Prozessüberwachung beim ultraschallunterstützten Schleifen*/Influence of the tool-workpiece contact on the ultrasonic amplitudes in the grinding process

2018 ◽  
Vol 108 (07-08) ◽  
pp. 513-518
Author(s):  
J. Bruckhoff ◽  
E. Uhlmann
Keyword(s):  
High Hardness ◽  
Grinding Process ◽  
Process Measurement ◽  
Hard Materials ◽  
Grinding Processes ◽  
Technical Ceramics

Hinsichtlich Zähigkeit verbesserte technische Keramiken führen in Kombination mit der materialspezifischen hohen Härte dieser sprödharten Werkstoffe zu Herausforderungen bei der Bearbeitung. Das präzise sowie wirtschaftliche Bearbeiten geschieht daher vorwiegend mit Schleifverfahren. Die Ultraschallunterstützung kann die Produktivität von Schleifprozessen erhöhen. In-Prozess-Messungen der Ultraschallamplitude sollen Aufschluss über die Wechselwirkungen von Werkstück und Werkzeug geben.   Due to improved toughness and material-specific high hardness of technical ceramics, the machining of these brittle-hard materials is challenging. Therefore, precise and economical processing is mainly done by grinding. Ultrasonic support can increase the productivity of grinding processes. In-process measurement of ultrasonic amplitudes provides information about the interaction between the workpiece and the tool.

Study Progress on Grinding Surface Residual Stresses for Nano-Ceramic Coatings

2013 ◽  
Vol 753-755 ◽  
pp. 277-280 ◽  
Author(s):  
Wei Xiang Liu
Keyword(s):  
Residual Stress ◽  
High Hardness ◽  
Ceramic Materials ◽  
Ceramic Coatings ◽  
Grinding Process ◽  
Monitoring And Control ◽  
Surface Residual Stress ◽  
Surface Residual Stresses ◽  
Process Monitoring And Control ◽  
Grinding Mechanism

Nano-ceramic materials had high hardness and wear resistance. Combined with current technology and cost saving, nanostructured coatings technology were carried out, using HVOF ( high velocity oxygen fuel) or plasma spraying technique can obtain high quality ceramic coating on metal substrate. Ceramic coatings produced cracks in the grinding due to grinding surface residual stress. the coatings grinding surface residual stress of engineering ceramics have been researched, grinding surface residual stress in the nanostructured ceramic coatings are being researched. the researches in this field include grinding process modeling, abrasives and grinding parameters, grinding process monitoring and control and realization of the software, the grinding mechanism and grinding damage on the surface, grinding force prediction, on-line detection, grinding on nanocoating material is a multivariable complex process.

Near Optimal Grinding Process Design Using Neural Network and Real Coded Genetic Algorithm

2006 ◽  
Author(s):  
Indrajit Mukherjee ◽  
Pradip Kumar Ray
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Process Design ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Optimization Techniques ◽  
Grinding Process ◽  
Automotive Manufacturing ◽  
Grinding Processes ◽  
Real Coded Genetic Algorithm

A typical grinding process is an essential manufacturing operation and has been considered to be a precise and economical means of shaping the parts into the final products with required surface finish and high dimensional accuracy. The need to economically process hard and tough materials which can withstand varying stress conditions to ensure prolonged service life of parts has become a real challenge for researchers and practitioners. In this context, with the advance development and automation of grinding processes, use of appropriate modelling and optimization techniques has been continually emphasized. In view different types of end product and process requirements in grinding processes, optimization often becomes non-linear, multiple response constrained problem with multi-modal distribution of response quality characteristics. The objective of this study is to apply back propagation neural network modelling technique for prediction of a computer numeric-controlled (CNC) rough grinding process behaviour, and thereby determine overall near optimal process design using real coded genetic algorithm. The study proposes an integrated approach using back propagation neural network algorithm, composite desirability function, and real-coded genetic algorithm. The effectiveness and suitability of the approach is determined based on data analysis of a single-pass 6-cylinder engine liner CNC rough grinding (honing) operation in a leading automotive manufacturing unit in India.

Manufacturing and Properties of Tungsten Carbide-Oxide Composites

2017 ◽  
Vol 742 ◽  
pp. 223-230 ◽  
Author(s):  
Anne Vornberger ◽  
Johannes Pötschke ◽  
Christian Berger
Keyword(s):  
Mechanical Properties ◽  
Tungsten Carbide ◽  
Metal Content ◽  
High Hardness ◽  
Metal Carbide ◽  
Hard Materials ◽  
Binder Free ◽  
Oxide Composites ◽  
Hardness Values ◽  
Binder Metal

Conventional WC-Co hardmetals are widely used in various applications due to their excellent properties. High hardness can be achieved using compositions with little to no content of cobalt or nickel. These binder metals are hazardous to health, making a substitution not only desirable because of availability and cost reasons. A new possibility to manufacture such hard materials is the combination of tungsten carbide with oxides such as Al2O3 and ZrO2. In this way the binder metal content can be replaced. Furthermore the content of the also expensive WC can be reduced. Such metal carbide – oxide composites with oxide contents between 16 vol% and 40 vol% were manufactured. The completely dense composites feature high hardness values of 2000 HV10 to 2400 HV10 while also having an acceptable fracture toughness of up to 7 MPa⋅m1/2. The improved mechanical properties make the replacement of WC-Co hardmetals and binder free WC ceramics in special areas possible.

