Simulation Model for the Shape Error Estimation During Machining With Flat Lapping Kinematics

2010 ◽  
Author(s):  
Mariusz Deja
Keyword(s):  
Simulation Model ◽  
Error Estimation ◽  
Average Distance ◽  
Active Surface ◽  
Shape Error ◽  
Shape Accuracy ◽  
Machined Parts ◽  
Shape Errors ◽  
Tool Shape ◽  
High Degree

The selection of a finishing process for a particular application depends on part shape and size, ease of fixturing, requirements concerning the acceptable shape errors. Lapping is the basic flattening process which allows for achieving a high degree of flatness and parallelism of machined parts. It is still one of the most common processes to flatten the sliced silicon wafers. Grinding or wire-sawing induced waviness can be effectively removed or reduced by lapping. A required high degree of the tool flatness is not maintained permanently. The active surface of the tool used for machining with lapping kinematics has some shape errors of concavity or convexity due to the wear. This in turn influences the shape accuracy of the workpiece and the tool flatness must be checked after machining of some workpiece batches. Depending on the tool shape error either the facing operations are carried out to flatten the active surface of the tool or proper kinematical parameters are applied which allow for obtaining required workpiece flatness. Computer simulations can be useful to make o proper decision about achievable accuracy for actual tool shape error. Simulation model for the shape error estimation based on the kinematics of lapping and local shape errors of the tool is presented in the paper. The movement of the workpiece is analyzed and the average distance from the workpiece surface, represented by discrete points, to the tool surface is calculated. Proposed model can be applied for lapping or grinding with single or double discs lapping kinematics. Geometrical and kinematical relations with some simulations are presented in the work.

scholarly journals A Pilot Study on Machining Difficult-to-Cut Materials with the Use of Tools Fabricated by SLS Technology

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5306
Author(s):  
Mariusz Deja ◽  
Dawid Zieliński
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Active Surface ◽  
Abrasive Machining ◽  
Machining Time ◽  
Shape Accuracy ◽  
Gas Industry ◽  
Industrial Sectors ◽  
Prototype Tool ◽  
Process Factors

The growing use of contemporary materials in various industrial sectors, such as aerospace, automotive, as well as the oil and gas industry, requires appropriate machining methods and tools. Currently, apart from the necessity to obtain high-dimensional and shape accuracy, the efficiency and economic aspects of the selected manufacturing process are equally important, especially when difficult-to-cut materials, such as hard and brittle ceramics, have to be machined. In the research presented in this paper, a prototype tool fabricated from polyamide powder by the SLS method was used in flat-lapping of Al2O3 ceramics, showing the promising potential and efficacy of rapid tooling and manufacturing in the area of abrasive machining. The influence of the selected input process factors, such as machining time, the type of abrasive suspension, kinematic parameters, and unit pressure, on technological effects, was analyzed. The microscopic observations of the active surface of the prototype tool showed its reinforcement with loose diamond abrasive particles (size D107), resulting in the effective material removal and improved surface finish of Al2O3 ceramic samples. The directions for further development of tools fabricated by the SLS method for applications in abrasive machining were also envisaged by the authors.

Development of FSW Simulation Model-Effect of Tool Shape on Plastic Flow

2015 ◽  
pp. 281-288
Author(s):  
Yurika Miyake ◽  
Fumikazu Miyasaka ◽  
Shuhei Matsuzawa ◽  
Shunta Murao ◽  
Kenta Mitsufuji ◽  
...  
Keyword(s):  
Simulation Model ◽  
Plastic Flow ◽  
Tool Shape ◽  
Fsw Simulation

SYNCHRONIZATION IN THE FAMILY OF CHAOTIC SMALL-WORLD NETWORKS

2008 ◽  
Vol 19 (01) ◽  
pp. 111-123 ◽  
Author(s):  
LIANGMING HE ◽  
DUANWEN SHI
Keyword(s):  
Chaotic System ◽  
Average Distance ◽  
Small World ◽  
Clustering Coefficient ◽  
Small World Networks ◽  
Characteristic Path Length ◽  
Unified Chaotic System ◽  
The Family ◽  
Regular Networks ◽  
High Degree

