What can you do with 3D Laser Scanning?

Laser scanning in an industrial metrology context can be used for several distinct purposes. ROMER seven axis SI Absolute Arms is equipped with PC-DMIS software and 3D laser scanners, accurately performs all of these functions in a single system. Its Absolute Encoders 'know' where the arm is at all times (eliminating homing procedures) and zero-G counterbalance ergonomics make it seem to float in the operator's hand. 

Fig 1::Point Cloud created with laser scanning

Laser scanner output creates a three-dimensional model of a surface, which due to its high density (often millions of points) is called a "point cloud" or "cloud of points". Figure 1 shows a large point cloud set representing an entire vehicle. The different colors represent different individual scanning passes on the part.

Target Inspection and Validation

The 3D point cloud created by the 7 axis Absolute Arm combined with PC-DMIS can be used for dimensional inspection or GD&T, and the results compared againt nominal CAD values. With Cloud-to-CAD comparison, large point clouds can be overlaid on the CAD model for fast visual inspection of deviations (sometimes called a "weathermap" or "color map", see figure 2). Laser scanning can also be used for traditional (non-CAD) inspection using feature construction and dimensioning.

'Weathermap' style inspection image

Example inspection and validation applications:

• Verifying a part meets CAD, for incoming inspection, in-process inspection or final validation.
• Verify Tool & Die dimensions to determine wear, evaluate repair or check modifications
• First article inspection
• Contour measurement, comparing parts to corresponding CAD models, 2D cross-sections or 3D topographical mapping.
• Production line or assembly process fine tuning
• Inspection of the mating of two parts.

Reverse Engineering

Reverse Engineering is the process of taking a physical part, measuring it to determine its characteristics and the processing the data to creating a CAD model. This is often used in cases where the product design process has significant manual operation, such automotive design. Despite the advances in CAD, many designs still start life as a physical model which then needs to be turned into electronic form.

Point clouds generated by laser scanning are processed in various ways to make them ready for conversion to CAD. Reverse Engineering software such as PC-DMIS Reshaper is used to create or import the scanned point cloud, manipulate, mathematically smooth and combine the scanned data so a representative surface model can be created.

Example reverse engineering applications:

• Create a 3D model for further CAD design or adaptation.
• Characterization of a mating surface so that another piece can be connected or joined to it.
• 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.

Copy/Scaling Milling and Rapid Prototyping

One-off replicas may not require creation of a full CAD model. Stereo-lithography models or CAM-based milling in many cases can be done directly from the point cloud scan data or the mesh model. Basic resizing and scaling of the model may be possible. CAM software is used to read the scan cloud data and produce machining instructions for CNC machine tools.

Example applications:

• Historical or cultural heritage preservation where artifacts are scanned to observe wear or deterioration
• Rapid prototyping of handmade models
• Rescaling of a physical scanned model
• Scanning of models for electronic purposes such as movies and videogames

Ask us about our Laser Scanning Solutions.