Experimental Investigation of Residual Stresses after Heat Treatment and Grinding Processes in the Production of Ball Bearing Rings

2008 ◽  
Vol 571-572 ◽  
pp. 27-32 ◽  
Author(s):  
Volkan Güley ◽  
A. Erman Tekkaya ◽  
Turhan Savaş ◽  
Feridun Özhan
Keyword(s):  
Heat Treatment ◽  
Experimental Investigation ◽  
Residual Stresses ◽  
Process Parameters ◽  
Treatment Process ◽  
Ball Bearing ◽  
Grinding Process ◽  
Heat Treatment Process ◽  
Grinding Processes ◽  
Bearing Rings

Experimental investigation of residual stresses after heat treatment and grinding processes in the production of ball bearing rings has been carried out. The residual stresses were measured by X-ray diffraction method utilizing chromium radiation, which has an average penetration depth of 5 μm incident on 100Cr6 (AISI-E52100) ball bearing steel. The process parameters of heat treatment and grinding processes were varied so as to represent the extreme values that can be applied in the respective processes. Hardness and percent retained austenite limit the heat treatment process parameters; while roundness, surface roughness and form the grinding process. Tensile surface residual stresses on the raceway of ball bearing rings changes to compression after grinding in both circumferential and axial directions. In grinding relatively higher compressive stresses were measured in axial direction compared to the circumferential direction. This experimental investigation also showed that the influence of heat treatment process parameters on the magnitude and distribution of residual stresses survived even after grinding process; i.e. heat treatment and grinding processes cannot be evaluated independently in process design for favourable residual stresses.

Plastic Deformation of Nanometric Grinding Process for FCC Metal

2010 ◽  
Vol 154-155 ◽  
pp. 1336-1341
Author(s):  
Wei Wen Zhang ◽  
Gang Guo ◽  
Yun Huang ◽  
Zhi Huang
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Grinding Process ◽  
Face Centered Cubic ◽  
Grinding Processes ◽  
Cubic Structure ◽  
Simulation Results ◽  
Face Centered ◽  
Dislocation Defects ◽  
Fcc Metal

This paper focuses on the simulations of nanometric grinding process on face centered cubic structure (FCC) single metal crystals (Cu, Ni) using Molecular dynamics. In order to analyze the plastic deformation of sample metals in nanometric grinding processes, we propose an approach using techniques of central symmetry parameters and neighbor changing ratios. The simulation results show that besides the normal dislocation defects, weak slipping defects locating on {111} crystal planes are found under the surface layer. In addition, the distribution of the neighbor changing ratio indicates that the nano grinding processes will likely cause the global plastic deformation in the surface layer.

Simulation Analysis and In-Process Measurement of the Workpiece Temperature Distribution in Large Surface Grinding

2015 ◽  
Vol 656-657 ◽  
pp. 353-356
Author(s):  
Takashi Onishi ◽  
Moriaki Sakakura ◽  
Yusuke Nakano ◽  
Makoto Harada ◽  
Kazutoshi Kawakami ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Power Consumption ◽  
Simulation Analysis ◽  
Surface Grinding ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Measured Temperature ◽  
Shape Error ◽  
Analysis Method ◽  
Process Measurement

In surface grinding, the shape error is occurred by the thermal deformation of a ground workpiece. To finish the workpiece with high accuracy, it is necessary to understand the temperature distribution of the workpiece during grinding process. However there is no study to analyze the temperature distribution of a large workpiece during surface grinding process. In this study, an advanced simulation analysis method of the temperature distribution for a large workpiece was developed. In the developed simulation analysis method, the temperature distribution was calculated from the power consumption of the wheel motor. The power consumption can be obtained easily without any specialized equipment. To evaluate the developed simulation analysis method, in-process measurement of the temperature distribution of a large workpiece was also carried out. A large workpiece ground in this study weights about 1.3 tons. The temperature distribution was measured with thermistors mounted in many places of the ground workpiece. At the area close to the grinding surface, it was found that temperature rises immediately after the passage of grinding wheel with measuring the developed in-process measurement system. On the other hand, at the area far from the grinding point, temperature does not change quickly. The in-process measured temperature distribution agreed well with the simulated results.