In this paper we investigate by computer simulation the synchronizability of the family of small-world networks, which consists of identical chaotic units, such as the Lorenz chaotic system, the Chen chaotic system, Lü chaotic system, and the unified chaotic system (unit). It is shown that for weak coupling, synchronization clusters emerge in the networks whose disorder probabilities p are large but do not emerge in the networks whose disorder probabilities p are small; while for strong coupling under which the regular networks do not exhibit synchronization, all dynamical nodes, behaving as in the random networks, mutually synchronize in the networks which own very small disorder probability p and have both high degree of clustering and small average distance. Based on the concepts of clustering coefficient C(p), characteristic path length L(p) and global efficiency E(G), these phenomena are discussed briefly.

scholarly journals DNA barcoding Australasian chondrichthyans: results and potential uses in conservation

2008 ◽  
Vol 59 (1) ◽  
pp. 57 ◽  
Author(s):  
Robert D. Ward ◽  
Bronwyn H. Holmes ◽  
William T. White ◽  
Peter R. Last
Keyword(s):  
Dna Barcoding ◽  
Average Distance ◽  
Life History Stage ◽  
Cryptic Speciation ◽  
Sequence Variability ◽  
Great Hope ◽  
Species Cluster ◽  
High Degree ◽  
Taxonomic Examination ◽  
Very High

DNA barcoding – sequencing a region of the mitochondrial cytochrome c oxidase 1 gene (cox1) – promises a rapid and accurate means of species identification, and of any life history stage. For sharks and rays, it may offer a ready means of identifying legal or illegal shark catches, including shark fins taken for the profitable shark fin market. Here it is shown that an analysis of sequence variability in a 655 bp region of cox1 from 945 specimens of 210 chondrichthyan species from 36 families permits the discrimination of 99.0% of these species. Only the two stingarees Urolophus sufflavus and U. cruciatus could not be separated, although these could be readily distinguished from eight other congeners. The average Kimura 2 parameter distance separating individuals within species was 0.37%, and the average distance separating species within genera was 7.48%. Two specimens that clustered with congeners rather than with their identified species-cluster were noted: these could represent instances of hybridisation (although this has not be documented for chondrichthyans), misidentification or mislabelling. It is concluded that cox1 barcoding can be used to identify shark and ray species with a very high degree of accuracy. The sequence variability characteristics of individuals of five species (Aetomylaeus nichofii, Dasyatis kuhlii, Dasyatis leylandi, Himantura gerrardi and Orectolobus maculatus) were consistent with cryptic speciation, and it is suggested that these five taxa be subjected to detailed taxonomic examination to confirm or refute this suggestion. The present barcoding study holds out great hope for the ready identification of sharks, shark products and shark fins, and also highlights some taxonomic issues that need to be investigated further.

Study on the Shape Error in the Cylindrical Traverse Grinding of a Workpiece with High Aspect Ratio

2014 ◽  
Vol 1017 ◽  
pp. 78-81
Author(s):  
Takashi Onishi ◽  
Takuya Kodani ◽  
Kazuhito Ohashi ◽  
Moriaki Sakakura ◽  
Shinya Tsukamoto
Keyword(s):  
Aspect Ratio ◽  
Elastic Deformation ◽  
High Aspect Ratio ◽  
Grinding Force ◽  
Grinding Process ◽  
Shape Error ◽  
Shape Accuracy ◽  
Low Stiffness ◽  
Traverse Grinding ◽  
Main Factor

In cylindrical traverse grinding of a long workpiece with high aspect ratio, the shape accuracy of a workpiece worsens due to its low stiffness. In this study, the grinding force was measured during grinding process to calculate the elastic deformation of a workpiece caused by the normal grinding force. By comparing calculated elastic deformation with the measured shape error of ground workpiece, the cause for the shape error in case of grinding a long workpiece was investigated experimentally. From experimental results, it is confirmed that the main factor of the shape error of the long workpiece is its elastic deformation during grinding process.

scholarly journals Spatial data analysis for laser scanning based shape error inspection

