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The Challenge:
A client, a medical device manufacturer, to
modify an existing model of a plastic resin heart to demonstrate a new
cardiac device product. The company needed modifications on the unit
to fit the new device and then manipulate it in the CAD software to
create the demonstration piece. The design engineer noted that the
heart model was a “tricky, amorphic shape which is difficult to scan
with a contact process.” It also had an irregular internal, partially
open cavity, which needed to be very accurate since that is where the
new device would be inserted.
The Solution:
The design company heard about GKS through
an associate who had used its services in the past. “He told me GKS gave
him the best in results and he was right.” After doing his own research
on the Internet about how to obtain the data he needed, the designer
says that GKS stood out as an experienced and well regarded company.
Once the designer contacted Larry Carlberg
at GKS, a division of Laser Design, Inc., in Minneapolis, MN, he was
impressed with Carlberg’s knowledge and expertise. Right away, Carlberg
strategized about how to best create the necessary scan of the resin
heart. GKS maintains several Laser Design scanners, so the appropriate
size and resolution was readily available in house. Ultimately, Carlberg
decided to use the RPS 150 Laser Probe since it has an accuracy of less
than .001 inches and made the modeling task after the scan easier.
With over 25 years in the business, GKS
metrologists have experience with all kinds of unusual custom projects.
Carlberg explained the approach he would take and how to address the
issues of the irregular surfaces as well as the internal cavity. He was
able to provide examples of similar projects GKS had successfully
completed in the past and show the outstanding resulting image files.
Carlberg instilled confidence in the capabilities of the process. By
the time the design engineer actually sent the part to GKS, he had a
high degree of confidence in Carlberg’s abilities.
However, a good deal of the design company’s
project schedule with its client was spent in finding the best source
for the scanning service, so when Carlberg received the heart model, GKS
was in the hot seat to produce results quickly. “They got the scan done
in just days and we were able to make our schedule with the client,”
remarked the designer. From first contact to finished project was just
two weeks.
Because the laser scanning system projects a
line of laser light onto surfaces while cameras continuously triangulate
the changing distance and profile of the laser line as it sweeps along,
the problems of missing data on an irregularly shaped or hollowed out
surface is eliminated. The system measures fine details and captures
complex freeform geometry so that the object can be exactly replicated.
Laser scanners quickly measure articles, picking up tens of thousands of
points per second, and generating huge numbers of data points without
the need for templates or fixtures. The most difficult challenge in
scanning the heart model, according to Carlberg, was the many small
venous features. “We received the model with unnecessary items
removed, but the intricate small features were still present on the
model.”
The Results:
The Geomagic software provided with the
Laser Design scanner greatly simplified the process of moving from the
point cloud to the computer aided design (CAD) model, making it possible
to generate a CAD model of the scanned part that faithfully duplicates
the original part in minimal time.
“The skills necessary to model the
many small features on the heart model and maintain a reasonable budget
is a combination of the Geomagic Studio package, and the experience
level of our modelers in using the advanced tools in Studio,” said
Carlberg.
He continued, “Even though the design
company didn’t feel we needed to replicate to the same level of feature
detail, the modeling process demands we deal with the tiny surface
abnormalities. Otherwise the model would generate undesirable ripples
on the surfaces. The surface model we generated in Studio had
outstanding replication of the plastic model that could not have been
achieved by conventional modeling packages.”
According to the design engineer, “The scan
file of the heart model came back looking great. It was fully surfaced.
We were able to import it cleanly into our CAD program, SolidWorks,
without errors. The file came out really well, better than I had
expected.”
Once imported into CAD, the design company
was able to add the features the client wanted. Then the data was
exported to create a rapid prototype SLA model on which they could
demonstrate their new cardiac device product to their customers.
The demonstrations the company’s client gave
for their medical professional customers went very well. The improved
RP heart model functioned perfectly with the new device, creating more
business for the design client, as well as the design company. “GKS is
the best in the business.”
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