Determination of optimum target values for a tool wear process based on a surrogate variable

2015 ◽  
Vol 84 (9-12) ◽  
pp. 2491-2497 ◽  
Author(s):  
Cheol Eun Jeong ◽  
Hyuck Moo Kwon ◽  
Sung Hoon Hong ◽  
Taeho Park ◽  
Min Koo Lee
Gefahrstoffe ◽  
2020 ◽  
Vol 80 (06) ◽  
pp. 227-233 ◽  
Author(s):  
I. Beslic ◽  
J. Burger ◽  
F. Cadoni ◽  
D. Centioli ◽  
I. Kranjc ◽  
...  

In 2015 the European Joint Research Center (JRC) for air quality in Ispra, Italy, carried out an intercomparison for the determination of PM10 and PM2.5 in ambient air. Five laboratories also analyzed the content of heavy metals (arsenic, cadmium, lead and nickel) in PM10 from filter samples collected during the intercomparison. Thus, all steps from sampling in the field to instrumental quantification of heavy metals in the laboratory could be statistically analyzed. The different techniques of sampling and sample work-up had no significant influence on the analysis results. However, the method of instrumental analysis strongly influenced them: The results of laboratories using the Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) coincided well in most cases. For laboratories using the Energy Dispersed X-Ray Fluorescence (ED-XRF) technique the uncertainty of the results strongly depended on the metal concentration. For cadmium the concentrations generally were too low for analysis by ED-XRF, for arsenic, lead and nickel the relative uncertainties decreased exponentially with increasing concentrations. The relation between metal concentration and the relative uncertainty of analysis results could be described as power functions. Analysis of lead and nickel by ED-XRF is well possible in the range of the EU limit and target values for these metals.


2018 ◽  
Author(s):  
Kai Guo ◽  
Bin Yang ◽  
Jie Sun ◽  
Vinothkumar Sivalingam

Titanium alloys are widely utilized in aerospace thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is thus of great importance to understand and quantitatively predict tool life. In this study, the wear of coated carbide tool in milling Ti-6Al-4V alloy was assessed by characterization of the worn tool cutting edge. Furthermore, a tool wear model for end milling cutter is established with considering the joint effect of cutting speed and feed rate for characterizing tool wear process and predicting tool wear. Based on the proposed tool wear model equivalent tool life is put forward to evaluate cutting tool life under different cutting conditions. The modelling process of tool wear is given and discussed according to the specific conditions. Experimental work and validation are performed for coated carbide tool milling Ti-6Al-4V alloy.


2013 ◽  
Vol 763 ◽  
pp. 51-64
Author(s):  
Mohammed Nouari ◽  
Hamid Makich

To understand the effect of the workpiece microstructure on the tool wear behavior, anexperimental investigation was conducted on machining two different microstructures of supertitanium alloys: Ti-6Al-4V and Ti-555. The analysis of tool-chip interface parameters such asfriction, heat flux and temperature rise and the evolution of the workpiece microstructure underdifferent cutting conditions have been discussed. As cutting speed and feed rate increase, the meancutting forces and temperature show different progressions depending on the consideredmicrostructure. Results show that wear modes for cutting tools used in machining the Ti-555 alloyshow contrast from those exhibited by tools used in machining the Ti6AI4V alloy. In fact, onlyabrasion wear was observed for cutting tools in the case of machining the near-β titanium Ti-555alloy. The last alloy is characterized by a fine-sized microstructure (order of 1 μm). For the usualTi6Al4V alloy, adhesion and diffusion modes followed by coating delamination process on the toolsubstrate have been clearly identified. Moreover, a deformed layer was observed under secondaryelectron microscope (SEM) from the sub-surface of the chip with β-grains orientation along thechip flow direction. The analysis of the microstructure confirms the intense deformation of themachined surface and shows a texture modification, without phase transformation. For the Ti-555β-alloy, β grains experiences more plastic deformation and increases the microhardness of theworkpiece inducing then an abrasion wear process for cemented carbide tools. For the Ti6Al4Vmicrostructure, the temperature rise induces a thermal softening process of the workpiece andgenerates adhesive wear modes for cutting tools. The observed worn tool surfaces confirm theeffect of the microstructure on tool wear under different cutting conditions for the two studiedtitanium alloys.


1999 ◽  
Author(s):  
Konstantinos D. Bouzakis ◽  
Spiros Kombogiannis ◽  
Aristomenis Antoniadis ◽  
Nectarios Vidakis

Abstract Tool wear prediction models for gear hobbing were presented in the first part of this paper. To determine the constants of the equations used in these models, fly hobbing experiments with uncoated and coated HSS tools were conducted. Hereby, it was necessary to modify the fly hobbing kinematics from continuous tangential feed to continuous axial feed. The experimental data were evaluated, and correlated to the analytical ones, elaborated through the described digital simulation of the cutting process. The determined constants of the wear laws for the investigated tools were used in a further developed user friendly software, enabling the prediction of the tool wear accomplishment in gear hobbing. On that account the wear development can be precisely foreseen and the tangential shift of the tool is optimized. The open and modular structure of the developed code enables the continuous enrichment of its database with other type of coating and workpiece materials. With the aid of the aforementioned techniques, the superiority of coated HSS tools in comparison to uncoated ones is also quantitatively exhibited.