2021 ◽  
Author(s):  
Haibin Jia
Keyword(s):  
Fourier Transform ◽  
Spatial Data ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Industrial Applications ◽  
Spatial Data Analysis ◽  
Inspection System ◽  
Shape Error ◽  
Shape Errors ◽  
Weld Inspection

Laser scanning, a widely used technology, has been highly developed and adopted in various industrial applications. The methodologies used for scanner date processing are mostly point based. In this thesis, a new approach is presented to analyze spatial data obtained from a 3-D laser scanner for shape error inspection. Different from traditional methodologies, the method proposed in this research is frequency based. The method utilizes the Fourier transform to decompose a 2-D curve or 3-D shape into its spatial components by applying two 1-D FFT (Fast Fourier Transform) on 2-D curves or two 2-D FFT on 3-D shapes. The spatial components including frequency, amplitude, and phase are defined as shape characteristics to represent the shape under inspection. By relating spatial components with GD&T (Geometric Dimensioning and Tolerancing) standards using proper analysis techniques, such as frequency spectrum and cross correlation, shape errors can be detected and characterized. One of the applications of this method is automated inspection. In this research, the spatial data method is applied to MIG (Metal Inert Gas) weld inspection. Experiments are carried out to analyze the 2-D curve of a projection weld data, and the 3-D scanning data directly. A MIG weld inspection system is also developed for production use.

scholarly journals THE METHODOLOGY AND SOFTWARE FOR CALCULATING THE ERROR OF CYLINDRICAL SURFACE

2019 ◽  
pp. 151-161
Author(s):  
S. Timofeev ◽  
Maxim Lesunov ◽  
A. Hurtasenko ◽  
I. Maslova
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Geometric Parameters ◽  
Shape Error ◽  
Software Module ◽  
Form Errors ◽  
Correct Assignment ◽  
Special Software ◽  
Shape Errors ◽  
The Cross

Various techniques and devices are used to determine the shape errors of large-sized parts of technological units. This is important for the correct assignment of parameters for further reduction processing by special machines and machine tools. The acquired errors arise for several reasons: 1) large dimensions and weight of rotating parts, 2) the instability of the axis of the rotating part mounted on two support rollers, 3) the available initial and acquired shape error in the cross section of the part. It is important to define the types of form errors of the surfaces, error analysis, prediction and calculation of deviations from roundness in the cross section of the bandage, and the evaluation of cylindricity. Modeling of the process of operation and diagnostics of the unit, development of methods for determining errors, calculation of real values of deviations from the original contour on the basis of reconstruction of the contour of the section becomes important and necessary. These processes are performed using modern CAD systems and software. Obtaining data arrays in the process of measurements and their processing with the help of a special software module that performs an interactive calculation of shape errors with different geometric parameters of the cross-section of the bandage, provides the ability to obtain information about the state of the outer surfaces and parts of the supports on the operating unit. This article presents a method for determining the geometric parameters of the shape in the cross section of the rotation part, algorithms and software for reconstructing the contours of the cross sections of the part and calculating the shape error of the outer cylindrical surfaces

scholarly journals NEW MODEL OF MACHINE FOR PROCESSING SURFACES OF LARGE-SIZED PARTS HAVING THE SHAPE OF BODIES OF ROTATION

2021 ◽  
Vol 6 (8) ◽  
pp. 94-100
Author(s):  
S. Timofeev ◽  
D. Gavrilov ◽  
Vladislav Khurtasenko ◽  
M. Voronkova
Keyword(s):  
Machining Process ◽  
Machine Model ◽  
Shape Accuracy ◽  
Bodies Of Revolution ◽  
Repair Work ◽  
Term Operation ◽  
Shape Errors ◽  
Dynamic Rigidity ◽  
Efficient Processing ◽  
Rotary Kilns

