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 Schneider Electric, a huge multinational
corporation, specializes in world-class power and control products,
through its excellent brands, Merlin Gerin, Square D, and Telemecanique,
that fulfill customers’ requirements in the residential, building,
industry, energy, and infrastructure markets. When Rus Emerick,
Specialist in Process Improvement at Schneider Electric first used Laser
Design’s Surveyor DS-2020 laser scanning system, he expected to acquire
clean, accurate scan data, and his expectations were more than met.
What he didn’t expect was being able to use the same scan data in many
ways, from design and first article inspection to functional forensics
and even training, saving his company both time and money in the
process.
Using the Laser Design line-range 3D laser
scanner Emerick was able to take a part, scan it into a CAD file, edit
the data, and create a better part. However, he didn’t realize until he
was deep into the process just how many other ways he would be able to
use the data sets he collected. “Depending on what the user needs, one
scan can be used in many ways. All the 3D data is available after the
initial scanning process without making additional scans. Think ‘One to
Many’ as the key concept.”
 The Laser Design DS-Series scanning systems
project a line of laser light onto surfaces while cameras
continuously triangulate the changing distance and profile of the laser
line as it sweeps along. Problems of missing data on an irregularly
shaped or hollowed out surface are 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.
With the versatility of the Laser Design
3D laser scanning system and portability of laser scanning data,
companies like Schneider Electric can design anywhere, build anywhere,
and qualify anywhere.
1. Design and Engineering
The first and most
widespread application of scan data is in Design and Engineering for new
product development, legacy product recreation, and process analysis.
New Product
Development: Part shapes are designed and then modeled in a pliable
material such as clay or foam. The prototype model is scanned to create
actual CAD data. From there the design engineer imports the data into
Pro-E for prototype validation, to run analyses on the design, and to
tweak the design without having to use more physical models.
Legacy Product
Verification and Recreation: Scanning is also used in an
“art-to-part” process of legacy part modeling, using the original
drawing of the part added to the point cloud of new scan data from
scanning the existing part. Using the actual part as a reference along
with the scan data analysis, a new parametric Pro-E model is created.
Process Analysis:
With the abundance of 3D data from the laser scanner the engineer can
develop and validate processes such as twist and warp, wall thickness,
and form analysis with Geometric Dimensioning and Tolerancing (GD&T).
GD&T defines the nominal or as-intended geometry of parts and
assemblies, so that the allowable variation in form and size of
features, and orientation of features can be determined.
2. First Article Inspection Report
(FAIR)
A nother typical application for using
the scan data is in the First Article Inspection Report (FAIR).
First Article
Inspection Reporting (FAIR) is a gradual process that detects critical,
major, and minor flaws in a part as it nears the end of the development
cycle. Even before a FAIR is performed on a part nearing production,
the usefulness and correctness of the part need to be determined. A very
quick “pre-inspection” using Geomagic Qualify Review validates the form
analysis of parts before detailed measurements are taken on the first
article. This assures that the tooling is creating the desired shape
and features and that they are all in the right place, a step that can
prevent wasting time and money on a worthless part.
Once the part is
pre-inspected and the basic form is validated, the detailed FAIR
commences. Conventional first article drawings contain hundreds of
dimensions. In order to check them all for accuracy a touch-probe would
have to measure each and every dimension on the physical part and
compare it to the drawing, a process that would take days on a simple
part and much longer, weeks or months, on a part with complicated or
irregular geometry.
For example, imagine
a conventional first article drawing with 711 dimensions. If the first
article has only two dimensions out of tolerance, tremendous time and
man-power resources could be wasted in measuring the whole part with
conventional touch- or single-point scanning methods trying to determine
where those two problem areas are located. Using the original scan data
to create a FAIR shows how every physical dimension stacks up against
the CAD model.
The Digital Shape Sampling Process (DSSP)
with line-laser scan data from a part of any type, shape, or size, which
is usually collected in a matter of minutes, generates a color-coded
report in Qualify Review showing exactly where the part is out of
tolerance and by how much. Color-coded FAIRs make it possible to
incrementally modify a part and preserve an archive of historical 3D
images of each revision allowing for evolutionary comparisons.
