scholarly journals Influence of dressing strategy on tool wear and performance behavior in grinding of forming tools with toric grinding pins

2021 ◽  
Author(s):  
Berend Denkena ◽  
Alexander Krödel-Worbes ◽  
Michael Keitel ◽  
Philipp Wolters
Keyword(s):  
Tool Wear ◽  
Residual Stresses ◽  
Cross Sections ◽  
Wear Behavior ◽  
Grinding Tool ◽  
Vitrified Bond ◽  
And Performance ◽  
Forming Tools ◽  
G Ratio ◽  
Compressive Residual Stresses

AbstractThe performance of grinding tools in grinding processes and the resulting surface and subsurface properties depend on various factors. The condition of the grinding tool after dressing is one of these factors. However, the influence of the dressing process on the condition of the grinding tool depends on the selected process parameters and is difficult to predict. Therefore, this paper presents an approach to describe the influence of the dressing process on tool wear of toric grinding pins and the resulting subsurface modification. For this purpose, toric grinding pins with a vitrified bond were dressed with two different strategies and the wear and operational behavior were investigated when grinding AISI M3:2 tool steel with two different grinding strategies. In general, the investigations have shown that the dressing process influences the performance and wear behavior differently depending on the grinding strategy used. The degree of clogging is influenced by the geometric contact sizes. In the case of small engagement cross sections with simultaneously large contact lengths the thermal tool load is distributed over a small annular area of the tool and favors clogging. Crushing and additional transverse loading of the grains result in an almost clog-free tool surface. This also leads to a lower G-ratio. Crushing leads to an intensified decrease of the torus radii. The influence of the dressing strategy can also be observed in the induced residual stresses. Toric grinding pins dressed by crushing induce lower compressive residual stresses into the workpiece, which can be attributed to the self-sharpening effect. This effect reduces the mechanical and thermomechanical load of the workpiece during machining.

Effective Lifetime Estimate of Crimped Powerline Splice Connector Operated at High Temperature

2008 ◽  
Author(s):  
John Jy-An Wang ◽  
Edgar Lara-Curzio ◽  
Tom King ◽  
Ke An ◽  
Camden Hubbard
Keyword(s):  
High Temperature ◽  
Residual Stresses ◽  
Transmission Lines ◽  
Power Transmission ◽  
Accelerated Aging ◽  
Accurate Estimate ◽  
Power Transmission Lines ◽  
Effective Lifetime ◽  
And Performance ◽  
Compressive Residual Stresses

This paper addresses the thermal-mechanical properties and performance characteristics of full tension splice connectors under high temperature operation, in particular those used in overhead transmission and distribution lines. Due to the increase in power demand existing overhead power transmission lines often need to operate at temperatures higher than those originally considered for their design. This has led to the accelerated aging and degradation of splice connectors. The compressive residual stresses induced by the crimping process within the splice connector provide the clamping forces to secure the conductor and therefore, the determination of the state of compressive residual stresses in splice connectors is a necessary requirement to provide an accurate estimate of their service lifetime. This paper presents a protocol for integrating analytical and experimental approaches to evaluate the integrity of a full tension single-stage splice connector assembly.

Effect of Tool Wear on Rolling Contact Fatigue Performance of Superfinish Hard Machined Surfaces

2008 ◽  
Author(s):  
Youngsik Choi ◽  
C. Richard Liu
Keyword(s):  
Tool Wear ◽  
Residual Stresses ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
The State ◽  
Rolling Contact ◽  
Fatigue Performance ◽  
Nose Radius ◽  
Compressive Residual Stresses ◽  
Machined Surfaces

This study investigates the effect of tool wear on the rolling contact fatigue performance of superfinish hard machined surfaces. Specimens were machined at two different cutting tool conditions: new and worn tools. The condition of a new tool is defined as the state of an unused tool, while that of a worn tool is defined as the state of a tool after being used for machining 150 identical specimens at the same machining conditions. It is noted that tool wear induces less compressive residual stresses for the specimens machined by square tools, while tool wear induces more compressive residual stresses in a deeper region for the specimens machined by round tools, which have a relatively large tool nose radius. In the micro-hardness distribution, the specimen machined by a worn tool typically shows a more softened layer than the specimen machined by a new tool. The rolling contact fatigue test results indicate that the rolling contact fatigue life of the specimen machined by a new tool is generally longer than that of the specimen machined by a worn tool.

