evaluated using tool life studies and the 3D wear volume measurements of the worn surface. Chip morphology analyses were done to assess the in-situ tribological performance of the coatings. The micro-mechanical properties of the coatings were also studied in detail to co-relate with the coatings’ performances. The results obtained show that during the rough turning of Ti6Al4V alloy with intensive BUE formation, the harder TiB2 coatings performed worse, with coating delamination on the rake surface under operation, whereas the softer version of the coating exhibited significantly better tool life without significant coating failure.


2020 ◽  
Author(s):  
Sudeep Kumar Singh ◽  
Adarsha Arijit Sahoo ◽  
Biswojit Pattnayak ◽  
Biswo Bhushan Tarai ◽  
A.M. Mohanty

Author(s):  
Aamer Kazi ◽  
Yi-Tang Kao ◽  
Bruce Tai

Abstract Single polycrystalline diamond compact (PDC) cutting is a practical technique to understand the rock-tool interactions in drag-bit type geothermal drilling operations. This paper introduces a rotary cutting method to determine specific cutting energy (SCE) and compares it with the conventional linear cutting method. In this work, granite is selected to represent hard rock formations in geothermal drilling. Cutting tests are conducted on a CNC machine with a realistic cutting speed of 12.7 m/min and several chip loads ranging from 0.08 to 0.25 mm. The cutting force is measured using a dynamometer, and then converted to SCE. The results show that the rotary method produces an inverse relationship between SCE and chip load, whereas the linear method shows the opposite. As a result, the produced SCE by the rotary method tends to be lower than that of the linear method at a higher chip load at and over 0.16 mm. The difference may be attributed to the cutting configuration and associated force components.


2018 ◽  
Author(s):  
Kai Guo ◽  
Bin Yang ◽  
Jie Sun ◽  
Vinothkumar Sivalingam

Titanium alloys are widely utilized in aerospace thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is thus of great importance to understand and quantitatively predict tool life. In this study, the wear of coated carbide tool in milling Ti-6Al-4V alloy was assessed by characterization of the worn tool cutting edge. Furthermore, a tool wear model for end milling cutter is established with considering the joint effect of cutting speed and feed rate for characterizing tool wear process and predicting tool wear. Based on the proposed tool wear model equivalent tool life is put forward to evaluate cutting tool life under different cutting conditions. The modelling process of tool wear is given and discussed according to the specific conditions. Experimental work and validation are performed for coated carbide tool milling Ti-6Al-4V alloy.


2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771061 ◽  
Author(s):  
Duc Tran Minh ◽  
Long Tran The ◽  
Ngoc Tran Bao

In this article, an attempt has been made to explore the potential performance of Al2O3 nanoparticle–based cutting fluid in hard milling of hardened 60Si2Mn steel (50-52 HRC) under different minimum quantity lubrication conditions. The comparison of hard milling under minimum quantity lubrication conditions is done between pure cutting fluids and nanofluids (in terms of surface roughness, cutting force, tool wear, and tool life). Hard milling under minimum quantity lubrication conditions with nanofluid Al2O3 of 0.5% volume has shown superior results. The improvement in tool life almost 177%–230% (depending on the type of nanofluid) and the reduction in surface roughness and cutting forces almost 35%–60% have been observed under minimum quantity lubrication with Al2O3 nanofluids due to better tribological behavior as well as cooling and lubricating effects. The most outstanding result is that the uncoated cemented carbide insert can be effectively used in machining high-hardness steels (>50 HRC) while maintaining long tool life and good surface integrity (Ra = 0.08–0.35 µm; Rz = 0.5–2.0 µm, equivalent to finish grinding) rather than using the costlier tools like coated carbide, ceramic, and (P)CBN. Therefore, using hard nanoparticle–reinforced cutting fluid under minimum quantity lubrication conditions in practical manufacturing becomes very promising.


2018 ◽  
Vol 22 (Suppl. 5) ◽  
pp. 1459-1470 ◽  
Author(s):  
Predrag Jankovic ◽  
Milos Madic ◽  
Dusan Petkovic ◽  
Miroslav Radovanovic

The problem of cutting difficult-to-machine materials used in the aerospace industry, aircraft industry, and automobile industry, led to the development and application one of today?s most attractive technology for contour cutting - abrasive water jet cutting. For the efficient use of abrasive water jet cutting, it is of great importance to analyze the impact of process parameters on performance indicators, such as cutting quality, productivity, and costs. But also, from the energy utilization point of view, it is very important to analyze the impact of these parameters on the specific cutting energy which represents the amount of energy spent on the removal of material in the unit time. Having this in mind, this study presents the experimental results of abrasive water jet cutting of aluminum alloy with the aim of creating a mathematical model for estimating specific cutting energy as an important indicator of the degree of utilization of the available energy in the cutting process. The mathematical model of the specific cutting energy is explicitly represented as a non-linear function of the process parameters, obtained by the artificial neural network.


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