During long-term operation of rotating parts of technological machines, which include tires and support rollers of rotary kilns, rolling surfaces lose their shape accuracy and quality. Built-in machine modules are used to restore large-sized parts in the form of bodies of revolution. Such repair work requires special technological approaches and careful preparation before starting. It is necessary to take into account the real geometry of the surface of the part being repaired, which may have shape errors in the longitudinal and cross section due to wear, and conduct a preliminary analysis of the state of the part. It is also necessary to take into account the large dimensions and weight of the workpiece, and the inconsistent position of its axis during rotation. The technologies used and mobile machines for carrying out these repairs still have drawbacks that do not allow for efficient processing and affect the accuracy and quality of the resulting surface. The solution to this problem can be the development of new models of machine tools for processing large-sized bodies of revolution, the design of which will be more perfect in comparison with the previous models. To achieve this goal, it is necessary to study and analyze the existing domestic and foreign models of mobile machines and the principle of their operation. The proposed new machine model should have sufficient static and dynamic rigidity, as well as have a module responsible for adaptive control of the machining process, which will compensate for unstable positioning of parts during machining.

Precision Shape Control of Laminated Membrane Reflector Based on the Photo/Piezoelectric Hybrid Actuation Method

2013 ◽  
Author(s):  
Hong-Hao Yue ◽  
Yu-Fei Long ◽  
Jing Jiang ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Shape Control ◽  
Control Method ◽  
Earth Orbit ◽  
Shape Error ◽  
Shape Accuracy ◽  
Future Space ◽  
Active Shape ◽  
Hybrid Actuation ◽  
Converse Piezoelectric Effect ◽  
Plane Membrane

According to the design requirement of large aperture, light mass and longevity, membrane reflectors have already become the developing direction for future space reflectors. In order to overcome membrane reflectors’ defect of low stiffness, active control for reflectors must be adopted to ensure the shape accuracy. This paper puts forward an active shape control method based on PVDF piezoelectric film for plane membrane reflectors: using in-plane laminated PVDF piezoelectric actuators to change the shape of the plane membrane reflector by activating the PVDF converse piezoelectric effect, so that active shape control can be achieved. In this paper, a plane membrane reflector model is built. Then shape error caused by thermal effect in medium earth orbit (MEO) and geosynchronous earth orbit (GEO) in which membrane reflectors mainly work is analyzed. After that the shape and layout of PVDF actuators is designed and the validity of the control method is verified by simulation. Lastly, the PLZT/PVDF hybrid drive theory is induced, and the possibility of distance control is demonstrated based on the photo/piezoelectric control strategy.

FUNDAMENTALS OF THE DESIGN OF FUNDAL MANDRELS FOR THE INSTALLATION OF THIN-WALLED WORKPIECES. PART 1

2021 ◽  
pp. 14-23
Author(s):  
D. S. Blinov ◽  
I. S. Chunosov
Keyword(s):  
Contact Pressure ◽  
Mechanical Engineering ◽  
Engineering Calculation ◽  
Radial Clearance ◽  
Mechanics Of Machines ◽  
Shape Error ◽  
Shape Errors ◽  
Thin Walled ◽  
Form Deviation ◽  
Radial Gap

There are a number of problems in mechanical engineering technology. One of them is related to the installation on the machine and the previous processing of thin-walled rings, which are widely used in mechanical engineering. Due to the low bending stiffness of thin-walled rings after processing there are a large magnitude of rigidity of the form (deviation from roundness). As production experience has shown, in the conditions of mass production, it is advisable to use fungal mandrels and adjustments to reduce shape errors. They allow for a small radial gap between the holes of the ring and the fungal cam to have extended contact rings with cams along the angular coordinate. However, there are no methods for calculating the parameters of contact interaction with cams, considering a number of factors, primarily the radial clearance. Hence, it is impossible to calculate more accurately the error of the form after processing. In this paper (it is supposed to be continued), based on methods for calculating flat rings of construction mechanics of machines, a method for determining the stress-strain state of a thin-walled state is proposed, considering the contact pressure. In this case, the semiangle of contact of the ring with the fungal cam and the shape of the contact pressure plot are determined. This allows you to calculate the stress state of the thin-walled ring and the shape error when processing more accurately in a fungal mandrel, as well as reasonably assign the dimensions of the mandrel parts. Due to the exceptionally large number of calculations in the calculations according to the proposed method, it can only be implemented using a computer program, which creates great difficulties in analyzing different source data. Therefore, it is planned to rework the completed developments into an engineering calculation method with graphs in dimensionless form.

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