scholarly journals Interaction Mechanism of Thermal and Mechanical Field in KDP Fly-Cutting Process

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 855
Author(s):  
Chenhui An ◽  
Ke Feng ◽  
Wei Wang ◽  
Qiao Xu ◽  
Xiangyang Lei ◽  
...  
Keyword(s):  
Phase Transition ◽  
Inertial Confinement Fusion ◽  
Single Point ◽  
Cutting Temperature ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Dihydrogen Phosphate ◽  
Machined Surface ◽  
Kdp Crystal ◽  
Fly Cutting

As an important nonlinear optical material, potassium dihydrogen phosphate (KDP) crystal is used in high-power laser beams as the core element of inertial confinement fusion. It is the most general method of single point diamond fly-cutting (SPDF) to produce high precision and crack-free KDP surfaces. Nevertheless, the cutting mechanism of such material remains unclear, and therefore needs further analysis. Firstly, the stress field, cutting force and cutting temperature under different working conditions are calculated by a KDP crystal cutting simulation model. Then, the rules and the cause of change and interaction mechanisms of force and temperature are analyzed by comparing the measurement experiments with simulations. Furthermore, the causes of chip formation and micro-cracks on the machined surface are analyzed based on thermo-mechanical coupling and chip morphology. The conclusion can be deduced: Although the temperature has not reached the phase transition temperature during the finishing process, under high cutting speeds and large unformed chip thickness, such as semi-finishing and roughing, the temperature can reach up to 180 °C or higher, and KDP crystals are very likely to phase transition—chip morphology also verifies this phenomenon.

scholarly journals Using polarization control plate to suppress transverse stimulated Raman scattering in large-aperture KDP crystal

2018 ◽  
Vol 36 (4) ◽  
pp. 454-457 ◽  
Author(s):  
Xinmin Fan ◽  
Sensen Li ◽  
Xiaodong Huang ◽  
Jianxin Zhang ◽  
Chunyan Wang ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Inertial Confinement Fusion ◽  
Stimulated Raman Scattering ◽  
Dihydrogen Phosphate ◽  
Inertial Confinement ◽  
Kdp Crystal ◽  
Polarization Control ◽  
Large Aperture ◽  
Control Plate ◽  
Stimulated Raman

AbstractTransverse stimulated Raman scattering (TSRS) is strongly generated in the third-harmonic-generation crystal potassium dihydrogen phosphate (KDP) and can even damage the KDP crystal in inertial confinement fusion drivers. In this work, a method to suppress TSRS is proposed in which the polarization control plate (PCP) is moved to a new position in the existing optical path. The proposed method can suppress TSRS significantly and doubles the laser threshold intensity in KDP crystal when the order of the PCP is 16. This result is attributed to the reduction of the gain length for the Stokes radiation. The proposed method may also be used to suppress other nonlinear effects, including transverse stimulated Brillouin scattering in large-aperture optical components.

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.

A Vacuum Sucking Approach to Preventing Chips from Attaching to Machined Surface in Cutting of KDP Crystals

2010 ◽  
Vol 443 ◽  
pp. 573-581
Author(s):  
Zi Wen Zheng ◽  
Hao Feng Chen ◽  
Yi Fan Dai ◽  
Hang Gao ◽  
Gui Lin Wang ◽  
...  
Keyword(s):  
High Power ◽  
Inertial Confinement Fusion ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Dihydrogen Phosphate ◽  
Inertial Confinement ◽  
Machined Surface ◽  
Kdp Crystals

Potassium Dihydrogen Phosphate (KDP) crystals are used for the key components in high power density solid-state laser for Inertial Confinement Fusion. KDP crystals are mainly machined in the dry cutting condition to avoid ‘Fogging’ of the crystals. The main difficulty identified in dry machining of KDP is chip removal from the machined surface. A vacuum sucking device based on venturi vacuum pump is used to suck the chips during cutting, and the relationship between level of vacuum in cutting zone and the comply air pressure was established. An empirical model for chip emission during turning processes is used to analyze the influence of cutting parameters on the chip emission. The influence of cutting parameters on the removal of chips is investigated. Finally, a face turning of KDP crystals is carried out with the turning parameters of feed rate 1um/rev, depth of cut of 0.8 um/rev and the cutting speed from 1.82m/s to 3.9m/s. A super-smooth surface with chips free in the whole sample is achieved, having the surface roughness of 2.994nm (Ra) measured by AFM. The surface quality achieved satisfies the requirements of KDP crystals implemented in high power lasers.

Chips Morphology Analysis under Graphene Oxide Suspension with Tungsten Carbide Tool in Drilling Ti-6Al-4V

2017 ◽  
Vol 730 ◽  
pp. 289-294 ◽  
Author(s):  
Shuang Yi ◽  
Guang Xian Li ◽  
Song Lin Ding ◽  
John Mo
Keyword(s):  
Graphene Oxide ◽  
Tungsten Carbide ◽  
Chip Formation ◽  
Chip Thickness ◽  
Physical And Mechanical Properties ◽  
Chip Morphology ◽  
Drilling Process ◽  
Machined Surface ◽  
Tungsten Carbide Tool

Recently, titanium alloys have been widely used in industry owing to their excellent physical and mechanical properties. However, the severe cutting conditions such as abrasion, adhesion and high temperature accelerate the rate of chip formation and strongly affect the quality of machined surface. This paper investigates that the effect of the conventional coolant (CC) and graphene oxide suspended (GO) on the drilling process of titanium alloy Ti-6Al-4V using tungsten carbide tools. Here are two main chip formation could be found that zigzag chips and spiral chips. Through the analysis of chip morphology, it was found that under graphene oxide suspended fluid. It can be found that using conventional coolant would form the zigzag chips, while it formed spiral chips when graphene oxide suspended fluid applied. In addition, by analysing the chip free surfaces, the chip lamella stuck and chip flaw happened when conventional fluid used. While the back surfaces could be found that less chip stuck and crack occurred when graphene oxide suspended coolant applied. Finally, chip thickness were investigated that thinner chip thickness was found when graphene oxide suspended fluid used.

