Mitsubishi Electric. Mitsubishi Electric Advance

31 Pages·1.926 MB·English

ISSN 1345-3041
VOL. 106/JUN. 2004
The latest NC systems, servo systems and peripheral equipment edition.
A Quarterly Survey of New Products, Systems, and Technology
(cid:1) Vol. 106/June 2004 Mitsubishi Electric ADVANCE
Cover Story
Mitsubishi Electric's FA Products
The latest NC systems, servo systems and Mitsubishi Electric's FA products at the
cutting edge of technology meet the
peripheral equipment edition.
demands of factories around the world.
Full nano-control CNC forhigh-precision
CONTENTS processing, the optimum servo system for
various industrial fields and CC-link
devices to promote factory automation... all
facilitate the next level in productivity and
TECHNICAL REPORTS newfound success.
Overview............................................................................................ 1
by Akira Sugiyama
EZMotion-NC E60: A Compact, High-Performance Editor-in-Chief
Controller for China ........................................................................... 2
Yoshikazu Mishima
by Fumio Iwai and Mutoshi Fukutani
Editorial Advisors
A Nanometer Control CNC System for Machine Tools.................... 5
by Kiyoshi Kuchiki and Mitsuyasu Kachi Chisato Kobayashi
Koji Kuwahara
Main-Spindle AC Servo Drive System for 400V NC Machines...... 10 Keizo Hama
by Toshiki Tanaka and Kazuyuki Nakamura Kazuo Seo
Hiroshi Hasegawa
High-Speed, High-Efficiency Built-In Spindle Motors ..................... 14
Hiroshi Muramatsu
by Akihiro Shimada and Kouki Naka
Masato Fujiwara
Control Functions for Printing Machines ........................................ 18 Fuminobu Hidani
by Makoto Nishimura and Koichiro Ueda Yukio Kurohata
Hiroshi Yamaki
A Universal-Bus Controller—SSCNET & Positioning Board..........21
Kiyohide Tsutsumi
by Itsuo Seki
Osamu Matsumoto
CC-Link and CC-Link/LT Technologies for Open-Field Networks....25 Hiromasa Nakagawa
by Masanori Kachi
Vol. 106 Feature Articles Editor
Mitsuyasu Kachi
Editorial Inquiries
Keizo Hama
Corporate Total Productivity Management
& Environmental Programs
Fax [phone]
Product Inquiries
Kenji Katazawa (p2~p17)
Numerical Controller Business
Development Dept.
Fax [phone], 6137
Kazunori Fukushima (p18~p28)
Overseas Marketing Dept.
Industrial & Factory Automation
Fax [phone], 6076
Mitsubishi Electric Advance is published on
line quarterly (in March, June, September,
and December) by Mitsubishi Electric
Corporation.
Copyright © 2004 by Mitsubishi Electric
Corporation; all rights reserved.
Printed in Japan.
TECHNICAL REPORTS
Overview
Higher Precision Production Systems and FA Equipment
by Akira Sugiyama*
I
n production systems, it is of prime importance to produce the optimum quanti-
ties of product with the best possible timing at the lowest possible cost. These
objectives cannot be achieved without configuring process-intensive production
systems capable of manufacturing high added-value products, and such systems
themselves require the adoption of high added-value compound machine tools and
their associated technologies.
First, high added-value compound machine tools are vital for the following reasons.
The manufacturing industry has entered the era of information technology, and
faces increasingly severe demands for higher precisions and finer processing. High-
quality mirror finishes, ultrahigh-precision metal molds and microscopic holes, and
high-speed processing of new materials, are called for in processing. Mitsubishi
Electric Corporation has always sought to anticipate users’ needs, and is carrying
out technological developments that enable numerically controlled machine tools
to create ultrahigh-precision metal molds. Our servo motors, too, provide for adaptive
control, auto tuning, vibration suppression, etc.
Second comes the configuring of production systems to create high added value.
The corporation has made major contributions to the minimization of costs by
integrating shop-floor production systems with MES, SCM and ERP, etc., to form
flexible systems in which information is acquired and analyzed to achieve higher
operating ratios, reduced mechanical losses, and lower labor and running costs.
The high-speed, high-capacity CC-Link open-field network has spread quickly in
factories. Our corporate partners already exceed 450 companies, and the full range
of products in various sectors and applications mean that optimum systems can
readily be configured.
