shaping the future of metrology - Brown & Sharpe

Wichita, Kansas
Aerospace Shop Soars Over
Measurement Bottlenecks
B usiness has been brisk for L & S
Machine Company Inc., an aerospace
machine shop in Wichita, Kansas.
The company machines 500 different
aerospace part numbers a year.This is a
dramatic increase from approximately
250 part numbers just two years ago.
Growth has placed a tremendous load on
the company’s dimensional measurement
capabilities.
A Division of
Tru Circle Corporation,
L & S
Machine employs
about 160
people. For the fiscal years ’97 and ’98,
sales bookings have increased by approximately
25 percent and 30 percent respectively.This
very healthy growth rate
is due, in part, to the company’s willing-
16 mfg. Shaping the Future of Metrology
If a manufacturing non-conformity is found, PC-
DMIS for WINDOWS can display dimensional data
on the computer’s screen, along with a drawing of
the part. Analysis of the drawing helps engineers
pinpoint process problems.
ness to take on the manufacturing of 100
percent more part numbers. Along with
this opportunity has come the responsibility
to set up, trouble-shoot, and validate
twice as many manufacturing
processes.
Rather than buy more measurement
equipment and double its inspection staff,
L & S has kept pace with the increased dimensional
measurement work by relying
on PC-DMIS for
WINDOWS graphicscoupled
CMM software
to improve measurement
capabilities and
throughput.The software has also made a
significant contribution to the company’s
overall improvements in productivity and
adherence to production schedules during
the past three years.
The parts are typically complex 3, 4,
and 5-axis components with true position
tolerances down to .001". They are
used in a wide range of assemblies and
subassemblies for commercial and military
aircraft, including structural members,
landing gear and wing flaps.
For many years, inspection had been
the number one bottleneck in the manufacturing
process. Before installing PC-
DMIS for WINDOWS, in-process inspection
was complicated. Operators had to memorize
numerous codes to access the various
programming and measurement features.
Even performing rough, in-process
checks was time consuming because
every specific set of points measured required
its own program. According to
Skip Steely, Quality Assurance Manager,
inspection was laborious, and training
CMM operators was difficult.
Improving
Programming Throughput
Now, instead of memorizing codes,
operators use a screen drawing of the part
to select dimensions that need to be measured,
and measurement parameters are
entered quickly by filling out simple
menus. PC-DMIS software displays the
drawing based on an IGES file supplied by
the customer.Typically the IGES file is used
as-is. However, if the customer supplies a
complex, multi-layered drawing (e.g. in
CATIA ® ), this can be easily reduced to the
essentials needed for measurement using a
program called CAMAX ® .
Steely said that writing a conventional
CMM part program used to take
about 40 to 80 hours. “Now we have that
down to about 16 to 40 hours depending
on the complexity of the part.We’ve
essentially cut our initial part programming
time in half,” he said.
With PC-DMIS, separate programs are
not required for rough, in-process checks.
The operator can select any set of points
on the screen drawing, and PC-DMIS will
automatically measure them.The disparity
between finished part and rough part tolerances
are handled simply by entering
appropriate values in a pop-up menu.
Since there is no longer a programming
time penalty to do rough checks, they are
performed more frequently. Fast, rough
checks have helped L & S reduce in-spec
PC-DMIS for WINDOWS, retrofitted to this LK G 80C coordinate measuring machine, has helped L&S
Machine Company improve inspection throughput without the need for additional equipment.
Because inspection routines are much faster now, machine tools average 95 percent utilization.
variation on some parts, and this translates
to improved quality and productivity
in assembly.
L & S has three measurement systems,
one manufactured by Brown & Sharpe
and two by LK. Since PC-DMIS software
is common to all three, only one program
needs to be written per part, no
matter how many machines it will be
measured on.That also results in a reduction
in programming man-hours.
While conventional programming
is typically performed
as a teach-and-learn opera-
tion at the CMM, an offline
version of PC-DMIS
makes it possible to
perform all of the programming
on a personal
computer. L & S has
two off-line licenses for
PC-DMIS which assures that
measurement will no longer be an obstacle.
Part programming can now begin
before the first piece has been manufactured,
and CMMs are more frequently
“We’ve essentially
cut our initial part
programming time
in half.”
available for measuring parts, since they
are not required for part programming.
Optimizing CMM
Operator Productivity
L & S is managing substantial increases
in production with only a modest
increase in inspection personnel.This is
fortunate because experienced people are
hard to find.
“We try to hire the best CMM
operators we possibly can,” said
Steely, “but unfortunately,
Wichita is a Boeing, Lear Jet,
and Cessna town. Most of
the talent is locked into
positions with those other
companies. PC-DMIS allows
us to bring in inspectors
who have had limited CMM
experience and train them to be
proficient.” Using this philosophy, L & S
recently increased the number of CMM
operators on staff from four to six.
“If they are used to the WINDOWS
mfg. The Brown & Sharpe Publication of Precision Manufacturing
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