Dynamic error of multiaxis machine tools considering position dependent structural dynamics and axis coupling inertial forces

2021 ◽  
pp. 095440542110284
Author(s):  
Lei Yang ◽  
Xing Zhang ◽  
Lei Wang ◽  
Wanhua Zhao
Keyword(s):  
Structural Dynamics ◽  
Machine Tools ◽  
High Speed ◽  
Dynamic Error ◽  
Inertial Forces ◽  
Machining Performance ◽  
Working Process ◽  
Rigid Body Dynamic ◽  
Dynamic Errors ◽  
Gantry Machine Tool

During the working process of high-speed multiaxis machine tools, inertial forces can cause vibration and deformation of mechanical structure, which lead to the dynamic error of tool center point (TCP) relative to worktable and can adversely affect the machining performance. Considering the varying feed positions and accelerations during machining, a parameter-varying multi-rigid-body dynamic model of a 3-axis gantry machine tool is proposed. This model represents the position dependent structural dynamics and inertial forces, which can simulate the dynamic error of TCP relative to worktable within the entire workspace. The results show that the dynamic error in one direction is affected by the feed motions of multiple feed axes. The magnitudes of the dynamic error significantly vary with the position of Z-axis. And the dynamic errors in Y- and Z-direction show different varying trends. Then the theoretical model is used to discuss the dynamic error and position dependency. The expressions of TCP dynamic response and inertial forces reveal the reason why the dynamic errors in Y- and Z-direction show different varying trends.

Development of High-Speed, High-Precision 5-Axis Integrated Machine Tools

2007 ◽  
Vol 1 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Masahiko Mori ◽  
◽  
Hidehito Ota ◽  
Makoto Fujishima
Keyword(s):  
High Precision ◽  
Machine Tools ◽  
High Speed ◽  
Direct Drive ◽  
Machining Performance ◽  
Rotary Axis ◽  
Rotary Actuator

This paper describes the development of high-speed, high-precision 5-axis machine tools which can be used for both milling and turning. Conventional 5-axis machine tools are generally difficult to operate because the visibility is poor. Moreover, their precision is inadequate and the rotary axis speed is insufficient for turning. To deal with these factors, we developed a simple, high-precision 2-axis rotary actuator with high-speed direct drive motors. We studied the machining performance of 5-axis machining centers equipped with such direct drive motors.

Dynamic Analysis of a Mesoscale Machine Tool

2005 ◽  
Vol 128 (1) ◽  
pp. 194-203 ◽  
Author(s):  
Sang Won Lee ◽  
Rhett Mayor ◽  
Jun Ni
Keyword(s):  
Dynamic Behavior ◽  
Structural Dynamics ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
Scaling Law ◽  
Milling Process ◽  
Lumped Parameter Model ◽  
Machining Performance ◽  
Significant Difference ◽  
Joint Dynamics

Miniaturized machine tools, referred to as mesoscale machine tools (mMTs) henceforth, have been proposed as a way to manufacture micro/mesoscale mechanical components. A thorough study of the dynamic behavior of the mMT is required for the successful development of its machine structure. This paper demonstrates the development of an mMT, the performance evaluation of its mesoscale milling process, and the characterization of its dynamic behavior. The mMT is developed by using an air turbine spindle and three piezoelectric linear stages, and its volumetric size is 150×70×140mm. A series of micro/mesoscale milling experiments are conducted, and the performances in the developed mMT testbed are evaluated. The dynamic characteristics of the mMT can be different from those of conventional machine tools because the mMT is a miniaturized structure and comprises different machine components. Therefore, the effect of the miniaturization of a structure on the change of its dynamic behavior, called scaling law of the structural dynamics, is studied numerically and experimentally. The dynamic characteristics of the developed mMT that are estimated from the scaling law of the structural dynamics are much different from those obtained from an experimental modal analysis, and the flexible joints of the developed mMT are mainly responsible for this significant difference. Therefore, the joint dynamics of the mMT are studied by introducing an equivalent lumped parameter model, thus enabling simple identification of the joint dynamics and the effective modification of its critical joints to enhance a machining performance.

CMM Design Based on Fundamental Design Principles

2014 ◽  
Vol 1036 ◽  
pp. 517-522
Author(s):  
Aurel Tulcan ◽  
Liliana Tulcan ◽  
Daniel Stan
Keyword(s):  
High Speed ◽  
Mechanical Design ◽  
Dynamic Error ◽  
Great Influence ◽  
Element Analysis ◽  
Error Sources ◽  
Second Stage ◽  
High Predictability ◽  
Dynamic Errors ◽  
High Repeatability

The paper presents an approach concerning the CMM design. The first stage of this research deals with the acquisition and the development of knowledge about the CMM design. The main mechanical design aspects to achieve a high positioning and measuring accuracy are presented and two main objectives are assigned: high repeatability (design for repeatability) and high predictability of the machine response to the main error sources (design for predictability). In the second stage of this research the dynamic errors states for this CMM design have been analyzed. In high-speed measuring processes dynamic errors will have a great influence on the accuracy. This study has been performed by using finite-element analysis (FEA) of the mechanical frame. The total deformation of the mechanical frame for different accelerations of the moving assemblies has been calculated. The major deflections at the probe position due to the accelerations are obtained by using FEA. These results give a prediction about the dynamic error of the CMM.

