The choice of the ceramic tools in course of the performance-oriented technology process planning

Author(s):  
V. V. Kuzin ◽  
S. N. Grigor'ev ◽  
S. Yu. Fedorov

The strength of different ceramic tools were tested in course of the M-NP alloy turning processing in the wide range of cutting conditions, the high operating characteristics of the tools were defned when using M-05‒M20. The determined regularities were organized and introduced into the information selection system which allowed the ceramic tools choice in course of the technological preparation for the production taking into account the tool's operating performance.Ill.4. Tab. 2. Ref. 30.

2018 ◽  
Vol 245 ◽  
pp. 15002 ◽  
Author(s):  
Roman Davydov ◽  
Valery Antonov ◽  
Dmitry Molodtsov ◽  
Alexey Cheremisin ◽  
Vadim Korablev

The rapid spread of storm floods over large areas requires flood management throughout the river basin by the creation an innovative system of flood control facilities of various functional purposes distributed in the area. The central part of the system is the hydro system with hydro power plant. In addition, the flood control facilities on the side tributaries with self-regulating reservoir are included in the system. To assess the effect of controlling extreme water discharges by flood control facilities, it is necessary to develop special mathematical models reflecting the specifics of their operation. Unified mathematical models of the operation modes of a hydro complex with hydroelectric power station and flood control facility are created. They are implemented in a computer program that provides the ability to determine the main parameters and operating characteristics of hydro systems when performing multivariate calculations in a wide range of initial data. This makes possible specifying the parameters and operation modes of each hydro system with the current economic and environmental requirements, to assess the energy-economic and environmental consequences in the operation of the system of flood control facilities distributed in the area. The article analyses the results of the extreme water discharge’s regulation by the hydro system on the main river and flood control facilities on the side tributaries, considering environmental requirements.


Tribology ◽  
2005 ◽  
Author(s):  
Alexander Bardetsky ◽  
Helmi Attia ◽  
Mohamed Elbestawi

Experimental study has been carried out to establish the effect of cutting conditions (speed, feed, and depth of cut) on the cutting forces and time variation of carbide tool wear data in high-speed machining (face milling) of Al-Si cast alloys that are commonly used in the automotive industry. The experimental setup and force measurement system are described. The test results are used to calibrate and validate the fracture mechanics-based tool wear model developed in Part 1 of this work. The model calibration is conducted for two combinations of cutting speed and a feed rate, which represent a lower and upper limit of the range of cutting conditions. The calibrated model is then validated for a wide range of cutting conditions. This validation is performed by comparing the experimental tool wear data with the tool wear predicted by calibrated cutting tool wear model. The prediction errors were found to be less then 7%, demonstrating the accuracy of the object oriented finite element (OOFE) modeling of the crack propagation process in the cobalt binder. It also demonstrates its capability in capturing the physics of the wear process. This is attributed to the fact that the OOF model incorporates the real microstructure of the tool material.


Author(s):  
Bakhtiyar Ismailov ◽  
Zhanat Umarova ◽  
Khairulla Ismailov ◽  
Aibarsha Dosmakanbetova ◽  
Saule Meldebekova

<p>At present, when constructing a mathematical description of the pyrolysis reactor, partial differential equations for the components of the gas phase and the catalyst phase are used. In the well-known works on modeling pyrolysis, the obtained models are applicable only for a narrow range of changes in the process parameters, the geometric dimensions are considered constant. The article poses the task of creating a complex mathematical model with additional terms, taking into account nonlinear effects, where the geometric dimensions of the apparatus and operating characteristics vary over a wide range. An analytical method has been developed for the implementation of a mathematical model of catalytic pyrolysis of methane for the production of nanomaterials in a continuous mode. The differential equation for gaseous components with initial and boundary conditions of the third type is reduced to a dimensionless form with a small value of the peclet criterion with a form factor. It is shown that the laplace transform method is mainly suitable for this case, which is applicable both for differential equations for solid-phase components and calculation in a periodic mode. The adequacy of the model results with the known experimental data is checked.</p>


1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.


Author(s):  
Subrata Mukherjee ◽  
Xuhui Huang ◽  
Lalita Udpa ◽  
Yiming Deng

Abstract Systems in service continue to degrade with passage of time. Pipelines are among the most common systems that wear away with usage. For public safety it is of utmost importance to monitor pipelines and detect new defects within the pipelines. Magnetic flux leakage (MFL) testing is a widely used nondestructive evaluation (NDE) technique for defect detections within the pipelines, particularly those composed of ferromagnetic materials. Pipeline inspection gauge (PIG) procedure based on line-scans or 2D-scans can collect accurate MFL readings for defect detection. However, in real world applications involving large pipe-sectors such extensive scanning techniques are extremely time consuming and costly. In this paper, we develop a fast and cheap methodology that does not need MFL readings at all the points used in traditional PIG procedures but conducts defect detection with similar accuracy. We consider an under-sampling based scheme that collects MFL at uniformly chosen random scan-points over large lattices instead of extensive PIG scans over all lattice points. Based on readings for the chosen random scan points, we use Kriging to reconstruct MFL readings over the entire pipe-sectors. Thereafter, we use thresholding-based segmentation on the reconstructed data for detecting defective areas. We demonstrate the applicability of our methodology on synthetic data generated using popular finite element models as well as on MFL data collected via laboratory experiments. In these experiments spanning a wide range of defect types, our proposed novel MFL based NDE methodology is witnessed to have operating characteristics within the acceptable threshold of PIG based traditional methods and thus provide an extremely cost-effective, fast procedure with competing error rates that can be successfully used for scanning massive pipeline sectors.


