Static and dynamic behavior of steel-reinforced epoxy granite CNC lathe bed using finite element analysis

2020 ◽  
Vol 234 (4) ◽  
pp. 595-609
Author(s):  
Shanmugam Chinnuraj ◽  
PR Thyla ◽  
S Elango ◽  
Prabhu Raja Venugopal ◽  
PV Mohanram ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cast Iron ◽  
Machine Tool ◽  
Dynamic Characteristics ◽  
Torsional Rigidity ◽  
Element Model ◽  
Element Analysis ◽  
Cnc Lathe ◽  
Machine Tool Structures

Machine tools are used to manufacture components with desired size, shape, and surface finish. The accuracy of machining is influenced by stiffness, structural damping, and long-term dimensional stability of the machine tool structures. Components machined using such machines exhibit more dimensional variations because of the excessive vibration during machining at higher speeds. Compared to conventional materials like cast iron, stone-based polymer composites such as epoxy granite have been found to provide improved damping characteristics, by seven to ten folds, due to which they are being considered for machine tool structures as alternate materials. The stiffness of structures made of epoxy granite can be enhanced by reinforcing with structural steel. The current work highlights the design and analysis of different steel reinforcements in the lathe bed made of the epoxy granite composite to achieve equivalent stiffness to that of cast iron bed for improved static and dynamic performances of the CNC lathe. A finite element model of the existing the cast iron bed was developed to evaluate the static (torsional rigidity) and dynamic characteristics (natural frequency) and the results were validated using the experimental results. Then finite element models of five different steel reinforcement designs of the epoxy granite bed were developed, and their static and dynamic behaviors were compared with the cast iron bed through numerical simulation using finite element analysis. The proposed design (Design-5) of the epoxy granite bed is found to have an improvement in dynamic characteristics by 4–10% with improved stiffness and offers a mass reduction of 22% compared to the cast iron bed, hence it can be used for the manufacture of the CNC lathe bed and other machine tool structures for enhanced performance.

Structural investigation of steel-reinforced epoxy granite machine tool column by finite element analysis

2019 ◽  
Vol 233 (11) ◽  
pp. 2267-2279 ◽  
Author(s):  
Prabhu Raja Venugopal ◽  
M Kalayarasan ◽  
PR Thyla ◽  
PV Mohanram ◽  
Mahendrakumar Nataraj ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cast Iron ◽  
Machine Tool ◽  
Dynamic Characteristics ◽  
Element Model ◽  
Static Stiffness ◽  
Element Analysis ◽  
Static And Dynamic Characteristics ◽  
Machining Center

Higher damping with higher static stiffness is essential for improving the static and dynamic characteristics of machine tool structures. The structural vibration in conventional machine tools, which are generally made up of cast iron and cast steel, may lead to poor surface finish and the dimensional inaccuracy in the machined products. It leads to the investigation of alternative machine tool structural materials such as concrete, polymer concrete, and epoxy granite. Although epoxy granite has a better damping capacity, its structural stiffness (Young's modulus) is one-third as compared to cast iron. Therefore, the present work represents optimization of the structural design of the vertical machining center column by introducing various designs of steel reinforcement in the epoxy granite structure to improve its static and dynamic characteristics using experimental and numerical approaches. A finite element model of the existing cast iron vertical machining center column has been developed and validated against the experimental data obtained using modal analysis. Furthermore, finite element models for various epoxy granite column designs have been developed and compared with the static and dynamic characteristics of cast iron column. A total of nine design configurations for epoxy granite column with steel reinforcement are evolved and numerical investigations are carried out by finite element analysis. The proposed final configuration with standard steel sections has been modeled using finite element analysis for an equivalent static stiffness and natural frequencies of about 12–20% higher than cast iron structure. Therefore, the proposed finite element model of epoxy-granite-made vertical machining center column can be used as a viable alternative for the existing column in order to achieve higher structural damping, equivalent or higher static stiffness and, easy and environmental-friendly manufacturing process.

Estimation of Dynamic Mechanical Error for Evaluation of Machine Tool Structures

2012 ◽  
Vol 6 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Daisuke Kono ◽  
◽  
Sascha Weikert ◽  
Atsushi Matsubara ◽  
Kazuo Yamazaki ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Machine Tool ◽  
Driving Force ◽  
Inertial Force ◽  
Element Analysis ◽  
Simple Method ◽  
Dynamic Mechanical ◽  
Machine Tool Structures ◽  
Multi Body

