1. CAD/CAM CONSIDERATIONS
ABOUT FMS
SUDHIR REDDY S.V.R
(09311D0412)

2. Topics to be Covered:
CAD Considerations About FMS
CAM Considerations About FMS

3. CAD Considerations About FMS:
CAD is the point where design intent takes on electronic form, can
facilities the manufacturing operation
In operation for many years are forced to rethink their approach to
design and drafting to enable the company to enjoy the advantages of
flexible Manufacturing.
The following tools which can help with the implementation of
this direction.
(a). Library of Parts.
(b). Group Technology.
(c). Special CAD requirements for FMS data preparation.

4. (a). Library of Parts:
A library of parts is a database which aids the product designer who
is faced with a very large selection of potential components when
creating a design.
Its major application is a catalog of parts to be included in an
assembly .
In many cases , it is necessary to custom –develop a library of parts
system optimized to the product, business and company to be using it.
The library of parts requires the following capabilities are shown in
below figure,

5. Attributes are related to geometry
logically

6. (i).It must be searchable so that designers can let the computer do
the work of selecting the right component for a specific application
from a large catalog( perhaps tens of thousands).
(ii).It must provide ancillary information on parts that meet search
criteria so that the designers can decide if parts suggested by the
computer will meet the need.
When a fully Functional library of parts is available , it is found
that more efficient use of available parts can be made.
Ancillary information about each component is generally stored in
the library of parts along with the design so that it can be included in
an assembly.

7. When component attributes are stored in the assembly ,they may be
extracted by software to produce files required for assembly ,
machining operations , bills of material and other uses.
Designing , populating and maintaining a library of parts data base
can be very labor intensive and time consuming.

8. (b). Group Technology:
 GT deals with the identification of similar parts and group them
for the purpose of manufacturing and design generally.
 It is possible only if it is convenient to retrieve the needed
information and therefore , duplication would invariably takes place.
So, an efficient design retrieval system is essential which would
require some form of part identification and coding.
For part identification and coding , the attributes of the component
should be used namely of design and manufacturing , i.e., geometric
shape , size and the process of manufacture.

9. GT approach is different from the existing one and the working of
the entire organization will be effected due to this approach .
This technology streamlines procedure and is amenable to
computerization and in the longer process.
It forms the basis of integrated manufacture and thus would prove an
important step in inducting automation in small and medium batch
manufacture.

10. (c). Special CAD requirements for FMS
data preparation:
When product and process are designed together , a product model
can be developed which contains all the information necessary for
effective interfacing to the FMS.
The usefulness of a model created in CAD is directly proportional
to its intelligence content .
They are three major facts of intelligence are
(i) Geometry.
(ii) Attributes.
(iii) Design Cycle Data Preparation.

11. (i) Geometry:
•The geometry of a part is the computer’s model of its physical
shape.
•The minimum requirement in a CAD model destined to be used
for FMS is a 3D wire frame.
•When part designs may contain ambiguities in a wire frame
model , it is necessary to add surface representation to the part.
•Solid modeling offers the ultimate in part intelligence content ,
but adds little that is of use to the CAM engineer.

12. (ii) Attributes:
• Attributes are information items about a part which are stored
along with the CAD design , they contain data that may or may not
be displayed when the part is viewed or plotted.
•These attributes can be created manually when the CAD designer
draws the part or created by engineering-assistance software which
queries the designer for information,
- Once a design has been created, software can be created
which extracts attribute information as required for use in various
FMS subsystems.
•Design of the attribute database for a product is based on the
product’s characteristics and the needs of downstream applications.
•For an assembly , a database often will have a hierarchical structure.

13. Steps in going from CAD to CAM to
FMS-ready system

14. CAM Considerations About FMS:
A new part to the FMS is a multistep procedure which includes
considerations of requirements for machining, raw material, material
handling and inspection.
Each additional item then becomes part that can be produced in
the FMS.
Manufacturing data therefore require the same level of control as
is provided to tracking engineering changes and design levels in the
CAD arena.
A typical FMS cell will have a fairly limited range of products.

15. It can build, so it is possible for NC programmers to develop a
high skill level within this narrow range.
Robot Programming can be improved by using a simulator
package for off-line programming.
A number of systems are available which provide the ability to
develop robot programs off-line and visualize the robot moving
through steps.
A difficulty often encountered is that there are few standards in
robot languages.