The FMS Henry C. Co Technology and Operations Management, California Polytechnic and State University

The FMS

Henry C. CoTechnology and Operations Management, California Polytechnic and State University

Flexible Manufacturing System (Henry C. Co) 2

Competitive Priorities Since W.W.II, U.S. manufacturing has dominated the

world … until the middle of the 1960s, when market competition became more intense. During 1960 to 1970 cost was the primary concern. Later quality became a priority. As the market became more and more complex, speed

of delivery became something customer also needed. A new strategy was formulated: Customizability.

The companies have to adapt to the environment in which they operate, to be more flexible in their operations and to satisfy different market segments (customizability).

Thus the innovation of FMS became related to the effort of gaining competitive advantage.


What is an FMS? A flexible manufacturing system (FMS) is

a manufacturing system in which there is some amount of flexibility that allows the system to react in the case of changes, whether predicted or unpredicted.

Two categories of flexibility Machine flexibility, covers the system's ability

to be changed to produce new product types, and ability to change the order of operations executed on a part.

Routing flexibility, which consists of the ability to use multiple machines to perform the same operation on a part, as well as the system's ability to absorb large-scale changes, such as in volume, capacity, or capability.



Design TechnologyComputer-Aided Design (CAD)

Refers to the use of computers to interactively design products and prepare engineering documentation

Extensions: Design for Manufacture and Assembly

(DFMA) - enables testing of design integration before manufacturing

3-D Object Modeling - enables the building of small models of the product



Standard for the Exchange of Product Data (STEP)

Standard for exchange of CAD data Includes 3-D CAD data Enhances collaboration using talent

wherever it is in the world reducing design lead time and development cost.



Computer-Aided Manufacturing (CAM)

Refers to the use of specialized computer programs to direct and control manufacturing equipment



Benefits of CAD and CAM

Product quality Shorter design time Production cost reductions Database availability New range of capabilities Reduces need for “similar” parts



Numerical Control

Numerical control (NC) - machine can be controlled electronically

Computer Numerically Controlled (CNC) - machine actually has its own microprocessor and memory

Direct Numerical Control (DNC) - wired to a central computer



Process Control - Operation

Sensors, often analog devices, collect data Analog devices read data on some periodic

basis, perhaps once a minute or once a second Measurements are translated into digital signals,

and transmitted to a digital computer Computer programs read the file (the digital

data) and analyze the data Output may be a: message on printer or console,

signal to a motor to change a value setting, warning light or horn, process control chart, etc.



Machines that hold, move, or grasp items

Perform monotonous or dangerous tasks

Used when speed, accuracy, or strength are needed

© 1984-1994 T/Maker Co.

Robots



Types of Robots

Large articulated robot

Cartesian(rectilinear)

Spherical(polar)

CylindricalArticulated

(revolute, jointed,anthropomorphic)



Automated Storage and Retrieval System (ASRS)

Provide for automatic placement and withdrawal of parts and products into and from designated places in a warehouse.



Material handling machines

Used to move parts & equipment in manufacturing

May be used to deliver mail & meals in service facilities

© 1984-1994 T/Maker Co.

Automatic Guided Vehicles (AGV)



Using automated machines (DNC) & materials handling equipment together

Often connected to centralized computer

Also called automated work cell Computer

Machine 1

Machine 2

Robotor AGV

Auto ToolChg.

Auto ToolChg.

Flexible Manufacturing Systems (FMS)


FMS and FMC Early FMSs were large and very complex, consisting

of dozens of CNCs and sophisticated material handling systems. They were very automated, very expensive and controlled by incredibly complex software. There were only a limited number of industries that could afford investing in a traditional FMS as described above.

Currently, the trend in FMS is toward small versions of the traditional FMS, called flexible manufacturing cells (FMC). Today two or more CNC machines are considered a

flexible cell and two more more cells are considered a flexible manufacturing system.

Thus, a Flexible Manufacturing System (FMS) consists of several machine tools along with part and tool handling devices such as robots, arranged so that it can handle any family of parts for which it has been designed and developed.

The Manufacturing Cell


A flexible manufacturing cell (FMC) consists of two or more CNC machines, a cell computer and a robot.

The cell computer (typically a programmable logic controller) is interfaced with the microprocessors of the robot and the CNCs.



The Cell Controller The functions of the cell controller

include work load balancing, part scheduling, and material flow control.

The supervision and coordination among the various operations in a manufacturing cell is also performed by the cell computer.

The software includes features permitting the handling of machine breakdown, tool breakage and other special situations.


The Cell Robot In many applications, the cell robot

also performs tool changing and housekeeping functions such as chip removal, staging of tools in the tool changer, and inspection of tools for breakage or expressive wear. When necessary, the robot can also initiate emergency procedures such as system shut-down.

Parker-Hannifin Corporation, Forrest City, NC.

The FMS


FMS Components Most FMS systems comprise of three

main systems Work machines (typically automated CNC

machines) that perform a series of operations;

An integrated material transport system and a computer that controls the flow of materials, tools, and information (e.g. machining data and machine malfunctions) throughout the system;

Auxiliary work stations for loading and unloading, cleaning, inspection, etc.


FMS Goals Reduction in manufacturing cost by lowering

direct labor cost and minimizing scrap, re-work, and material wastage.

Less skilled labor required. Reduction in work-in-process inventory by

eliminating the need for batch processing. Reduction in production lead time permitting

manufacturers to respond more quickly to the variability of market demand.

Better process control resulting in consistent quality.


Advantages of FMS Faster, lower- cost changes from one part to

another which will improve capital utilization Lower direct labor cost, due to the reduction

in number of workers Reduced inventory, due to the planning and

programming precision Consistent and better quality, due to the

automated control Lower cost/unit of output, due to the greater

productivity using the same number of workers

Savings from the indirect labor, from reduced errors, rework, repairs and rejects


Disadvantages of FMS Limited ability to adapt to changes in

product or product mix (e.g., machines are of limited capacity and the tooling necessary for products, even of the same family, is not always feasible in a given FMS)

Substantial pre-planning activity Expensive, costing millions of dollars Technological problems of exact component

positioning and precise timing necessary to process a component

Sophisticated manufacturing systems


COMPUTER INTEGRATED MANUFACTURING


CIM VS FMS

Documents

The FMS Henry C. Co Technology and Operations Management, California Polytechnic and State University