Review on Grinding Tool Wear in Terms of Sustainability

2014 ◽  
Author(s):  
Barbara S. Linke
Keyword(s):  
Tool Wear ◽  
Environmental Sustainability ◽  
Tool Material ◽  
Economic Sustainability ◽  
Wheel Wear ◽  
Material Loss ◽  
Grinding Processes ◽  
Tool Profile ◽  
Grinding Tool ◽  
G Ratio

Products and manufacturing processes need to become more sustainable. Grinding tools and grinding processes are no exception. The wear of grinding tools is an important factor in their grinding performance and affects the grinding process outcome strongly. Different wear mechanisms on the grit and bond level lead to a change in tool profile and sharpness. This paper discusses and defines common terms used in the literature. Wheel wear occurs in three phases, initial wear, steady-state wear, and wheel collapse. In multi-layer tools, a steady self-sharpening state is preferable. This means that tool material loss is intrinsic to grinding processes and needed for the process to function. The G-ratio is a common parameter to evaluate tool life but not exhaustive. Economic, environmental and social sustainability of tool wear touches many different aspects which are sometimes contrary, e.g. in terms of economic sustainability tool manufacturers need tool wear to sell replacements, but tool wear leads to more waste and reduces environmental sustainability.

Fabrication and Performance of Symmetrical Gradient Ceramic Nozzles

2012 ◽  
Vol 472-475 ◽  
pp. 1063-1068
Author(s):  
Jian Xin Deng ◽  
Yang Yang Chen ◽  
You Qiang Xing
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Hot Pressing ◽  
Erosion Resistance ◽  
Gradient Structure ◽  
Erosion Wear ◽  
Entry And Exit ◽  
Air Jet ◽  
And Performance ◽  
Compressive Residual Stresses

A model for the design of symmetrical gradient ceramic nozzles is presented. The purpose is to form compressive residual stresses at the entry and exit of the ceramic nozzle, and to reduce the erosion wear at these areas during abrasive air-jet machining. A SiC/(W,Ti)C ceramic nozzle with symmetrical gradient structure at its entry and exit was produced by hot pressing. The residual stresses inside this layered nozzle in the fabricating process were calculated by means of the FEM. The mechanical properties at individual layers were measured, the microstructure was examined. The erosion wear of this symmetrical gradient ceramic nozzle was investigated and compared with an unstressed reference nozzle. The production of symmetrical gradient structures with compressive residual stresses within the entry and exit of the nozzle has been proved to be a suitable way to obtain ceramic nozzles with superior erosion resistance.

scholarly journals Review on Grinding Tool Wear With Regard to Sustainability

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Barbara S. Linke
Keyword(s):  
Tool Wear ◽  
Wear Mechanisms ◽  
Social Impact ◽  
Worker Safety ◽  
Manufacturing Processes ◽  
Process Stability ◽  
Grinding Processes ◽  
Tool Profile ◽  
Grinding Tool ◽  
And Performance

Manufacturing processes have to become more sustainable. For grinding processes, this means that tool wear and performance need to be critically evaluated in their economic, environmental, and social impact. Tool wear affects several stakeholders. Different wear mechanisms on the grit and bond level lead to a change in tool profile and sharpness. For the user, wear changes tool costs, process stability, and maybe worker safety. Tool manufacturers need tool wear to sell replacements, whereas tool users might not like the higher waste and costs from tool wear but need tool self-sharpening.

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

scholarly journals Deep Learning Approach for Vibration Signals Applications

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3929
Author(s):  
Han-Yun Chen ◽  
Ching-Hung Lee
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Parameters Optimization ◽  
Frequency Spectra ◽  
Vibration Signals ◽  
Bearing Faults ◽  
Time Frequency ◽  
And Performance ◽  
The One ◽  
Short Time

This study discusses convolutional neural networks (CNNs) for vibration signals analysis, including applications in machining surface roughness estimation, bearing faults diagnosis, and tool wear detection. The one-dimensional CNNs (1DCNN) and two-dimensional CNNs (2DCNN) are applied for regression and classification applications using different types of inputs, e.g., raw signals, and time-frequency spectra images by short time Fourier transform. In the application of regression and the estimation of machining surface roughness, the 1DCNN is utilized and the corresponding CNN structure (hyper parameters) optimization is proposed by using uniform experimental design (UED), neural network, multiple regression, and particle swarm optimization. It demonstrates the effectiveness of the proposed approach to obtain a structure with better performance. In applications of classification, bearing faults and tool wear classification are carried out by vibration signals analysis and CNN. Finally, the experimental results are shown to demonstrate the effectiveness and performance of our approach.

scholarly journals Investigation of the Wear Behavior of PVD Coated Carbide Tools during Ti6Al4V Machining with Intensive Built Up Edge Formation

