Efficient line changeover: the key to lean manufacturing
Efficient line changeover:
the key to lean manufacturing
by Douglas Farlow, Production Solutions, Inc., Poway, CA USA
Changes in the domestic printed
circuit board assembly industry
have resulted in a dominant
shift to a high-mix, low-volume
(HMLV) manufacturing envi-
ronment with a high frequency
of line changeovers. Reducing
changeover time and optimizing
the changeover process are criti-
cal to efficient and profitable
HMLV operation. For extreme
HMLV applications—new
product introduction (NPI),
prototyping or short run manu-
facturing—changeover efficiency
is an absolute necessity.
The proper selection of tools
and procedures to reduce the
setup process time for screen
printers, pick and place ma-
chines and dispensing equip-
Figure 1. Substrate support system.
ment is necessary to insure
minimal changeover durations
introduction
conveyors and wave solder machines may
and increased line uptime. This
How is fast and efficient changeover
also require attention. Automatic optical
paper addresses the root cause
defined? Historically, rapid line changeover
inspection (AOI) systems are becoming
of non-revenue generating line has had several definitions in the electron-
more common in-line, but with much of
stoppages, such as feeder setup, ics manufacturing industry. Terms such
the changeover being done either offline or
substrate support setup, pro-
as SMED (single minute exchange of die),
during production.
gramming, tooling changeover,
SDED (single digit exchange of die), Six
equipment maintenance and
Sigma and lean manufacturing are just
Quality considerations
breakdown, and process correc-
a few initiatives that apply to this strat-
As board complexity has evolved, so has
tions and presents a case study
egy. Currently, a sub ten-minute goal for
the creation of support methods. Absolute
complete line changeover is still a target for
on the economic impact of line
support is essential to insure high-quality
many HMLV manufacturers.
changeover in terms of hourly
printing. In the past, single-sided boards
Line changeover encompasses several
required simple support pins or bars. How-
revenue per SMT line, burden
main areas of the production equipment.
ever, as fine pitch devices, lead free solders,
cost per hour and line optimiza-
Screen printers and placement equipment
BGAs, 0201 and now 01005 discrete com-
tion rates. are the two most time consuming. Screen
ponents, double-sided boards and increas-
printers require stencil change, program-
ingly thinner substrates have emerged, the
ming, paste loading, conveyor change and
demand for improved support has forced
board support. Pick and place machines
the industry to find better methods.
Keywords: Line Changeover, require conveyor change, programming,
As electronics designers create boards
Lean Manufacturing, Board feeder setup and board support setup.
that have components occupying almost
Support, SMED, SDED
Other equipment in a typical production
all of both sides of the PCB, available and
line, such as reflow ovens and cleaners,
usable support pin real estate has all but
may need new profiles programmed and
disappeared. This has forced the board
conveyor changeover. Areas such as transfer
assembler to find creative and sometimes
34 – Global SMT & Packaging – March 2009
www.globalsmt.net
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