As an integrated manufacturer of factory-automation equipment, our advanced
technologies will always be at the service of those, wherever they may be and
whatever the needs of their sector of industry or their specific applications, who
face demands for high-precision, efficient and flexible manufacturing. ❑
*Akira Sugiyama is Group President, Factory Automation Systems.
June 2004 · 1
TECHNICAL REPORTS
EZMotion-NC E60: A Compact, High-
Performance Controller for China
by Fumio Iwai and Mutoshi Fukutani*
Even in the Chinese manufacturing industry,
whose expansion has been drive by its low pro-
duction costs, there has been strong demand for
better capability to respond with high-quality
manufacturing of small lots of multiple product
variants. The EZMotion-NC E60, which embod-
ies Mitsubishi Electric’s computerized numeri-
cal control (CNC) technologies acquired over
more than 30 years, is a controller for machine
tools that, while providing high performance, is Fig. 2 External view of dedicated display and
both compact and inexpensive. While the small keyboard for EZMotion-NC E60
form factor and low cost ensure an extensive
range of applications, even down to facilitating companies, low manufacturing costs alone are
the automation of manually operated machine not enough to maintain competitiveness and
tools, its high performance and extensibility they are generating strong demand for small-lot
mean that the EZMotion-NC E60 is destined to production of multiple component variants,
become a supporting pillar of Chinese manufac- made to the same high standards of quality and
turing industry. Fig. 1 shows the EZMotion-NC precision available in America, Europe, and Ja-
E60 unit and Fig. 2 shows the dedicated display pan.
and keyboard. In China, however, most of the machine tools
used by manufacturing industry are either manu-
ally operated or driven by simple servo functions
or other crude controls, and are non-program-
mable. Nor does the market demand the same
type of machine tools, equipped with functions
that enable machining of diverse complex forms,
that are the mainstream in the manufacturing
industry in Japan and the West.
The EZMotion-NC E60 was developed as a
controller that meets the specific needs of ma-
chine-tool operation in the Chinese manufac-
turing industry. Fig. 3 shows the target market
in China.
Fig. 1 Photograph of the EZMotion-NC E60 unit
(with the dedicated keyboard fitted to the
back)
Development goals
Until recently, the Chinese manufacturing in-
dustry has been doing its utmost to minimize
production costs by mass producing a limited
number of parts. Now, however, demand is com-
ing mainly from the many American, European,
and Japanese companies that have been shift-
ing their manufacturing bases to China. For these Fig. 3 Target market in China
*Fumio Iwai and Mutoshi Fukutani are with Nagoya Works.
2 · Mitsubishi Electric ADVANCE
TECHNICAL REPORTS
Features of the EZMotion-NC Technology Adopted in the EZMotion-NC E60
The development of the EZMotion-NC E60 con-
troller for machine tools, which provides high IMPLEMENTATION OF CNC ARCHITECTURE. The
performance in a compact form factor, was based EZMotion-NC E60 was designed to share the
on Mitsubishi CNC technologies acquired over basic architecture of Mitsubishi CNCs. Func-
more than 30 years. By rigorously selecting the tions were selected for inclusion and restricted
functions provided and drastically reducing the according to detailed analysis of the needs of
component count, the new controller can be the Chinese market. To enable machine tool
offered at a much lower cost than competitive builders to do their work without concern for
controllers. inherent mechanical vibration, the functions
Progress in reducing the heat generated by include both smooth control of acceleration and
microprocessors and other electronic compo- deceleration and, using electronic filters, auto-
nents has enabled a smaller form factor and matic suppression of mechanical resonance.
mounting footprint. Below shows the main speci- Moreover, an auto-tuning function was incor-
fications of the EZMotion-NC E60. porated to optimally adjust each axis and insti-
tute a simple means of ensuring that the
interpolation performance for any axis does not
Max. no. of control axes 5
suffer even though the machine operator may
Max no. of NC axes 3 (substrate: x, y, z)
be inexperienced with electrical servos.
Max no. of spindles 1 Furthermore, so that the complexities of tool
Max. PLC axe s 1
life management can be handled by the control-
Max. no. of paths 1
ler, functions to control the tools used were in-
Min. control precision 3µ cluded as standard.
Least command increment 1 m
To aid those responsible for machine repair and
Built-in PLC max. no. of steps 4000step
µ maintenance, alarm log, operation log and other
PLC capacity (basic commands) 2 s/step
functions have been supplemented by provision
PLC development tools GX-Developer
(tools developed by MELSEC) for the installation of an interface facilitating
remote implementation of service tasks when,
Program storage capacity 160m (equiv. to 63,000 characters)

in the near future, the communications infra-
Display device 9-inch CRT / 7.2-inch LCD

structure is sufficiently developed. Fig. 4. shows
Machin e 256/240 point
Max. input/ input/output analog output one point standard a typical system configuration.

