Experimental Investigation on Tool Wear During the Milling Processes for the Post-Processing of Selective Laser Melted Inconel 718 Alloys

Author(s):  
Dong Min Kim ◽  
Eunju Park ◽  
Namhun Kim ◽  
Hyung Wook Park

The importance of the post-processing is increasing to remove the supporter afterward the additive manufacture process. The machining, known as the material removal process, achieve the high efficiency and rapid process as compared with the others techniques. This paper experimentally investigated the tool wear during the milling operations of the additive manufactured workpieces for the post-processing. The XRD analysis resulted that Inconel 718 powder used in the additive manufacturing has crystal structure FCC, which homologies the chemical compositions in wrought Inconel 718. The selective laser melting process had built the additive manufactured samples with two different orientations. Wrought Inconel 718 was the lowest hardness among the workpieces, whereas the severe tool wear was observed during the milling operation of wrought Inconel 718. The defects as the pores and cavities in the additive manufactured parts lead the low tool wears, even though the high hardness on the surfaces of the SLM Inconel 718. Further, the built orientation dominated the re-melted zone in the SLM parts, the contact between the tool and re-melted zone controlled the tool wears. Therefore, it should consider the built orientations to apply the machining as the post-processes.

2021 ◽  
Vol 1016 ◽  
pp. 1114-1120
Author(s):  
Henryk Paul ◽  
Piotr Bobrowski ◽  
Robert Chulist ◽  
Magdalena M. Miszczyk ◽  
Mariusz Prazmowski

The interplay of various hardening and softening processes during explosive welding and post-processing annealing have been analysed in titanium/copper bimetallic sheets using scanning electron microscopy and microhardness measurements. Severe plastic deformation and intermetallics’ formation are typical processes leading to hardening, whereas dynamic/static recrystallization and the transformation of amorphous phases into crystalline ones lead to softening. In the as-welded state the interfacial layers of both parent sheets are severely deformed. However, they can undergo intense recrystalization in areas near large melted zones. Inside the melted zones a wide variety of chemical compositions can be detected, however, most of the phases do not appear in the Ti-Cu equilibrium phase diagram. The post-processing annealing at 973 K for 1 h leads to full recrystallization of severely deformed layers of parent sheets and transforms the non-equilibrium phases forming melted zone into the equilibrium TiCu4 and Ti3Cu4 ones via spinodal decomposition. Simultaneously, the growth of four intermetallic layers: Ti2Cu, TiCu, Ti3Cu4, TiCu4 situated along the whole interface was detected.


In various machining processes, the vibration signals are studied for tool condition monitoring often referred as wear monitoring. It is essential to overcome unpredicted machining trouble and to improvise the efficiency of the machine. Tool wear is a vital problem in materials such as nickel based alloys as they have high hardness ranges. Though they have high hardness, a nickel based alloy Inconel 718 with varying HRC (51, 53, and 55), is opted as work material for hard turning process in this work. Uncoated and coated carbide tools are employed as cutting tools. Taguchi’s L9 orthogonal array is considered by taking hardness, speed, feed and depth of cut as four input parameters, the number of experiments and the combinations of parameters for every run is obtained. The vibration signals are recorded at various stages of cutting, till the tool failure is observed. Taking this vibration signal data as input to ANOVA and Grey relation analysis (GRA) which categorizes the optimal and utmost dominant features such as Root Mean Square (RMS), Crest Factor (CF), Skewness (Sk), Kurtosis (Ku), Absolute Deviation (AD), Mean, Standard Deviation (SD), Variance, peak, Frequency and Time in the tool wear process


2016 ◽  
Vol 1136 ◽  
pp. 203-208
Author(s):  
Tatsuya Furuki ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Kiyofumi Inaba ◽  
...  

In recent years, the demand for carbon fiber reinforced plastics (CFRP), which have excellent mechanical properties, is increasing in various fields. In particular, the amount of CFRP used accounts for more than 50% of the body structure weight of the state-of-the-art airplanes. Moreover, in such airplanes, stack material, which is a combination of CFRP and titanium alloy (Ti-alloy), is frequently used. Therefore, a novel high-efficiency end-milling technology for cutting CFRP and Ti-alloy simultaneously is required. It is known that for restraining the occurrence of tool wear, diamond coating, which has high hardness, is useful. On the other hand, in the case of machining of Ti-alloy, several problems arise due to the machining heat. Consequently, in this study, we focus on cBN (cubic boron nitride). In order to compare diamond coating and cBN, end-mills, which were electroplated diamond grains, were also fabricated. In this study, as a cutting experiment, side milling of stack material, which is a combination of CFRP and Ti-6Al-4V, was carried out using the fabricated tools. Then, we discuss their cutting performance by measuring the CFRP temperature and chip temperature, tool wear, surface roughness, and surface integrity. As a result, it could be expected to precisely cut the stack material with the fabricated electroplated cBN end-mill. However, it is seen that improvement of the tool shape or the electrodeposition process is required.


2016 ◽  
Vol 68 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Xiaohong Lu ◽  
Zhenyuan Jia ◽  
Hua Wang ◽  
Likun Si ◽  
Yongyun Liu ◽  
...  

