04/19/23

Manufacturing Systems AutomationIntroduction*

Dr. L. K. Gaafar

*Based on information from Groover, 2001. Automation, Production Systems, and Computer-Integrated Manufacturing.

04/19/23

The Production System

Manufacturing

support systems

Manufacturing facilities: factory, equipment

04/19/23

Discrete Manufacturing

Batch Production

Mass Production

Job shop

Quantity

AutomationSpecialization

Var

iety

MH

Com

plex

ity

Skills

04/19/23

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

04/19/23

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

04/19/23

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

04/19/23

Facility Layout

Four types of layouts:

Process: suitable for job shop

Fixed Position: suitable for large products

Cellular: suitable when products are similar in batch production and sometimes in job shop

Product flow: suitable for mass production

04/19/23

Process layout

– For small, discrete-parts manufacturing

– Machines are grouped into departments according to type of operation

– Advantages: work schedule more flexible

– Disadvantages: WIP is large (cost in inventory and storage space), high material handling cost, larger batches are made than are required (to justify setup), difficulty in maintaining control of parts, highest skill level required from operators

Facility Layout

04/19/23

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

04/19/23

    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

04/19/23

    Group technology (cellular) layout – Several different types of machines are grouped together to form a

cell - 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 is

reduced, 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 be run simultaneously, higher skill level required from operators

Facility Layout

04/19/23

Example Industries

Aerospace– Typically, complex, three-dimensional shapes, exotic

materials, medium-volume to low-volume production quantities

– Military and space technology filters down to industrial applications

– Pioneered work in NC machining, CAD/CAM, composites and flexible manufacturing system applications

– Goals: energy efficiency, high strength-to-weight ratio

04/19/23

Example Industries

Automotive– Relatively large production quantities, multiple options: automated

assembly is difficult

– Traditionally, primary processes were metalworking: machining of power train parts, forming and bending sheet metal; assembly by spot welding and mechanical fasteners; finishing by spray painting and plating

– New materials: plastics, fiberglass

– Increasing automation: robots for spot welding and spray painting

– Improved quality with production groups that assemble large portions of the automobile

04/19/23

Example Industries

Chemical – Chemical processes for man-made fibers and plastics,

oil distillation and pharmaceutical industries

– Continuous flow of product and byproducts; some batch processing

– reasonably easy to automate

04/19/23

Example Industries

Food – Large volume industry

– Standard products and operations, therefore reasonably easy to automate

– Many products use continuous processes; discrete processes includes packaging

04/19/23

Example Industries

Semiconductor – Large volume industry

– Emphasis on design and production of low-cost integrated circuits

– Smaller size and more stringent requirements for cleanliness

– Process requirements have forced automation

04/19/23

Increase production rate eliminate portions of process that directly increase production time: machine processing time, handling time, setup times (SMED)

Remove humans from hazardous environments exposure to chemicals, fumes, temperature or radiation robotic applications: L/UL furnaces, spray painting, welding

Remove humans from processes that require extremely clean environments: e.g., semiconductors, drugs

Reduce number of defective products Reduce direct labor

one worker monitors a larger number of machines

Reasons for Automating

04/19/23

Reduce work-in-process parts being processed, part waiting to be processed large WIP: longer time to fill orders, more storage space, value of unfinished goods that could be invested elsewhere reduced WIP: better control and scheduling

Reduce manufacturing lead time processing time, setup time, waiting time setup time: flexible automation, common fixtures and tooling processing time: combining or eliminating operations, increase speed (work measurement principles)

Increase quality repeatable operations through every cycle - tighter control limits, easier detection when process is out of control status of manufacturing operations

Reasons for Automating

04/19/23

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

04/19/23

OSHAOccupational Safety and Health Administration

The mission of the Occupational Safety and Health Administration (OSHA) is to save lives, prevent injuries and protect the health of America's workers. To accomplish this, federal and state governments must work in partnership with the more than 100 million working men and women and their six and a half million employers who are covered by the

04/19/23

Machines Transfer lines Assembly Material Handling Inspection (coordinate measuring machines, CMM)

Automated Manufacturing Systems

04/19/23

CAD CAE CAPP CAM CIM

Computer Aided

04/19/23

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

04/19/23

Programmable Automation (NC, CNC, robots)– 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

Types of Automation

04/19/23

Flexible Automation (FMS)– 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 speed

and 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 complex

machining

Types of Automation

04/19/23

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

04/19/23

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

04/19/23

Manual Labor in Automated Systems

Even if all of the manufacturing systems in the factory are automated, 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.

04/19/23

AUTOMATION PRINCIPLES AND STRATEGIES

USA Principle:

1. Understand the existing process

2. Simplify the process

3. Automate the process

04/19/23

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).

04/19/23

AUTOMATION PRINCIPLES AND STRATEGIES

Automation Migration Strategy

Phase 1: Manual production using single station manned cells operating independently.

Phase 2: Automated production using single station automated cells operating independently.

Phase 3: Automated integrated production using a multi-station automated system with serial operations and automated transfer of work units between stations.

04/19/23

3500 BC Use of Wheel and axle for transportation500 BC Lathe used for wood turning1569 Screw-cutting lathe developed -- Jacques Besson1769 James Watt invented the steam engine -- later used to

provide power to industry1774 Precylinder-boring mill developed -- John Wilkinson1790 Samuel Slater opens the first successful textile mill in the

United States1793 Eli Whitney builds the first cotton gin1798 Eli Whitney invents a milling machine to produce

standardized parts in muskets

Historical Development of Manufacturing

04/19/23

1801 J.M. Jacquard invented a silk-loom-- punched cards controlled the machine

1851 Issac Singer patented his sewing machine1900 High-speed steel cutting tools developed1903 Oxyacetylene welding torch developed1903 First fully automated machine-made bottles produced1907 Paint spray gun developed1913 Ford Motor Co. opens first moving assembly line 1914 Centrifugal casting of cast iron pipe -- re-usable molds are used1920 Ford introduces continuous casting of cast iron for engine

blocks

Historical Development of Manufacturing

04/19/23

1921 Jigs and fixtures used in the jig-boring machine to make rifles and revolvers -- Enfield, England

1930 First automatic factory -- Made chassis frames for cars: one every six seconds

1952 First commercial NC machine1962 First industrial robot1963 Electro-coating methods for painting car bodies is developed1964 Technique for fast-breaking electric motors developed --

machine tools can now be stopped quickly1985 First products manufactured in space went on sale -- tiny

plastic beads, perfectly round and uniform in size

Historical Development of Manufacturing

04/19/23

Cowboy after OSHA, by J. N. Devin ( 1972)