Application of Sandwich-Based Designs on Main Structural Parts of Machine Tools

Author(s):  
Jan Smoli´k ◽  
Viktor Kuli´sˇek ◽  
Miroslav Janota

New, higher and challenging properties of new high-speed machines and high-performance machines bring up many questions connected to the design and properties of the main machine tool structures. Parameters like static stiffness, eigenfrequencies, modal damping and mass of parts may be identified as very important, and all these properties need to be improved. The most important material properties in the field of machine tools are presented in this paper. A case study based on a modification of a real horizontal machining centre is introduced. The modification consists in using a sandwich design concept in the main structural machine tool part. The sandwich concept, widely known and used in the aerospace industry and, more generally, the transportation industry, is not commonly used in machine tool design. A significant reduction of mass has been achieved by manufacturing a hybrid column with aluminum foam cores, while static stiffness has not been affected.

2006 ◽  
Vol 129 (3) ◽  
pp. 636-643 ◽  
Author(s):  
Bethany A. Woody ◽  
K. Scott Smith ◽  
Robert J. Hocken ◽  
Jimmie A. Miller

High-speed machining (HSM) has had a large impact on the design and fabrication of aerospace parts and HSM techniques have been used to improve the quality of conventionally machined parts as well. Initially, the trend toward HSM of monolithic parts was focused on small parts, where existing machine tools have sufficient precision to machine the required features. But, as the technology continues to progress, the scale of monolithic parts has continued to grow. However, the growth of such parts has become limited by the inability of existing machines to achieve the tolerances required for assembly due to the long-range accuracy and the thermal environment of most machine tools. Increasing part size without decreasing the tolerances using existing technology requires very large and very accurate machines in a tightly controlled thermal environment. As a result, new techniques are needed to precisely and accurately manufacture large scale monolithic components. Previous work has established the fiducial calibration system (FCS), a technique, which, for the first time provides a method that allows for the accuracy of a coordinate measuring machine (CMM) to be transferred to the shop floor. This paper addresses the range of applicability of the FCS, and provides a method to answer two fundamental questions. First, given a set of machines and fiducials, how much improvement in precision of the finished part can be expected? And second, given a desired precision of the finished part, what machines and fiducials are required? The achievable improvement in precision using the FCS depends on a number of factors including, but not limited to: the type of fiducial, the probing system on the machine and CMM, the time required to make a measurement, and the frequency of measurement. In this paper, the sensitivity of the method to such items is evaluated through an uncertainty analysis, and examples are given indicating how this analysis can be used in a variety of cases.


2009 ◽  
Vol 626-627 ◽  
pp. 429-434 ◽  
Author(s):  
Liang Zhao ◽  
Ya Dong Gong ◽  
Guang Qi Cai

The stiffness model of the parallel machine tool is established by static analysis, the static stiffness analysis is carried out through numerical Simulation and the stiffness distribution is given. On the basis of this, the optimal objective is given which is the average of 729 values of -axis stiffness and -axis stiffness corresponding to 729 positions in the workspace. With MATLAB software, the effects are simulated which the structural parameters of the parallel machine tool have on their stiffness, their change rules are gained, and this provides a basis for the structural design of this type of machine tools.


1985 ◽  
Vol 107 (4) ◽  
pp. 316-324 ◽  
Author(s):  
R. Komanduri ◽  
J. McGee ◽  
R. A. Thompson ◽  
J. P. Covy ◽  
F. J. Truncale ◽  
...  

This paper presents a methodology for determining the machine tool system requirements for high-speed machining (HSM)/high-throughput machining (HTM). Both technological and economic factors should be considered in the formulation of the model for determining machine tool system requirements. The HSM function model is given here in the form of ICAM-defined (IDEFo) charts with corresponding text. For machining most aluminum alloys, the maximum cutting speed is not limited by tool life, and the technology for high-speed machine tools (spindles, table drives, controls, chip management, and other features) exists today. Therefore, HSM of aluminum alloys can be implemented. Selection of a suitable HSM system involves detailed technological analysis and economic justification for a given part-family production configuration. The recent introduction of Si3N4 based tool materials has enabled significantly higher cutting speeds (up to 1524 mpm or 5000 sfpm) in the machining of gray cast iron. However, the machine tools using this type of tool material should be more rigid and capable of higher power, higher speed, and faster feed in order to increase productivity and reduce manufacturing costs. In the machining of the difficult-to-machine materials (e.g., superalloys), the cutting speed is still limited by tool wear. Nevertheless, a high-throughput machining (HTM) strategy is pertinent for this application.