output points
Operation pa nel 128/96 points
USE OF 64-BIT RISC MICROPROCESSOR. To
achieve high-speed, high-precision machining
control in an ultra-compact form factor, a 64-bit
RISC microprocessor was used.
EXMotion-NC E60
I/O card
Encoder
Servo drive unit
and
Servo motor
Manual signal generator
General purpose IM motor
inverter
Fig. 4 Typical system configuration
June 2004 · 3
TECHNICAL REPORTS
In making units compact it is naturally essen- increase the internal processing performance.
tial to minimize the component count, but the This additional engine carries out internal NC
heat generated by the electronics, particularly sequence processing and other tasks that are
the microprocessor, is an even more important normally handled by the main microprocessor
issue. Then again, machine tools produce metal (64-bit RISC CPU). Working independently in
swarf and use cutting fluid, which are serious parallel with the main CPU, there is no need to
hazards for electronic devices. Consequently, change the software when adding or removing
the electronics are usually installed in special this supplemental engine.
metal cabinets within the workplace. Even Even if, after a machine tool has already been
though the devices themselves are getting more received from a supplier, it is necessary to add
compact, they still generate considerable heat. carrier devices or measuring equipment that
To dissipate this, the cabinet size has to remain requires high-speed sequential control, there is
large or some means of cooling has to be in- no need to add a separate dedicated program-
stalled. mable logic controller (PLC) because the
To resolve this issue, instead of the usual type EZMotion-NC E60 master controller is able to
of SISC microprocessor that is found in personal provide the requisite functions.
computers, the EZMotion-NC E60 is built around
a 64-bit RISC microprocessor that is more pow- The Chinese manufacturing industry has regis-
erful and generates less heat. tered prodigious growth, and is now ready to
make further advances in quality and sophisti-
ULTRA-DENSE CHIP DEVELOPMENT TECHNOLOGY. cation. This new controller, carefully tailored
This is used for specialized applications, taking to match the specific present and future needs
advantage of the corporation’s richly varied ex- of Chinese industry, will be a key element in its
perience in chip development, through the ap- next major expansion. ❑
plication of simulation expertise, to create a
single specialized ultra-densely integrated mi-
croprocessor. We integrated circuitry peripheral
to the CPU by packing in memory control, dis-
play control, and servo-drive unit circuits, along
with all the requisite high-speed networking and
other functions that formerly required separate
chips. In this way, we were able to greatly re-
duce both the device mounting footprint and the
heat generated by the circuits.
HEAT SIMULATION AND THERMAL ANALYSIS.
We drew upon the corporation’s expertise in heat
simulation and thermal analysis to design the
EZMotion-NC E60 so as to distribute its compo-
nents optimally and thus avoid localized hot
spots inside the unit. Combined with the use of
a relatively cool-running CPU, the multiplier ef-
fect of using dedicated densely integrated on-
chip circuitry and low-voltage control circuits
has eliminated the need to install a cooling fan
in the controller. Measuring 185 x 125 x 48mm,
the unit is extremely compact; the size and ther-
mal characteristics have made it possible to
mount the keyboard on the back of the unit,
something formerly impractical. This advance,
as well as allowing much smaller cabinets to be
used for the controllers, contributes to machine
cost reduction and greater freedom of design.
POTENTIAL FOR MACHINE FUNCTION UP-
GRADES. In parallel with the EZMotion-NC E60
itself, a supplemental engine was developed to
4 · Mitsubishi Electric ADVANCE
TECHNICAL REPORTS
A Nanometer Control CNC System
for Machine Tools
by Kiyoshi Kuchiki and Mitsuyasu Kachi*
The parts of electronic and optical components trol system. The following explanation traces op-
used in information technology and requiring pre- erations in order from left to right; the flow is
cisions of the order of nanometers or tens of na- basically the same as for conventional CNC sys-
nometers have been increasing rapidly in recent tems. The command analysis section interprets
years. Mitsubishi Electric Corporation has de- the NC processing program language input as
veloped computerized numerical control (CNC) text. The path-analysis section calculates speeds
with the nanometer-level control required for ul- and paths from the data generated by interpret-
trahigh-precision machine tools. This article de- ing each command. Then the interpolation sec-
scribes the configuration and the various tion, at constant time intervals (typically of a
technologies for the hardware, software and drive few milliseconds) synchronized with the basic
section used in the system implementing this CNC clock, is called to generate in real time
nanometer control, and the results of system the interpolation data (F∆t below) for each axis
evaluation. and to send the positional and speed data to the
The new system and the associated technolo- servo amp. The most important characteristic
gies are expected to make major contributions of the system is that all data units are in na-
to future progress in the precision of processing nometers, including calculations.
