scholarly journals Effects of Wet Separated and High Speed Milling Fly Ash Added in High Volume to Cementitious Materials

2020 ◽  
Author(s):  
Usman Haider ◽  
Asif Ali ◽  
Zdeněk Bittnar ◽  
Muhammad Humayon ◽  
Jan Valentin
Keyword(s):  
Fly Ash ◽  
Brown Coal ◽  
Maximum Concentration ◽  
High Speed ◽  
Autogenous Shrinkage ◽  
High Volume ◽  
Cementitious Materials ◽  
Mean Value ◽  
Milling Process ◽  
High Speed Milling

In this research high speed milling was carried out on particles of brown coal raw fly ash, on second layer, and on third layer particles obtained from wet separation of brown coal raw fly ash. Due to milling process, median particle size d50 of raw fly ash, second layer, and third layer reduced by 46 %, 23 %, and 77 %, densities reduced by 11 %, 17 %, and 8 % respectively. Due to milling process, formation of agglomerations was observed, the standard deviation of the chemical composition of each element from the mean value reduced. After milling, high volume cementitious paste mixes were prepared with 60 % cement replacement. Due to the milling process the increase in compressive strength at 28 and 90 days was observed for raw fly ash is 59 % and 16 %, for second layer is 12 % and 15 %, for third layer and milled third layer is 78 % and 75 %. Flexural strength testing showed that due to the milling process the deflections at maximum loads have reduced considerably leading to brittle behavior of milled cementitious specimens. The testing for Mercury Intrusion Porosimetry showed that the cementitious specimens of third layer have maximum concentration of large capillary pores between 0.05 and 10 µm, whereas, all others have maximum concentration of medium capillary pores between 0.01 and 0.05 µm. Autogenous shrinkage of cementitious specimens was measured for first sixteen hours after mixing which showed that the second layer particles have the least shrinkage as compared to all other specimens.

scholarly journals Effect of High Speed Milling Process Parameters on the Milling Force and Surface Topography of AM50A Magnesium Alloy

2018 ◽  
Vol 36 (1) ◽  
pp. 124-131
Author(s):  
Hongji Zhang ◽  
Yuanyuan Ge ◽  
Hong Tang ◽  
Yaoyao Shi ◽  
Zengsheng Li
Keyword(s):  
Magnesium Alloy ◽  
Surface Quality ◽  
High Speed ◽  
Milling Process ◽  
Spindle Speed ◽  
Feed Speed ◽  
Milling Force ◽  
High Speed Milling ◽  
Milling Parameters

Within the scope of high speed milling process parameters, analyzed and discussed the effects of spindle speed, feed rate, milling depth and milling width on milling forces in the process of high speed milling of AM50A magnesium alloy. At the same time, the influence of milling parameters on the surface roughness of AM50A magnesium alloy has been revealed by means of the measurement of surface roughness and surface micro topography. High speed milling experiments of AM50A magnesium alloy were carried out by factorial design. Form the analysis of experimental results, The milling parameters, which have significant influence on milling force in high speed milling of AM50A magnesium alloy, are milling depth, milling width and feed speed, and the nonlinear characteristics of milling force and milling parameters. The milling force decreases with the increase of spindle in the given mill parameters. For the effects of milling parameters on surface quality of the performance, in the milling depth and feeding speed under certain conditions with the spindle speed increases the surface quality of AM50A magnesium alloy becomes better with the feed speed increases the surface quality becomes poor. When the spindle speed is greater than 12000r/min, the milling depth is less than 0.2mm, and the feed speed is less than 400mm/min, the milling surface quality can be obtained easily.