Dynamic motion errors of machine tools consist of errors in the mechanical system and the servo system. In this study, a simple method to estimate the dynamic mechanical error is proposed to evaluate machine tool structures. The dynamic mechanical error in the low frequency range is estimated from the static deformation due to the driving force, the counter force, and the inertial force. The error in a high-precision machine tool is estimated for comparison with measurements. Two calculation tools, finite element analysis and rigid multi-body simulation, are used for the estimation. Measured dynamic mechanical errors can be correctly estimated by the proposed method using finite element analysis. The tilt of driven bodies is the major reason for dynamic mechanical errors. When the reduction factor representing the structural deformation is properly determined, the rigid multi-body simulation is also an effective tool. Use of the proposed method for modification planning is demonstrated. Stiffness enhancement of the saddle was an effective modification candidate to reduce the dynamic mechanical error. If the error should be reduced to sub-micrometer level, the location of components should be modified because the Abbe offset and the offset of the driving force from the inertial force must be shortened.

The Research of the Dynamic Characteristics of Horizontal Jig Boring Machine

2013 ◽  
Vol 712-715 ◽  
pp. 1391-1394
Author(s):  
Zhi Li ◽  
X. S. Zhao ◽  
D. W. Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Machine Tool ◽  
Dynamic Characteristics ◽  
Experimental Test ◽  
Structure Modification ◽  
Analysis Software ◽  
Machine Model ◽  
Element Analysis ◽  
Set Up

Modal analysis is one way of studying the dynamic characteristics of the mechanical. In order to study the dynamic characteristics of machine tool,numerical machine model is set up with finite element analysis software,of which validity is verified by experimental modal analysis.The experimental test also provide the boundary conditions, so as to further structure modification and dynamic characteristic design

Study on static and dynamic characteristics of nettle–polyester composite micro lathe bed

2016 ◽  
Vol 233 (2) ◽  
pp. 141-155 ◽  
Author(s):  
N Mahendrakumar ◽  
PR Thyla ◽  
PV Mohanram ◽  
C Raja Kumaran ◽  
J Jayachandresh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cast Iron ◽  
Dynamic Characteristics ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Worst Case ◽  
Design Modification ◽  
Static And Dynamic Characteristics ◽  
Polyester Composite

Nowadays, natural fibre-reinforced composites find applications in almost all engineering fields. This work is an attempt to realise improvement in dynamic characteristics of micro lathe bed using Himalayan nettle (Girardinia heterophylla) polyester (NP) composite as an alternate material. In order to study and validate the improvements envisaged, a cast iron micro lathe bed is considered as reference. Numerical (FE) model of the cast iron micro lathe bed was developed and validated through experimental static and modal analysis. Finite element analysis of the micro lathe bed with the existing cast iron material as well as with nettle–polyester composite as alternate material was also carried out using worst case cutting forces, and based on the relative performances, the need for form design modification for the proposed material was identified. To enhance the bending and torsional stiffness of the nettle–polyester composite lathe bed, various cross sections and rib configurations were studied and the best among them was identified and the same was implemented in the nettle–polyester composite micro lathe bed design. Finite element analysis of the newly designed nettle–polyester composite micro lathe bed was performed and the improvements in dynamic characteristics were evaluated. The newly designed nettle–polyester composite micro lathe bed was fabricated and the predicted enhancement in static and dynamic characteristics was verified experimentally. The studies indicated that nettle–polyester composite could be considered as a suitable alternate to cast iron structures in machine tools.

The Analysis on Dynamic Characteristics and the Structural Optimization of HRG Polishing Machine Tool

2013 ◽  
Vol 770 ◽  
pp. 54-58 ◽  
Author(s):  
Ming Jun Chen ◽  
Lin Yu ◽  
He Nan Liu ◽  
Wan Qun Chen
Keyword(s):  
Finite Element ◽  
Machine Tool ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Element Model ◽  
Machining Accuracy ◽  
Cnc Machine ◽  
Element Analysis ◽  
Dynamic Performances ◽  
Supporting Frame

The dynamic characteristics of machine tool directly affect machining accuracy of the final parts. Taking the self-developed HRG ultra-precision polishing CNC machine tool as the research object, the simplified finite element model is established with the finite element analysis software to do the dynamic analysis and the natural frequency is detected as the index of the dynamic performances. Based on the comparative analysis of the natural frequency and vibration modes, the gantry and the supporting frame are recognized as structural weaknesses of the machine tool, and then the modal test is done to verify simulation results. Eventually the structural weaknesses are optimized effectively. The 1st order nature frequency of the optimized gantry and the optimized supporting frame is increased 75.5% and 80.8% respectively so that they have better dynamic performances, resulting in offering higher workpiece quality and process stability.

