Hybrid modeling and analysis of multidirectional variable stiffness of the linear rolling guideway under combined loads

2020 ◽  
Vol 234 (13) ◽  
pp. 2716-2727
Author(s):  
Lei Yang ◽  
Lei Wang ◽  
Wanhua Zhao
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Complex Loading ◽  
Variable Stiffness ◽  
Time Varying ◽  
Modeling And Analysis ◽  
Combined Loads ◽  
Machine Tool Structure ◽  
High Feed ◽  
Stiffness Characteristics

In the working process of high-speed multiaxis machine tools, inertial loads due to high feed acceleration and time-varying gravity loads due to changing configuration of multiaxis structure result in time-varying complex loads applied to linear rolling guideway. Existing models cannot efficiently represent the effect of complex loads on multidirectional stiffness variation of linear rolling guideway. In this paper, a hybrid model of multidirectional stiffness of linear rolling guideway and the solving algorithm are proposed. The complex loading conditions of linear rolling guideway in high-speed multiaxis machine tool structure are considered. And contact flexibilities between rolling balls and grooves are modeled with the effect of elastic deformations of runner block and rail. The proposed model can calculate the multidirectional stiffness with high accuracy. Meanwhile the differences between the stiffness characteristics in different directions are represented correctly. The variations of multidirectional stiffness of linear rolling guideway under time-varying combined loads are analyzed. This study provides an effective way to comprehensively evaluate the stiffness characteristics of linear rolling guideway which can contribute to the dynamic analysis and active design of high-speed machine tool structure.

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 New High-Speed Machine Tool Structure by Holistic Mechatronic Systems Design

Procedia CIRP ◽  
2012 ◽  
Vol 1 ◽  
pp. 307-312 ◽  
Author(s):  
R. Neugebauer ◽  
S. Ihlenfeldt ◽  
U. Frieß ◽  
M. Wabner ◽  
S. Rauh
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Systems Design ◽  
Mechatronic Systems ◽  
Machine Tool Structure ◽  
High Speed Machine

scholarly journals Effect of Time-Varying Moving Structures on the Spatial Accuracy of Five-Axis Machine Tools

2021 ◽  
Author(s):  
Tzu-Chi Chan ◽  
Jyun-Sian Yang
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
High Speed ◽  
Time Varying ◽  
Spatial Accuracy ◽  
Static And Dynamic Characteristics ◽  
Five Axis ◽  
Speed Accuracy ◽  
Machine Structure

Abstract Machine tools are constantly in motion during machining; however, studies have not considered the effect of the dynamic and static characteristics of the machine caused by the movement of the structure over time. In this study, the time-varying moving structure in the spatial coordinate arm is analyzed to improve the spatial accuracy of the motion of a five-axis machine tool in the cutting area. The objective is to design a high-speed five-axis moving-column machine tool and to perform structural analysis of spatial accuracy. We studied the static and dynamic characteristics of a five-axis machine tool, designed and improved its mechanical structure, and optimized its structural configuration. With further analysis, the entire machine structure was enhanced to improve its static and dynamic characteristics. The static and dynamic characteristics of the machine structure were found to directly affect its processing performance and the precision of the workpiece machined by the tool. Through this study, the design technology for speed, accuracy, and surface roughness of the machine tool was further improved.

High-speed test of thermal effects for a machine-tool structure based on modal analysis

1986 ◽  
Vol 8 (2) ◽  
pp. 72-78 ◽  
Author(s):  
M. Matsuo ◽  
T. Yasui ◽  
T. Inamura ◽  
M. Matsumura
Keyword(s):  
Machine Tool ◽  
Modal Analysis ◽  
Thermal Effects ◽  
High Speed ◽  
Speed Test ◽  
Machine Tool Structure

Modeling and Analysis of Fixel Designs for Micromanufacturing Active Fixturing

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Troy B. Rippere ◽  
Koustubh J. Rao ◽  
Gloria J. Wiens
Keyword(s):  
Manufacturing Systems ◽  
Compliant Mechanisms ◽  
Variable Stiffness ◽  
Theoretical Models ◽  
Milling Process ◽  
Contact Forces ◽  
Modeling And Analysis ◽  
Design Alternatives ◽  
Expected Performance ◽  
Stiffness Characteristics

