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Old Molds Made New for Tool
Company with Laser Scanning
 The
Company:
The company’s business is based on
producing special tooling, precision parts, and both injection and blow
molds, with a strong commitment to excellence. Involved in all phases of
a project, the engineers plan and design, as well as engineer and
produce exacting parts and molds. From the highly specialized assembly
of a fuselage, to wings for an aircraft, to precisely manufactured
component parts, this tool company has expertise for the job.
The Challenge:
The company makes molds that
deliver consistent, repeatable parts for their customers. All of its
mold manufacturing processes meet the standards of ISO 9001 and SPE. QS
9000/TE.
A manufacturer of
roofing materials had been using the same molds for years to make shake
shingles of PVC and wood. “The molds were old and beat-up,” said the
project designer. The manufacturer needed new molds, but didn’t have
the CAD data to have them created by the tool company.
The designer
contacted several laser scanning service bureaus and even had a test
shingle scanned by one of them, but the data was inadequate and the
finished models did not meet the company’s precise standards. Big
chunks of detailed data were missing from the shake patterns.
The search to find a
laser scanning service provider had eaten away at the manufacturing
schedule, so the designer was happy and relieved when he came across GKS
Inspection Services, a division of Laser Design, Inc., in Minneapolis,
MN. The test scan GKS created for him was much better than the
competition and up to the quality standards required by his company.
The Solution:
The designer sent
side-by-side pictures of the GKS scan and the insufficient scan by the
competition to Larry Carlberg, service bureau manager at GKS, to show
the difference in quality. He commented at this point, “Your stuff is
going to work great.” Then the designer gave the go-ahead to proceed
with scanning two injection-molded shake shingles with different types
of geometry. The variation in the shingle design gives the look of the
installed roof enough dissimilarity to avoid repetition. The surfaces of
the shingles are irregular to simulate wood grain with variable
thicknesses. Later, the designer also sent a v-shape ridge cap shingle
to GKS for scanning which added the complexity of sidewalls at right
angles to the scan setup.
With over 25 years in
the business, GKS metrologists have experience with all kinds of laser
scanning projects. Carlberg explained the approach he would take and how
to address the issues of the irregular surfaces and undercuts. “The key
to the best solution is to understand the customer’s problem, and apply
our technology and experience to achieve it,” said Carlberg. The company
makes products from the injection molding process. This type of
geometry is very difficult to replicate by traditional CAD methods.
Reverse engineering by laser scanning is an ideal application. “We at
GKS can replicate organic geometry very precisely because of the highly
accurate scan data itself and the software used to preserves this
accuracy. Our knowledge of the unique challenges presented lets us apply
techniques that distinguish us from our competitors.”
 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 surface is eliminated. This laser line is much like
spray painting the part with points, moving back and forth until the
complete part is captured. The system measures fine details and captures
complex freeform geometry so that the object can be exactly replicated.
Laser scanners measure articles quickly, picking up tens of thousands of
points per second, and generating huge numbers of data points without
the need for templates or fixtures.
Carlberg used the
high accuracy RPS-120 probe with a high scan density to make sure the
data was good. “Without good scan data, the output is substandard,” he
commented. Carlberg positioned the laser at an angle which allowed him
to capture sidewall geometry of the ridges representing the wood grain.
“Much like you would do for a good paint job, we rotate the part 180
degrees and ‘spray’ it with points again, getting blocked geometry that
was not captured previously.” On the v-shaped ridge cap, tooling balls
were used as reference geometry to align the first leg of the V with the
second, bringing them together in a single point cloud containing over 7
million points. The points are processed into a surface model and
exported into 3D NURBS models. In this case, Geomagic Studio was used
for processing. Correct software is a key step in processing quality
data into quality surfaces.
The Results:
 “The
quality of GKS’s work was good,” said the designer. “The scan data was
very detailed and it only took a couple of days.” He was also pleased
with the customer service and level of communication he received from
Larry Carlberg at GKS. Carlberg noted, “We produced our typical
outstanding results for this type of project, even though the geometry
was very complex.”
After receiving the
scan files from GKS, the tool company created a black graphite electrode
with the data as the first step to constructing a new injection mold
because graphite is easier to machine with the fine details required.
The charged electrode was then used to burn the mold out of steel, a
process that was repeated twice to increase its detail and accuracy.
Once the molds were complete, the original customer, the shingle
manufacturer, made parts from the new molds. “Everything Larry has
given us has worked well for us,” concluded the designer.
For more information
about how GKS Inspection Services can improve your manufactured product,
save you money and decrease your development time, call Larry Carlberg
at 952-252-3433 or send an email to
measure@gks.com.
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