scholarly journals Influence of CaF2@Al2O3 on Cutting Performance and Wear Mechanism of Al2O3/Ti(C,N)/CaF2@Al2O3 Self-Lubricating Ceramic Tools in Turning

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2922
Author(s):  
Shuai Zhang ◽  
Guangchun Xiao ◽  
Zhaoqiang Chen ◽  
Chonghai Xu ◽  
Mingdong Yi ◽  
...  
Keyword(s):  
Adverse Effect ◽  
Solid Lubricant ◽  
Cutting Temperature ◽  
The Self ◽  
Cutting Performance ◽  
Ceramic Tool ◽  
Ceramic Tools ◽  
Al2o3 Particles ◽  
Better Than

This study aimed at improving the cutting performance of a ceramic tool to which were added solid lubricant particles. We prepared the self-lubricating ceramic tool by adding CaF2@Al2O3 instead of CaF2, and the self-lubricating ceramic tool with Al2O3 as matrix phase, Ti(C,N) as reinforcement phase. The properties of the ceramic tool with different contents of CaF2@Al2O3 and CaF2 were studied by turning 40Cr. Compared with the ceramic tool with 10 vol.% CaF2, the main cutting force and the cutting temperature of the ceramic tool with 10 vol.% CaF2@Al2O3 decreased by 67.25% and 38.14% respectively. The wear resistance and machining surface quality of the ceramic tool with CaF2@Al2O3 were better than the ceramic tool to which were directly added CaF2. The optimal content of CaF2@Al2O3 particles was determined to be 10 vol.%. The addition of CaF2@Al2O3 particles effectively reduces the adverse effect of direct addition of CaF2 particles on the ceramic tool, and plays a role in improving the cutting performance of the ceramic tool.

Cutting Behavior of Self-Lubricating Ceramic Tool in Dry Machining of 40Cr Quenched Steel

2021 ◽  
Vol 871 ◽  
pp. 176-188
Author(s):  
Ben Yuan Wang ◽  
Guang Chun Xiao ◽  
Zhao Qiang Chen ◽  
Ming Dong Yi ◽  
Jing Jie Zhang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Cutting Force ◽  
Solid Lubricant ◽  
Cutting Temperature ◽  
Cutting Parameters ◽  
Ceramic Composites ◽  
Ceramic Tool ◽  
Cutting Depth ◽  
Ceramic Tools

In this paper, the dry cutting performance of Al2O3/TiC-based ceramic composites with nanoCaF2 was studied. Compared with the Al2O3/TiC ceramic tool, the Al2O3/TiC/CaF2 ceramic tool has lower cutting force, cutting temperature and surface roughness when milling 40Cr hardened steel. Three cutting parameters of cutting speed, feed per tooth, and cutting depth were used to conduct orthogonal experiments to study its changing trend. Through testing of cutting force, cutting temperature and surface roughness, and by comparison with ceramic tools without nanosolid lubricant added, the order of influence of three cutting parameters on cutting force, cutting temperature and surface roughness was obtained. The experimental results showed that the cutting force, cutting temperature and surface roughness of Al2O3/TiC/CaF2 ceramic tools containing nanoCaF2 werebetter than those of Al2O3/TiC ceramic tools. The cutting force, the cutting temperature, and the surface roughness were respectively reduced by 16.5%, 25.8% and 43% compared to when no solid lubricant was added. In addition, after adding solid lubricant, the effect of cutting depth on cutting force was significantly reduced. The average friction coefficient of the tool rake surface was 31.1% lower than that of ceramic tools without solid lubricant. In order to explain this phenomenon, through scanning electron microscopy (SEM) scanning and energy spectroscopy (EDS) elemental analysis, the wear reduction mechanism of solid lubricants was analyzed, that is, during the cutting process, nanosolid lubricants precipitated and formed lubricating film on the rake surface of the tool to reduce the friction coefficient. This was also the main reason for reducing the cutting temperature.

Effect of Cutting Speed on Chipping and Wear of the SiAlON Ceramic Tool in Dry Finish Turning of the Precipitation Hardenable IN100 Aerospace Superalloy

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Mohamed A. Shalaby ◽  
Stephen C. Veldhuis
Keyword(s):  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Ceramic Tool ◽  
Finish Turning ◽  
Ceramic Tools ◽  
Sialon Ceramic ◽  
Tool Edge ◽  
Chip Compression Ratio

Inconel 100 (IN100) aerospace superalloy is used in manufacturing aero-engine components that operate at intermediate temperatures. It is considered to be a hard-to-cut material. Chipping of the tool edge is one of the major failure mechanisms of ceramic tools in finish cutting of superalloys, which causes a sudden breakage of the cutting edge during machining. Cutting temperature significantly depends on cutting speed. Varying the cutting speed will affect the frictional action during the machining operations. However, proper selection of the cutting variables, especially the cutting speed, can prevent chipping occurrence. In this work, the influence of controlling the cutting speed on the chipping formation in dry finish turning of IN100 aerospace superalloy using SiAlON ceramic tool has been investigated. Scanning electron microscope (SEM)/energy dispersing spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and three-dimensional wear measurements were used to make the investigations of the worn tool edges. It was found that variations of the cutting speeds in a certain range resulted in the generation of different lubricious and protective tribo-films. The presence of these tribo-films at the cutting region proved essential to prevent chipping of the cutting tool edge and to improve its wear resistance during finish turning of age-hardened IN 100 using SiAlON ceramic tools. Chip compression ratio and calculated values of the coefficient of friction at the tool–chip interface confirmed these results.