This paper presents an investigation of fixel design alternatives for active (dynamic) fixturing to be incorporated into mesoscale manufacturing systems. Using simple compliant mechanisms and components, fixels exhibiting mechanically adjustable stiffness characteristics are achievable. Via manual or automated stiffness adjustments, these fixels provide functionality for enabling greater control of the dynamic response of the workpiece subject to vibrations and/or variations in contact forces at the tool-workpiece-fixture interface. To quantify the fixel functionality, this paper presents theoretical models of the stiffness characteristics expressed as a function of the mechanical variable(s), thus forming a basis for exploring the adjustability in stiffness achievable for each fixel design. Also presented are results of the dynamic behavior of the active fixturing implemented in a milling process based on a “regenerative force, dynamic deflection model” augmented with the active fixturing variable stiffness model and inclusion of tool runout. These simulation results indicate the expected performance of the active fixturing upon its implementation in actual fixturing for the creation of micron features on micro- and macroparts.

Analysis of Particle Damping Characteristics on Steel Vertical Machining Centre Column with Epoxy Reinforced Granite

2020 ◽  
Vol 50 ◽  
pp. 94-102
Author(s):  
S. Nallusamy ◽  
K. Sujatha ◽  
K. Rajan ◽  
K.R. Vijaya Kumar
Keyword(s):  
Cast Iron ◽  
Machine Tool ◽  
High Speed ◽  
Good Choice ◽  
Work Piece ◽  
Damping Capacity ◽  
Static Stiffness ◽  
Machining Performance ◽  
Machine Tool Structure ◽  
Steel Balls

In high speed machining, performance is generally influenced by the dynamic behaviour of the machine tool structures. The machine tool structure is required to be rigid in order to remove the undesirable vibration and to improve the work piece quality. The most conventional material used in machine tool structure is cast iron which has both stiffness and dynamic characteristics to perform at varying speeds. The objective of this work is to improve damping capacity of vertical machining centre column. The damping capacity of column can be increased further by using passive damping method of ball packing. Damping capacity is a crucial factor which makes the dissipation of vibration happens at faster rate. As compared with cast iron established studies shows that epoxy granite a composite material improves damping capacity. Epoxy granite though could be a good choice for improving the machine tool performance at high speeds but is poor in static stiffness compared to cast iron. In this investigation it was observed that, the static stiffness of epoxy granite composite vertical machining centre column could be increased by using steel reinforcements. The final results reveal that, steel balls with epoxy granite provide faster dissipation time of 15ms at 70% packing ratio as compared to glass balls that showed dissipation time of 35ms. Also it was seen that, the steel balls offer the better damping capacity at optimum packing ratio of 50% mainly due to its specific gravity and mass of the balls.

scholarly journals Modeling and Analysis of a Linear Generator for High Speed Maglev Train

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 24637-24645
Author(s):  
Sansan Ding ◽  
Weitao Han ◽  
Jinji Sun ◽  
Fujie Jiang ◽  
Guimei Deng ◽  
...  
Keyword(s):  
High Speed ◽  
Maglev Train ◽  
Modeling And Analysis ◽  
Linear Generator

scholarly journals The Impact of Participation in PPP Projects on Total Factor Productivity of Listed Companies in China

2021 ◽  
Vol 13 (14) ◽  
pp. 7603
Author(s):  
Xiangdong Liu ◽  
Guangxi Cao
Keyword(s):  
Total Factor Productivity ◽  
High Speed ◽  
Operation Mode ◽  
Listed Companies ◽  
Financing Constraints ◽  
Eastern Region ◽  
Time Varying ◽  
Factor Productivity ◽  
The Impact ◽  
China’S Economy

The key to transforming China’s economy from high-speed growth to high-quality development is to improve total factor productivity (TFP). Based on the panel data of China’s listed companies participating in PPP (Public–Private Partnerships) projects from 2010 to 2019, this paper constructs the time-varying DID method to test the impact of participation in PPP projects on the company’s TFP empirically, explore the mechanism of the effect of participation in PPP projects on the company’s TFP, and then conduct heterogeneous analysis from four perspectives: region, industry, ownership form, and operation mode. The empirical results show that participation in PPP projects can significantly promote the growth of the company’s TFP, which mainly comes from the promotion of the innovation level of listed companies and the alleviation of financing constraints by participating in PPP projects. In addition, participation in PPP projects has a significant impact on TFP of listed companies in the eastern region, listed companies in the secondary and tertiary industries, state-owned listed companies, and listed companies participating in PPP projects under the BOT mode.

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