The FAIR process can be automated with
pre-set critical dimensions that generate a Pass/Fail result, so that
faulty parts are rejected at the earliest possible step. Once the part
passes inspection, it proceeds to the next step in the manufacturing
process. With laser scanning, engineers are assured that the whole part
is within acceptable tolerances instead of a much smaller percentage of
the part that is possible with touch-probe technologies or slower and
less accurate lasers. The report images can display, for example, only
the critical dimensions or the dimensions to be evaluated for Capability
Studies which are the next application we will examine.
3. Capability Studies
Diving into more detail than the FAIRs
are Capability Studies, which examine complicated geometric aspects of a
part such as multiple cavities.
When evaluating a part that will be used
in production, several incremental steps are taken by different
departments in the process. Capability Studies are usually automated
where parameters of tolerance intervals are defined and then applied to
all the samples examined. A typical part will use line-laser scan files
to conduct checks in the following sequence:
A. Form Analysis: The owner or
originator of the part, usually the Engineering Department, will do a
simple comparative scan of a pre-production part to assure that the part
meets global tolerance requirements and has no missing features or
errors in the overall part.
B. Optimization: During the same
timeframe, the Production Department, whose job it is to make the
production process predictable and repeatable, will review comparative
scans and share the findings with the entity actually doing the
manufacture of the part. Many times the tooling is dimensionally
correct but due to various process parameters, the final geometry of the
part has been changed. This is valuable information for optimizing the
manufacturing process.
C. Tool Wear: The Production
Department will frequently scan the actual tooling rather than
the part to establish baseline dimensions of a completed tool and do
subsequent scans to observe any tool wear which may effect the parts
being produced.
D. Trend Analysis: Once part
production has been approved after the above steps, a random sampling of
production grade parts is scanned. This starts the FAIR process.
Individual company’s Qualification Guidelines determine the number of
parts it qualifies; it may be 1, 5 or even 30 parts. Each part is laser
scanned and the same analysis is done on each sample using the
automation capability in GeoMagic Qualify. This assures that the same
measurement was made on each sample in the same place with the same
datum alignment with the reference part (CAD model).
The statistical result of the dimensional
study done by the animation, known as Trend Analysis, is communicated
with the term Cp/Cpk (Process Capability/Process Capability Index). The
Process Capability (Cp) is a simple indicator of process capability,
whereas the Process Capability Index (Cpk) is an adjustment of the
Process Capability for the effect of non-centered distribution. In
other words, the capability refers to the correctness of the process as
well as of the geometry. The percentage portrays how the part conforms
to the dimensions and the ability of the process to deliver a correct
part.
E. Testing: In certain instances,
the scan may be turned into a polygon model and the resulting model used
in computer simulations such as Mold Flow, CFD, or stress analysis
programs.
4. Tool Validation
Scan data can be used for Tool
Validation processes such as Tool/Part
Evolution Analysis and Tool Analysis.
In any manufacturing process tooling is
needed to create parts and/or certain features of parts.
Injection molding tools are often validated with laser scanning, as are
punch dies and compression tools. Non-contact laser scanning is the
ideal method to check the accuracy of the whole mold or die. Undercuts
and negative geometry do not pose problems in gathering complete data
sets.
In the Capability Study described above, a
tool may be scanned for wear. However, in the Tool Validation
application, the focus is on making sure each tool involved is
dimensionally accurate and stays that way. In a Tool Analysis, the scan
can be used to predict tool wear; in a tool/part evolution analysis, the
scan aids in repairing, maintaining, or changing out tools to keep the
parts dimensionally correct.
5. Reverse Engineering
Reverse
Engineering is a versatile, many-pronged use of scan data.
Occasionally a part exists for which a 2D
drawing is available but no 3D CAD model. In this case, the actual
reference part is laser scanned and the 3D data obtained is compared to
the CAD model made from the drawing. The extracted data is used to
construct the features in Pro-Engineer. In effect, an inspection of the
physical part is conducted as defined by the drawing, replacing missing
documentation.
In addition, scan data from physical parts
can be used to compare different versions of the parts or the same part
made from different materials to determine what deviations, if any,
occur when non-geometric elements are modified.
