Use of Shock Compared With Harmonic Excitation in Machine Tool Structure Analysis

1974 ◽  
Vol 96 (1) ◽  
pp. 187-195 ◽  
Author(s):  
J. Tlusty ◽  
K. C. Lau ◽  
K. Parthiban
Keyword(s):  
Machine Tool ◽  
Structure Analysis ◽  
Machine Tools ◽  
Harmonic Excitation ◽  
Mode Shapes ◽  
Shock Excitation ◽  
Machine Tool Structure ◽  
Degree Of Stability ◽  
The Individual

The paper recapitulates the method of analyzing stability against chatter of machine tools as it has been practised by one of the authors for many years. Several new features of the method are presented and, mainly, comments are given on the use of shock excitation for determining both the receptances of the structure and its mode shapes. The method itself consists of comparing results of cutting tests and of excitation tests for various directional orientations of the cut in the structure and of identifying the contribution of the individual modes to the resulting degree of stability.

Vibration Analysis of Radial Drilling Machine Structure Using Finite Element Method

2012 ◽  
Vol 472-475 ◽  
pp. 2717-2721 ◽  
Author(s):  
Rajiv Kumar ◽  
Mohinder Pal Garg ◽  
Rakesh C. Sharma
Keyword(s):  
Machine Tool ◽  
Natural Frequency ◽  
Mode Shapes ◽  
Drilling Machine ◽  
Element Analysis ◽  
Stiffness Matrices ◽  
Machine Tool Structure ◽  
Radial Drilling ◽  
Machine Structure

Manufacturing industries now a days have stringent expectation from the machine tools in terms of productivity as well as quality of products.Vibration plays an important role in determining the quality of product.If the pattern of vibration prevailing in the machine tool during cutting is known,then machine tool structure can be designed in such a way so that natural frequency of machine tool structure can be isolated from the forced frequency.So, this study is focused on finding the natural frequency and mode shapes of radial drilling machine structure.Finite element analysis has been done to find out the natural frequencies and mode shapes of radial drilling machine structure.Assembled mass and stiffness matrices are obtained for each element and solved by using inverse iteration technique.

Modal Testing for Heavy Machine Tool Using Active Excitation

2014 ◽  
Vol 536-537 ◽  
pp. 1326-1332 ◽  
Author(s):  
Bo Luo ◽  
Bin Li ◽  
Xin Yong Mao ◽  
Hui Cai
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Inertial Force ◽  
Modal Testing ◽  
Modal Parameters ◽  
Part Quality ◽  
Machine Tool Structure ◽  
Machining Speed ◽  
Heavy Machine ◽  
Large Machine

For application in large machine tools, the machined part quality, accuracy as well as machining speed depende greatly on the dynamics of the structure. In this paper, an active-excitation modal analysis (AEMA), using inertial force of the moving slider to excite the structural modes, is proposed. Modal parameters of the machine tool structure estimated by AEMA are experimentally validated. Since the artificial excitation produced by elaborate excitation equipment is replaced by the inertial force of the slider, the proposed method is much more practical and economical than traditional methods.

scholarly journals Analysis of Dynamic Characteristics for Machine Tools Based on Dynamic Stiffness Sensitivity

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2260
Author(s):  
Chunhui Li ◽  
Zhiqiang Song ◽  
Xianghua Huang ◽  
Hui Zhao ◽  
Xuchu Jiang ◽  
...  
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
Dynamic Stiffness ◽  
Variable Stiffness ◽  
Structural Vibration ◽  
Dynamic Experiment ◽  
Machine Tool Structure ◽  
Analysis Experiment ◽  
Five Axis

Dynamic parameters are the intermediate information of the entirety of machine dynamics. The differences between components have not been combined with the structural vibration in the cutting process, so it is difficult to directly represent the dynamic characteristics of the whole machine related to spatial position. This paper presents a method to identify sensitive parts according to the dynamic stiffness-sensitivity algorithm, which represents the dynamic characteristics of the whole machine tool. In this study, two experiments were carried out, the simulation verification experiment (dynamic experiment with variable stiffness) and modal analysis experiment (vibration test of five-axis gantry milling machine). The key modes of sensitive parts obtained by this method can represent the position-related dynamic characteristics of the whole machine. The characteristic obtained is that the inherent properties of machine-tool structure are independent of excitation. The method proposed in this paper can accurately represent the dynamic characteristics of the whole machine tool.