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 266
Author(s):  
M.S.I. Chowdhury ◽  
B. Bose ◽  
S. Rawal ◽  
G.S. Fox-Rabinovich ◽  
S.C. Veldhuis
Keyword(s):  
Tool Wear ◽  
Titanium Alloys ◽  
Wear Behavior ◽  
Cutting Temperature ◽  
Ti6al4v Alloy ◽  
Adhesive Interaction ◽  
Heavy Load ◽  
Micromechanical Properties ◽  
Rough Turning ◽  
Coated Carbide

Tool wear phenomena during the machining of titanium alloys are very complex. Severe adhesive interaction at the tool chip interface, especially at low cutting speeds, leads to intensive Built Up Edge (BUE) formation. Additionally, a high cutting temperature causes rapid wear in the carbide inserts due to the low thermal conductivity of titanium alloys. The current research studies the effect of AlTiN and CrN PVD coatings deposited on cutting tools during the rough turning of a Ti6Al4V alloy with severe BUE formation. Tool wear characteristics were evaluated in detail using a Scanning Electron Microscope (SEM) and volumetric wear measurements. Chip morphology analysis was conducted to assess the in situ tribological performance of the coatings. A high temperature–heavy load tribometer that mimics machining conditions was used to analyze the frictional behavior of the coatings. The micromechanical properties of the coatings were also investigated to gain a better understanding of the coating performance. It was demonstrated that the CrN coating possess unique micromechanical properties and tribological adaptive characteristics that minimize BUE formation and significantly improve tool performance during the machining of the Ti6Al4V alloy.

scholarly journals Thermal Effects on Surface and Subsurface Modifications in Laser-Combined Deep Rolling

2021 ◽  
Vol 5 (2) ◽  
pp. 55
Author(s):  
Robert Zmich ◽  
Daniel Meyer
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Thermal Loads ◽  
Deep Rolling ◽  
Mechanical Loads ◽  
Thermomechanical Process ◽  
Compressive Stresses ◽  
New Process ◽  
Negative Effect ◽  
Compressive Residual Stresses

Knowledge of the relationships between thermomechanical process loads and the resulting modifications in the surface layer enables targeted adjustments of the required surface integrity independent of the manufacturing process. In various processes with thermomechanical impact, thermal and mechanical loads act simultaneously and affect each other. Thus, the effects on the modifications are interdependent. To gain a better understanding of the interactions of the two loads, it is necessary to vary thermal and mechanical loads independently. A new process of laser-combined deep rolling can fulfil exactly this requirement. The presented findings demonstrate that thermal loads can support the generation of residual compressive stresses to a certain extent. If the thermal loads are increased further, this has a negative effect on the surface layer and the residual stresses are shifted in the direction of tension. The results show the optimum range of thermal loads to further increase the compressive residual stresses in the surface layer and allow to gain a better understanding of the interactions between thermal and mechanical loads.

scholarly journals Additive Manufactured 316L Stainless-Steel Samples: Microstructure, Residual Stress and Corrosion Characteristics after Post-Processing

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 182
Author(s):  
Suvi Santa-aho ◽  
Mika Kiviluoma ◽  
Tuomas Jokiaho ◽  
Tejas Gundgire ◽  
Mari Honkanen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Sample Surface ◽  
Post Processing ◽  
Magnesium Chloride Solution ◽  
Manufacturing Method ◽  
Four Point Bending ◽  
Traditional Manufacturing ◽  
Processing Steps ◽  
Compressive Residual Stresses

Additive manufacturing (AM) is a relatively new manufacturing method that can produce complex geometries and optimized shapes with less process steps. In addition to distinct microstructural features, residual stresses and their formation are also inherent to AM components. AM components require several post-processing steps before they are ready for use. To change the traditional manufacturing method to AM, comprehensive characterization is needed to verify the suitability of AM components. On very demanding corrosion atmospheres, the question is does AM lower or eliminate the risk of stress corrosion cracking (SCC) compared to welded 316L components? This work concentrates on post-processing and its influence on the microstructure and surface and subsurface residual stresses. The shot peening (SP) post-processing levelled out the residual stress differences, producing compressive residual stresses of more than −400 MPa in the AM samples and the effect exceeded an over 100 µm layer below the surface. Post-processing caused grain refinement and low-angle boundary formation on the sample surface layer and silicon carbide (SiC) residue adhesion, which should be taken into account when using the components. Immersion tests with four-point-bending in the heated 80 °C magnesium chloride solution for SCC showed no difference between AM and reference samples even after a 674 h immersion.

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