2013 ◽  
pp. 213-270

Abstract This chapter covers the practical aspects of machining, particularly for turning, milling, drilling, and grinding operations. It begins with a discussion on machinability and its impact on quality and cost. It then describes the dimensional and surface finish tolerances that can be achieved through conventional machining methods, the mechanics of chip formation, the factors that affect tool wear, the selection and use of cutting fluids, and the determination of machining parameters based on force and power requirements. It also includes information on nontraditional machining processes such as electrical discharge, abrasive jet, and hydrodynamic machining, laser and electron beam machining, ultrasonic impact grinding, and electrical discharge wire cutting.


1989 ◽  
Vol 35 (3) ◽  
pp. 360-363 ◽  
Author(s):  
B L Bacon ◽  
H L Pardue

Abstract Here we describe the evaluation of several data-processing options for the kinetic determination of creatinine by use of the Jaffé reaction. Data-processing options evaluated include initial-rate, two-point fixed-time, rate at t = k-1, and multipoint curve-fitting predictive methods. We evaluated these options for a buffered formulation of the Jaffé reagent and studied the effects of potential interferents, including glucose, acetoacetate, bilirubin, and albumin, on each option. To reduce effects of bilirubin, we evaluated the inclusion of a preoxidation step with ferricyanide. All the data-processing options gave good precision and linearity between the measurement objective and creatinine concentration. However, differences between slopes of calibration plots in aqueous and serum matrices ranged from a high of +60% for the two-point, fixed-time method to a low of -11% for the curve-fitting, predictive method. Standard additions of creatinine to sera were quantified reliably (yielding 96% to 102% of target values) by the predictive method and less reliably (62% to 102%) by the other methods. We conclude that the predictive method has the potential to yield the most reliable results for creatinine.


1997 ◽  
Vol 80 (6) ◽  
pp. 1287-1297 ◽  
Author(s):  
Paul A Brereton ◽  
Paul Robb ◽  
Christine M Sargent ◽  
Helen M Crews ◽  
Roger Wood ◽  
...  

Abstract An interlaboratory study of a graphite furnace atomic absorption spectrophotometry (GFAAS) method for the determination of lead in wine was conducted. Seventeen laboratories from France, United States, and the United Kingdom, using a variety of GFAAS instruments, took part in the study. The method incorporated a novel matrix-matching procedure to minimize matrix effects between standards and samples. Six wine test materials were prepared and sent to participants as 12 blind duplicate or split level samples. There was good agreement between results obtained from participants and target values (24–279 μg/L) obtained with an inductively coupled plasma-mass spectrometry method. The precision of the GFAAS method was well within the range predicted by the Horwitz equation for the 6 test materials analyzed. Repeatability standard deviations ranged from 3 to 17%. Reproducibility standard deviations were in the range of 10 to 30%. The method is recommended for use for official purposes.


Procedia CIRP ◽  
2020 ◽  
Vol 93 ◽  
pp. 1435-1441
Author(s):  
Thomas Junge ◽  
Hendrik Liborius ◽  
Thomas Mehner ◽  
Andreas Nestler ◽  
Andreas Schubert ◽  
...  

2004 ◽  
Vol 50 (8) ◽  
pp. 1396-1405 ◽  
Author(s):  
Marina Patriarca ◽  
Marco Castelli ◽  
Federica Corsetti ◽  
Antonio Menditto

Abstract Background: Lead is an environmental pollutant, and human exposure is assessed by monitoring lead concentrations in blood. Because the main source of environmental exposure has been the use of leaded gasoline, its phase-out has led to decreased lead concentrations in the general population. Therefore, validated analytical methods for the determination of lower lead concentrations in blood (<150 μg/L) are needed. In addition, new ISO standards require that laboratories determine and specify the uncertainty of their results. Methods: We validated a method to determine lead in blood at concentrations up to 150 μg/L by electrothermal atomic absorption spectrometry with Zeeman background correction according to EURACHEM guidelines. Blood samples were diluted (1:1 by volume) with 2 mL/L Triton X-100. NH4H2PO4 (5 g/L) and Mg(NO3)2 (0.5 g/L) were used as modifiers. Matrix-matched standards were used for calibration. Results: We determined the limits of detection (3.1 μg/L) and quantification (9.4 μg/L). Repeatability and intermediate imprecision within the range 35–150 μg/L were <5.5% and <6.0%, respectively. We assessed trueness by use of certified reference materials, by recovery tests, and by comparison with target values of other reference materials (candidate external quality assessment samples). The expanded uncertainty ranged from 20% to 16% (with a confidence level of 95%) depending on concentration. Conclusions: This study provides a working example of the estimate of uncertainty from method performance data according to the EURACHEM/CITAC guidelines. The estimated uncertainty is compatible with quality specifications for the analysis of lead in blood adopted in the US and the European Union.


Sign in / Sign up

Export Citation Format

Share Document