Author(s):  
Chang Liu ◽  
Jacob Dobson ◽  
Peter Cawley

Permanently installed guided wave monitoring systems are attractive for monitoring large structures. By frequently interrogating the test structure over a long period of time, such systems have the potential to detect defects much earlier than with conventional one-off inspection, and reduce the time and labour cost involved. However, for the systems to be accepted under real operational conditions, their damage detection performance needs to be evaluated in these practical settings. The receiver operating characteristic (ROC) is an established performance metric for one-off inspections, but the generation of the ROC requires many test structures with realistic damage growth at different locations and different environmental conditions, and this is often impractical. In this paper, we propose an evaluation framework using experimental data collected over multiple environmental cycles on an undamaged structure with synthetic damage signatures added by superposition. Recent advances in computation power enable examples covering a wide range of practical scenarios to be generated, and for multiple cases of each scenario to be tested so that the statistics of the performance can be evaluated. The proposed methodology has been demonstrated using data collected from a laboratory pipe specimen over many temperature cycles, superposed with damage signatures predicted for a flat-bottom hole growing at different rates at various locations. Three damage detection schemes, conventional baseline subtraction, singular value decomposition (SVD) and independent component analysis (ICA), have been evaluated. It has been shown that in all cases, the component methods perform significantly better than the residual method, with ICA generally the better of the two. The results have been validated using experimental data monitoring a pipe in which a flat-bottom hole was drilled and enlarged over successive temperature cycles. The methodology can be used to evaluate the performance of an installed monitoring system and to show whether it is capable of detecting particular damage growth at any given location. It will enable monitoring results to be evaluated rigorously and will be valuable in the development of safety cases.


Author(s):  
Vipin Sharma ◽  
Caroline C. Hayes

Abstract We present in this paper 1) operation ordering principles and 2) a customizable process planner, Intra-Setup Planner that implements those principles. The principles and the planner focus on sequencing cutting operations within individual setups for three and five axis prismatic milling applications. There is no general agreement on ordering principles largely because different shops have very different needs. To address a wide range of users’ needs, we have designed both the ordering principles and the Intra-Setup Planner to support flexibility rather than providing a single one-size-fits-all prescription for operation ordering. The Intra-Setup Planner provides a convenient user interface, Rule Editor through which users can select the ordering principles that suit their own situation, an automated planner that will follow the user selected principles, and a Plan Editor to allow final adjustments. The combination of flexible principles and user control maximize the strengths of human and machine intelligence.


1999 ◽  
Vol 16 (1) ◽  
pp. 43-47 ◽  
Author(s):  
Laura S. Kenefic ◽  
Ralph D. Nyland

Abstract Sugar maple (Acer saccharum Marsh.) height-diameter and age-diameter relationships are explored in a balanced uneven-aged northern hardwood stand in central New York. Results show that although both height and age vary considerably with diameter, these relationships can be described by statistically valid equations. The age-diameter relationship compares favorably to one reported by Tubbs (1977) for sugar maple in unmanaged (virgin) northern hardwoods, suggesting that periodic cuttings improved growing conditions in our stand. Deliberate attempts to control size-class distribution and tree spacing should continue to increase diameter growth rates and decrease the time needed to reach certain threshold tree sizes. Growth rates that can be reasonably expected in this and similarly structured stands are provided. Lastly, a wide range of heights and diameters are documented, confirming the structural complexity associated with the balanced selection system. An equation to predict sugar maple height from diameter is provided and may prove useful when assessing habitat or visual characteristics of complex uneven-aged stands. North. J. Appl. For. 16(1):43-47.


Author(s):  
E J A Armarego ◽  
D Ostafiev

It has long been recognized that the selection of cutting conditions in process planning should optimize the economic performance of machining operations although it appears that common practice favours the use of ‘recommended’ cutting conditions which are known to be non-optimal. This practice seems to be partly due to the difficulties in establishing equations for the many technological machining performance measures and partly due to the complex nature and slow progress made in developing reliable multi-constraint optimization analyses. This paper presents multi-constraint optimization analyses and computer aided strategies for selecting the ‘optimal’ feeds and speeds in single-pass rough turning operations. The optimization, based on criteria typified by the minimum time and cost per component and suitable for the newer coated lathe tools with in-built chip breaker groove designs, incorporates chip breaking constraints for turning on computer numerical control (CNC) lathes. Despite the complexity of the analyses, clearly denned strategies that guarantee the global optimal solutions have been developed. Extensive simulation studies have highlighted the considerable economic benefits of using ‘optimal’ rather than ‘recommended’ cutting conditions, the potential for increased benefits from improved chip control and tool magazine designs and the need for technological performance equations as well as optimization analyses for the wide spectrum of machining operations for use in modern process planning.


2008 ◽  
Vol 3 (3) ◽  
Author(s):  
Bruce R. Johnson ◽  
Glen T. Daigger ◽  
John T. Novak

The advent of sludge reduction technologies that are capable of significantly reducing sludge production from wastewater treatment facilities has garnered much interest from the wastewater treatment profession. As part of CH2M HILL's effort to better understand the mechanisms behind these processes, a research effort was completed that was focused on developing an ASM based model which adequately reflects the performance of the Cannibal® Sludge Reduction process by Siemens. A modification is proposed of the standard ASM 2d model to capture the effects of biological sludge reduction used in the Cannibal Solids Reduction process. This model is able to capture the essential aspects of this system and provides a more quantitative method for the sizing and performance of these types of systems. The primary components of this modification include separation of the microbiological decay products from the traditional particulate inert fraction, and into a separate particulate decay product for aerobic/anoxic microbes (XDAA). A new process rate is included in the model for anaerobic “hydrolysis” of XDAA to XS. The results were compared against the experience of Siemens on a wide range conditions. The results indicate that this model predicts operating characteristics of the Cannibal process with a reasonable level of accuracy.


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