scholarly journals IoT Devices and Applications for Wire-Based Hybrid Manufacturing Machine Tools

2020 ◽  
Author(s):  
Austen Thien ◽  
Christopher J. Saldana ◽  
Thomas Feldhausen ◽  
Thomas Kurfess
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Disruptive Technology ◽  
Hybrid Manufacturing ◽  
Hybrid Machine Tool ◽  
Subtractive Manufacturing ◽  
Hybrid Machine ◽  
Iot Devices ◽  
The Individual ◽  
Manufacturing Machine

Abstract Hybrid manufacturing machine tools have the potential to be a disruptive technology as they can leverage the benefits of both additive and subtractive manufacturing by incorporating both processes on the same machine while limiting the downsides of the individual processes. Since these machines use two very disparate manufacturing processes and hybrid manufacturing is an emerging technology, it will be useful to monitor data coming from the machine and apply it to improve the manufacturing process, the operation of the machine, and to integrate the machine into the larger digital framework of Industrial Internet of Things (IoT). The present work discusses IoT devices that would be beneficial to add to a hybrid machine tool as well as applications for those devices. The proposed methods discussed in this work have not been experimentally implemented on a hybrid machine tool and so there are no performance data available yet. The hybrid machine tool used as a basis to generate these IoT applications is the Mazak VC-500A/5x AM Hot Wire Deposition, which is a 5-axis machine tool incorporated with a wire feedstock 4kW laser deposition system. Methodologies and applications will be outlined for machine health and process monitoring. Other areas covered include process benchmarking, secure networking options for the proposed IoT framework, and hybrid process improvement. Limitations of these methods and future work for new sensor devices and application areas is also discussed.

Experimental Complex Modal Analysis of Machine Tool Structures

1989 ◽  
Vol 111 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Y. C. Shin ◽  
K. F. Eman ◽  
S. M. Wu
Keyword(s):  
Machine Tool ◽  
Modal Analysis ◽  
Mode Analysis ◽  
Mode Shapes ◽  
Coupled Modes ◽  
Complex Mode ◽  
Machine Tool Structure ◽  
Experimental Complex ◽  
Complex Modal Analysis ◽  
Complex Modal

Despite the well-established theories and considerable experimental research, the identification of the complex mode shapes of a real machine tool structure with general damping still remains a formidable task. Moreover, the existence of closely coupled modes with heavy damping introduces additional difficulties. This paper presents a detailed procedure for experimental complex modal analysis of a machine tool structure by the Dynamic Data System method. The accuracy and efficiency are first illustrated by numerical examples through simulation studies. It has been shown that closely coupled modes and modes with heavy damping can be successfully identified from both simulated and actual experimental data from a machine tool. Complex mode shapes were also obtained without adding any complexity or losing accuracy as compared to normal mode analysis. The experimental results obtained by the proposed method were compared with those based on the FFT algorithm.

Efficient Dynamic Parameter Identification Framework for Machine Tools

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Thomas Semm ◽  
Markus Sellemond ◽  
Christian Rebelein ◽  
Michael F. Zaeh
Keyword(s):  
Machine Tool ◽  
Parameter Identification ◽  
Dynamic Behavior ◽  
Machine Tools ◽  
Dynamic Models ◽  
Dynamic Parameter ◽  
Multibody Model ◽  
Physical Prototype ◽  
The Individual ◽  
Dynamic Parameter Identification

Abstract Modeling the dynamic behavior of a machine tool accurately is a difficult but crucial task when optimizing a machine tool’s design. An accurate representation of the real behavior is essential to ensure the transferability of simulations from a virtual prototype to a physical prototype. Due to the complexity of modern machine tools, a large number of parameters have an influence on the dynamic behavior. The parameterization of the used dynamic models is still challenging, especially if intricate local models are used for the individual effects. This paper presents an efficient framework for parameterizing a dynamic model of a machine tool containing linear local damping and stiffness parameters. For parameter identification, measurements of single components on simple test rigs as well as measurements of the whole machine tool were carried out. Different numerical optimization algorithms as well as objective functions were compared and applied to a three-axis machine tool structure for parameter fitting. By using a parametric reduced-order flexible multibody model for the fitting, high accuracy can be combined with high computational efficiency. The use of the presented approach allows an efficient parameter estimation and lays the groundwork for an influence analysis and the targeted optimization of a machine tool.

