Analyzing of Dynamic Characteristics of Special CNC Machine Tool

2010 ◽  
Vol 29-32 ◽  
pp. 2037-2041
Author(s):  
Ke Wang ◽  
Guang Lv ◽  
Xing Wei Sun

The dynamic characteristics of machine tool is an important factor, which make affect on the cutting stability of machine tool. The poor dynamic characteristics will seriously affect the stability of cutting, make the low cutting efficiency and low machining precision, and also accelerate the wear of tools and even reduce the machine’s service life. So it is necessary to analyze the dynamic characteristics of machine tool, and according to the results of analysis to optimize structural parameters and motion parameters of the machine tools. This paper analyses the dynamic characteristics of machine bed and machined work piece of the CNC special machine tool for Kelly with the finite element software, and analysis of excitation characteristics of cutting tool. It also makes optimization design to the machine bed, through the analysis and optimization, the natural frequency and stiffness will be obviously improved. According to the structure and calculation of the motion parameters we can get the exciting force frequency to workpiece when it is cut, using interlocking tooth cutting method to replace the initial symmetrical cutting method in order to avoid the resonance produced in the cutting process and improve stability. The exciting frequency when cutting can be improved and the probability of resonance when cutting is lowered. All these ensure high efficiency and high stability cutting.

2021 ◽  
Vol 12 (1) ◽  
pp. 539-557
Author(s):  
Lihong Jin ◽  
Junpeng Shao ◽  
Xigui Wang ◽  
Yongmei Wang ◽  
Baixue Fu

Abstract. Previous studies have attempted to identify weak links in the dynamic characteristics of the planetary gear reducer (PGR) exterior body structure (EBS). Through numerical simulation, these studies analyzed the mode and natural frequencies and the vibration types of each order of the EBS. However, these scholars have never focused on the main factors affecting the dynamic characteristics of the EBS of this subject. This study in the topic has analyzed the vibroacoustic characteristics of an EBS and optimized its design using numerical simulation. Herein, the contribution of the vibration transfer path from the excitation points on the exterior body to the machine foot is emphatically revealed, and the influences of the main structural parameters on the transfer characteristics are discussed. An optimal EBS for a PGR with lower acoustic vibrations is designed in detail, and a composite EBS with damping vibration attenuation and acoustic absorption is proposed. The radiation acoustic characteristics without acoustic protection and damping materials are analyzed. These research results are implemented in order to realize the dynamic characteristics, transmission, and radiation acoustic characteristics as objects of optimization, and the structural design parameters of the PGR exterior body are deeply optimized using dynamic modification and sensitivity analysis. This topic focuses on the vibroacoustic coupling of EBS in stationary fluid and average flow field. Based on the analysis method of theoretical modeling and numerical calculation, the EBS dynamic response and vibroacoustic characteristics under the action of frontal excitation external acoustic flow field are studied, which will be beneficial to explore the comprehensive optimization design of PGR dynamic and vibroacoustic properties.


2011 ◽  
Vol 80-81 ◽  
pp. 1051-1054
Author(s):  
Chun Xia Zhu ◽  
Bin Li ◽  
Ji Man Luo

In order to analyze accurately the dynamic characteristics of guideway joints of CNC, the finite element model(FEM) of guideway joints of CNC is built in ANASYS software, which that springs and damping units imitate guideway joints in this paper. The proposed method can predict the regular pattern which joint stiffness and joint span affect natural frequency and harmonic response. The research demonstrates that the method predicts well the dynamic characteristics of the guideway joints of CNC; therefore, it can be a reference for dynamic optimization design of guideway joints of CNC machine tool.


2010 ◽  
Vol 44-47 ◽  
pp. 1387-1391
Author(s):  
Bi Zhong Xia ◽  
Ping Fa Feng ◽  
Hua Yong Yang

A hydraulic power limiting valve, HPLV, is a key hydraulic element to realize power limiting control for hydraulic drive system in engineering machinery. By tracing with the discharge pressure of hydraulic pump, HPLVs are used to real-time control the pilot pressure that corresponds to the displacement of hydraulic pump, and match the output power of hydraulic pump with the power of its prime mover within high efficiency scope. So good dynamics is important for HPLVs to reflect the frequently change of pump pressure. Based on the description of a typical HPLV with two-spring structure, its principle and the working process are discussed, then the mathematical model is established and the effects of several main structural parameters on its dynamic characteristics are carried out.


2019 ◽  
Vol 27 (2) ◽  
pp. 170-185
Author(s):  
Shihao Liu ◽  
Yanbin Du ◽  
Mao Lin

In order to improve the efficiency and effectiveness of the lightweight design of the gantry machine tool, a lightweight structural optimization design system for the gantry machine tool was constructed. Serialized gantry machine tools were parametrically modeled, and a load model with multiple operating conditions was established. A twice optimization design method integrating zero-order optimization, parameter rounding, and structural re-optimization was proposed. Using the proposed method, a lightweight structural optimization design system for gantry machine tool with parametric design, lightweight design, and other functions was developed. The developed gantry machine tool lightweight structural optimization design system was applied to complete the lightweight structural optimization design of gantry frame of a certain gantry machine tool, so the structural parameters of the gantry frame were optimized. Although the maximum stress and the maximum deformation of the gantry frame increases within the allowable range, the experimental comparison before and after the optimization shows that the mass of the whole gantry frame is reduced by 9.24%, which is beneficial to save the manufacturing cost. The research results show that the constructed lightweight structural optimization design system of the gantry machine tool has high engineering practicality.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 165-172
Author(s):  
Dongge Deng ◽  
Mingzhi Zhu ◽  
Qiang Shu ◽  
Baoxu Wang ◽  
Fei Yang

