Lecture 25 flexible manufacturing systems [compatibility mode]

ME-418 CAD/CAM
Lecture #: 25
Flexible Manufacturing Systems
Ref: Groover (Chap – 16)

Lecture By: Muftooh Ur Rehman Siddiqi
Research Associate
Office # G-17
Email: muftooh@giki.edu.pk

Faculty of Mechanical Engineering
Ghulam Ishaq Khan Institute of Engineering Sciences & Technology, Pakistan

Flexible Manufacturing System (FMS)
It is the most automated and technology sophisticated of the GT
cells.
cells.

An FMS integrates into one highly automated
manufacturing systems including flexible automation,
CNC machines, distributed computer control,
automated material handling and storage and group
technology.

© Muftooh Ur Rehman Siddiqi, FME GIK Institute, Pakistan

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Reasons for Automation


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Prod. Variety and Qty. for Diff. Automation

FMS lies here


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History of FMS
The FMS was first conceptualized for machining, and it
required the prior development of NC.
NC.
This concept is credited to David Williamson, a British
engineer during mid-1960s.
mid-1960s
In late 1960s the first FMS machining system was installed at
1960s
IngersollIngersoll-Rand company in Virginia. Other companies like
Virginia.
Caterpillar, Cincinnati Milacron and General Electric followed
it.
it.
Germany implemented its first FMS in 1969, in cooperation
1969,
with the university of Stuttgart.
Stuttgart.
Russia and Japan implemented FMS in 1972.
1972.

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What is an FMS?
A FMS is a highly automated GT machine cell, consisting of a
cell,
group of processing workstations (usually CNC machine tools),
interconnected by an automated material handling and storage
system and controlled by a distributed computer system.
system.
The reason the FMS is flexible is that it is capable of
processing a variety of different part styles simultaneously at
the various workstation and the mix of part styles and
quantities of production can be adjusted in response to
changing demand patterns.
patterns.


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What is an FMS? (contd…)
The FMS is most suited for the mid-variety, mid-volume
midmidproduction range.
range.
The machining process is presently the largest application area
for FMS technology.
technology.
An FMS relies on the principle pf group technology.
technology.
However no manufacturing system can be completely flexible.
flexible.
There is a limit to the ranges of parts or products that can be
made in FMS. In other words FMS is designed to produce a
FMS.
single part family or limited range of part families.
families.


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Required Conditions to Implement FMS
Presently, the plant either (1) produces parts in batches or (2)
automate.
uses manned GT cells and management want to automate.
It must be possible to group a portion of the parts made in the
plant into part families, whose similarities permit them to be
families,
processed on the machines in the FMS. Similarities can either
FMS.
be design or manufacturing attributes.
attributes.
The parts or products made by the facility are in the midmidvolume, mid-variety production range.
midrange.


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Characteristics of FMS
The difference between implementing a manually operated
machine cell and installing an FMS are:
are:
1. FMS requires a significantly greater capital investment
because new equipment is being installed rather than existing
equipment being rearranged.
rearranged.
2. The FMS is technologically more sophisticated for the human
resources who must make it.
it.


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What Makes it Flexible?
Following are the three capabilities that a manufacturing system
must posses to be flexible:
flexible:
1. The ability to identify and distinguish among the different
parts or product styles processed by the system.
system.
2. Quick changeover of operating instructions.
instructions.
3. Quick changeover of physical setup.
setup.
Flexibility is an attribute that applies to both manual and
automated systems.
systems.


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Criteria for FMS
To qualify as being FMS, a manufacturing systems should satisfy
following criteria in an automated manufacturing system.
system.
Part variety test. An the system process different part styles in
test.
a non-batch model?
nonSchedule change test. Can the system readily accept changes in
test.
production schedule and changes in either part mix or
production quantities?
Error recovery test. Can the system recover gracefully from
test.
equipment malfunctions and breakdowns, so that production
is not completely disrupted?
New part test. Can new part designs be introduced into the
test.
existing product mix with relative ease.
ease.

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Types of FMS
FMS is designed for a specific application, that is a specific family
of parts and processes. Therefore each FMS is custom
processes.
engineered, each FMS is unique.
unique.
FMS can be distinguished according to the kind of manufacturing
operations they perform
1. Processing operations
2. Assembly operations
FMS can also be classified by
1. Number of machines.
machines.
2. Level of Flexibility


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Number of Machines
FMS can be distinguished according to the number of machines
in the system. The following are the typical categories:
system.
categories:
Single machine cell (SMC) consists of one CNC machining center
combined with a parts storage system for unattended operation.
operation.
Flexible machine cell (FMC) consists of two or three processing
workstations (typically CNC machining or turning centers) plus a
part handling system. The part handling system is connected to a
system.
load/unload station.
station.
Flexible manufacturing system (FMS) has four or more
processing workstation connection mechanically by a common
part handling systems and electronically by a distributed
computer system.
system.

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Number of Machines


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Difference b/w FMC and FMS
An important distinction b/w FMC and FMS is the number of
machines:
machines: an FMC has two or three m/c, while FMS has four or
more.
more.
FMS generally includes non-processing work-stations like
nonworkCoordinate Measuring Machine (CMM) that support production
but do not directly participate in it.
it.
The computer control system of FMS is generally larger and
more sophisticated, such as diagnostics and tool monitoring.
monitoring.