Experimental Study on the Cutting Performance of TiC-Based Nanocomposite Ceramic Tools in Turning 40Cr Steel

2011 ◽  
Vol 325 ◽  
pp. 309-314
Author(s):  
Han Lian Liu ◽  
Ming Hong ◽  
Chuan Zhen Huang ◽  
Bin Zou
Keyword(s):  
Flank Wear ◽  
Adhesive Wear ◽  
Cutting Tools ◽  
Cutting Performance ◽  
Rake Face ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Ceramic Tools ◽  
Multi Scale ◽  
40Cr Steel

TiC-based ceramic cutting tools with three different particle size levels of Al2O3 additives were fabricated and tested. Theses tool materials were identified as TA, TA10A5 and TA30A5 respectively in this study. Another commercial cutting material identified as LT55 was used in this study as baseline to investigate cutting performance by comparing the flank wear size. The experimental results showed that multi-scale nanocomposite ceramic tool TA10A5 had much better wear resistance than the other tools when turning at a lower speed. The wear mechanisms were mainly adhesive wear in the rake face. While cutting at a higher speed, the breakage failure occurred for the tools TA10A5 and TA30A5.

Development of Self-Toughening Silicon Nitride Matrix Nanocomposite Ceramic Tools and Cutting Performance

2008 ◽  
Vol 375-376 ◽  
pp. 128-132
Author(s):  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Han Lian Liu
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Cutting Performance ◽  
Hot Press ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Ceramic Tools ◽  
Sintering Processes ◽  
Matrix Nanocomposite ◽  
Scanning Electron

A series of self-toughening silicon nitride matrix nanocomposite ceramic tool materials are fabricated by hot-press technology at different sintering processes. And their microstructure has been observed and analyzed by a scanning electron microscope (SEM). Finally, the tests of mechanical properties and the cutting performance of the new ceramics are presented. The research results showed that the nanocomposite ceramic tool materials GGW20T5 and GGW20TC25 have better mechanical properties and possess a stronger wear resistance in cutting 40Cr alloy steel.

Finite Element Analysis on Green Grinding Ti6Al4V Alloy with Inner-Lubricating Wheel

2013 ◽  
Vol 860-863 ◽  
pp. 1600-1603
Author(s):  
Wen Guo Huo ◽  
Lan Rong Cai ◽  
Shao Juan ◽  
Feng Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Solid Lubricant ◽  
Cutting Temperature ◽  
The Self ◽  
Grinding Temperature ◽  
Element Analysis ◽  
Obvious Effect ◽  
Tc4 Alloy ◽  
Machining Properties

The objective of this work is to model the cutting properties generated during grinding with internal lubricating wheel. Grinding FEM was carried out with this internal lubricating wheel. The machining properties were assessed in terms of grinding temperature. The results showed that an obvious effect in decreasing the cutting temperature can be obtained by reducing the friction coefficient between the self-lubricating wheel and the TC4 alloy through delivering the solid lubricant directly to the surface of the wheel without the use of inner coolant conditions.

Cutting Performance of Ceramic Tools in Turning of Mild Steel

2012 ◽  
Vol 523-524 ◽  
pp. 493-496 ◽  
Author(s):  
Ryutaro Tanaka ◽  
Akira Hosokawa ◽  
Tatsuaki Furumoto ◽  
Takashi Ueda
Keyword(s):  
Mild Steel ◽  
Tool Life ◽  
Cutting Speed ◽  
Alumina Ceramic ◽  
Cutting Performance ◽  
The Other ◽  
Ceramic Tool ◽  
Ceramic Tools ◽  
Coated Carbide ◽  
Standard Steel

This study deals with the cutting performance of ceramic tools in turning of mild steel and BN free-machining steel based on it. The tool lives of ceramic tools in turning standard steel were less than 15 min at the cutting speed 250 m/min. On the other hand, the tool lives in turning of BN free-machining steel were obvious longer than that of standard steel. The tool life of TiC added alumina ceramic tool reached almost 10 hours in the case that the tool life criteria was set at VB=0.3mm. This tool life was twice as long as that of coated carbide tool.

scholarly journals Effect of Number of Home Exercises on Compliance and Performance in Adults Over 65 Years of Age

1999 ◽  
Vol 79 (3) ◽  
pp. 270-277 ◽  
Author(s):  
Kristin D Henry ◽  
Cherie Rosemond ◽  
Lynn B Eckert
Keyword(s):  
Assessment Tool ◽  
Optimal Number ◽  
The Self ◽  
Self Report ◽  
Initial Session ◽  
Correct Alignment ◽  
Quality Of Movement ◽  
And Performance ◽  
Better Than

