Frequently Asked Questions about ROMER's Laser Scanning probes. (And Laser Scanning Probe Technology in General)

What is a Laser Triangulation Probe?

Laser triangulation probes proejct a flat plane of eye-safe, laser tuned light on the surface to be inspected.  The reflection from the object is captured with a camera, and data is processed using a sophisticated set of alogrithms that characterize the data into three-dimensional point could data.  These probes are often generically referred to as a "laser probe" " scanning probe", "laser scanner" or "3D scanner".

What can you do with 3D Laser Scanning?

Laser scanning in an industrial metrology context can be used for several distinct purposes.  ROMER arms equipped with 3D laser scanners can generally perform all of these functions in a single system, depending on what software they are equipped with:

Inspection and Validation
Laser scanning produces a 3D point cloud for Cloud-to-Cad comparison, feature recognition for dimensional inspection, and GD&T analysis.  It can also be used for traditional (non-CAD) inspection using feature construction and dimensioning.
Examples:
Verifying a part meets CAD, for incoming inspection, in-process inspection or final validation.
Verify Tool & Die wear or rework
Contour measurement, comparing parts to corresponding CAD models, 2D cross-sections or 3D topgraphical mapping.
Inspection of the mating of two parts.

Reverse Engineering
Produces a 3D model which can be converted to CAD that describes a sample part. Reverse Engineering software is used to import the scanned point cloud, manipulate, mathematically smooth and combine the scanned data so a representative NURBS surface model can be created. 
Examples:
Create a 3D model for further CAD design or adaptation.
Create a “legacy” or “golden” part where no CAD or part drawing exists.
Create an “as-built” model of a tool so wear over time can be compared
Competitive part/product analysis
Archival or historical preservation of artifacts to create a 3D record or copy.

Rapid Prototyping
A sample part or physical model is scanned and converted to CAD representation of the part, which can then be reproduced with a 3D printer.

Copy Milling
Producing a duplicate of a sample part directly from the point cloud scan data.  CAM software is used to read the scan cloud data and produce machining instructions for machine tools.

How Fast is the Scanning?

This depends significantly on the probe and the probe's field of view.  On laser probes in general, you will see the points collected "on screen" in real time. Sometimes this is referred to as "painting the part".   Making scans at different angles to ensure all the relevant geometry is captured often results in a point cloud captured in the model of the SUV at right, where it looks like someone went crazy with the spray paint.   Also significant is the scanner's number of points per second capability and the scanning path size.  The animation below compares the difference between a V4 and V5 scanning speed path on a 1 meter square flat plate at a mid field of view.  The V5 with a 105mm line width at mid-field of view, captures the surface in just under 3 minutes, where the V4ix would take over 13 minutes for the same part.

Scanning speed can be very important if you are trying to cover lots of ground and don't have a lot of time to do it, or if you have an extremely large part, like a whole airplane.

Is more points better?

This depends in part on what you intend to use the data for.  Surfaces that are extremely complex with lots of curvature will benefit from higher density scanning.   Flatter surfaces, not as much.  Feature extraction of characteristics such as holes, slots, cylinders and other prismatic shapes and also edges will benefit from higher density data as well.  Consider the two images below, which are identical scans of a 15mm hole.   The scan on the left was created with a low-density scanning probe, the one on the right with a top-of-the-line V5 probe.  The extraction of and form measurement of the hole on the right will tend to be more accurate with the higher density data.  Higher denisty data will capture textures more effectively, if this is important to you.

Does Ambient Light Affect the Sensor?

Typical plant environments are acceptable to the operation of the ScanShark sensor. The sensor is not suitable for direct water or oil spray environments as it can adhere to the laser and camera lenses.  The temperature should be between 15 and 35 °C and the humidity between 0 and 90% non-condensing.  Environments where dirt, oil or other contaminents are present that can adhere to the sensor should be avoided, as this can influence measuring performance.  These sensors are capable of reliable operation 24/7 in plant environments for many years.

Filtered vs. Unfiltered Data...What's the difference, really?

Filtered data is sensor data that has been “filtered” or “processed” as the point cloud is being generated. This is typically performed by the 3rd party software packages as the sensor data is being read in to the software The raw sensor data is compromised because it's being filtered "while captured" and thereby data quality is an unknown entity.

Unfiltered data is sensor data in it’s raw state, including all the outlier data, regardless of its cause.  The original data can be evaluated independently. Using unfiltered data provides the true capability of the sensors' ability to accurately scan; to compare true data to nominal (print or CAD) data

ScanShark Advantage: Ability to capture raw, unfiltered scan data independent of any 3rd party software, Raw scan data can be evaluated or fed real-time to any 3rd party software.

When I scan a part, does a CAD model come out at the end?

This is perhaps the most widely misunderstood aspect of laser scanning.  The arm and scanner capture the geometry of the part in a 3D point cloud format. This is simply a file of the points in relation to one another, it is not a CAD file.  To get a CAD file, you need to first create some sort of polygon based model from the point clouds, and then work to characterize the surfaces and features as a CAD model, often in a CAD system.  These are offline processes which take place once the scan data collection is complete, and is actually the most time-consuming part of working with the 3D scan data.  The image on the left is point cloud, again, showing the various scanned areas as different colored patches, the model on the right is the same data converted into a polygon mesh model.

Can I use the Same Probe on an Arm and Bridge CMM?

The ScanShark V4ix is capable of being mounted on both a Stationary (Bridge) CMM such as a Brown & Sharpe Global , or Sheffield Discovery and a portable (Articulated Arm) CMM like the ROMER Infiinite 2.0.   The same head can be exchanged between one system and another, thus doubling your utility for your scanner purchase.  (Note: this is not a "plug and play" install on the CMM and requires some additional hardware and software.  Please contact us if you're interested in using this capability) The V5 does not have this capability, it can only be used on a portable arm CMM.