Purpose – The paper aims to study the wear and breakage characteristics of coated carbide cutting tools through micro-milling slot experiments on superalloy Inconel 718. Design/methodology/approach – During the micro-milling process, the wear and breakage appearance on the rake face and flank face of the cutting tools, as well as the failure mechanism, have been studied. Furthermore, the wear and breakage characteristics of the micro-cutting tools have been compared with the traditional milling on Inconel 718. Findings – The main failure forms of the micro tool when micro-milling Inconel 718 were tool tip breakage and coating shed on the rake and flank faces of the cutting tool and micro-crack blade. The main causes of tool wear were synthetic action of adhesive abrasion, diffusion wear and oxidation wear, while the causes of abrasive wear were not obvious. Practical implications – The changing trend in tool wear during the micro-milling process and the main reasons of the tool wear are studied. The findings will facilitate slowing down the tool wear and prolonging the tool life during micro-milling Inconel718. Originality/value – The results of this paper can help slow down the tool wear and realize high efficiency, high precision and economical processing of small workpiece or structure of the nickel-based superalloy.


2021 ◽  
Vol 2129 (1) ◽  
pp. 012070
Author(s):  
Syahilia Syahira Safie ◽  
Muhamad Nasir Murad ◽  
Tan Chye Lih

Abstract Inconel 718 is hard to cut material due to its high hardness, high strength at elevated temperatures, low thermal diffusivity and affinity to react with tool materials. The high temperature during machining results in aggressive tool wear and poor hole quality. Therefore, the application of metal cutting fluids (MCF) as a lubricating and cooling agent is very significant in the drilling of nickel-based superalloys such as Inconel 718. The present study embraces these issues by evaluating the performance of non-edible vegetable oils such as castor and neem oil under minimal quantity lubrication (MQL) conditions towards the tool wear and surface roughness. The drilling experiments were carried out using coated (TiAlN) carbide drill with diameter of 6 mm at different cutting speeds of 10 and 20 m/min and a constant feed of 0.015 mm/rev. The results of this study showed that castor oil significantly outperformed the neem oil in drilling performance regarding tool wear and surface roughness.


2019 ◽  
Vol 69 (4) ◽  
pp. 1-8
Author(s):  
Dasari Kondala Rao ◽  
Kolla Srinivas

AbstractIn various machining processes, the vibration signals are studied for tool condition monitoring often referred as wear monitoring. It is essential to overcome unpredicted machining trouble and to improvise the efficiency of the machine. Tool wear is a vital problem in materials such as nickel based alloys as they have high hardness ranges. Though they have high hardness, a nickel based alloy Inconel 718 with varying HRC (51, 53, and 55), is opted as work material for hard turning process in this work. Uncoated carbide, coated carbide and ceramic tools are employed as cutting tools. Taguchi’s L9 orthogonal array is considered by taking hardness, speed, feed and depth of cut as four input parameters, the number of experiments and the combinations of parameters for every run is obtained. The vibration signals are recorded at various stages of cutting, till the tool failure is observed. Taking this vibration signal data as input to ANOVA and Grey relation analysis (GRA) which categorizes the optimal and utmost dominant features such as Root Mean Square (RMS), Crest Factor (CF), Skewness (Sk), Kurtosis (Ku), Absolute Deviation (AD), Mean, Standard Deviation (SD), Variance, peak, Frequency and Time in the tool wear process.


2010 ◽  
Vol 26-28 ◽  
pp. 988-992
Author(s):  
Xin Yu Song ◽  
Jun Zhao

TiAlN/TiN multilayer PVD coated carbide is one of the dominant tool materials for the turning applications of Inconel 718 due to its high hardness, high wear resistance, and high thermal stability. The results of a thorough investigation on TiAlN/TiN multilayer PVD coated carbide inserts were presented for turning Inconel 718. The tool wear of the PVD coated carbide inserts were tested and analyzed at different cutting speeds from 50m/min to 90m/min and different feed rates from 0.1mm/r to 0.4mm/r. The wear patterns and wear mechanisms of PVD coated carbide were analyzed. Results show that the dominant wear patterns are rake face wear, flank wear, micro-chipping, coating delamination, notch wear, built-up edge and breakage. The main wear mechanisms are adhesion, diffusion, abrasive and oxidation.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 951
Author(s):  
Tomáš Primus ◽  
Josef Hlavinka ◽  
Pavel Zeman ◽  
Jan Brajer ◽  
Martin Šorm ◽  
...  

The lifetime and properties of cutting tools and forming moulds can be prolonged and enhanced by the deposition of hard, thin coatings. After a certain period of usage, the coating will deteriorate. Any remaining coating must be removed prior to successful recoating. Laser stripping is a fast and environmentally friendly coating removal method. In this paper, we present laser removal of two types of coatings deposited on a 1.2379 tool steel substrate, namely, an AlTiN coating with high hardness and a DLC C coating with a small coefficient of friction (COF). A powerful nanosecond laser was employed to remove the coating from the substrate with high efficiency, along with suitable residual surface roughness. Measurements were taken of surface roughness, removed depth, and working time on a stripped area of 1 cm2. The samples were evaluated under a microscope, with a 3D profilometer, and by EDS chemical analysis. Successful removal of the coating was confirmed by optical analysis, but detailed chemical characterisation showed that about 30% of the coating element may remain on the surface. Moreover, a working time of less than 7.5 s per cm2 was obtained in this study. In addition, it was shown that the application of a second low energy, high frequency laser beam pass leads to remelting of the peaks of the material and reduced surface roughness.


CIRP Annals ◽  
2021 ◽  
Author(s):  
Volodymyr Bushlya ◽  
Filip Lenrick ◽  
Axel Bjerke ◽  
Hisham Aboulfadl ◽  
Mattias Thuvander ◽  
...  

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