Thermal field distribution in fly-cutting of KDP crystal and its influence on chip morphology

2016 ◽  
Vol 24 (8) ◽  
pp. 1948-1955
Author(s):  
汪圣飞 WANG Sheng-fei ◽  
安晨辉 AN Chen-hui ◽  
张飞虎 ZHANG Fei-hui ◽  
游 雾 YOU Wu ◽  
雷向阳 LEI Xiang-yang
Keyword(s):  
Field Distribution ◽  
Thermal Field ◽  
Chip Morphology ◽  
Kdp Crystal ◽  
Fly Cutting ◽  
On Chip

Machinability of the EBM Ti6Al4V in Cryogenic Turning

2015 ◽  
Vol 651-653 ◽  
pp. 1183-1188 ◽  
Author(s):  
Stefano Sartori ◽  
Alberto Bordin ◽  
Stefania Bruschi ◽  
Andrea Ghiotti
Keyword(s):  
Tool Wear ◽  
Liquid Nitrogen ◽  
Surface Integrity ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Fluid ◽  
Cobalt Chromium ◽  
Machined Surface ◽  
Surgical Implants ◽  
Cutting Zone

In machining operations, the adoption of a cutting fluid is necessary to mitigate the effects of the high temperatures generated on the cutting zone, and, therefore, to avoid severe detrimental effects on the tool wear and surface integrity. In the biomedical field, the traditional processes to manufacture surgical implants made of Titanium and Cobalt Chromium Molybdenum alloys involve turning and milling operations. To cool the cutting tool with standard oil emulsions leaves contaminants on the machined surfaces, which require further cleaning steps that are expensive in terms of time and costs. Currently, this limitation is marginally overcome by machining without the coolant; however, as a consequence, severe tool wear and poor surface integrity take place. In the last years, many studies have been conducted on the application of Liquid Nitrogen as a coolant in machining difficult-to-cut materials such as Ti6Al4V. Thanks to its properties to evaporate immediately when getting in contact with the cutting zone, thus living the workpiece and chips dry and clean other than its ability to lower the cutting temperature. The adoption of Liquid Nitrogen as a cooling mean in machining surgical implants may represent an optimum solution enhancing the benefits of dry machining. This work is aimed at evaluating the performances of the Liquid Nitrogen as a coolant in semi-finishing turning of Ti6Al4V produced by Electron Beam Melting, a comparison with dry turning is presented. The alloy machinability in such conditions is evaluated in terms of tool wear, machined surface integrity and chip morphology.

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.

Study on the machining process of micro V-shaped groove by using a revolving tip

2017 ◽  
Vol 232 (9) ◽  
pp. 1523-1537
Author(s):  
Bo Xue ◽  
Yongda Yan ◽  
Gaojie Ma ◽  
Zhenjiang Hu
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Machining Process ◽  
Burr Formation ◽  
Uncut Chip Thickness ◽  
Machined Surface ◽  
Advantages And Disadvantages

This paper proposed a machining method for micro V-shaped grooves, which was achieved by introducing the revolving trajectory on the basis of tip scratching process. By coordinating the revolving direction and the tip orientation, four kinds of revolving scratches were developed which had the revolving radii larger than the groove depths. It was found that there were two revolving scratches among these four being able to eliminate the side burrs and produce much smaller cutting forces during machining grooves compared to the traditional scratch, respectively named as the up-milling of face-forward and the down-milling of edge-forward. By considering the tip geometry in the traditional scratching process, the burr formation has been studied which was mainly affected by the effect of chip interference and the amount of uncut chip thickness. By analyzing the machining trajectory, the undeformed chip, the machined surface and the chip morphology, the reason why the up-milling of face-forward and the down-milling of edge-forward had good performances for machining V-grooves was elucidated in detail. Meanwhile, the differences between these two revolving scratches were discussed, and their advantages and disadvantages were also given.

scholarly journals Morphological Analysis of KDP-Crystal Workpiece Surfaces Machined by Ultra-Precision Fly Cutting

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 432 ◽  
Author(s):  
Dongju Chen ◽  
Shiwei Zhang ◽  
Jingfang Liu ◽  
Chunqing Zha ◽  
Ri Pan
Keyword(s):  
Influencing Factor ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Machined Surface ◽  
Fractal Method ◽  
Kdp Crystal ◽  
Power Spectral ◽  
Ultra Precision ◽  
The Relationship ◽  
Machined Surfaces

Potassium dihydrogen phosphate crystals exhibit excellent nonlinear optical properties that are significantly affected by the surface morphology of the crystal. To comprehensively examine and characterize the morphological features of these crystals, the machined surfaces of workpieces are analyzed using wavelet, fractal, and power spectral density (PSD) methods. First, the fractal method is employed to analyze the features of the machined surfaces of different materials and examine the relationship between the surface roughness and fractal dimension of different materials. Then, the morphological anisotropy of the machined surfaces is analyzed using the two-dimensional PSD method. Based on the orientation of the machined surfaces of the workpieces, the tangential waves on the surfaces are analyzed using wavelet-transform and PSD methods. From a frequency-domain perspective, the scales of various influencing factor signals are identified. Additionally, the frequency range of the spindle vibration is determined based on the machining experiment. On this basis, the cause of the machined surface waviness errors is revealed.

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.

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