Engineers need to consider the challenges when using 3D scanning technology.
By Rosa Seda, Tech Writer
3D laser scanning is a non-contact, non-destructive method of capturing the shape of a physical object. Since the 1990’s, it has steadily become more available to the engineering community. 3D scanning has proliferated across many different fields such as medical, military, aerospace and manufacturing and is now an accepted part of architectural design domains.
The process of 3D scanning analyzes an object to collect data on the objects shape and appearance. The model that it constructs consist of a point cloud of surface samples of the subject. The points are then used to extrapolate a shape. The collected data can be used to create a 3D model via reverse engineering tools.
3D scanners are often useful used for either reverse engineering activities or quality measurements. With the reverse engineering, the object is scanned and software is used to translated it back into CAD. The created CAD file can be useful when exiting products or legacy parts do not have drawings and there is a need to modify or document the design. It can also be useful when integrating a components into an existing product such as casting, aircraft, building or when repairing worn or broken parts.
CAD files created by a 3D scanning process can also be used for quality measurements to remove any errors associated with part handling. Sure measurements have even been used to identify cracks in cultural monuments such as Mt Rushmore (1).
What are the drawbacks with 3D scanning technology? As in most measurement systems, the scanning process must be free of vibration – e.g, by mounting on a stable fixture.
A consistent lighting environment is also needed. The object being scanned should not be shiny, dark or have transparent areas. To overcome this issues, aerosol sprays are often used to temporarily coat the object. Another issue relates to measuring the internal features that the 3D scanner cannot scan within the line of sight of the laser. The scanner triangulate features, so high accuracy measurements may be challenging.