Control of Machine Tools

1997 ◽  
Vol 119 (4B) ◽  
pp. 749-755 ◽  
Author(s):  
Yoram Koren
Keyword(s):  
Adaptive Control ◽  
Machine Tool ◽  
Real Time ◽  
System Performance ◽  
Machine Tools ◽  
Experimental Results ◽  
The Individual ◽  
Selection Of

This paper reviews the progress in machine tool control during the last three decades. Three types of controls are discussed: (i) Servocontrol loops that control the individual axes of the machine, (ii) interpolators that coordinate the motion of several axes, and (iii) adaptive control that adjusts the cutting variables in real time to maximize system performance. We cover a selection of the most advanced techniques utilized in each of these types, and draw conclusions based on experimental results.

scholarly journals Dynamic Modeling and Experimental Research on Position-dependent Behavior of Twin Ball Screw Feed System

2021 ◽  
Author(s):  
Meng Duan ◽  
Hong Lu ◽  
Xinbao Zhang ◽  
Zhangjie Li ◽  
Yongquan Zhang ◽  
...  
Keyword(s):  
Machine Tool ◽  
Dynamic Model ◽  
Machine Tools ◽  
Experimental Tests ◽  
Ball Screw ◽  
Fe Model ◽  
Feed System ◽  
Dependent Behavior ◽  
Machine Tool Structure ◽  
Important Means

Abstract To establish the dynamic model of machine tool structure is an important means to assess the performance of the machine tool structure during the cutting process. It’s necessary to study the dynamics of the machine tools in different configurations for the sake of analyzing the dynamic behavior of the machine tools in the entire workspace. In this paper, a robust approach is presented to build an efficient and reliable dynamic model to evaluate the position-dependent dynamics of the twin ball screw (TBS) feed system. First, the TBS feed system is divided into several components and a finite element (FE) model is built for each component. Second, the Craig-Bampton method is proposed to reduce the order of the substructures. Third, a multipoint constraints (MPCs) method was introduced to model the mechanical joints substructures of the TBS system, and the spring-damper element (SDE) is employed to connect the condensation nodes. Finally, a series experimental tests and full order FE analysis are conducted on the self-designed TBS worktable in the four positions to validate the effectiveness of the proposed dynamic model. The results show that the proposed approach evaluates accurately the position-dependent behavior of the TBS system.

scholarly journals Dynamic Interaction Between Precision Machine Tools and Their Foundations

2020 ◽  
Vol 14 (3) ◽  
pp. 386-398
Author(s):  
Bernd W. Peukert ◽  
◽  
Andreas Archenti
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Dynamic Interaction ◽  
Machining Accuracy ◽  
Precision Machine ◽  
Novel Approach ◽  
Machine Tool Structures ◽  
Manufacturing Accuracy ◽  
Precision Machine Tools ◽  
The Individual

The manufacturing accuracy of modern machine tools strongly depends on the placement of the machine tool structure on the factory’s foundation. Civil engineering knows a variety of foundation types and factory planners must carefully consider local circumstances such as the size and the properties of the regional subsoil as well as the individual requirements of machine tools. Two of the major reasons for the effect of the foundation onto the machining accuracy are the added stiffness and the increased mass from the installation site’s foundation. A change of these characteristics greatly affects the dynamic characteristics of the overall machine tool and therefore also the machining dynamics. Although some general rules and guidelines exist for the design of foundations, their dynamic interaction with the supported precision machine tool structures is not well understood yet. This paper presents a series of measurements on two different types of machine tool foundations and highlights the characteristic differences in their dynamic interaction. It also proposes a novel approach to validate the conclusions with the use of foundation and machine tool scale models. These results can serve factory planners of precision targeting shop floors as a valuable guide for deciding on a suitable foundation for lowering the individual machine tool vibrations and/or reducing the dynamic interaction between closely located machine tools.

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