It is necessary to develop a high homogeneous, low power consumption, high frequency and small-size shim coil for high precision and low-cost atomic spin gyroscope (ASG). To provide the shim coil, a multi-objective optimization design method is proposed. All structural parameters including the wire diameter are optimized. In addition to the homogeneity, the size of optimized coil, especially the axial position and winding number, is restricted to develop the small-size shim coil with low power consumption. The 0-1 linear programming is adopted in the optimal model to conveniently describe winding distributions. The branch and bound algorithm is used to solve this model. Theoretical optimization results show that the homogeneity of the optimized shim coil is several orders of magnitudes better than the same-size solenoid. A simulation experiment is also conducted. Experimental results show that optimization results are verified, and power consumption of the optimized coil is about half of the solenoid when providing the same uniform magnetic field. This indicates that the proposed optimal method is feasible to develop shim coil for ASG.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1548
Author(s):  
Jiuling Hu ◽  
Lianjin Hong ◽  
Lili Yin ◽  
Yu Lan ◽  
Hao Sun ◽  
...  

At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.


Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1044
Author(s):  
Yaroslav Frolov ◽  
Maxim Nosko ◽  
Andrii Samsonenko ◽  
Oleksandr Bobukh ◽  
Oleg Remez

The most complex issue related to the design of high efficiency composite materials is the behavior of the reinforcing component during the bonding process. This study presents numerical and experimental investigations of the shape change in the reinforcing inlay in an aluminum-steel mesh-aluminum composite during roll-bonding. A flat composite material consisting of two outer strips of an EN AW 1050 alloy and an inlay of expanded C10 steel mesh was obtained via hot roll bonding with nominal rolling reductions of 20%, 30%, 40% and 50% at a temperature of 500 °C. The experimental procedure was carried out using two separate rolling mills with diameters equal to 135 and 200 mm, respectively. A computer simulation of the roll bonding was performed using the finite element software QForm 9.0.10 by Micas Simulations Limited, Oxford, UK. The distortion of the mesh evaluated via the change in angle between its strands was described using computer tomography scanning. The dependence of the absorbed impact energy of the roll bonded composite on the parameters of the deformation zone was found. The results of the numerical simulation of the steel mesh shape change during roll bonding concur with the data from micro-CT scans of the composites. The diameter of rolls applied during the roll bonding, along with rolling reduction and temperature, have an influence on the resulting mechanical properties, i.e., the absorbed bending energy. Generally, the composites with reinforcement exhibit up to 20% higher impact energy in comparison with the non-reinforced composites.


2014 ◽  
Vol 538 ◽  
pp. 91-94
Author(s):  
Wei Ping Luo

A virtual prototype model of Machine Tool has been constructed by using the Pro/E software and the ANSYS software. Considering the effects of contact surfaces, dynamic analyses of Machine Tool are studied. The effects of contact surfaces on the dynamic characteristics of machine tool are studied. So that the purpose predicting and evaluating synthetically the machine tool dynamic performance without a physical sample can be achieved.


2011 ◽  
Vol 418-420 ◽  
pp. 2055-2059 ◽  
Author(s):  
Yu Lin Wang ◽  
Na Jin ◽  
Kai Liao ◽  
Rui Jin Guo ◽  
Hu Tian Feng

The head frame is a key component which plays a supportive and accommodative role in the spindle system of CNC machine tool. Improving the static and dynamic characteristics has profound significance to the development of machine tool and product performance. The simplified finite element modal is established with ANSYS to carry out the static and modal analysis. The results showed that the maximum deformation of the head frame was 0.0066mm, the maximum stress was 3.94Mpa, the deformation of most region was no more than 0.0007mm, which all verified that the head frame had a good stiffness and deforming resistance; several improvement measures for dynamic performance were also proposed by analyzing the mode shapes, and the 1st order natural frequency increased 7.33% while the head frame mass only increased 1.58% applying the optimal measure, which improved the dynamic characteristics of the head frame effectively.


Author(s):  
Liu Ruiwei ◽  
Hongwei Guo ◽  
Zhang Qinghua ◽  
Rongqiang Liu ◽  
Tang Dewei

Balancing stiffness and weight is of substantial importance for antenna structure design. Conventional fold-rib antennas need sufficient weight to meet stiffness requirements. To address this issue, this paper proposes a new type of cable-rib tension deployable antenna that consists of six radial rib deployment mechanisms, numerous tensioned cables, and a mesh reflective surface. The primary innovation of this study is the application of numerous tensioned cables instead of metal materials to enhance the stiffness of the entire antenna while ensuring relatively less weight. Dynamic characteristics were analyzed to optimize the weight and stiffness of the antenna with the finite element model by subspace method. The first six orders of natural frequencies and corresponding vibration modes of the antenna structure are obtained. In addition, the effects of structural parameters on natural frequency are studied, and a method to improve the rigidity of the deployable antenna structure is proposed.


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