EdiMech

Flexible Manufacturing Systems (FMS)

 

 “FMS consists of a group of processing work stations interconnected by means of an automated material handling and storage system and controlled by integrated computer control system.” Or FMS is called flexible due to the reason that it is capable of processing a variety of different part styles simultaneously at the workstation and quantities of production can be adjusted in response to changing demand patterns.

Fig.6: Flexible manufacturing system

 

 

BASIC COMPONENTS OF FMS

The basic components of FMS are:

A.     Workstations

B.      Automated Material Handling and Storage system.

C.      Computer Control System

 

A. Workstations: In present day application these workstations are typically computer numerical control (CNC) machine tools that perform machining operation on families of parts. Flexible manufacturing systems are being designed with other type of processing equipments including inspection stations, assembly works and sheet metal presses. The various workstations are

(i) Machining centers

(ii) Load and unload stations

(iii) Assembly work stations

(iv) Inspection stations

(v) Forging stations

(vi) Sheet metal processing, etc.

 

B. Automated Material Handling and Storage system: The various automated material handling systems are used to transport work parts and subassembly parts between the processing stations, sometimes incorporating storage into function. The various functions of automated material handling and storage system are

(i) Random and independent movement of work parts between workstations

(ii) Handling of a variety of work part configurations

(iii) Temporary storage

(iv) Convenient access for loading and unloading of work parts

(v) Compatible with computer control

 

C. Computer Control System: It is used to coordinate the activities of the processing stations and the material handling system in the FMS. The various functions of computer control system are:

(i) Control of each work station

(ii) Distribution of control instruction to work station

(iii) Production control

(vi) Traffic control

(v) Shuttle control

(vi) Work handling system and monitoring

(vii) System performance monitoring and reporting

 

The FMS is most suited for the mid variety, mid value production range

 

Fig.7: Application Characteristic of FMS

 

 

AIMS OF FMS

·         To reduce costs

·         Better utilization of the production equipment reduction of stocks (ex: Work in progress— capital shorter through put times)

·         Reduction of piece part unit costs.

·         To increase Technical Performance:

·         Increased production levels

·         Greater product mixture

·         Simultaneous product mixture manufacturing

·         Integration of the production system into the factory’s logistical system

·         Smaller batch sizes

·         Shorter or zero change over or reset of times

·         To improve Order Development:

·         Shorter lead times/delivery times

·         Determination of production capacities

·         To assist future Corporate Security:

·         Increased Competitiveness

·         Increased Quality

·         Improved Company Image

 

 

OBJECTIVES OF FMS: The principle objectives of FMS are

 

A. To improve operational control through:

Ø  Reduction in the number of uncontrollable variables.

Ø  Providing tools to recognize and react quickly to deviations in the manufacturing plan

Ø  Reducing the dependence of human communication.

B. To reduce direct labor:

Ø  Removing operators from the machining site (their responsibilities activities can be broadened).

Ø  Eliminating dependence on highly skilled machines (their manufacturing skills can be better utilized in manufacturing engineering functions).

Ø  Providing a catalyst to introduce and support unattended or lightly attended machining operation.

C. To improve short run responsiveness consisting of:

Ø  Engineering changes

Ø  Processing changes

Ø  Machining downtime or unavailability

Ø  Cutting tool failure

Ø  Late material delivery

D. To improve long-run accommodations through quicker and easier assimilation of:

Ø  Changing product volumes

Ø  New product additions and introductions

Ø  Differentiation part mixes

Ø  Increase Machine Utilization by:

·         Eliminating machine setup

·         Utilizing automated features to replace manual intervention

·         Providing quick transfer devices to keep machines in the cutting cycle

Ø  Reduce inventors by:

·         Reducing lot sizes

·         Improving inventors turn-over

·         Providing the planning tools for JIT manufacturing

 

Advantages of Flexible manufacturing system

 

§  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 Flexible manufacturing system

 

§  Limited ability to adapt to changes in product or product mix (ex. 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