What is Dimensional Measurement? Quality Control Approaches with 3D Scanning
What is Dimensional Measurement? Quality Control Approaches with 3D Scanning
Understanding Dimensional Measurement
Dimensional measurement is the process of evaluating whether a part’s geometry matches the intended design within defined tolerances. Traditional inspection tools such as calipers, micrometers, and CMMs have increasingly been supplemented—or replaced—by non-contact 3D scanning systems.
Shifting to 3D Scan-Based Quality Control
3D scanning captures millions of points from a part’s surface to generate a high-resolution digital model. This model is then compared to the original CAD to perform deviation analysis, dimensional verification, and tolerance evaluation. It’s especially effective for parts with complex geometries.
How Deviation Analysis is Performed
Deviation analysis involves aligning the scanned mesh to the CAD model. Software then calculates the deviation at each point between the actual and nominal surfaces and presents it in a color-coded map. This visualization helps instantly spot out-of-spec areas.
Blue indicates material shortage (undersize), red shows excess (oversize), and green denotes areas within tolerance. This makes it easier for engineers to evaluate critical features in injection molding, casting, and sheet metal forming processes.
Moreover, reference geometries like planes, axes, and symmetry lines can be defined to allow precise measurement of individual features—such as hole positions, height discrepancies, or positional shifts from the original design.
Integration into Quality Workflows
3D scan-based inspection enables rapid checks within production lines. It's used for incoming inspection, first article inspection (FAI), process validation, and ongoing production control. Compared to traditional methods, it delivers much faster and broader feedback.
Software Tools and Reporting Methods
Tools like PolyWorks, GOM Inspect, and Geomagic Control X produce color maps, 2D section analyses, tabular data, and automatically generated reports. These outputs can be customized to meet ISO 9001 and other documentation standards in manufacturing.
