Microscale Drilling of Bulk Metallic Glass

2013 ◽  
Vol 1 (4) ◽  
Author(s):  
James Zhu ◽  
Hyun Jin Kim ◽  
Shiv G. Kapoor
Keyword(s):  
Metallic Glass ◽  
Tool Wear ◽  
Bulk Metallic Glass ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Acoustic Emissions ◽  
Chip Morphology ◽  
High Rate ◽  
Burr Height ◽  
Drilling Performance

The microscale drilling performance of a Zr-based bulk metallic glass (BMG) is investigated in this paper. Crystallization, drill temperature, axial force, spindle load (SL), acoustic emissions (AE), chip morphology, hole diameter, and entry burr height are measured and analyzed with varying cutting speed and chip load. The progression of tool wear is assessed using stereo-microscopy techniques. At small chip loads, minimum chip thickness (MCT) is observed to shift cutting mechanics from a shear-dominated to a ploughing-dominated regime. Consequently, evidence of drill instability and larger burr height are observed. As drilling temperatures rise above the glass transition temperature, the BMG thermally softens due to the transition to a super-cooled liquid state and begins to exhibit viscous characteristics. In the tool wear study using tungsten carbide microdrills, rake wear is found to dominate compared to flank wear. This is attributed to a combination of a high rate of diffusion wear on the rake face as well as lower abrasion on the flank due to the decreased hardness from thermal softening-induced viscous flow of BMG.

scholarly journals Investigation of Tool Wear and Chip Morphology in Dry Trochoidal Milling of Titanium Alloy Ti–6Al–4V

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1937 ◽  
Author(s):  
Dongsheng Liu ◽  
Ying Zhang ◽  
Ming Luo ◽  
Dinghua Zhang
Keyword(s):  
Titanium Alloy ◽  
Tool Wear ◽  
Titanium Alloys ◽  
High Efficiency ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Depth Of Cut ◽  
Trochoidal Milling ◽  
Radial Depth

Titanium alloys are widely used in the manufacture of aircraft and aeroengine components. However, tool wear is a serious concern in milling titanium alloys, which are known as hard-to-cut materials. Trochoidal milling is a promising technology for the high-efficiency machining of hard-to-cut materials. Aiming to realize green machining titanium alloy, this paper investigates the effects of undeformed chip thickness on tool wear and chip morphology in the dry trochoidal milling of titanium alloy Ti–6Al–4V. A tool wear model related to the radial depth of cut based on the volume of material removed (VMR) is established for trochoidal milling, and optimized cutting parameters in terms of cutting speed and axial depth of cut are selected to improve machining efficiency through reduced tool wear. The investigation enables the environmentally clean rough machining of Ti–6Al–4V.

scholarly journals Chip Morphology and Delamination Characterization for Vibration-Assisted Drilling of Carbon Fiber-Reinforced Polymer

2019 ◽  
Vol 3 (1) ◽  
pp. 23 ◽  
Author(s):  
Ramy Hussein ◽  
Ahmad Sadek ◽  
Mohamed Elbestawi ◽  
M. Attia
Keyword(s):  
Carbon Fiber ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Geometrical Accuracy ◽  
Carbon Fiber Reinforced

Carbon fiber-reinforced polymers (CFRP) are widely used in the aerospace industry. A new generation of aircraft is being built using CFRP for up to 50% of their total weight, to achieve higher performance. Exit delamination and surface integrity are significant challenges reported during conventional drilling. Exit delamination influences the mechanical properties of machined parts and, consequently, reduces fatigue life. Vibration-assisted drilling (VAD) has much potential to overcome these challenges. This study is aimed at investigating exit delamination and geometrical accuracy during VAD at both low- and high-frequency ranges. The kinematics of VAD are used to investigate the relationship between the input parameters (cutting speed, feed, vibration frequency, and amplitude) and the uncut chip thickness. Exit delamination and geometrical accuracy are then evaluated in terms of mechanical and thermal load. The results show a 31% reduction in cutting temperature, as well as a significant enhancement in exit delamination, by using the VAD technology.

scholarly journals Fractal Characteristics of Chip Morphology and Tool Wear in High-Speed Turning of Iron-Based Super Alloy

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1020
Author(s):  
Xu Zhang ◽  
Guangming Zheng ◽  
Xiang Cheng ◽  
Rufeng Xu ◽  
Guoyong Zhao ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Tool Wear ◽  
High Speed ◽  
Cutting Speed ◽  
Fractal Dimensions ◽  
Chip Morphology ◽  
Color Changes ◽  
Fractal Characteristics ◽  
Iron Based ◽  
Super Alloy