2014 ◽  
Vol 701-702 ◽  
pp. 874-878
Author(s):  
Shao Hsien Chen ◽  
Chin Mou Hsu ◽  
Kuo Lin Chiu ◽  
Chu Peng Chan

Swivel spindle head is a key component used in five-axis machine tool of high performance and is of great importance in application and design. Nowadays, more and more components are manufactured by high performance multi-axis CNC machine tools, such as components of spaceflight, renewable energy and automobile, etc. Therefore, high performance machine tools of multiple axes are more and more urgently demanded, while Swivel spindle head is one of the most important components for a multi-axis machine tool. Hence, Swivel spindle head is one of the key to developers multi-axis machine tool . The study explores the highly responsive direct-driving motor able to drive the spindle head to rotate with multi-driving rotary technology. The dual-driving motor rotates via multi-driving units, generates torsion that magnifies and eliminates its clearance, and then drives the spindle head to rotate. Results of the test show that the completed machine tool can meet the standards of dual axis rotary head with high preformation in, no matter, speed, distance, positional accuracy, repeated accuracy or maximum torque, etc.


2012 ◽  
Vol 523-524 ◽  
pp. 544-549
Author(s):  
Ryota Sawamura ◽  
Shinya Ikenaga ◽  
Atsushi Matsubara

High performance milling spindles, which have high rigidity and high speed, are required for high productive machining. In order to evaluate the rigidity change of the spindle, authors has been developed a magnetic loading device. This device provides attractive force in radial direction to a dummy tool attached to a spindle. By using this device, the static stiffness of the rotating spindle has been successfully evaluated. However the loading rate could not be controlled due to the electric response lag caused by the magnetic field. To solve this problem, electric response of the coil-tool system with the air gap is analyzed and the dynamic response is estimated. The air-gap's influence on the load was also evaluated. Based on the analysis, a dynamic loading test is designed carried out for the measurement of the rigidity of a machine tool spindle.


1983 ◽  
Vol 105 (1) ◽  
pp. 88-96 ◽  
Author(s):  
M. Yoshimura ◽  
T. Hamada ◽  
K. Yura ◽  
K. Hitomi

This paper proposes a design optimization method in which simplified structural models and standard mathematical programming methods are employed in order to optimize the dynamic characteristics of machine-tool structures in practical applications. This method is composed of three phases: (1) simplification, (2) optimization, and (3) realization. As design variables employed in this optimization are greatly reduced, machine-tool structures are optimized effectively in practice. With large design changes being conducted through this multiphase procedure, dynamic characteristics of machine tools can be greatly improved. This method is demonstrated on a structural model of a vertical lathe.


2014 ◽  
Vol 555 ◽  
pp. 555-560 ◽  
Author(s):  
Doru Bardac ◽  
Constantin Dogariu

This paper presents a method to investigate the characteristics of a turning high-speed spindle system. The geometric quality of high-precision parts is highly dependent on the performance of the entire machining system,especially by the main spindle behaviour. The machine tool main spindle units is focused on direct driven spindle units for high-speed and high performance cutting. This paper analyzes the static behavior for a turning machine spindle and presents some activities to improve the CAD model for such complex systems. The proposed models take into account the spindle with the detailed bearing system. The analysis was performed during the design activity and was based on Finite Elements Method. Starting from the 3D designed model, using FEM done by means of ANSYS analysis the structure stiffness was evaluated and, by consequence, the influence on the machine tool precision. The aim of this paper is to develop a finite element model of the machine spindle system and to use this method for design optimization. The 3D model was designed using the SolidWorks CAD software. The static analysis was completed by modal, harmonic response and thermal analysis, but their results will be presented in other papers.


1992 ◽  
Vol 114 (2) ◽  
pp. 244-253 ◽  
Author(s):  
J. A. Brandon ◽  
K. J. H. Al-Shareef

After a period of relative quiescence, optimization of the design of high performance machine tools has become the subject of considerable recent research activity. Advances in the general areas of optimization theory and signal processing have enabled effective solutions to problems regarded as intractable by earlier analysts. There is, however, a danger that valuable early research may be discounted or overlooked when there is a substantial period of dormancy in a discipline. The survey links early work with current activity in the optimization of machine tool spindle bearing systems.


Author(s):  
Tzu-Chi Chan ◽  
Jyun-Sian Yang

Abstract With the development of machine tools trending toward high precision, intelligence, multi-axis, and high speed, the improvement of the processing performance and rigidity of the machine is considerably important. The objective of this study is to design of a high-speed five-axis moving-column machine tool and perform structural analysis and optimization. We study the static and dynamic characteristics of the five-axis machine tool, design and improve the mechanical structure, and optimize the structural configuration of the machine. The entire machine structure is further analyzed and enhanced to improve its static and dynamic characteristics, including static rigidity, modal, transient, and spectral response characteristics. The static and dynamic characteristics of the machine structure directly affect the machine processing performance, and further affect the work piece precision machined by the tool. Through this study, the design technology for speed, accuracy, and surface roughness of the machine tool are further improved.


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