A Crossover from High Stiffness to High Hardness: The Case of Osmium and Its Borides

2016 ◽  
Vol 71 (9) ◽  
pp. 831-836
Author(s):  
Yongming Bian ◽  
Xiaomei Liu ◽  
Anhu Li ◽  
Yongcheng Liang
Keyword(s):  
Transition Metal ◽  
Light Element ◽  
High Hardness ◽  
First Principles Calculations ◽  
Superhard Materials ◽  
Great Expectations ◽  
Hard Materials ◽  
High Stiffness ◽  
Valence Electron Density ◽  
Metal Borides

AbstractTransition-metal light-element compounds are currently raising great expectations for hard and superhard materials. Using the widely attracting osmium (Os) and its borides (OsB, Os2B3 and OsB2) as prototypes, we demonstrate by first-principles calculations that heavy transition metals, which possess high stiffness but low hardness, can be converted into highly hard materials by incorporating of light elements to form compounds. Such a crossover is a manifestation that the underlying sources of high stiffness and high hardness are fundamentally different. The stiffness is related to elastic deformation that is closely associated with valence electron density, whereas the hardness depends strongly on plastic deformation that is determined by bonding nature. Therefore, the incorporation of light atoms into transition metal should be a valid pathway of designing hard and superhard materials. This strategy is in principle also applicable to other transition-metal borides, carbides, and nitrides.

Development on Micro Precision Truing Method of ELID-Grinding Wheel (1st Report: Principle & Fundamental Experiments)

2005 ◽  
Vol 291-292 ◽  
pp. 207-212 ◽  
Author(s):  
Hitoshi Ohmori ◽  
Shao Hui Yin ◽  
Wei Min Lin ◽  
Yoshihiro Uehara ◽  
Shinya MORITA ◽  
...  
Keyword(s):  
High Precision ◽  
High Efficiency ◽  
High Hardness ◽  
Experimental Results ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Elid Grinding ◽  
High Toughness ◽  
Diamond Grinding

Metal bonded diamond grinding wheels are widely used in the grinding process, especial in ELID grinding. However, truing is difficult owing to the high toughness of metal bond materials and high hardness of diamond abrasives. To realize high precision and high-efficiency truing, we propose a new micro-truing method consisting of electro-discharge truing and electrolysis-assisted mechanical truing in this paper. The process principle and fundamental experimental results are introduced, and the truing performance is discussed. Research results show that the proposed new method is effective for truing metal bonded diamond grinding wheels.

scholarly journals Development of New Structural Materials with Improved Mechanical Properties and High Quality of Structures through New Methods

2016 ◽  
Vol 5 (3) ◽  
pp. 52
Author(s):  
Salokhiddin Nurmurodov ◽  
Alisher Rasulov ◽  
Nodir Turakhodjaev ◽  
Kudratkhon Bakhadirov ◽  
Lazizkhan Yakubov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
High Hardness ◽  
Structural Materials ◽  
Practical Implementation ◽  
Hard Alloys ◽  
Plasma Chemical ◽  
Hard Materials ◽  
Initial Stage

<p class="1Body">Up-to-date science and technology requires further development and wide introduction of new high- performance processes to produce refractory metals. These may include plasma chemical technology of high dispersed powders production. Practical implementation of plasma chemical method in producing and processing of high dispersed powders is in its initial stage. Along with this at the present time the demand for processing of structural materials with improved physical and mechanical properties is now steadily increasing. Such materials have low machinability due to high hardness and durability at high temperatures which results in heavy wear of a cutting tool. To improve the efficiency when processing hard-to-cut materials it is necessary to enhance the tool’s durability; this can be provided by application of new grades of hard alloys received from tungsten nanopowders. New alloy, obtained by the new developed technology, has higher degree of hardness and wear resistance compared with existing alloys and will be intended for hard materials processing.</p>

Laboratory Experiment of New Cutting Materials in Milling Processes

2014 ◽  
Vol 611 ◽  
pp. 467-471 ◽  
Author(s):  
Igor Vilček ◽  
Jozef Kováč ◽  
Jaroslava Janeková
Keyword(s):  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
High Hardness ◽  
Hardened Steel ◽  
Production Costs ◽  
Machining Processes ◽  
Hard Materials ◽  
Removal Processes ◽  
Conventional Machining ◽  
Cutting Tool Materials

The development of manufacturing technology is mostly given by economics, environmental trends and the development of cutting materials and machine tools. Manufacturing is a significant part of the worldwide economy. Machining (material removal processes) represents major part of production costs. This paper yield inquiries into the hard and precise milling with a focus on force effects in experimental machining, tool wear and final surface qualities (roughness, micro hardness). The precision machining of hardened steel differs from conventional machining in terms of the hardness of the workpiece materials and the cutting tool materials that are required. Hard materials are characterized by high hardness (> 45 HRC) and abrasiveness. Machining processes require cutting tools of much higher hardness and also higher resistance of the abrasive wear. Recently developed cubic boron nitride (CBN) and coated sintered carbides cutting tools are considered to have the ability of cutting such as steel. CBN cutting tools show good performance during machining of the hardened steel because of their hot hardness and good fracture toughness.

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