Considering that iron-based super alloy is a kind of difficult-to-cut material, it is easy to produce work hardening and serious tool wear during machining. Therefore, this work aims to explore the chip change characteristics and tool wear mechanism during the processing of iron-based super alloy, calculate the fractal dimensions of chip morphology and tool wear morphology, and use fractals to analyze their change trend. Meanwhile, a new cutting tool with a super ZX coating is used for a high-speed dry turning experiment. The results indicate that the morphology of the chip is saw-tooth, and its color changes gradually, due to the oxidation reaction. The main wear mechanisms of the tool involve abrasive wear, adhesive wear, oxidation wear, coating spalling, microcracking and chipping. The fractal dimension of the tool wear surface and chip is increased with the improvement of cutting speed. This work investigates the fractal characteristics of chip morphology and tool wear morphology. The fractal dimension changes regularly with the change of tool wear, which plays an important role in predicting this tool wear. It is also provides some guidance for the efficient processing of an iron-based super alloy.

Machinability of BMG

2012 ◽  
Vol 521 ◽  
pp. 225-253
Author(s):  
Mustafa Bakkal
Keyword(s):  
High Temperature ◽  
Metallic Glass ◽  
Viscous Flow ◽  
Bulk Metallic Glass ◽  
Light Emission ◽  
Cutting Speed ◽  
Good Surface ◽  
High Cutting Speed ◽  
Exothermic Chemical Reaction ◽  
Good Surface Roughness

This chapter covers the series of machinability evaluation test result and discussions of Zr52.5Ti5Cu17.9Ni14.6Al10bulk metallic glass (BMG). These tests are lathe turning, drilling, milling and preliminary level grinding tests. In the continuous machining methods such as turning, drilling and grinding of BMG, above a threshold cutting speed, the low thermal conductivity of BMG leads to chip temperatures high enough to cause the chip oxidation and associated light emission. The high temperature produced by this exothermic chemical reaction causes crystallization within the chips. Chips morphology suggests that increasing amounts of viscous flow control the chip-removal process. Moreover, viscous flow and crystallization can occur during the machining of the bulk metallic glass, even under the high temperature gradient and strain rate. High cutting speed significantly reduced the forces for BMG machining due to thermal softening. However, in intermittent cutting process which is milling, there is no high temperature problem, special burr formations the rollover and the top burr were observed along the slot and achieved good surface roughness, Ra= 0.113 μm, using conventional WC-Co cutting tool. In each method, tests repeated for the conventional materials for comparison purpose. This study concludes the precision machining of BMG is possible with the selection of feasible tools and process parameters for each method.

Experimental Investigation of Tool Wear and Chip Morphology in Turning Titanium Alloy Ti6Al4V

2014 ◽  
Vol 800-801 ◽  
pp. 81-86
Author(s):  
Zhen Li ◽  
Er Liang Liu ◽  
Teng Da Wang ◽  
Jiao Li ◽  
Yong Chun Zheng
Keyword(s):  
Titanium Alloy ◽  
Tool Wear ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Adhesion Wear ◽  
On Chip ◽  
Titanium Alloy Ti6al4v ◽  
Cutting Experiments

The various feed rate and cutting speed have an important influence on cutting force, tool wear and chip morphology in machining titanium alloy. Cutting experiments are carried out analyzing the titanium alloy Ti6Al4V under different cutting speed and feed rate, the cutting force values are obtained. The analysis results show that the dominant wear pattern is adhesion wear and chipping. And the tool wear also has an influence on chip morphology.

scholarly journals The effect of MQL on tool wear progression in low-frequency vibration-assisted  drilling of CFRP/Ti6Al4V stack material

2021 ◽  
Author(s):  
Ramy Hussein ◽  
Ahmad Sadek ◽  
Mohamed Elbestawi ◽  
Helmi Attia
Keyword(s):  
Tool Wear ◽  
Vibration Amplitude ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Low Frequency ◽  
Drilling Process ◽  
Machining Parameters ◽  
Geometrical Accuracy ◽  
Low Frequency Vibration

Abstract In this paper, the tool wear mechanism in low-frequency vibration-assisted drilling (LF-VAD) of carbon fiber reinforced polymer (CFRP)/Ti6Al4V stacks has been proposed using variably machining parameters. Based on the kinematics analysis, the effect of vibration amplitude on the chip formation, uncut chip thickness, chip radian, and axial velocity was presented. Subsequently, the effect of LF-VAD on the cutting temperature, tool wear, delamination, and geometrical accuracy was presented for different vibration amplitude. The LF-VAD with the utilization of minimum quantity lubricant (MQL) resulted in a successful drilling process of 50 holes, with a 63 % reduction of the cutting temperature. For the rake face, LF-VAD reduced the adhered height of Ti6Al4V by 80 % at low cutting speed and reduced the crater depth by 33 % at the high cutting speed. On the other hand, LF-VAD reduced the flank wear land by 53 %. Furthermore, LF-VAD showed a significant enhancement on the CFRP delamination, geometrical accuracy, and burr formation.

