scholarly journals Design of Optical Free-Form Surface Milling Machine Based on Mechanical Shunt and Dynamic Analysis

2021 ◽  
Vol 11 (24) ◽  
pp. 11764
Author(s):  
Qi Li ◽  
Tianbiao Yu ◽  
Zixuan Wang ◽  
Wanshan Wang
Keyword(s):  
Multibody Dynamics ◽  
Natural Frequencies ◽  
Free Form ◽  
Vibration Modes ◽  
Milling Machine ◽  
Optical Components ◽  
Process Characteristics ◽  
Adams Software ◽  
Free Form Surface ◽  
Simulation Results

An optical free-form surface milling machine is designed according to the process characteristics and cutting force of optical components manufacturing. The Z-axis column of the milling machine is designed by a mechanical shunt. In this paper, based on the principle of multibody dynamics (MBD), a virtual prototype (VP) of the optical free-form surface milling machine was established by the ADAMS software. The Z-axis characteristics of the milling machine were simulated and studied, and a modal analysis was carried out to obtain the natural frequencies and vibration modes of the milling machine. The simulation results show that the Z-axis of the milling machine has excellent dynamic characteristics when the gravity balance device is not working. The average torque of the Z-axis motor is 0.5 N·m when the gravity balance device is working, the average torque of the Z-axis motor is 0.1 N·m, and the average torque is reduced by 80%; therefore, the gravity balance device can obviously lower the load of the Z-axis motor, and improve the efficiency of the milling machine.

Micro-Object Orientation Control by Using Different Vibration Modes of Board Stage

2010 ◽  
Vol 447-448 ◽  
pp. 488-492 ◽  
Author(s):  
Toshitake Tateno ◽  
Akira Kakuta ◽  
Kotaro Okui
Keyword(s):  
Natural Frequencies ◽  
Vibration Mode ◽  
Control Method ◽  
Fem Analysis ◽  
Manufacturing Processes ◽  
Vibration Modes ◽  
Orientation Control ◽  
Simulation Results ◽  
Board Stage ◽  
Small Parts

This paper deals with an orientation control method for micro objects, which have a size in the order of 100 micro meters, by using a board stage that is vibrated in the natural frequencies of various vibration modes. Orientation control is important for manufacturing processes, such as the assembling of small parts. Since it is difficult to grip and to manipulate micro objects, a simple and reliable method is desired. In this paper, the vibration mode is used for generating different motions of the stage and for controlling the orientation of the objects on the stage. Since each vibration mode has a unique vibration motion, different motions can be selected by choosing the vibration frequency. In order to design the stage so that the objects turn toward target direction, Finite Element Method (FEM) analysis was applied. And, the designed vibration stage was fabricated using a stainless steel thin plate. Experimental results showed that the actual vibration is similar with the simulation results. As an example of the orientation control of the micro objects, some small electronics parts were tested and they could be turned toward the target directions.

Position and mass identification in nanotube mass sensor using neural networks

2019 ◽  
Vol 233 (15) ◽  
pp. 5377-5387
Author(s):  
SE Habibi ◽  
MA Nematollahi
Keyword(s):  
Neural Networks ◽  
Carbon Nanotube ◽  
Natural Frequencies ◽  
Dynamics Simulation ◽  
Vibration Modes ◽  
Mass Sensor ◽  
Single Walled Carbon Nanotube ◽  
Potential Applications ◽  
Simulation Results ◽  
Mass Identification

Carbon nanotube-based nanosensors have shown many promising potential applications in exploring the nano-world. To benefit the maximum capabilities of the nano mass sensor, it must be able to measure both of the augmented mass and its trapping position. Here, this requirement is fulfilled by employing artificial neural networks as an inverse tool. Accordingly, considering the single-walled carbon nanotube mass sensor as a vibrating Love shell, its equivalent characteristics are obtained by matching the shell response with the corresponding molecular dynamics simulation results. Then, the responses (natural frequencies) at different vibration modes are utilized for training a properly selected neural network. Afterward, the ability of the proposed neural networks to predict the mass and the trapping position of the augmented mass is investigated. The results indicated that the presented method can effectively predict the mass and position of an attached particle.

