World-class CIM in America Essay

With competitive pressures in most industries at a fever pitch, CIM is truly an idea whose time has come. Integrating machine-tool
controllers with local-area networks so they can chat with engineering
minicomputers that talk to general-business mainframes can reinvigorate
an existing plant. And it is.



An example is General Electric’s Steam Turbine-Generator
Business (STGB), Schenectady, NY–a paperless factory that will help GE
respond to an increasingly service-oriented market for
electric-generating equipment. A 30 percent reduction in manufacturing
cycle time is expected along with significant cost reductions in direct
labor, indirect labor, salaried personnel, and inventory. Already the
break-even volume has been reduced 70 percent.

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“With CIM we are getting the right information to the right
people at the right time to make the right decision,” says Randall
J Alkema, general manager of STGB’s engineering and manufacturing
department.



Why CIM?



Alkema points out that the move to CIM began in 1980 with
implementation of a 10-year master plan (updated every two years)
calling for computer integration of the entire 10-plant complex–a
projected $50-million investment. This is a strategic response to a
major shift in the electric-utility industry.



Electric utilities, the primary users of large turbines and
generators, are buying few new units. Instead, they are investing in
service and parts to run old equipment longer. The change is a result
of reduced electrical load growth caused by conservation, high reserve
margins, and high financing costs.


Today, STGB’s primary business is supplying service and parts
for its fleet of more than 4000 operating turbine-generator sets.
Whereas manufacturing cycle times in the new-unit business are measured
in years, cycle times measured in hours or days are required in the
replacement-parts business.



That’s particularly true when a generator breaks down. Such
occurrences are rare; however, each day the machine is out of service
can cost a utility hundreds of thousands of dollars. Now, STGB’s
small-parts shop (the prototype CIM installation) can manufacture and
ship some emergency parts the day the order is received. Similar
high-priority orders previously took days.



“CIM also is important in making routine replacement
components,” emphasizes Alkema, “a business that requires
manufacturing parts in high volume in an almost endless variety of
designs. For example, in the small-parts shop, a data base contains
about 25,000 unique part designs for manufacturing small turbine
components such as packing rings, spill strips, packing casings, oil
deflectors, bolts, nuts, and studs. The shop (employing 180 people, 24
NC machines, and 90 manual machines) turns out 350,000 parts/year to
fill more than 15,000 orders.”



CIM begins at order entry, where an automated Honeywell
mainframe-based quotation system provides price information to customers
throughout North America, Figure 1. When an order is placed, it is
logged instantly by an on-line system, which triggers design and
manufacturing processes.



An automated process planning system, running on a Data General
MV/10000, receives the order from the mainframe and matches it to a
part-recognition (group-technology) code. The system determines the
most efficient routing for the part, selects the proper materials, and
chooses the correct NC family part program.



Doing drawings



A Calma CAD system is used extensively in turbine-generator
engineering at STGB. Drawings are done on 3-D interactive graphics
terminals that have improved productivity about 3:1 over conventional
drafting. CAD also enhances product quality by minimizing errors.



The original CAD setup (installed in 1978) consisted of two Data
General Eclipse minicomputers and seven graphics workstations. STGB
since has expanded its CAD system to include six Eclipse minis and a
Digital Equipment VAX 11/780 mini supporting 22 color and
black-and-white workstations, two on-line plotters, two off-line
plotters, six printers, and 11 alphanumeric terminals, Figure 2.


Software running on the system includes DDM (Design Drafting ;
Manufacturing) and GDS I (Graphics Display System). The former is used
for 3-D mechanical design of steam turbine and generator parts; the
latter is used for printed-circuit-board design to support
turbine-generator control equipment.



About 1.5 million paper drawings at STGB soon will be stored on
optical disks, inscribed and read using lasers, and linked to remote
drawing retrieval stations by microwave transmission.



Digital engineering information, significantly enhanced by the DAL
(Design Analysis Language) and GPL (Graphics Programming Language)
languages, automatically forms the basis for the part-recognition code
that electronically defines parts and feeds the process planning system.



The CAD facility operates on three shifts–two for production
tasks, one for system operational tasks. More than 100 drafters and
engineers have been trained in-house to use the system.



Total factory management



Design information is sent to an NC programming package that runs
on a Data General 32-bit minicomputer, which automatically develops
required machining data. This information then is downloaded to an NC
programming system that processes and postprocesses the family-of-parts
program (language is APT IV). Postprocessing generates the estimated
time to manufacture the part, which is passed back to the process
planning system.



The NC programming system transmits the part program to the
manufacturing shop’s factory-management system, which provides DNC,
shop-floor control, and factory communications.



Shop-floor control consists of programs for material dispatch,
scheduling, production control, material tracking, production change
capability, labor reporting, machine and process status, and factory
instructions. This module uses the same hardware as the DNC and
factory-communications systems to operate in an on-line, real-time mode
and transmit information to and from the host.



The factory communications function, which provides communications
between machine operators and the host computer, is carried out via
terminals in the factory, Figure 3. Shop workers receive job
assignments through the terminals, for example. Assignments are
determined by a computer using a priority algorithm based on customer
delivery requirements.



Factory communication provides the network for communications
between the operators and their support functions as well, e.g.,
foreman, methods, production control, quality control, and maintenance.
It also passes data back to the business and financial computer systems
to keep track of job completions, inventory status, and job costs.



When a machine tool finishes a part, it notifies the
factory-management system. The machine operator then enters real-time
labor details into the system via the computer terminal. The factory
communications module subsequently notifies an inspector that the part
is ready.



After examining it, the inspector enters an approval code at the
terminal. The factory communications system notifies a materials
handler that the part is ready to move to another machine or to
shipping. To close the loop, dock workers enter appropriate information
into terminals when the part is shipped.



Out on the floor



Computers provide the foundation for streamlining information flow;
however, automated machining systems play an important role in CIM as
well. One such system at STGB involves a pair of flexible machining
cells used for rough milling turbine buckets, a process now completed up
to eight times faster than a year ago. The cells are among many NC
machining processes being woven into the system.



Buckets, airfoil-shaped turbine parts that convert the energy in
high-pressure steam to rotary motion, are manufactured in high volume
and in hundreds of designs. Milling contoured stainless steel parts is
an exacting operation, as each bucket of a particular design must be
identical to others of that design to ensure that the turbine rotor is
balanced.



The cells are fed by two robots, Figure 4. Work is carried to and
from the system and between cells by conveyors.



The cells can be reprogrammed off-line to handle different bucket
designs as the CIM system feeds new customer orders into the shop’s
load.



Last autumn, the Society of Manufacturing Engineers presented its
annual LEAD award (Leadership Excellence in the Application and
Development of Computer-Integrated Manufacturing) to STGB’s CIM
project team. Their effort is a multidisciplinary world-class example
of applying advanced manufacturing technologies.

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