Abstract Background and Purpose. There is limited research on the effects of the number of exercises a person is told to perform on compliance and performance, as defined by cueing requirements, correct alignment, and quality of movement. Some studies of medication suggest that compliance decreases as the number of medications increases. The purpose of this study was to determine whether older adults comply and perform better (ie, requiring less cueing, exhibiting correct alignment, and exhibiting controlled, coordinated, and continuous movements) when they are asked to do 2, 5, or 8 exercises. Subjects. Subjects were 11 women and 4 men, aged 67 to 82 years (X̄=72.8), who were living independently in their communities. Methods. Subjects were randomly prescribed 2, 5, or 8 general strengthening home exercises. They were instructed on their exercises at an initial session and asked to record the number of repetitions performed each day in a self-report exercise log. At a return session 7 to 10 days later, subjects were scored on their performance of the prescribed exercises using a newly designed assessment tool. Results. The group that was prescribed 2 exercises performed better, as defined by their performance tool score, than the group that was prescribed 8 exercises. The group that was prescribed 5 exercises was not different from the groups that performed 2 or 8 exercises. No differences were found among groups regarding the self-report measurement of compliance. There was a moderate correlation between performance scores and the self-report percentage rates. Conclusion and Discussion. Subjects who were prescribed 2 exercises performed better than subjects who were prescribed 8 exercises. The question of an optimal number of exercises to prescribe to elderly people warrants further study.

Self-Compassion and Quality of Life in Adults Who Stutter

2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd
Keyword(s):  
Quality Of Life ◽  
Social Connectedness ◽  
The Self ◽  
Future Research ◽  
Self Compassion ◽  
Adults Who Stutter ◽  
And Gender ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.

Kepuasan Masyarakat Terhadap Pelayanan Kelurahan Setelah Pemekaran Di Tangerang Selatan

Liquidity ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 151-159
Author(s):  
Pitri Yandri
Keyword(s):  
Public Perception ◽  
Service Personnel ◽  
Urban Services ◽  
Hospitality Workers ◽  
Care Workers ◽  
Before And After ◽  
Cartesian Diagram ◽  
Better Than

The purpose of this study is (1) to analyze public perception on urban services before and after the expansion of the region, (2) analyze the level of people's satisfaction with urban services, and (3) analyze the determinants of the variables that determine what level of people's satisfaction urban services. This study concluded that first, after the expansion, the quality of urban services in South Tangerang City is better than before. Secondly, however, public satisfaction with the services only reached 48.53% (poor scale). Third, by using a Cartesian Diagram, the second priority that must be addressed are: (1) clarity of service personnel, (2) the discipline of service personnel, (3) responsibility for care workers; (4) the speed of service, (5) the ability of officers services, (6) obtain justice services, and (7) the courtesy and hospitality workers.

The Vietnamese Version of the Health-related Quality of Life Measure for Children with Epilepsy (CHEQOL-25): Reliability

MedPharmRes ◽  
2017 ◽  
Vol 1 (1) ◽  
pp. 9-14
Author(s):  
Tri Doan ◽  
Tuan Tran ◽  
Han Nguyen ◽  
◽  
◽  
...  
Keyword(s):  
Quality Of Life ◽  
Good Practice ◽  
The Self ◽  
Self Report ◽  
Health Related Quality ◽  
Life Measure ◽  
Related Quality ◽  
Health Related ◽  
Parent Proxy

Purpose: This study aimed to translate and culturally adapt the self-report and parent-proxy Health-Related Quality of Life Measure for Children with Epilepsy (CHEQOL-25) into Vietnamese and to evaluate their reliability. Methods: Both English versions of the self-report and parent-proxy CHEQOL-25 were translated and culturally adapted into Vietnamese by using the Principles of Good Practice for the Translation and Cultural Adaptation Process. The Vietnamese versions were scored by 77 epileptic patients, who aged 8–15 years, and their parents/caregivers at neurology outpatient clinic of Children Hospital No. 2 – Ho Chi Minh City. Reliability of the questionnaires was determined by using Cronbach’s coefficient α and intra-class correlation coefficient (ICC). Results: Both Vietnamese versions of the self-report and parent-proxy CHEQOL-25 were shown to be consistent with the English ones, easy to understand for Vietnamese children and parents. Thus, no further modification was required. Cronbach’s α coefficient for each subscale of the Vietnamese version of the self-report and parent-proxy CHEQOL-25 was 0.65 to 0.86 and 0.83 to 0.86, respectively. The ICC for each subscale of the self-report and parent-proxy CHEQOL-25 was in the range of 0.61 to 0.86 and 0.77 to 0.98, respectively. Conclusion: The Vietnamese version of the self-report and parent-proxy CHEQOL-25 were the first questionnaires about quality of life of epileptic children in Vietnam. This Vietnamese version was shown to be reliable to assess the quality of life of children with epilepsy aged 8–15 years.

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