Measurement of the spindle system dynamic stiffness of a machine tool using a biaxial non-contact loading device

2018 ◽  
Vol 2018.12 (0) ◽  
pp. C04
Author(s):  
Ryoma Kishino ◽  
Atsushi Matsubara ◽  
Iwao Yamaji
Keyword(s):  
Machine Tool ◽  
Dynamic Stiffness ◽  
System Dynamic ◽  
Contact Loading ◽  
Spindle System ◽  
Loading Device

Dynamic Analysis of Helical Milling Unit Based on Virtual Machine Tool

2011 ◽  
Vol 188 ◽  
pp. 463-468 ◽  
Author(s):  
Xu Da Qin ◽  
Qi Wang ◽  
H.Y. Wang ◽  
Song Hua
Keyword(s):  
Machine Tool ◽  
Virtual Machine ◽  
Dynamic Stiffness ◽  
Three Dimensional ◽  
Geometrical Model ◽  
Helical Milling ◽  
Response Analysis ◽  
Computer Simulation Model ◽  
Element Analysis ◽  
Virtual Machine Tool

The virtual prototype is a computer simulation model of the physical product that can be analyzed like a real machine. This paper studies the helical milling unit based on the virtual machine tool. The helical milling unit is first designed according to the kinematics of the helical milling. The main parts of the equipment include rotating mechanism, orbital agency and radial offset organization. Based on the feasibility analysis of the structure, the three-dimensional geometrical model is built in the Solidworks software. The key parts in the model are separated from the device and introduced into the finite element analysis (FEA) software, according to the cutting loads tested from experiment, static and dynamic modal analysis and harmonic response analysis are carried out for the key parts of this device. The results show that the static and dynamic stiffness can meet design requirement.

scholarly journals Analysis on Dynamic Contact Characteristics and Dynamic Stiffness Estimating Method of Single Nut Ball Screw Pair Based on the Whole Rolling Elements Model

2020 ◽  
Vol 10 (17) ◽  
pp. 5795
Author(s):  
Ye Chen ◽  
Chunyu Zhao ◽  
Zhenjun Li ◽  
Zechen Lu
Keyword(s):  
Machine Tool ◽  
Mass Production ◽  
Contact Stiffness ◽  
Dynamic Stiffness ◽  
Dynamic Contact ◽  
Ball Screw ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Feed System ◽  
Stiffness Model

The purpose of this paper is investigating the characteristics of dynamic contact and dynamic stiffness of the single nut ball screw pair (SNBSP). Then a new sensorless method is proposed to extract the SNBSP dynamic contact stiffness of a mass production CNC machine tool feed system. First of all, the transformation relationship between each coordinate system of SNBSP is established. Secondly, the dynamic model of all ball–raceway contact pairs is established. Based on this, a dynamic contact stiffness model is established. The dynamic contact parameters are obtained by the numerical method. It is found that the influence of screw speed on screw and nut raceway normal force distribution are opposite. This will affect the variations of dynamic contact stiffness. It is also clear that the effect of axial load on dynamic stiffness is significant. Then, an effective method is proposed to estimate the dynamic contact stiffness of a mass production CNC machine tool feed system without any external sensors. The axial force of feed system is estimated by using torque current of servo motor. Current signals can be obtained through FANUC Open CNC API Specifications (FOCAS) library functions, and then dynamic contact stiffness can be calculated through the stiffness model without external sensors. Finally, a feed system dynamic model is built, and the contact model and sensorless stiffness estimating method are verified by experiments in this dynamic system.

Modeling and Synchronous Control of Dual Mechanically Coupled Linear Servo System

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
Wu-Sung Yao
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Dynamic Stiffness ◽  
System Modeling ◽  
Coupled System ◽  
Mechanical Coupling ◽  
Synchronous Control ◽  
Linear Motors ◽  
Operation Speed ◽  
Control Scheme

This paper presents a system modeling technique for a high-speed gantry-type machine tool driven by linear motors. One feed axis of the investigated machine tool is driven by the joint thrust from two parallel linear motors. These two parallel motors are coupled mechanically to form the Y-axis while another standalone motor fixed to a support forms the X-axis. The components in the X-axis, which is treated as the mechanical coupling, are carried by the slides of the Y-axis motors. This configuration is applied to improve the dynamic stiffness of the system and operation speed/acceleration. However, the precise synchronous control of the two parallel and coupled motors would be the major challenge. To overcome this challenge, a multivariable system identification method is developed in this paper. This method is used to construct an accurate system mathematical model for the target coupled system. A synchronous control scheme is then applied to the model obtained using the proposed technique. The performance of the system is experimentally verified with a high-speed S-curve motion profile. The results substantiate the constructed system model and demonstrate the effectiveness of the control scheme.