Tool-Path Scheduling for Free-Form Surface Based on MasterCAM

2014 ◽  
Vol 556-562 ◽  
pp. 1400-1403 ◽  
Author(s):  
Wen Jing Ren ◽  
Jian Yun He ◽  
Yuan Yu
Keyword(s):  
Tool Path ◽  
Flow Line ◽  
Freeform Surface ◽  
Free Form ◽  
Milling Machine ◽  
Tool Paths ◽  
Nc Milling ◽  
Free Form Surface ◽  
Path Scheduling

The tool-path generating methods of roughing and finishing provided by MasterCAM were systematically analyzed including their features and applications. Then a blade with freeform surface milled by different tool-paths was simulated. According to the comparison of simulation effects and information, the flow-line tool-path was proposed to be optimal for machining blade with freeform surface. Finally, the blade was finished with optimal tool-path using a 3-axis NC milling machine.

Development of Automatic System for Process Planning and NC Program Generation on Turning-Milling Machine Tool With Three Turrets

2017 ◽  
Author(s):  
Ryo Fukuda ◽  
Ririko Kiyooka ◽  
Hideki Aoyama
Keyword(s):  
Machine Tool ◽  
Process Planning ◽  
Numerical Control ◽  
Free Form ◽  
Milling Machine ◽  
Machining Features ◽  
Process Plan ◽  
Program Generation ◽  
Nc Program ◽  
Free Form Surface

The objective of this study is to develop an automatic process planning and a numerical-control (NC) program generation system for free-form machining, using a turning-milling machine tool with multi-turrets. In this research, machining feature recognition was carried out based on the delta-volume decomposition to achieve process planning. This system can recognize machining features that include one free-form surface and can create a tool path for the free-form surface. A process plan candidate is generated via the assignment of machining features to each turret and the determination of the processing order of the machining features in each turret. The system generates many process plan candidates, and evaluates them based on the evaluation point of the user. In this research, the plan with the shortest machining time is selected. Next, the system automatically generates an NC program for each turret. Ultimately, a machining experiment using a turning-milling machine tool with three turrets was conducted to verify the usefulness of the system.

scholarly journals ANÁLISE COMPARATIVA DOS MODOS E FREQUENCIAS NATURAIS DE VIBRAÇÃO DE VIGAS ENGASTADA LIVRE E BI-ENGASTADA SUJEITAS À OSCILAÇÕES LIVRES

2018 ◽  
Vol 10 (4) ◽  
pp. 18-27
Author(s):  
Cássio Fabian Sarquis de Campos ◽  
Daniele Araújo Altran ◽  
Gustavo Figueiredo Formagio
Keyword(s):  
Natural Vibration ◽  
Natural Frequencies ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Free Form ◽  
Vibration Modes ◽  
Structural Problems ◽  
External Forces ◽  
Computational Resources ◽  
Free Sets

The objective of this work was the theoretical and computational modeling of free-form and bi-set beams, objectively showing their ways of vibrations and their natural frequencies. The study of the dynamics of rigid or flexible structures, under the action of external forces, such as regular marine waves, winds, external mechanical vibrations of any order, is of extreme importance for the prevention of possible structural problems, for example, displacements, partial or total ruptures of these structures. All the study was carried out Recebido em: 10/08/2018Revisado em: 28/08/2018Aprovado em: 20/09/2018 19Colloquium Exactarum, v. 10, n.4,Out-Dez. 2018, p.18–27. DOI: 10.5747/ce.2018.v10.n4.e252using the methods of Computational Analysis of the Natural Vibration Modes and Frequencies of a Free Beam of Forms for Free Frequencies and Computational Calculation of Lies and Natural Vibration Frequencies of a Beam Without Free Sets of Free Oscillations and the Computational Computation of Lies and Natural Frequencies of Vibration of a Bi Beam established by the Method ofAssumed Modalities. The computational resources used to do the theoretical remodeling of the beams and their functions were Matlab®and Maple®. Employees to implement three-dimensional vibration modes and development of new studies with different bundles and physical properties. This comparative work of the beams provided the mathematical and dynamic knowledge of modeling of the structures, being they, modeling skills through programming.