by machine tools. The CNC equipment itself is connected to the
servo amp by fiber optics and optical communi-
The Configuration of the Nanometer Control cations are used to transfer data at very high
CNC System frequencies between them. The servo amp is re-
Fig. 1 shows the configuration of the new con- sponsible for controlling the current axial posi-
CNC-main Servo-spindle Amplifier
nanometer unit control
Full S/W processing by CPU
NC Program Tool data command
Command Position(cid:5) nanometer unit control
GXFO120(cid:1)00.Y0(cid:2)30. Casonomaftmlwysaairnsed saonPfatalwythasrise Inpstreoorcfptewoslaasrtieniogn SFFFp∆∆∆etttexyzd PCoosnittrioonl CSopneterdol CCuornrternotl
(cid:3)(cid:3)(cid:3)(cid:3) (cid:6)nano(cid:7)
Power device(IPM)
1div = (Current supply
0.5nm to motor)
YY[[µµmm]] Y[µm]
(cid:4)(cid:4) (cid:4)
(cid:4)(cid:4)23(cid:4)(cid:4)23 FF∆∆ttYY (cid:4)(cid:4) (cid:4)(cid:4) (cid:4)(cid:4) (cid:4)(cid:4)23 F∆tY (cid:4) (cid:4) (cid:4)
11 33 FF∆∆ttxx 66 99 XX[[µµmm]] 1 3 F∆tx6 9 X[µm] Position(cid:3)Speed
feedback
Micron interpolation Nanometer interpolation motor
Power
supply Position
detector
Fig. 1 CNC system control configuration
*Kiyoshi Kuchiki and Mitsuyasu Kachi are with Nagoya Works.
June 2004 · 5
TECHNICAL REPORTS
tion, and when a new F∆t is sent by the CNC, it Table 1. Nanometer control CNC hardware
specifications
ultimately drives the motor by controlling the
Item Specification Note
electrical current under positional and speed con-
Latest64bit-RISC
trol. MainCPU processor
Mainmemory 32MB
Optical
Hardware Technologies Servonetwork communications Built-insystemLSI
An explanation of the hardware developed for PLCcontrol Specialprocessor Built-insystemLSI
nanometer CNC control follows. Since the hu-
MachineI/O 2ch Built-insystemLSI
man-machine interface used for nanometer CNC
ConformstoPCI2.2
control is a personal computer, we adopted a PCInterface PCIbus standard
PCI card for the CNC control hardware so that Externalsize 175x107mm
it can be mounted on the PCI bus supported as
standard on such computers. The external ap- the consistent use of nanometer units through-
pearance of this hardware is shown in Fig. 2. out; that is, in the NC processing program, the
parameters and other input information, and
right through to the output to the servo amp
position and speed data. At the same time, the
values of position and speed commands support
the same range of maximum values as is pos-
sible when machining to micrometer tolerances.
Previously, if the minimum CNC command unit
became smaller, there was the disadvantage that
the maximum command values also decreased
proportionately. The present system overcomes
this problem so that nanometer control can be
applied not only to very fine structures but also
Fig. 2 Nanometer control CNC hardware to the machining of large structures.
In order to achieve this, the bit length of posi-
The latest and most advanced 64bit RISC CPU tion and speed data was changed from 32 to 64
was adopted for CNC control, and main memory bits for the nanometer calculations. Further, the
uses synchronous RAM, giving it a basic per- fundamental period needs to be speeded up in
formance over double that of the previous type. order to perform very high and ultra-high preci-
An ASIC was developed that concentrates CNC sion machining smoothly at high speeds. In fact,
functions into a single “system” LSI. These func- the software achieves a two- to four-fold increase
tions include communications with the servo amp, in speed. The main functions are as given in
mechanical I/O communications, PLC control, ex- Table 2.
