Typically, laser scanning is ten times faster than the most advanced touch probe speed because lasers are able to collect over 75,000 3D coordinates per second.
The Challenge
An individual
sportscar enthusiast was in the process of restoring a 1960s Porsche.
He wanted the engine to run at 7600 rpm, but the three original cast
rocker arms could not handle the stresses generated at that speed. He
needed new parts whose functional shapes were identical to the old ones,
but whose material physical properties were different (stronger).
The enthusiast had
tried to measure the parts with calipers, but the shapes were too
complex to make thorough accurate measurements. He has also tried
having a machinist reproduce and transfer the geometries of the three
rocker-style arms to aluminum roller-style rocker arms instead of cast
steel “tappet”-style rockers. After many attempts, none of the rockers
was close to spec and the third, more complex rocker proved to be
impossible to measure and recreate even after multiple tries with manual
measuring techniques.
The customer sent
the original and the prototype aluminum rockers along with the engine
head to GKS Inspection Services to be laser scanned.
The Solution
 At
GKS, the three original rockers were scanned as well as the three
aluminum prototypes on the Surveyor WS-2030 (20” X 30” X 20” work
volume), a dual-purpose Wenzel CMM with Laser Design 3D laser scanning
technology. With the ultra-precise SLP-250 laser line scanning probe,
the system obtained superior accuracies of 10µ per point with averaging.
 The
parts were mounted on the CMM’s programmable rotary stage to capture the
geometry from several different orientations. The WS-2030 native
software, Surveyor Scan Control, takes only a few minutes to set up and
runs automatically unattended. Even scanning six parts from several
perspectives, the
process was fast and the results were perfect.
 Typically,
laser scanning is ten times faster than the most advanced touch probe
speed because lasers are able to collect over 75,000 3D coordinates per
second. Laser scanning is ideal for improving part quality because the
whole surface of an object is scanned, not just landmark dimensions, so
free-form surfaces and irregular shapes are easily captured. The
rockers were scanned completely in a few minutes for each part,
outputting millions of coordinates defining the complete shape.
Geomagic Studio software was used for processing the data and models
were exported in SolidWorks.
The Results
 From
the sets of scans, GKS reverse engineering specialists were able to
reengineer the more robust shape of the prototypes into the originals’
and correct out of spec areas. “We actually placed a standardized
roller on the valve side of the rocker where the original was only a
solid radius,” explained the engineer. “We analyzed and matched the
complex geometry of the rockers and created a model. The customer ran
the model through virtual failure analysis software and, after a few
changes, he had modern-style rocker arm models which could withstand the
rpm’s of his newly rebuilt motor.”
The ultra-precise
touch probe measuring capability (to ±3µ) combined with the high-speed
laser scanning technology make this process fast, automated,
user-friendly, and ultimately less expensive. The manual measuring
method tried prior to laser scanning was labor intensive, time
consuming, not as precise, and ultimately failed to yield usable
measurements. The sportscar enthusiast customer spent much time and
money to determine that because of the complexity of the part, contact
manual measurement would not provide the results he required to rebuild
the engine to the desired rpm capacity, whereas the Wenzel – Laser
Design CMM did so easily.
Laser Design’s
integration of the SLP laser scanning probe technology with the high
mechanical accuracy of the Wenzel CMM brings the best of both worlds to
one measuring system. Existing Wenzel CMM users will be amazed at the
time and cost savings and the superb accuracies of using non-contact 3D
laser measurement with Wenzel’s laser scanning partner, Laser Design,
Inc.
About Laser Design, Inc.
Laser Design, Inc.
has been the leading supplier of ultra-precise, 3D laser scanning
systems and services for over 20 years. Used for capturing the 3D shape
of objects with complex geometries and free-form surfaces, Laser
Design’s Surveyor line of automated and portable scanning systems are
ideal for 3D scanning applications involving inspection and reverse
engineering of complex shaped plastic and metal parts. The company’s
patented laser line-probe technology dramatically reduces scanning time
by collecting data substantially faster and more accurately than
conventional metrology technologies. For more information contact us.
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