12813_types of layout and discrete manufacturing

7/29/2019 12813_Types of Layout and Discrete Manufacturing

1/27

9/21/2013 Dr. Lotfi K. Gaafar 1

Manufacturing Systems Automation

*Based on information from

Groover, 2001.Automation,

Production Systems, and

Computer-Integrated

Manufacturing.


2/27


The Production System

Manufacturing

support systems

Manufacturing facilities:

factory, equipment


3/27


4/27


Discrete Manufacturing

Batch Production

Mass Production

Job shop

QuantityAutomation

Specialization

Variety

MaterialHandlingComplexity

Skills

1


5/27


Mass production*

Automation easily justified

Objectives: (1) reduce operation cycle time, (2) increase system reliability

Line is rarely changed - setup time not critical

Inflexible: not suitable for products with many options or limited

production runs

Discrete Manufacturing

* Check the textbook on the two types: quantity and flow line

1


6/27


Job shop production

Products produced in small volume

Automation difficult to justify unless products are too complex to

be produced manually

Objectives: (1) reduce setup time, (2) reduce processing time, (3)

reduce WIP

Most flexible of production strategies

Discrete Manufacturing 1


7/279/21/2013 Dr. Lotfi K. Gaafar 7

Batch production

Products produced in batches, lots or groups

Trade-off between job shop and mass production

Single setup for each batch

Increase batch size, but increase in waiting time, WIP and

inventory result

Objectives are same as job shop

Discrete Manufacturing 1



Facility Layout

Four types of layouts:

Fixed Position: suitable for large products

Process: suitable for job shop

Cellular: suitable when products are similar in batch

production and sometimes in job shop

Product flow: suitable for mass production

2



Fixed position layout Product must remain stationary throughout production sequence

Machines are brought to the product

Higher expense due to robustness and accuracy of equipment

Facility Layout 2


10/279/21/2013 Dr. Lotfi K. Gaafar 10

Process layout

For small, discrete-parts manufacturing

Machines are grouped into departments according to type ofoperation

Advantages: work schedule more flexible

Disadvantages: WIP is large (cost in inventory and storage

space), high material handling cost, larger batches are made thanare required (to justify setup), difficulty in maintaining control of

parts, highest skill level required from operators

Facility Layout 2


11/279/21/2013 Dr. Lotfi K. Gaafar 11

Group technology (cellular) layout

Several different types of machines are grouped together to form acell - each cell is designed to produce a family of parts

Suitable for small to mid-volume production of parts

Advantages: setup time is reduced, lead time is reduced, WIP isreduced, finished inventory is reduced, improved quality (group of

workers responsible for a cell) Disadvantages: parts must be grouped into families, layout is less

flexible than process layout, batches from same family cannot berun simultaneously, higher skill level required from operators

Facility Layout 2


12/279/21/2013 Dr. Lotfi K. Gaafar 12

Product flow layout

Suited for high volume production

Advantages: minimized material handling, easy to automate

material handling, less WIP, easier to control

Disadvantages: inefficient to alter the sequence of operations,

breakdown on one machine can stop the entire line

Facility Layout 2


13/27


14/27


Manufacturing Support Systems3


15/27


Machines

Transfer lines Assembly

Material Handling

Inspection (coordinate measuring machines, CMM)

Automated Manufacturing Systems3


16/27


Fixed Automation (transfer lines) Hard automation, automation for mass production

Produces large numbers of nearly identical parts

High initial investment for custom engineered equipment

Product design must be stable over its life

Advantages: equipment fine tuned to application -

decreased cycle time, infrequent setups, automated

material handling - fast and efficient movement of parts,

very little WIP

Disadvantage: inflexible

Types of Automation 3


17/27


Programmable Automation (NC, CNC, robots- e.g., chess)

Sequence controlled by a program

High investment in general purpose equipment

Lower production rates

Flexibility to deal with variation

Suitable for batch production

Smaller volumes (than fixed) of many different parts

More flexible than fixed automation

Major disadvantage: setup prior to each new part Large batch size (due to setups)

Speed sacrificed for flexibility



18/27


Flexible Automation (e.g., piston head) Extension of programmable automation

No time lost for change over

High investment in custom-engineered systems

Production of product mix

Flexibility to deal with design variations

Low to medium quantities

Compromise between fixed and programmable automation in speedand flexibility

Advantage: programming and setup performed off-line

More expensive - size and tool change capabilities

Small batch sizes are justified - reduced WIP and lead time

Typical parts are expensive, large and require some complexmachining



19/27




20/27


21/27


Reduce work-in-process

parts being processed, part waiting to be processedlarge WIP: longer time to fill orders, more storage space, value ofunfinished goods that could be invested elsewherereduced WIP: better control and scheduling

Reduce manufacturing lead time

processing time, setup time, waiting timesetup time: flexible automation, common fixtures and tooling

processing time: combining or eliminating operations, increasespeed (work measurement principles)

Increase qualityrepeatable operations through every cycle - tighter control limits,easier detection when process is out of controlstatus of manufacturing operations

Reasons for Automating 4


22/27


Increase productivity

Reduce labor cost

Address labor shortages

Reduce or eliminate routine manual and clerical tasks

Health and Safety

May be the only option

Stay up-to-date (avoid cost of catching up)

Reasons for Automating 5


23/27


Strengths of Humans Sense unexpected stimuli

Develop new solutions to problems

Cope with abstract problems Adapt to change

Generalize from observations

Learn from experience

Make difficult decisions based on incomplete data

Manual Labor in Automated Systems 5


24/27


Strengths of (computer-based) machines Perform repetitive tasks consistently

Store large amounts of data

Retrieve data from memory reliably Perform multiple tasks simultaneously

Apply high forces and power

Perform computations quickly

Manual Labor in Automated Systems 5


25/27


Manual Labor in Automated Systems

Even if all of the manufacturing systems in the factory areautomated, there will still be a need for the following kinds of

work to be performed:

Equipment maintenance. Maintain and repair, improve the

reliability, of automated systems.

Programming and computer operation.

Engineering project work. Upgrades, design tooling, continuous

improvement.

Plant management.

5


26/27


AUTOMATION PRINCIPLES AND STRATEGIES

USA Principle:

1. Understand the existing process

2. Simplify the process

3. Automate the process (if needed)

6


27/27

9/21/2013 27

AUTOMATION PRINCIPLES AND STRATEGIES

Ten Strategies for Automation

1. Specialization of operations.

2. Combined operations.

3. Simultaneous operations.

4. Integration of operations.5. Increased flexibility.

6. Improved material handling and storage.

7. On line inspection.

8. Process control and optimization.

9. Plant operations control.

10. Computer integrated manufacturing (CIM).

6

12813_types of layout and discrete manufacturing

Documents