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Level of Flexibility
Another classification of FMS is according to the level of
flexibility designed into the system.
system.
Dedicated FMS is designed to produce a limited variety of parts
styles, and the complete universe o parts to be made on the
system is known in advances. The term special manufacturing
advances.
system has also been used in reference to this FMS type.
type.
RandomRandom-order FMS is more appropriate when the part family is
large, there are substantial variations in part configurations,
there will be new part designs introduced into the system and
engineering changes in parts currently produced, and the
production scheduled is subject to change from day to day.
day.


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Level of Flexibility (contd…)
There is a trade-off b/w the flexibility and productivity in the two
tradetypes of system.
system.
The dedicated FMS is less flexible but more capable of higher
production rates.
rates.

Flexibility, Part variety

The random order FMS is more flexible but at the proce of lower
production rates.
rates.
Random
Order FMS
Dedicated
FMS

Production rate

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FMS Components
Following are the basic components of an FMS
Workstations
Material Handling and storage systems
Computer control system
Even, though it is highly automated, people are required to
operate the system.
system.
All these components are discussed in the following slides.
slides.


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Workstations
Following are the types of workstation typically found in an FMS
Load/Unload stations
Machining Stations
Other Processing Stations
Assembly
Other Stations and Equipment.
Equipment.


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Material Handling and Storage System
The second major component of an FMS is its material handing
and storage system.
system.
Function of the material handling system
Random, independent movement of work parts b/w stations.
stations.
Handle a variety of work part configurations
Temporary storage
Compatible with computer control


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FMS Layout Configurations
The material handling system establishes the FMS layout. There
layout.
are:
are:
Inline layout, the machines and handling system are arranged in
layout,
a straight line. In its simplest form, the parts progress from one
line.
workstation to the nest in a well defined sequence, with work
always moving in one direction and no back flow.
flow.
Loop layout, the workstations are organized in a loop that is
layout,
served by a part handling system. Parts usually flow in one
system.
direction around the loop, with capability to stop and be
transferred to any station. An alternative form of loop layout is
station.
the rectangular layout.
layout.


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FMS Layout Configurations
The ladder layout consists of a loop with rungs b/w the straight
sections of the loop, on which workstation are located. The rungs
located.
increase the possible ways of getting from one machine to the
next.
next. This reduces average travel distance and thereby reducing
transport time b/w workstations.
workstations.
The open field layout consists of multiple loops and ladders and
may include sidings as well. This type layout is generally
well.
appropriate for processing large family of parts.
parts.
The robot centered cell uses one or more robots as the material
handling system. Industrial robots can be equipped with grippers
system.
that make them well suited for handling of rotational parts.
parts.


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Computer Control System
Functions performed by the FMS computer control system:
system:
Workstation control
Distribution of control instruction to workstations
Production control
Traffic control
Shuttle control
Work piece monitoring
Tool control - (a) Tool location (b) Tool life monitoring
Performance monitoring and reporting
Diagnostics


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Human Resources
One additional components in the FMS is human labour.
labour.
Humans are needed to manage the operations of the FMS.
FMS.
Functions typically performed by humans include:
include:
1. Loading raw work parts into the system.
system.
2. Unloading finished parts (or assemblies) from the system.
system.
3. Changing and setting tools.
tools.
4. Equipment maintenance and repair.
repair.
5. NC part programming in a machining system.
system.
6. Programming and operating the computer system.
system.
7. Overall management of the system.
system.


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FMS Applications

Self study from book, ‘Automation, Production
Systems and Computer integrated
Manufacturing’, Chapter 16, Page 480~484.


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Benefits of FMS
The benefits that can be expected from an FNS include:
include:
Increase machine utilization
Fewer machine required
Reduction in factory floor space required
Greater responsiveness to change.
change.
Reduced inventory requirements
Lower manufacturing lead times.
times.
Reduced direct labor requirement and higher productivity.
productivity.


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FMS Planning and Implementation
Implementation of an FMS represents a major investment and
commitment by the user company. Therefore it is important that
company.
the installation preceded by through planning and design.
design.
Two issues are discussed here:
here:
1. FMS planning and design issues.
issues.
2. FMS operational issues.
issues.


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FMS Planning and Design Issues
FMS planning issues:
1. Part family
considerations
2. Processing
requirements
3. Physical characteristics
of the work parts
4. Production volume

FMS design issues
1. Types of workstations
2. Variation in process routing and
FMS layout
3. Material handling system
4. Work-in-process and storage
Work-incapacity
5. Tooling
6. Pallet fixtures


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FMS Operational Issues
Once FMS is installed then the existing resources of the FMS
must be optimized to meet production requirements and achieve
operational objectives related to profit, quality and customer
satisfaction.
satisfaction.
1. Scheduling and dispatching
2. Machine loading
3. Part routing
4. Part grouping
5. Tool management
6. Pallet and fixture allocation


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Thank you…


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Lecture 25 flexible manufacturing systems [compatibility mode]

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