computer integrated manufacturing: flexible manufacturing & material handling system

8/10/2019 Computer Integrated Manufacturing: Flexible Manufacturing & Material Handling System

1/38


2/38

Chapter 19:

Where to Apply FMS Technology The plant presently either:

Produces parts in batches or

Uses manned GT cells and management wants toautomate the cells

It must be possible to group a portion of the parts made in

the plant into part families

The part similarities allow them to be processed onthe FMS workstations

Parts and products are in the mid-volume, mid-variety

production range

2RJ, CIM JULY 2009


3/38

Flexible Manufacturing System -

Defined A highly automated GT machine cell, consisting of a group

of processing stations (usually CNC machine tools),

interconnected by an automated material handling and

storage system, and controlled by an integrated computer

system

The FMS relies on the principles of GT

No manufacturing system can produce an unlimited

range of products

An FMS is capable of producing a single part family or

a limited range of part families

Flexibility to work on mixed-model

3RJ, CIM JULY 2009


4/38

Types of FMS Kinds of operations

Processing vs. assembly

Type of processing If machining, rotational vs. non-rotational

Number of machines (workstations):

1. Single machine cell (n= 1)2. Flexible manufacturing cell (n= 2 or 3)

3. Flexible manufacturing system (n= 4 or more)

4RJ, CIM JULY 2009


5/38

Single-Machine Manufacturing Cell (n=1)

5RJ, CIM JULY 2009


6/38

A single-machine CNC machining cell (n=1)

6RJ, CIM JULY 2009


7/38

Flexible Manufacturing Cell

7RJ, CIM JULY 2009


8/38

A two-machine flexible manufacturing cell

for machining (n = 2 or 3)

8RJ, CIM JULY 2009


9/38

A five-machine flexible manufacturing system

for machining (n = 5)

9RJ, CIM JULY 2009


10/38

Features of the Three Categories

10RJ, CIM JULY 2009


11/38

FMS Components / Elements:1. Workstations (kinds of machines) & cells

2. Automated material and parts handling,

storage and transport system

3. Computer control system

4. Human labor

11RJ, CIM JULY 2009


12/38

1. Workstations Load and unload station(s)

Factory interface with FMS

Manual or automated

Includes communication interface with

worker to specify parts to load, fixtures

needed, etc.

12RJ, CIM JULY 2009


13/38

1. Workstations CNC machine tools in a machining type

system

CNC machining centers (3 to 5 axis)

Milling machines

Turning machines

Assembly machines

13RJ, CIM JULY 2009


14/38

2. Material-Handling and Storage

Systems Functions:

Random, independent movement of parts between

stations Capability to handle a variety of part styles: prismatic

& rotational

Standard pallet fixture base

Workholding fixture can be adapted Temporary storage

Convenient access for loading and unloading

Compatibility with computer control

14RJ, CIM JULY 2009


15/38

2. Material Handling Equipment Primary handling system establishes basic FMS layout

Secondary handling system - functions:

Transfers work from primary handling system toworkstations

Position and locate part with sufficient accuracy

and repeatability for the operation

Reorient part to present correct surface for

processing

Buffer storage to maximize machine utilization

15RJ, CIM JULY 2009


16/38

3. Computer Control System A computer system is interfaced to all

elements / components.

Categories of functions:

Workstation control

Production control

Traffic control

Tool control

RJ, CIM JULY 2009 16


17/38

4. Human Resource Humans are needed to manage the operations of the

system.

Functions include:

Loading raw workparts into the system

Unloading finished parts from the system

Changing and setting of tools Performing equipment maintenance and repair

Performing NC part programming, etc.