Analysis and Research of High Speed Milling of Thin-Walled Bracket Part Based on UG NX

2010 ◽  
Vol 129-131 ◽  
pp. 256-260
Author(s):  
Yi Shu Hao ◽  
Chuang Hai ◽  
Xin Xing Zhu
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Structural Features ◽  
Milling Process ◽  
Analysis Method ◽  
Three Dimensional Model ◽  
Machining Processes ◽  
Element Analysis ◽  
High Speed Milling ◽  
Tool Paths

Treating high speed milling theory as the guidance, this paper researched high speed milling process of bracket part based on UG NX. Combined with the structural features of bracket part, three dimensional model is built by UG NX CAD and machining processes are worked out after analysis. UG CAM module was applied to fabricate tool paths. At last, finite element analysis method is introduced to study the processing deformation by UG NX NASTRAN module, based on which measures to restrain processing deformations is advanced and processing sequences are optimized.

Compressive strength and hydration of high-volume wet-grinded coal fly ash cementitious materials

2019 ◽  
Vol 206 ◽  
pp. 248-260 ◽  
Author(s):  
Hongbo Tan ◽  
Kangjun Nie ◽  
Xingyang He ◽  
Xiufeng Deng ◽  
Xun Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coal Fly Ash ◽  
High Volume ◽  
Cementitious Materials

Stability Prediction during Thin-Walled Workpiece High-Speed Milling

2009 ◽  
Vol 69-70 ◽  
pp. 428-432 ◽  
Author(s):  
Qing Hua Song ◽  
Yi Wan ◽  
Shui Qing Yu ◽  
Xing Ai ◽  
J.Y. Pang
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Removal Rate ◽  
Cutting Parameters ◽  
Milling Process ◽  
Machining Process ◽  
High Speed Milling ◽  
Thin Walled ◽  
Optimization Of Cutting Parameters ◽  
Free Material

A method for predicting the stability of thin-walled workpiece milling process is described. The proposed approach takes into account the dynamic characteristics of workpiece changing with tool positions. A dedicated thin-walled workpiece representative of a typical industrial application is designed and modeled by finite element method (FEM). The workpiece frequency response function (FRF) depending on tool positions is obtained. A specific 3D stability chart (SC) for different spindle speeds and different tool positions is then elaborated by scanning the dynamic properties of workpiece along the machined direction throughout the machining process. The dynamic optimization of cutting parameters for increasing the chatter free material removal rate and surface finish is presented through considering the chatter vibration and forced vibration. The investigations are compared and verified by high speed milling experiments with flexible workpiece.

Studies on Cutting Forces of High Volume Fraction SiCp/Al Composites with Ultrasonic Vibration High Speed Milling

2011 ◽  
Vol 295-297 ◽  
pp. 785-788 ◽  
Author(s):  
Dao Hui Xiang ◽  
Guang Xi Yue ◽  
Xin Tao Zhi ◽  
Hai Tao Liu ◽  
Bo Zhao
Keyword(s):  
Cutting Forces ◽  
High Speed ◽  
Volume Fraction ◽  
Cutting Speed ◽  
High Volume ◽  
High Volume Fraction ◽  
Matrix Composites ◽  
Machining Performance ◽  
High Speed Milling ◽  
Hard Cutting

The orthogonal method was used for analyzing the machining performance of high volume fraction SiCp/Al metal matrix composites (SiCp/Al MMCs) during high speed milling and ultrasonic high speed milling in this paper. The influence of cutting speed, feed rate and cutting depth on 3-directional forces were investigated. The results show that the cutting forces are decreased due to the cutting mechanism of SiCp/Al MMCs is changed from brittle cutting to ductile cutting during ultrasonic high speed milling. In addition, the chips exist in forms of C-type chips because of increasing rake angles. Ultrasonic high-speed milling is a more highly effective hard cutting way compared with high speed milling.

Study on Finite Element Simulation of the Influence of Cutting Speed on Chip Formation of SiCpAl Composites in High Speed Milling

2014 ◽  
Vol 800-801 ◽  
pp. 290-295
Author(s):  
Chuang Liu ◽  
Shu Tao Huang ◽  
Ke Ru Jiao ◽  
Li Fu Xu
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
High Speed ◽  
Volume Fraction ◽  
Cutting Speed ◽  
High Volume ◽  
High Volume Fraction ◽  
High Speed Milling ◽  
Finite Element Software ◽  
High Efficient

Application prospect of the high volume fraction SiCp/Al composites becomes increasingly widespread, the study of cutting mechanism is important for achieving its high efficient and precision machining. In this paper, a three-dimensional beveled simulation model of high volume fraction SiCp/Al composites on high-speed milling is established by finite element software ABAQUS, the constitutive on model material, the tool-chip contact and the chip separation model is elected reasonably.The paper analyzes the effect of cutting speed on the chip formation and the stress distribution of the material. The results shows that: with the increasing of cutting speed, the chip is easily broken, cutting speed have little impact on the maximum stress of the material.

