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

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.

Author(s):  
Lei Yang ◽  
Xing Zhang ◽  
Lei Wang ◽  
Wanhua Zhao

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.


2016 ◽  
Vol 19 (1) ◽  
Author(s):  
MARIAN FUNARU ◽  
GHEORGHE STAN ◽  
LUCIAN MIHAILA ◽  
MARIUS PASCU ◽  
DRAGOS ANDRIOAIA

Growing performance demands in the mechanical manufacturing field have lead to a great development of the machine tools domain, regarding especially the productivity and the manufacturing precision. When equipping a machine tool with an automatic tool changer and an automatic pallet mechanism, the obtained result is a machining center. For small series products, milling machining centers fulfill the precision and productivity requirements, through the advantages of a reduced auxiliary time and reduced operating errors. This paper presents a new technical solution of the rotary table indexing mechanism used on milling machining centers, which offers a very high positioning precision, by using a curvic coupling and a hydraulically driven table clamp/unclamp mechanism.


2014 ◽  
Vol 8 (4) ◽  
pp. 511-522 ◽  
Author(s):  
Michael Gebhardt ◽  
◽  
Alexander Schneeberger ◽  
Sascha Weikert ◽  
Wolfgang Knapp ◽  
...  

This paper presents the results of detailed thermal analysis of a 5-axis machine tool with focus on the rotary axes. The rotary axes are characterized regarding their position and orientation errors as a function of the underlying thermal load, contributing significantly to the overall accuracy. A physical model is presented, which allows the simulation of the thermal behavior of the rotary axes based on the power input to the drives of the rotary axes and the heat conduction in a swiveling rotary table unit and convection into environment. This enables an external online-compensation of thermal errors. The compensation model is verified and validated.


2013 ◽  
Vol 819 ◽  
pp. 24-28
Author(s):  
Yan Yun Tang ◽  
Ze Yu Weng ◽  
Li Ka Fang ◽  
Xiang Gao ◽  
Jian De Hu ◽  
...  

The dynamic performance of modern machine tools is more and more highly emphasized. The research purpose of this paper is to research dynamic performance of gantry machining center through modal experiment. In this paper, the theory of relative excitation test on the machine tool is expounded, and relative excitation test is carried on gantry machining center and then the modal parameters of this machine tool are obtained through experimental modal analysis. Analyze the weak link of this gantry machining center, show that the stiffness of Z direction of Z to feed component of this machine tool is insufficient and the stiffness of X, Y direction of ram is insufficient.


2011 ◽  
Vol 121-126 ◽  
pp. 529-533
Author(s):  
Jian Han ◽  
Li Ping Wang ◽  
Ning Bo Cheng ◽  
Xu Wang

Thermal error in machine tools is one of the most significant causes of machining errors. This paper presents a new modeling method for machine tool error. Minimal-resource allocating networks (M-RAN) are used to establish the relationships between the temperature variables and thermal errors. Pt-100 thermal resistances and eddy current sensors are used to measure the temperature variables and the thermal errors respectively. A machining center is used to experiment. The test results show that method with minimal-resource allocating networks can predict the thermal errors of the machine accurately.


2011 ◽  
Vol 403-408 ◽  
pp. 4367-4370
Author(s):  
Yan Zhao ◽  
Wen Bin Li ◽  
Hao Ran Liu ◽  
Jing Shao

In order to improve the machining efficiency of the duralumin turbine rotor of maglev molecular pump, this paper proposes a new double-spindle horizontal milling machining center structure. Through a brief introduction to other types of machine tools, describes the characteristics of this new machine tool and symmetrical machining implementation. This paper proposes a new double-spindle horizontal milling machining centers so that the machining efficiency of duralumin turbine rotors is improve 100% more than that of the traditional machine tool in theory. Moreover, its machining accuracy get relative improve as the decrease of the dividing accumulative error. At the same time, the cost of workpiece is reduced greatly.


Author(s):  
Huimin Dong ◽  
Yang Tan ◽  
Delun Wang ◽  
Yali Ma

A machine tool is an assembly structure fitted by some moveable substructures, which the relative motion between the substructures creates normal and limit operating positions. Along with the substructures moving, the distributions of masses, stiffness and damping of the machine in space vary, leading to variety of structure distributions and dynamic properties. For exploring the dynamic properties distributions of machine tools, this paper presents a testing method under practical operational excitations, which is under operating excitations from remaining unbalanced value in the spindle, and collecting vibration signals of time and frequency at the spindle foreside at working positions. To identify resonance characteristics, a judging matrix is established by comparing vibration energy and vibration amplitude at 1st octave. By this method, MDH50 active pole horizontal machining center is tested, and the dynamic characteristics is determined. It reveals that dynamic characteristics of resonance come from the substructure independent resonance and their superposition in operating excitation. For verifying this result, FEA is conducted, in which 20 nodes brick element and spring element are applied to build the model entities and interfaces. The analysis result by FEM is consistent to the testing results. The research provides foundation for how setting up machining programs to avoid the resonance vibration of the machine in the operating.


