Production Technology

Production
Operations management

Chapter 8

Production Technology

FACTORY AUTOMATION

Production automation is fundamental to Japan's
competitiveness in terms of the cost and quality of its
consumer electronic products.
In addition, a growing labor shortage, demands for
improved working environments, and company-wide
computer-integrated manufacturing have made automation a
necessity for many companies.
Since most fabrication activities have already been
automated, the current focus of attention is on the
automation of assembly lines, where labor content has been
highest.
There are several stages of assembly line automation, with
varying impacts on flexibility and product design.

FACTORY AUTOMATION

The move from hand assembly to robot assembly of
existing products can be termed "first-generation"
automation. "Second-generation" lines require some product
design changes for assembly line automation. Automation
that requires broad product design changes is termed "third-
generation" automation.
The JTEC panel observed widespread automation during
its plant tours. The leading Japanese electronic companies
have implemented the following FA concepts (Kahaner
1993, 33-56):
in-line systems with a series of progressive operations

FACTORY AUTOMATION

computer control of raw material storage and retrieval
automated guided vehicles used in the delivery of material
to the assembly line, and in some cases, automated loading
of the assembly equipment
bar code identification of raw material and product mix
machine instructions downloaded from a host computer
in-line automated assembly and process equipment
in-line automated inspection and testing equipment
following each preceding assembly or fabrication operation
automated real-time process control to achieve automated
calibration of assembly equipment and products

FACTORY AUTOMATION

Key benefits cited for the use of automation include
reducing factory set-up time, manufacturing defects, product
lead time, and direct labor, and increasing the ability to
rapidly deploy manufacturing operations around the world.
Sony management described the following as an example
of the benefits gained from the company's factory
automation activities: It took three to four months to start up
Sony's original production lines in Japan, but it required
only two to three weeks to bring replicated lines up to speed
in Singapore and France. Changing models required only
9.1% of additional capital investment in Sony's first
changeover, 3.5% in the second changeover, and only 1.5%
in the third changeover.

FACTORY AUTOMATION

In addition, the move to automation resulted in improved
quality. The best defect rate using manual labor was 2000
parts per million (PPM), compared to 20 PPM after the first
week of automation.
Sony's personnel policy was to remove employees from
manual labor jobs through automation so that "they could
become more creative in solving problems and improving
operations."
Due to Sony's strong knowledge base in automation and
its focus on design for manufacturability, between 1987 and
1990 it increased sales by 121% with an increase of only 35
employees.

FACTORY AUTOMATION

Automation for Miniaturization
Japanese electronics companies have made and continue
to make large investments in production technologies and
factory automation because of their commitment to
miniaturization as well as to high product reliability and low
product cost. As electronic components shrink to as small as
1.0 mm by 0.5 mm (called "1005" parts), and as component
lead pitch approaches 0.2 mm, human assembly is no longer
feasible.
The Japanese strategy to develop key components for use
in electronic products has also required investments in
equipment development.

FACTORY AUTOMATION

"Off-the-shelf" equipment is generally inadequate to meet
the manufacturing needs of new component technologies.
Without exception, each Japanese company the JTEC panel
visited was designing and building critical equipment in-
house. According to these companies, equipment provides a
major competitive advantage because it is designed to
respond to the specific manufacturing requirements of the
companies' components or products.
The JTEC panel was impressed by the fact that some
Japanese component suppliers also supplied buyers with the
equipment required to assemble their advanced components.
TDK, Murata, and Matsushita,

FACTORY AUTOMATION

for example, developed internally the production
technology to make 1005 parts, and they also supplied the
assembly equipment required for customers to utilize these
ultra small parts in SMD assembly. The equipment makers
introduced the equipment at the same time as the new
miniature parts were made available to the market. The
production technology is being developed to ensure that new
components are rapidly included in next-generation product
designs.
Miniaturization is forcing assembly technologies to
become faster and more precise. Precision robots have
improved repeatability from .05 to .01 mm over the past
decade.

FACTORY AUTOMATION ISSUES

Final Assembly Design Techniques
In assembly operations, parts handling and feeding and
line control are very complex; however, with the advances
made in equipment, production control, and computers over
the past decade, automated assembly lines are no longer
unusual.. There are three critical advances (Kahaner 1993,
34):
positioning technology for robot control
flexible line construction technology for mixed flow
production of multiple product models
modular product design technology for assembly line
automation


Positioning is the most common problem for assembly
automation. Different sizes and shapes of components make
assembly difficult. Precision positioning of parts for printed
circuit boards in consumer electronic products is especially
challenging.
If the board is out of position, the problem is compounded.
This is a problem with board warp age where accurate sensor
detection is especially difficult. NEC in Gunma Prefecture
developed a triangular measuring optical sensor that is used
in a procedure to detect the height of three points on a print
board.


A two-dimensional curving warp can be represented by
three points, so the company had to come up with
innovations in measurement point selection and interpolation
techniques.
Jigs are fundamental to positioning parts properly before
assembly. Complex part shapes can make such positioning
difficult.
Visual sensors can detect the positions of parts and also
allow for mixed-flow production operations. These sensors
can also detect parts' shapes and therefore are useful in
product quality control applications.
Toshiba's most recent application of CCD technology to
visual sensors has allowed for 0.02 mm positioning accuracy.


More typical sensors, combined with the mechanical error
of a robot, result in errors of several hundred microns.
Flexible lines are required to cope with the demands of
multiple-model, mixed-flow production. Movable jigs and
visual sensors are used to adjust to changing parts shapes. In
mixed-flow assembly lines, product model information must
be controlled to match parts with the models on the line.
Some companies have used memory cards on parts pallets to
achieve this control. Integration of such parts flows with
mixed-line assembly is based on sophisticated parts-feeding
equipment, which may account for 80% of the automation
success.


Modular product designs are used to reduce equipment
costs and to improve product reliability. It is essential to
implement design features that are compatible with
automated assembly operations. It is then possible to
simplify assembly and enhance operational reliability by
orienting all the assembly steps in one direction or
employing connection techniques amenable to automation.
For complex assembly operations that could be handled by
robots, Fujitsu developed special supplemental mechanisms
that required changes in such details as screw shape.
Product structures are divided into a number of modules
for design purposes.


Each module is assembled on a sublime, and the assembly
operations not amenable to automation are concentrated in
the final assembly line. It is easy to achieve higher
automation rates in the total assembly process because each
module is designed to be compatible with automated
assembly. In the personal computer, for example, every
component used in final assembly simply slides into a slot or
connector without difficulty. At NEC's PC assembly factory,
each module is designed to be compatible with automation of
the total assembly process.


Now that robots have become highly functional, Seiko
Epson has designed its printers for the lowest total
manufacturing cost and then constructed its assembly line
accordingly. It has set about improving the automation rate
while developing ways to handle multiple-module, mixed-
flow production. The mixed-flow production approach helps
hold down equipment costs and allows for flexibility in
adjusting to demand fluctuations. Development of designs
compatible with assembly automation is a new key concept
that has great potential.

Automated Manufacturing Systems

CAD ,CAE ,CAPP
CAM ,CIM
Computer Aided
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

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

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

Types of Automation

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
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

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).

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.

AUTOMATION ADVANTAGES

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

AUTOMATION ADVANTAGES

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)

Factories of Future
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

Factories of Future
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

Factories of Future
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
Food
Large volume industry
Standard products and operations, therefore reasonably
easy to automate
Many products use continuous processes; discrete
processes includes packaging

Factories of Future
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

Plant Utilities

End Of

Chapter 8

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Production Technology

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Production Technology