Tool Overhang Effect on Cutting Force in High Speed Milling

2010 ◽  
Vol 34-35 ◽  
pp. 616-620 ◽  
Author(s):  
Zhen Yu Zhao ◽  
Ying Bin Du ◽  
Lei Ming Zhang ◽  
Bai Liu
Keyword(s):  
Cutting Force ◽  
High Speed ◽  
Milling Process ◽  
Processing Capacity ◽  
High Speed Machining ◽  
High Speed Milling ◽  
Rational Use ◽  
High Speed Impact ◽  
Overhang Length

Based on the amount of tool overhang under different high speed machining experiment, the overhang length on the high speed impact of cutting force in milling process is studies. On the basis, the proposed tool overhang and optimum program are proposed in high speed milling, through the rational use of tools to improve processing capacity of the tool.

Tool Wear Monitoring of High Speed Milling Based on Vibratory Signal Processing

2014 ◽  
Vol 565 ◽  
pp. 36-45
Author(s):  
Hadjadj Abdechafik ◽  
Kious Mecheri ◽  
Ameur Aissa
Keyword(s):  
Signal Processing ◽  
Tool Wear ◽  
Monitoring System ◽  
High Speed ◽  
Milling Process ◽  
Machining Performance ◽  
High Speed Milling ◽  
Tool Wear Estimation ◽  
On Line ◽  
Wear Monitoring

The objective of this study is to develop a process of treatment of the vibratory signals generated during a horizontal high speed milling process without applying any coolant in order to establish a monitoring system able to improve the machining performance. Thus, many tests were carried out on the horizontal high speed centre (PCI Météor 10), in given cutting conditions, by using a milling cutter with only one insert and measured its frontal wear from its new state that is considered as a reference state until a worn state that is considered as unsuitable for the tool to be used. The results obtained show that the first harmonic follow well the evolution of frontal wear, on another hand a wavelet transform is used for signal processing and is found to be useful for observing the evolution of the wavelet approximations through the cutting tool life. The power and the root mean square (RMS) values of the wavelet transformed signal gave the best results and can be used for tool wear estimation. All this features can constitute the suitable indicators for an effective detection of tool wear and then used for the input parameters of an on-line monitoring system. Nevertheless we noted the remarkable influence of the machining cycle on the quality of measurements by the introduction of a bias on the signal; this phenomenon appears in particular in horizontal milling and in the majority of studies is ignored

Dynamics and Stability of Milling Process Considering the Gyroscopic Effects

2009 ◽  
Vol 76-78 ◽  
pp. 624-629 ◽  
Author(s):  
Shan Shan Sun ◽  
W.X. Tang ◽  
H.F. Huang ◽  
Xi Qing Xu
Keyword(s):  
High Speed ◽  
Milling Process ◽  
Depth Of Cut ◽  
Stability Lobe Diagram ◽  
High Speed Milling ◽  
Stability Lobe ◽  
Ultra High Speed ◽  
Resonance Response ◽  
Critical Depth Of Cut ◽  
Gyroscopic Effects

A dynamics model is established considering gyroscopic effects due to high speed rotating spindle-tool system in ultra-high speed milling (USM). The proposed method for predicting stability enables a new 3D stability lobe diagram to be developed in the presence of gyroscopic effects, to cover all the intermediate stages of spindle speed. The influences of the gyroscopic effects on dynamics and stability in USM are analyzed. It is shown that the gyroscopic effects lower the resonance response frequencies of the spindle-tool system and the stable critical depth of cut in ultra-high speed milling.

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