18/38

FMS Benefits Increased machine utilization

Reasons:

24 hour operation likely to justify investment Automatic tool changing

Automatic pallet changing at stations

Queues of parts at stations to maximize utilization

Dynamic scheduling of production to account for

changes in demand

Fewer machines required

Reduction in factory floor space required

18RJ, CIM JULY 2009


19/38

FMS Benefits Greater responsiveness to change

Reduced inventory requirements

Different parts produced continuously rather than inbatches

Lower manufacturing lead times

Reduced labor requirements

Higher labor productivity

Opportunity for unattended production

Machines run overnight ("lights out operation")

19RJ, CIM JULY 2009


20/38

Storage SystemsFunctionto store materials (e.g., parts, work-in-

process, finished goods) for a period of time and

permit retrieval when required

Used in factories, warehouses, distribution centers,

wholesale dealerships, and retail stores

Important supply chain component Automation available to improve efficiency

20RJ, CIM JULY 2009


21/38

Conventional Storage Methods

Bulk storage - storage in an open floor area

Problem: achieving proper balance between storage

density and accessibility

Rack systems - structure with racks for pallet loads Permits vertical stacking of materials

Shelving and bins - horizontal platforms in structural

frame

Steel shelving comes in standard sizes Finding items can be a problem

Drawer storage - entire contents of each drawer can be

viewed

21RJ, CIM JULY 2009


22/38

Bulk Storage

Bulk storage arrangements: (a) high-density bulk storageprovides low accessibility, (b) bulk storage with loads forming

rows and blocks for improved accessibility

22RJ, CIM JULY 2009


23/38


24/38

Drawer Storage

24RJ, CIM JULY 2009


25/38

Automated Storage SystemsMechanized and automated storage equipment to reduce

the human resources required to operate a storage

facility Significant investment

Level of automation varies

In mechanized systems, an operator participates in

each storage/retrieval transaction In highly automated systems, loads are entered or

retrieved under computer control

25RJ, CIM JULY 2009


26/38

Objectives and Reasons for

Automating Storage Operations To increase storage capacity

To increase storage density

To recover factory floor space currently used for WIP To improve security and reduce pilferage

To reduce labor cost and/or increase productivity

To improve safety

To improve inventory control To improve stock rotation

To improve customer service

To increase throughput

26RJ, CIM JULY 2009


27/38

Types of Automated Storage System1. Automated Storage/Retrieval System

(AS/RS)

Rack system with mechanized or automated

crane to store/retrieve loads

2. Carousel Storage System

Oval conveyor system with bins to containindividual items

27RJ, CIM JULY 2009


28/38

AS/RSUnit load AS/RS

with one aisle

28RJ, CIM JULY 2009


29/38

CNC Machining Center with Automatic Pallet

Changer - Stores One Part (single station

manufacturing cells)

Automatic

pallet changer

integrated witha CNC

machining

center for

manual loadand unloading

of workparts.

29RJ, CIM JULY 2009


30/38

Storage Capacities Greater Than

One Machining centers:

Various designs of parts storage unit

interfaced to automatic pallet changer (orother automated transfer mechanism)

30RJ, CIM JULY 2009


31/38


One

Machining center and automatic pallet changer with pallet

holders arranged radially; parts storage capacity = 5

31RJ, CIM JULY 2009


32/38


One

Machining center and in-line shuttle cart system with pallet

holders along its length; parts storage capacity = 16

32RJ, CIM JULY 2009


33/38

Automated Guided Vehicles (AGVs)An Automated Guided Vehicle System (AGVS) is a

material handling system that uses independently

operated, self-propelled vehicles guided along definedpathways in the facility floor

Types of AGV:

Driverless trains

Pallet trucks Unit load AGVs



34/38

Automated Guided Vehicles:

Driverless Automated Guided Train


Common

application is

moving heavy

payloads over

long distances

in warehouses

and factories

withoutintermediate

stops along the

route


35/38


AGV Pallet Truck Used to move

palletized loads

along predetermined

routes

Vehicle is backed

into loaded pallet by

worker; pallet is then

elevated from floor

Worker drives pallet

truck to AGV guide

path and programs

destination


36/38


Unit Load Carrier Used to move unit

loads from station to

station

Often equipped forautomatic

loading/unloading of

pallets and tote pans

using roller conveyors,

moving belts, ormechanized lift

platforms


37/38

FMS: machine centres, measuring & inspection

station & AGV



38/38

Terminologies: Flexible manufacturing cellmade flexible by using

machine centres, CNC machines, industrial robots,

handling systems, etc.

Flexible manufacturing system

Machine cellmanually operated production machines

laid out in a line, L, U-shaped configuration (cellular

manufacturing). For family of parts that are similar.

Transfer lineproduction line for mass production

computer integrated manufacturing: flexible manufacturing & material handling system

Documents