Measurement of Young’s Modulus and Shear Modulus of Some Structures Welded Using Flux Cored Wire by Vibration Tests

2014 ◽  
Vol 216 ◽  
pp. 151-156 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Vodǎ ◽  
Gheorghe Drăgănescu
Keyword(s):  
Shear Modulus ◽  
Arc Welding ◽  
Natural Frequencies ◽  
Free Vibrations ◽  
Vibration Modes ◽  
Cored Wire ◽  
Flux Cored Arc Welding ◽  
Longitudinal Elastic Modulus ◽  
Vibration Tests ◽  
Non Destructive

The aim of this work was to determine by vibration tests the longitudinal elastic modulus and shear modulus of welded joints by flux cored arc welding. These two material properties are characteristic elastic constants of tensile stress respectively torsion stress and can be determined by several non-destructive methods. One of the latest non-destructive experimental techniques in this field is based on the analysis of the vibratory signal response from the welded sample. An algorithm based on Pronys series method is used for processing the acquired signal due to sample response of free vibrations. By the means of Finite Element Method (FEM), the natural frequencies and modes shapes of the same specimen of carbon steel were determined. These results help to interpret experimental measurements and the vibration modes identification, and Youngs modulus and shear modulus determination.

scholarly journals Vibration of Rotating and Revolving Planet Rings with Discrete and Partially Distributed Stiffnesses

2020 ◽  
Vol 11 (1) ◽  
pp. 127
Author(s):  
Fuchun Yang ◽  
Dianrui Wang
Keyword(s):  
High Speed ◽  
Differential Operators ◽  
Natural Frequencies ◽  
Rotation Speed ◽  
Distribution Area ◽  
Vibration Modes ◽  
Governing Equations ◽  
Vibration Properties ◽  
Wide Range ◽  
Forced Responses

Vibration properties of high-speed rotating and revolving planet rings with discrete and partially distributed stiffnesses were studied. The governing equations were obtained by Hamilton’s principle based on a rotating frame on the ring. The governing equations were cast in matrix differential operators and discretized, using Galerkin’s method. The eigenvalue problem was dealt with state space matrix, and the natural frequencies and vibration modes were computed in a wide range of rotation speed. The properties of natural frequencies and vibration modes with rotation speed were studied for free planet rings and planet rings with discrete and partially distributed stiffnesses. The influences of several parameters on the vibration properties of planet rings were also investigated. Finally, the forced responses of planet rings resulted from the excitation of rotating and revolving movement were studied. The results show that the revolving movement not only affects the free vibration of planet rings but results in excitation to the rings. Partially distributed stiffness changes the vibration modes heavily compared to the free planet ring. Each vibration mode comprises several nodal diameter components instead of a single component for a free planet ring. The distribution area and the number of partially distributed stiffnesses mainly affect the high-order frequencies. The forced responses caused by revolving movement are nonlinear and vary with a quasi-period of rotating speed, and the responses in the regions supported by partially distributed stiffnesses are suppressed.

scholarly journals Stochastic Natural Vibration Analyses of Free-Form Shells

2019 ◽  
Vol 9 (15) ◽  
pp. 3168
Author(s):  
Bingbing San ◽  
Yunlong Ma ◽  
Zhi Xiao ◽  
Dongming Feng ◽  
Liwei Yin
Keyword(s):  
Elastic Modulus ◽  
Shape Optimization ◽  
Shell Thickness ◽  
Natural Vibration ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Free Form ◽  
Probability Models ◽  
Geometric Imperfection ◽  
Natural Vibration Characteristics

This work investigates the natural vibration characteristics of free-form shells when considering the influence of uncertainties, including initial geometric imperfection, shell thickness deviation, and elastic modulus deviation. Herein, free-form shell models are generated while using a self-coded optimization algorithm. The Latin hypercube sampling (LHS) method is used to draw the samplings of uncertainties with respect to their stochastic probability models. ANSYS finite element (FE) software is adopted to analyze the natural vibration characteristics and compute the natural frequencies. The mean values, standard deviations, and cumulative distributions functions (CDFs) of the first three natural frequencies are obtained. The partial correlation coefficient is adopted to rank the significances of uncertainty factors. The study reveals that, for the free-form shells that were investigated in this study, the natural frequencies is a random quantity with a normal distribution; elastic modulus deviation imposes the greatest effect on natural frequencies; shell thickness ranks the second; geometrical imperfection ranks the last, with a much lower weight than the other two factors, which illustrates that the shape of the studied free-form shells is robust in term of natural vibration characteristics; when the supported edges are fixed during the shape optimization, the stochastic characteristics do not significantly change during the shape optimization process.

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