Experimental Research Regarding the Influence of Hydraulic Resistances on the Hydrostatic Guideways Stiffness

2014 ◽  
Vol 657 ◽  
pp. 475-479
Author(s):  
Marius Pascu ◽  
Gheorghe Stan
Keyword(s):  
Machine Tool ◽  
Hydraulic Resistance ◽  
Experimental Research ◽  
Machine Tools ◽  
Dynamic Stiffness ◽  
Experimental Results ◽  
Graphical Form ◽  
Experimental Setup ◽  
Experimental Database ◽  
Supply Circuit

A very important factor for the hydrostatic guideways is given by the presence of the restrictor on the supply circuit, whose hydraulic resistance may have important effects on the lubricant film behaviour and implicitly, on the static and dynamic stiffness of the system. This paper presents a new method of experimental research regarding the hydrostatic guideway stiffness, depending on the hydraulic resistances values which supply each pocket. During the experiments which approach the influence of the hydraulic resistances values of the restrictors on the hydrostatic guideway stiffness, a centered constant loads of 20, 50 and 100 [daN] was used. The experiments were carried out on an experimental setup composed of an open hydrostatic guideway, having the pocket dimensions of 150x88 [m, supplied with liquid under pressure through means of a pack of adjustable restrictors. The obtained experimental results are presented in both tabular and graphical form and constitute an experimental database which can be used by the machine tools designers and manufacturers. The paper contains recommendations regarding the usage of hydraulic resistances values depending on the machine tool type and size. Also, from the obtained results, recommendations can be made with regard to the type of restrictors to be used, so that the lubricant filtration grade is comprised between admissible values.

Evaluation of dynamic stiffness of machine tool spindle by non-contact excitation tests

CIRP Annals ◽  
2015 ◽  
Vol 64 (1) ◽  
pp. 365-368 ◽  
Author(s):  
Atsushi Matsubara ◽  
Shota Tsujimoto ◽  
Daisuke Kono
Keyword(s):  
Machine Tool ◽  
Dynamic Stiffness ◽  
Machine Tool Spindle

Effect of Clamped Toolholders on Dynamic Characteristics of Spindle System of Machining Center

2012 ◽  
Vol 6 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Haruhisa Sakamoto ◽  
◽  
Taiga Matsuda ◽  
Shinji Shimizu ◽  
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Physical Parameters ◽  
Characteristic Parameters ◽  
Spindle System ◽  
Press Fit ◽  
Equivalent Damping Coefficient ◽  
Response Method ◽  
Tooling System

In this study, dynamic characteristics are determined based on the impulse response method, the correction of discretization errors and the identification of equivalent physical parameters, as found in the vibration model having one degree of freedom. In the experiments, the test tool is cylindrical bar shaped and made from solid tungsten carbide, and four toolholders with chucking mechanisms, including the shrinkfit type, collet type, hydraulic type, and press-fit type, are used. Since it had been previously confirmed that one of the tool preparation jigs had dynamic characteristics similar to those of an actual machine tool’s spindle, the dynamic characteristics of the jig could be measured the way the spindle system is measured in this study. From the experimental examinations, the following were clarified. (1) Chucking of the tooling system enhances the first mode vibration of the spindle system markedly. (2) The type of tool chuck used changes the dynamic characteristics of the spindle system. The trend in the dynamic stiffness corresponds well with that in the equivalent damping coefficient but is opposite to that in the equivalent stiffness. (3) The magnitude order of the dynamic characteristic parameters of the spindle system corresponds well with the inherent values of the dynamic characteristic parameters of the toolholders themselves; that is, the inherent dynamic characteristics of the tooling system can be used as the criteria to estimate the effect on the dynamic characteristics of the spindle system.

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