Modeling of Dynamic Errors for a Table-Tilting Type 5-Axis Machine Tools

2013 ◽  
Vol 655-657 ◽  
pp. 1277-1281
Author(s):  
Yong Chao Zhang ◽  
Song Lin Wu ◽  
Jun Feng Zhang
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Dynamic Error ◽  
Transformation Matrix ◽  
Rotary Table ◽  
Static Error ◽  
Machining Center ◽  
Error Dynamic ◽  
Homogeneous Transformation Matrix ◽  
Dynamic Errors

The precision of its processes is affected by static error and dynamic error. This paper focuses on modeling about dynamic errors and proposed an algorithm of the dynamic error for Table-tilting 5-axis machine tool, which is using Homogeneous Transformation Matrix to establish the dynamic errors formula, so as to structure a model of its dynamic error. Dynamic errors about rotary and linear axis of a 5-axis machining center with tilting rotary table type are defined. At last, we performed the operation and measurement of Table-tilting 5-axis machine, in order to compare and verify the dynamic errors, and to use as adjusting the Table-tilting 5-axis machine tool, and improve the precision of its machining. The result of a synthesis example verifies the effectiveness of the proposed modeling.

scholarly journals Development of an Analyzing and Tuning Methodology for the CNC Parameters Based on Machining Performance

2020 ◽  
Vol 10 (8) ◽  
pp. 2702 ◽  
Author(s):  
Ben-Fong Yu ◽  
Jenq-Shyong Chen
Keyword(s):  
High Speed ◽  
Tool Path ◽  
High Surface ◽  
Tracking Error ◽  
Numerical Control ◽  
Machining Performance ◽  
High Surface Quality ◽  
Dynamic Errors ◽  
Proper Values ◽  
Cnc Controller

This paper proposes the development of a tuning methodology which can set the proper values of the Computer Numerical Control (CNC) parameters to achieve the required machining performance. For the conventional operators of machine tools, the CNC parameters were hard to be adjusted to optimal settings, which was a complicated and time-consuming task. To save time in finding optimal CNC parameters, the objective of this research was to develop a practical methodology to tune the CNC parameters effectively for easy implementation in the commercial CNC controller. Firstly, the effect of the CNC parameters in the CNC controller on the tool-path planning was analyzed via experiments. The machining performance was defined in the high-speed (HS) mode, the high-accuracy (HP) mode, and the high-surface-quality (HQ) mode, according to the dynamic errors of several specified paths. Due to the CNC parameters that have a particularly critical effect on the dynamic errors, the relationship between the CNC parameters and the dynamic errors was validated by the measured data. Finally, the tuning procedure defined the anticipated dynamic errors for the three machining modes with the actual machine. The CNC parameters will correspond with anticipated dynamics errors based on several specified paths. The experimental results showed that the HS mode was the fastest to complete the path, and the completion time of the HP and HQ modes were increased by 37% and 6%, respectively. The HP mode had the smallest dynamic errors than other modes, and the dynamic errors of the HS and HQ modes are increased by 66% and 16%. In the HQ mode, the motion oscillation was reduce significantly, and the tracking error of the HS and HP modes were increased by 85% and 28%. The advantage of the methodology is that it simplifies set-up steps of the CNC parameters, making it suitable for practical machine applications.

Discussion—Session III: High speed machine tools for aircraft production

1955 ◽  
Vol 34 (4) ◽  
pp. 224
Author(s):  
F.C. Cooke ◽  
S. Radcliffe ◽  
H.A. Chambers ◽  
C. Bromage ◽  
Menelaus ◽  
...  
Keyword(s):  
Machine Tools ◽  
High Speed ◽  
Discussion Session ◽  
Aircraft Production ◽  
High Speed Machine

Stability of Milling Operations With Asymmetric Cutter Dynamics in Rotating Coordinates

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Alptunc Comak ◽  
Orkun Ozsahin ◽  
Yusuf Altintas
Keyword(s):  
Time Domain ◽  
Machine Tools ◽  
High Speed ◽  
End Mill ◽  
Spindle Shaft ◽  
Milling Operations ◽  
Stability Model ◽  
Principal Directions ◽  
The Stability ◽  
Rotating Coordinates

High-speed machine tools have parts with both stationary and rotating dynamics. While spindle housing, column, and table have stationary dynamics, rotating parts may have both symmetric (i.e., spindle shaft and tool holder) and asymmetric dynamics (i.e., two-fluted end mill) due to uneven geometry in two principal directions. This paper presents a stability model of dynamic milling operations with combined stationary and rotating dynamics. The stationary modes are superposed to two orthogonal directions in rotating frame by considering the time- and speed-dependent, periodic dynamic milling system. The stability of the system is solved in both frequency and semidiscrete time domain. It is shown that the stability pockets differ significantly when the rotating dynamics of the asymmetric tools are considered. The proposed stability model has been experimentally validated in high-speed milling of an aluminum alloy with a two-fluted, asymmetric helical end mill.

Sign in / Sign up

Export Citation Format

Share Document