Page 105 - DMGT501_OPERATIONS_MANAGEMENT

Unit 4: Process Selection and Facility Layout

The computer graphics that CAD provides allows designers to create electronic images which Notes
can be portrayed in two dimensions, or as a three dimensional solid component or assembly
which can be rotated as it is viewed. Advanced software programs can analyze and test designs
before a prototype is made. Finite element analysis programs allow engineers to predict stress
points on a part, and the effects of loading.
Once a part has been designed, the graphics can be used to program the tool path to machine the
part. When integrated with an NC postprocessor, the NC program that can be used in a CNC
machine is produced. The design graphics can also be used to design tools and fixtures, and for
inspections by coordinate measuring machines. The more downstream use that is made of CAD,
the more time that is saved in the overall process.
Generative process planning is an advanced generation of CAD/CAM. This uses a more powerful
software program to develop a process plan based on the part geometry, the number of parts to
be made, and information about facilities in the plant. It can select the best tool and fixture, and
it can calculate cost and time.
Flexible Machining Systems (FMS) are extensions of group technology and cellular manufacturing
concepts. Using integrated CAD/CAM, parts can be designed and programmed in half the time
it would normally take to do the engineering. The part programs can be downloaded to a CNC
machining center under the control of an FMS host computer. The FMS host can schedule the
CNC and the parts needed to perform the work.
Computer integrated manufacturing can include different combinations of the tools listed above.

Issues involved in CIM

One of the key issues regarding CIM is equipment incompatibility and difficulty of integration
of protocols. Integrating different brand equipment controllers with robots, conveyors and
supervisory controllers is a time-consuming task with a lot of pitfalls. Quite often, the large
investment and time required for software, hardware, communications, and integration cannot
be financially justified easily.
Another key issue is data integrity. Machines react clumsily to bad data, and the costs of data
upkeep as well as general information systems departmental costs is higher than in a non-CIM
facility.

Another issue is the attempt to program extensive logic to produce schedules and optimize part
sequence. There is no substitute for the human mind in reacting to a dynamic day-to-day
manufacturing schedule and changing priorities.
Just like anything else, computer integrated manufacturing is no panacea, nor should it be
embraced as a religion. It is an operational tool that, if implemented properly, will provide a
new dimension to competing: quickly introducing new customized high quality products and
delivering them with unprecedented lead times, swift decisions, and manufacturing products
with high velocity.

4.4 Facilities Layout

The Facility Layout plan institutionalizes the fundamental organizational structure. Every layout
has four fundamental elements:
1. Space Planning Units (SPUs)
2. Affinities

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