2011 ◽  
Vol 188 ◽  
pp. 487-492 ◽  
Author(s):  
Q.J. Yang ◽  
D.N. Li ◽  
L.L. Kong ◽  
K. Li

In modern machining processes, Gantry Machining Center is one of the most important machine tools. Moreover, beam components directly relate to the overall performance. From multi-body simulation (MBS) and finite element analysis (FEA) respectively, the paper discusses current state of the multi-body dynamics modelling of the machine tool components in domestic and overseas. In this paper, We adopt a method, the multi-flexible body dynamics(MFBD) modeling method for machine tool transmission components (linear guidance and ball screw drives) in software Recurdyn, to create the conditions for MFBD simulation analysis of the beam components system. Much more, it provides a way of MFBD modelling for machine tools components in both the high-speed and high-performance.


2007 ◽  
Vol 1 (2) ◽  
pp. 78-86 ◽  
Author(s):  
Masamitsu Nakaminami ◽  
◽  
Tsutomu Tokuma ◽  
Toshimichi Moriwaki ◽  
Keiichi Nakamoto ◽  
...  

The functionality of compound multiaxis machine tools is becoming increasingly versatile as NC lathes evolve. A single compound multiaxis machine tool functions as a 2-axis NC lathe and as a 5 axis machining center. The compound multiaxis machine tool executes machining such as inclined surface and gear cutting, conventionally executed by dedicated machines with special jigs and fixtures. A survey has shown that most machining executed by conventional compound multiaxis machine tools consists of basic drilling and milling on the orthogonal plane, indicating that compound multiaxis machine tools specifications should be designed to meet these requirements. To improve competitiveness and return investment over conventional NC lathes and machining centers, productivity required for a compound multiaxis machine tool is derived based on the machining time of typical parts on conventional machines. Here, we address systematic analysis and methodology to determine compound multiaxis machine tool specifications from the viewpoints of quality and cost.


2016 ◽  
Vol 10 (2) ◽  
pp. 162-171
Author(s):  
Hafid Hafid ◽  
Tatang Sutisna

The design and manufacturing of the rotary table with the specification Ø 170 mm (6 inches) for CNC machine 4 axis has been done. The objective of manufacturing a rotary table is to increase the efficiency of CNC machine Hardford 4 axis to be above 80% in line machining center CV. IM’s workshop. The engineering methods was taken, consist of: working preparation, manufacturing of working drawing, engineering process, the manufacturing and testing. The prototype has been tested and operated, the resulting of increasing productivity of which were as follows: the process of assembling was increased to be 3 time ( before 1 time) and processing time for a specific case reduced from 5 hours to 3 hours, number of operators for the case of assembling the rotary reduced to 1 person (before 4 persons), safety and security become to be better. The results show increased efficiency of CNC machine Hardford, from under 50% to be above 80%. Based on the economical analysis obtained by the cost of good sold (C.G.S) of the rotary table is IDR 34.060.000. The results presented in this paper is expected to be case study for developing a business of the metal and engineering SMEs domestic to the effort of improving efficiency, quality, productivity and competitiveness in global market.ABSTRAKPerancangan dan pembuatan alat bantu meja putar (rotary table) dengan spesifikasi teknis Ø 170 mm (6 inci) untuk mesin CNC 4 axis telah dilakukan. Tujuan pembuatan rotary table adalah untuk meningkatkan efisiensi mesin CNC Hardford 4 axis di atas 80% pada line machining center Bengkel CV. IM. Metode rancang bangun yang dilakukan, meliputi: persiapan kerja, pembuatan gambar kerja, proses engineering, pembuatan dan uji coba. Prototip tersebut telah diuji coba dan dioperasikan dengan hasil peningkatan produktivitas sebagai berikut: proses pengerjaan bongkar pasang meningkat menjadi 3 kali (sebelumnya 1 kali) dan waktu pengerjaan untuk kasus tertentu berkurang dari 5 jam menjadi 3 jam, jumlah operator untuk kasus bongkar pasang rotary berkurang menjadi 1 orang (sebelumnya 4 orang), keselamatan kerja dan keamanan menjadi lebih baik. Hasil peningkatan berupa efisiensi mesin CNC Hardford 4 axis dari sebelumnya di bawah 50% menjadi di atas 80%. Berdasarkan hasil perhitungan analisis ekonomi diperoleh harga pokok produksi (HPP) alat bantu meja putar adalah sebesar Rp. 34.060.000. Bahasan ini diharapkan menjadi contoh kasus bagi pengembangan usaha IKM logam dan mesin dalam negeri untuk meningkatkan efisiensi, mutu, produktivitas dan keunggulan daya saing di pasar global.Kata kunci: alat bantu meja putar, mesin CNC, harga pokok produksi


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