The first scan of a production part can
also be used as the "gold standard" against which all future parts are
evaluated. This practice verifies that dimensional drift events do not
impact the integrity of the part’s geometry.
6. Last Article Inspection Report
(LAIR)
Another application for using the scan
data is in Last Article Inspection Reports (LAIR).
In addition to scanning first articles to
make sure they are in spec through the manufacturing process, laser
scanning can also be performed on last articles. With this LAIR scan,
engineers can compare the old part to the new part, making sure that
every item, first to last is within the required specifications and
meets quality standards. When manufacturing processes change, speedy
re-qualification of the accuracy is required so that the system can
return to production as soon as possible. Changes could include a tool
changeover, a tool move, a supplier change, a material change, or the
speed of the manufacturing process. The software creates reports to
identify and analyze only what changed in the part. The drawing can
display only critical dimensions or all dimensions to be evaluated for
other studies. The LAIR can determine a go/no-go status and make
part-to-part comparisons.
7. Functional Forensics
Laser scan data can also be used in
Functional Forensics. Industrial components require regular
nondestructive in-service testing to detect damage that is hard to
uncover by normal inspection procedures, for example cracks or corrosion
in industrial pipes or defects in aircraft shells. And sometimes parts
fail, both under test conditions and in the real world, and engineers
must determine the reason for the failure.
Nondestructive
Post-Functional Testing Analysis: Laser scanning allows engineers to
perform post-functional testing analyses maintaining the exact condition
of the part when it failed to determine the cause. Non-contact laser
scanning takes place in situ, with nothing disturbed. Measurements are
extremely accurate, so that even minute variations are documented. The
scan data is detailed as well, providing a complete picture of the
entire scene. In addition to laser scanning, computed tomography and 3D
x-rays are used to create another type of picture, for example, of a
sealed case, when data might be lost or corrupted by more invasive
techniques. The case remains sealed and none of the “evidence” is moved
or possibly corrupted.
Full Assembly
Geometry Verification: Functional testing can also be used to verify
full-assembly geometry of parts. Sometimes assembled parts will
perform correctly even though they may be somewhat out of the ideal
tolerance. 3D laser scanning determines
whether tolerances can be loosened and made easier to achieve, and still
be acceptable to the functionality of the assembly.
8. Customized Training
Users of different levels who require
varying degrees of expertise with the scanning technology and software
allow businesses to create a multilevel training program.
Again, one data set serves many purposes,
so scan hardware and software training is tailored to each user group’s
needs. The tiers of training include the super user group, mainly
engineers, who performs the laser scans, and teaches and uses the entire
suite of Geomagic software; the middle-level user group who creates scan
data but does not manipulate it; and the business user who is basically
everyone who will see a scan analysis. Qualify Review training suffices
for the last group since they do not create data, but only use
information extracted into a report to illustrate various scan cases.
Benefits of One –
To – Many Uses of 3D Laser Scan Data
When 3D laser
scanning can take on so many roles its value is enormous to its user.
Schneider Electric’s Emerick brought the value of the Laser Design
scanning system to the processes he was responsible for and reaped the
rewards in shorter lead times, better accuracies, and simplicity of
operation. He sums up the benefits of 3D laser scanning: “The key to
the laser scanning story is understanding that I can make one scan, and
depending on what the end users needs, all the pertinent dimensional
information is available to them, without having to make any additional
scans. I personally think it is a great story.”
More Information
about Laser Scanning
Laser Design, Inc.,
has been the leading supplier of ultra-precise, 3D laser scanning
systems and services for more than 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. Laser Design integrates Geomagic
software with its laser scanners to provide complete solutions for
reverse engineering and inspection applications.
Headquartered in
Minneapolis, the company also has Regional Technical Services and
Support Centers in Seattle and Detroit, and distributors throughout
Europe and Asia. Laser Design also operates GKS Inspection Services (www.GKS.com)
, an in-house service bureau division offering complete 3D scanning,
reverse engineering, and dimensional inspection services.
For further
information, contact C. Martin Schuster, by phone (952-252-3402), fax
(952-884-9653), via email to
laser@laserdesign.com or visit Laser Design’s web site at
http://www.laserdesign.com.
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