What is 3D Scanning?
What is 3D Scanning?
In the most general terms, 3D scanning, also referred to as 3D digitizing, is the utilization of a three dimensional data acquisition device to acquire a multitude of X,Y,Z coordinates on the surface of a physical object. Each discrete X,Y,Z coordinate is referred to as a point. The conglomeration of all these points is referred to as a “point cloud”. Typical format’s for point cloud data are either an ASCII text file containing the X,Y,Z values for each point or a polygonal mesh representation of the point cloud in what is known as an STL file format.
Why 3D scanning?
There is a wide range of 3D scanning technologies available to address a multitude of different applications ranging in size from an individual tooth to one of our national monuments. For this discussion we will confine our scanning parameters to product development / manufacturers.
There have been many studies that have shown that the company that delivers a product 1st to market captures the lion share of the revenue. With this goal in mind, product development / manufacturing companies are implementing 3D scanning solutions in an effort to reduce the time and costs associated with their Concept through Sustaining Engineering Product Life Cycle. There are many different points of entry in this product life cycle where an accurate As Built digital definition can add value.
Simplified serial depiction of an iterative generic Concept through Sustaining Engineering Process
A few tasks within this product development cycle that have benefited by the introduction of a 3D scanning solution are:
1st article inspection
Root Cause Analysis study
Performance correlations – FEA/CFD analysis
Key capabilities of the 3D scanning solution will be its ability to effectively capture an as thorough as required digital definition of the part / assembly with the required accuracy and data clarity to support the required deliverable. I highlight “as thorough as required” and “required accuracy and data clarity” because in some processes, not every downstream deliverable will require a complete scan or the same data accuracy.
Through our industry engagements we have seen many companies promised scanning capabilities, data accuracy, system flexibility and ease of downstream deliverables. For those of you who are users of 3D scanning solutions, you already know that the devil is in the details.
A 3D Scanner alone is not a solution and the devil is in the details
As an example, we have a range of clients scanning various geometries including hand crafted prototype models and production turbine blades to create a 1st time digital definition in CAD. Obviously the clay models are hand worked objects with imperfections that will be worked out in the CAD model creation process. This scan application may not require the same scanning accuracy as the turbine blade RE project. The blade RE project will benefit from a higher accuracy scanner and will invoke a different RE process. In the case of power generation components, we routinely scan 6 to 10 of the same blade, align all data sets to the same coordinate position and then generate a normalized final data set. The goal being this data set takes into account the manufacturing tolerances of all the scanned blades. This data set is then utilized for CAD modeling.
3D Turbine Blade Point Cloud with Cross Sections Using ATOS 3D Scanner
Turbine blade point cloud with cross sections, shaded scan image depicting .11 mm edge, inspection color plot, and actual blade in scanning frame
This example also brings to light how companies have unfortunately not optimized their scanning investment by considering the entire Concept through Sustaining Engineering Process. The hand crafted model scan was then utilized to generate an engineering model which was utilized to create a game controller tooling. 1st articles were then manufactured. These 1st articles require dimensional inspection. In many cases we see companies purchase a reverse engineering “accurate enough” scanner that cannot deliver to the downstream 1st article and QC required accuracies.
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