Test and Finite Element Analysis on Dynamic Characteristics of Trestle Wharf

2012 ◽  
Vol 594-597 ◽  
pp. 908-913
Author(s):  
Xi Ping Sun ◽  
Zhen Yu Zhu ◽  
Bing Hao Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Analysis ◽  
Finite Element Model ◽  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Element Model ◽  
Dynamic Responses ◽  
Steel Pipe ◽  
Element Analysis

The project intends to construct steel pipe piles on both sides of trestle wharf, and the soil vibrations caused by piling construction might have an important effect on the safe service of wharf. In this paper, the dynamic signals during piling construction were recorded and recognized by NExT-ERA. Meanwhile, modal analysis through finite element model of wharf was performed. Through a comparative analysis of the two results, the first two orders of frequency for wharf were obtained. The results would lay foundation for further analysis of dynamic responses of wharf when pile locations close to wharf.

Design and analysis of epoxy granite vertical machining centre base for improved static and dynamic characteristics

2019 ◽  
Vol 234 (3) ◽  
pp. 481-495 ◽  
Author(s):  
Prabhu Raja Venugopal ◽  
P Dhanabal ◽  
PR Thyla ◽  
S Mohanraj ◽  
Mahendrakumar Nataraj ◽  
...  
Keyword(s):  
Cast Iron ◽  
Machine Tool ◽  
Dynamic Characteristics ◽  
Element Model ◽  
Numerical Approach ◽  
Structural Vibration ◽  
Polymer Concrete ◽  
Static Stiffness ◽  
Static And Dynamic Characteristics ◽  
Machine Tool Structures

The structural vibration in conventional machine tools which are generally made of cast iron may lead to poor surface finish of the machined components. This has led to the investigations on alternative materials for machine tool structures such as concrete, polymer concrete and epoxy granite which have higher damping properties but lesser Young's modulus. However, higher static stiffness with higher damping is essential for improving the static and dynamic characteristics of machine tool structures. Hence, this work focuses on replacing the vertical machining centre base made of cast iron with steel reinforced epoxy granite to improve the structural static stiffness. A finite element model of the above base is developed and validated against the experimental data obtained using modal analysis. The validated numerical approach is applied for investigating the seven progressive design configurations of base reinforced with steel. It is found that the epoxy granite base of Design configuration-7 with L-channels has significantly reduced the deformation by 56 and 36% considering milling and drilling operations, respectively, in comparison to cast iron base. Further, the natural frequencies of the above configuration are higher in all the modes (by more than 50%) under consideration than those of the existing cast iron structure. Therefore, the proposed configuration of base is a viable alternative for the existing base in order to achieve higher structural damping. The novelty of the present work is the design of epoxy granite vertical machining centre base using steel reinforcements to improve structural rigidity with ease of manufacturing.

Dynamic Characteristic Analysis and Validation of Spindle Assembly of NC Machine Tool

2009 ◽  
Vol 626-627 ◽  
pp. 447-452 ◽  
Author(s):  
Yao Man Zhang ◽  
S.H. Wang ◽  
Yong Xian Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Machine Tool ◽  
Dynamic Characteristics ◽  
Spindle Assembly ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
Nc Machine Tool ◽  
The Finite Element Analysis ◽  
Nc Machine

One of the important factors resulting in the performances of the machinery is its dynamic characteristics. The spindle assembly is one of the usual parts of NC machine tool, so its dynamic-static characteristics will affect the performances of machine tool. The study is based on a NC machine tool produced by a certain plant of machine tools. The finite element dynamic analysis model of spindle assembly was developed by introducing two or three groups of circumferential spring damper elements which are arrange at different angle around the spindle, and the effect of different supporting conditions and different arrange angle on the modal analysis of the spindle assembly were discussed. The finite element analysis on spindle and spindle assembly has been made to confirm its dynamic characteristics. Then the finite element analysis models are validated by some experiments.

Finite Element Analysis for Static Stiffness of a Crankshaft Grinding Machine Tool

2014 ◽  
Vol 543-547 ◽  
pp. 76-79
Author(s):  
Ting Ting Guo ◽  
Teng Jiao Sun ◽  
Fang Shao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Machine Tool ◽  
Element Model ◽  
Machining Accuracy ◽  
Static Stiffness ◽  
Element Analysis ◽  
Technical Parameters ◽  
Grinding Machine ◽  
The Finite Element Model

Taking a grinding machine tool as an example, this paper obtained the static stiffness of the machine tool by finite element analysis method. The structure and technical parameters of the machine tool were introduced at first.Then, the finite element model of the machine tool was established. The static stiffness of the machine tool in x-, y-, and z-directions were simulated at last. The results show that, the static stiffness in x-direction is 2.0062×107 N/m, the static stiffness in y-direction is 0.821×107 N/m, and the static stiffness in z-direction is 0.2992×107 N/m. This paper provides advices for structure optimization of the machine tool which is convenient for improving the machining accuracy.

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