ternal bus control and serial communications. The
consequent reduction in component count has in- Table 2. Nanometer Control CNC Basic
Functions
creased reliability and operating frequency to give
a significantly higher performance with the aim Item ConventionalNC NanometerNC
of optimising bus allocation and improving Unitofminimumcommand1µm O O
throughput. It results in compact, high-perfor- 0.1µm O O
mance hardware. A ten-fold improvement in data- 0.01µm (10nano) x O
transfer rates has dramatically improved com- 0.001µm(1nano) x O
munications with the servo, while moving from Rangeofcommand(mm) ±99999.999 ±99999.999999
electrical to optical communications has enabled Feedrate(m/min)1µm Maximum1000 Maximum1000
Feedrate(m/min)1nm x Maximum1000
the frequency and capacity of data transfer between
CNC and servo to be raised to a level fully ad- Nanometerinterpolation x O
equate for nanometer control. The main hardware
specifications are given in Table 1. The Effectiveness of Nanometer Control
1. In comparison with the positional commands
Software Technologies using command units in microns, interpolations
The main issue with software is how to enable are performed that are smoother by a factor of
6 · Mitsubishi Electric ADVANCE
TECHNICAL REPORTS
Y(µm)
Y(µm)
Closeup
X(µm)
X:Y 2:1 taper cut
NC Program
G1 X2. Y1. F9.43; X(µm)
Fig. 3 Nanometer control interpolation path
1/1000, so that the machining movements pro- Drive Technology
ceed that much more smoothly, and provide ex- To achieve machining to nanometer accuracies,
tremely high-grade processing. A comparison we developed a new high-performance servo amp
of the interpolation paths for micron- and series, the MDS-Cn. By adopting a CPU with a
nanometer-unit control is shown in Fig. 3. performance an order of magnitude better than
2. Velocity fluctuations during interpolation be- the previous series, developing an ASIC, and
tween position commands are also reduced enabling it to cope with a high-speed optical fi-
by a factor of 1/1000, and by minimizing the ber network, we achieved a major increase in
size of the fluctuations in acceleration and basic performance. Fig. 5 shows the structure of
deceleration, the striations formed on the the nanometer control drive system.
surface of the workpiece can be made that
much smaller. Fig. 4 gives actual measure- Improvements to Amp and Servo Performance
ments of the fluctuations in velocity during The following explanation of the improvements
interpolation. achieved by the use of the MDS-Cn servo amp
3. Shape accuracy has been raised to new lev- is based on evaluation data.
els, approaching the theoretical limits for the Fig. 6 shows the smoothness of the actual mo-
intersections and angles of linear (or circu- tor velocity under nanometer servo control. The
lar) paths. For example, the precision of the comparison is with the previous amplifier: the
end point for an angular command or the ac- upper part of the diagram is for a constant-
curacy of a corner angle under high-speed, velocity command (approx. 400mm/min), while
high-precision control gives shapes that are the lower part shows the variations in velocity.
essentially free of error. For a resolution of 0.5µm in the positional com-
Fig. 4 Nanometer control speed fluctuation
June 2004 · 7
TECHNICAL REPORTS
NNaannoommeeteterr
ccoonntrtrool lC CNNCC
2. High accuracy rotary encoder
3. Low ripple servo motor
1.MDS-Cnamplifier
(cid:1)High efficiency CPU
(cid:1)High speed network between
CNC and driver
(cid:1)Nanometer control
(cid:1)High accuracy current detector
Fig. 5 Nanometer control drive system configuration
Position
command Previous (0.5µm) MDS-Cn(0.5nm)
resolution
Velocity
command
PPoossiittiioonn ccoommmmaanndd rriippppllee Position command ripple
550000nnmm 0.5nm
iimmpprroovvee
1199 ttiimmeess
Velocity 14nm
ripple 227722nnmm
Fig. 6 Smooth velocity loop control (constant velocity command: 400mm/min)
MDS-Cn
Previous
(Position command resolution(cid:1)0.5(cid:2)m) (Position command resolution (cid:1)0.5nm)
iimmpprroovveedd
1(cid:1)(cid:1)(cid:1)(cid:1)m/div 66 ffoolldd 1(cid:1)(cid:1)(cid:1)(cid:1)m/div
Circularity error: 1.9(cid:1)(cid:1)(cid:1)(cid:1)m(cid:3)p-p(cid:4) Circularity error : 0.3(cid:1)(cid:1)(cid:1)(cid:1)m(cid:3)p-p)
Fig.7 Improvement of circular path accuracy (interpolation between axes)
8 · Mitsubishi Electric ADVANCE