Design
improvements of machine tools structures using modal analysis approach
R.
Albijanic,
Lola
Institute, Belgrade,
M.
Kalajdzic
Production Engineering Department Mechanical Engineering Faculty
University of Belgrade / YU
Abstract
- The paper presents a practical application of the method of modal analysis and
structural modifications for improving dynamic performance of a machining center
and its vital units. In order to eliminate inadequacies of the structure, modal
parameters of the machining center were obtained by experiment. These parameters
include natural frequencies, damping ratios and mode shapes and they are used to
determine the directions in which the structural improvements should be made.
The measurements included the vertical column of the machining center, since it
plays a dominant role in its total dynamic behavior. The column and the bed were
modified according to the results. The stiffness of the bed was significantly
increased. Using the finite elements method (FEM), a parallel analysis of static
and dynamic characteristics of the machining center supporting structure was
performed. Capabilities of the existing program for structural modifications
were significantly improved.
Key
words: Machine tools, modal analysis,
structural modification, design improvement
Integrated
automation system for machining monitoring and control
Production
Engineering, Department of Materials Processing Royal Institute of Technology
Stockholm, Sweden
Abstract
- This paper presents the concept and practical implementation of an integrated
system for machining monitoring and control (MMCS). This system is designed to
operate in turning centers, and it represents a powerful extension to existing
CAD-CAM systems. In order to improve machining, the system coordinates several
functions, such as real time cutting force control and tool condition
monitoring. The system is centered around a software core, the technological
planning unit (TPU), which is the optimization software operating in a Windows
environment. The approach is based on the optimization of cutting conditions
according to a performance index. By using on-line process condition monitoring,
a self-optimization function can be implemented. Experimental results reveal
the benefits that can be gained by implementing the system on the shop floor.
Keywords:
machining control, technological process planning, tool condition monitoring,
machining condition optimization
Laboratory for
Machine Tools and Machine Dynamics Department of Mechanical Engineering,
Aristoteles University Thessaloniki
Abstract
- The setup procedure for finishing of workpieces with many holes in NC boring
is time consuming. The workpiece is placed on the machine tool table and must be
adjusted, so that the final holes overlap? the corresponding initial ones. This
adjustment requires coordinate measurements on the initial holes, and possibly
relocation of the final hole positions, considering the specified tolerances.
For the end-positions of the holes, the NC-code has to be prepared. In the
present paper a computer supported method is presented, which enables the
automatic execution of these procedures.
Key
words: NC-boring, workpiece setup, touch probe, coordinate
measurements
G.
Halevi
Technion - Israel Institute of Technology Dobnov St. 20a Tel-Aviv 64369 ISRAEL Fax. + 972 3 696 2833, Tel. + 972 3 696 2833
E-mail
merhlev@techunix.technion.ac.il
Abstract
- An organization for operation is continually undergoing modification and
changes in the equipment that it uses. In selection of new equipment
considerable judgment must be exercised to assure sound decisions. The equipment
must have the capacity and other technical operating characteristics that will
enable it to perform the required work, and must be economically justifiable on
the basis of the savings possible. Management relies on economic models and
techniques (e. g. Total Value Analysis. ROI, etc.) in making its decisions for
machine replacement. Different concerns will adopt different economic models.
However, no matter what economic model is employed, the decisions are restricted
to the engineering data fed into it. Thus, engineering is actually doing the
first screening of data that will be considered. Furthermore, engineering
transfer decisions and not the reasons, alternatives considered, that make them
arrive at that decision. Engineering, no doubt is doing the best they can.
However, engineering consideration and optimization are not always similar to
those of the management. Thus the data fed to the economic model are incomplete,
and uneconomical decisions might be reached even by employing advanced
economical models. This paper proposes a method that introduces engineering
technology into the economical model. By employing a matrix concept, sound
engineering data can be supplied to the economic models, and real economic
decisions can be made. The concept and use of the matrix in resource planning
will be described in this paper.
Keywords:
economic models, matrix, process planning, resource planning, decision support
systems
R.
Kovacevic and Z. M. Zhang
Welding Research
and Development Laboratory Center for Robotics and Manufacturing Systems
University of Kentucky Lexington, Kentucky 40506, USA
Abstract
- The weld pool contains abundant information about the welding process. Its
observation can generate data for studying the welding process. Its control
could provide an entirely new method to reach the desired weld quality. A
real-time sensing technique has been developed to sense the 2D shape of the weld
pool. Thus, abundant data can be acquired from the weld pool and used to
correlate the pool geometrical appearance with the weld penetration. The weld
pool is characterized using a few parameters. The desired weld pool can be
acquired by controlling these parameters. A number of closed-loop control
systems have been developed to control the welding process based on the vision
feedback of the weld pool.
Key
words:
welding, vision, neurofuzzy, image.
loan
D. Marinescu, Ruilin Yeng
Kansas State University, Department of Industrial and Manufacturing System Engineering, 237 Durland Hall, Manhattan, KS, 66506-5112, USA
Fax: (913) 532-7072
Abstract
- Single point scratching and experimental simulated lapping in ceramics using
Acoustic Emission (AE) have been carried out as the preliminary study of ceramic
real time lapping. Experiments show that AE signals have strong correlation with
chipping and cracking in single point scratching. The relationship between AE
signals and work parameters such as slide speed, normal force, and abrasive size
have been established.
Key
Words: Ceramics, Lapping, Acoustic Emission, Scratching
Seong-Hzuk
Zim and Soo-Hong Lee
Department of
Mechanical Engineering Yonsei University 134 Shin-Chon-Dong, Seo-Dae-Moon-Gu
Seoul, KOREA 120-749
Kyu-Kap
Cho
Department of
Industrial Engineering Pusan University
30
San Chang-Chun-Dong, Guem-Jeong-Gu Pusan, KOREA 609-735, September 13,1996
Abstract
- This study deals with a development of WIRE PATH SEARCHING MODULE as a part of
automobile wire harness design system. WRITE PATH SEARCHING MODULE manages the
free space, finds transition locations, and creates bundle paths to dramatically
reduce a tedious iterative routing process which results in easy optimization of
the bundle paths. A prime policy in the system configuration is to compromise
between man's and computer's ability, and make designer's leading role in
designing process possible. Human input is indispensable to cope with the
special cases which were not considered in the initial design stage of the
system. In this study, we improve the previous shortest-path-finding algorithm (VGraph
and RCA Method) into a new method called Extended RCA, Bundles, connectors and
transitions are handled as objects so one can manage and modify physical
properties of objects easily. Therefore a verification is allowed at any desired
stage of design. The reuse of previous result is facilitated by using Dependency
Structure, which represents the mutual relations among connectors, transitions,
and bundles. Dependency Structure makes the elimination of redundant calculating
process possible, and consequently routing time shorter.
Keywords:
Wiring Configuration, Transition, Extended RCA, Reuse of Previous Results
Dr
Mariana Milacic
Torus Theory -
Experiments for Engineering Design Mechanical Engineering Faculty 27 Mart
80,11000 Belgrade The Belgrade University, Yugoslavia
Abstract
-
Very large scale knowledge base is difficult to design without better
understanding of the knowledge
categorization and the knowledge transition processes. This
paper is a pioneer work in experimenting with a new approach to this problem for
engineering design activities. Torus theory is used for experimenting in
geometry, topology, automata theory, double pendulum and manufacturing systems
design. Knowledge crystalization methodology is performed on Euclid's and
Newton's houses of knowledge. The main objective of this paper is to provide
the new way to build an intelligent expert system for engineering design.
Key
words:
house of knowledge, topology, automata theory, pendulum, manufacturing system.