Experimental Investigation of the Machinability of Epoxy Reinforced With Graphene Platelets

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Ishank Arora ◽  
Johnson Samuel ◽  
Nikhil Koratkar
Keyword(s):  
Electron Microscopy ◽  
Tool Wear ◽  
Cutting Force ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Micro Milling ◽  
Polymer Phase ◽  
Material Microstructure ◽  
Machined Surface ◽  
Transmission Electron

The objective of this research is to study the effect of graphene platelet (GPL) loading on the machinability of epoxy-based GPL composites. To this end, micro-milling experiments are conducted on composites with varying GPL content and their results are contrasted against that of plain epoxy. The material microstructure is characterized using transmission electron microscopy and scanning electron microscopy methods. Chip morphology, cutting force, machined surface morphology, and tool wear, are employed as the machinability measures for comparative purposes. At lower loadings of GPL (0.1% and 0.2% by weight), the deformation of the polymer phase plays a major role; whereas, at a higher loading of 0.3% by weight, the GPL agglomerates and interface-dominated failure dictates the machining response. The minimum chip thickness value of the composites decreases with an increase in GPL loading. Overall, the 0.2% GPL composite has the highest cutting force and the lowest tool wear.

Experimental Investigation of the Machinability of Epoxy Reinforced With Graphene Platelets

2012 ◽  
Author(s):  
Ishank Arora ◽  
Johnson Samuel ◽  
Nikhil Koratkar
Keyword(s):  
Electron Microscopy ◽  
Tool Wear ◽  
Cutting Force ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Micro Milling ◽  
Polymer Phase ◽  
Material Microstructure ◽  
Machined Surface ◽  
Transmission Electron

The objective of this research is to study the effect of graphene platelet (GPL) loading on the machinability of epoxy-based GPL composites. To this end, micro-milling experiments are conducted on composites with varying GPL content and their results are contrasted against that of plain epoxy. The material microstructure is characterized using transmission electron microscopy and scanning electron microscopy methods. Chip morphology, cutting force, machined surface morphology, and tool wear, are employed as the machinability measures for comparative purposes. At lower loadings of GPL (0.1% and 0.2% by weight) the deformation of the polymer phase plays a major role, whereas at a higher loading of 0.3% by weight, the GPL agglomerates and interface-dominated failure dictates the machining response. The minimum chip thickness value of the composites decreases with an increase in GPL loading. Overall, the 0.2% GPL composite has the highest cutting force and the lowest tool wear.

scholarly journals Machinability and Surface Generation of Pd40Ni10Cu30P20 Bulk Metallic Glass in Single-Point Diamond Turning

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 4 ◽  
Author(s):  
Jie Xiong ◽  
Hao Wang ◽  
Guoqing Zhang ◽  
Yanbing Chen ◽  
Jiang Ma ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Tool Path ◽  
Single Point ◽  
Chip Morphology ◽  
Diamond Turning ◽  
Surface Generation ◽  
Workpiece Material ◽  
Machined Surface

Pd40Ni10Cu30P20 bulk metallic glass (BMG) is widely used in industrial fields due to its excellent oxidation resistance, corrosion resistance, and thermal stability. However, the lack of research on the machinability and cutting performance of BMG using single-point diamond turning (SPDT) limits its application for engineering manufacturing. In the present research, a series of turning experiments were carried out under different cutting parameters, and the machinability reflected by the quality of machined surface, chip morphology, and tool wear were analyzed. Based on the oxidation phenomenon of the machined surface, a molecular dynamics (MD) simulation was conducted to study the mechanism and suppression of the machined surface oxidation during the cutting. The results show that: (1) The Pd-based BMG had good machinability, where the machined surface roughness could go down to 3 nm; (2) irregular micro/nanostructures were found along the tool path on the outer circular region of the machined surface, which greatly affected the surface roughness; and (3) the cutting heat softened the workpiece material and flattened the tool marks under surface tension, which improved the surface quality. This research provides important theoretical and technical support for the application of BMG in optical mold manufacturing.

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