White Light Scanning - Automating a More Comprehensive Inspection Process 2005-01-0892

Advancements in three-dimensional non-contact optical structured white light scanning (digitizing) technologies have proven successful in achieving the required accuracy to accomplish the majority of inspection tasks. Reaching this milestone, many companies are now complimenting their current metrology implementations with non-contact digitizing solutions. These systems provide additional benefits ranging from increased throughput, more complete geometry analysis, and a flexibility to interrogate inspection results independent of part set-up chosen during the measurement process. Structured white light scanning is not the same technology as the “laser scanning” group of metrology products that industry has tried to implement with varying levels of success. The non-contact structured white light data acquisition process has proven extremely useful when the object to be inspected is complex by way of compound surfaces, abundant number of features, size, or number of locations to be measured. Automating the inspection task has proven useful when requirements dictate many of the same or similar “family of parts” require inspection. First article inspections can also be performed in an automated fashion.

Differing from traditional contact or tactile digitizing techniques that measure a discrete point upon contact or laser systems that measure either a point or a band of data when moved across the object surface, optical “whole field” measuring techniques acquire data in a manner analogous to snapping camera images of an object. The result is a digital representation of the object consisting of thousands, even millions if necessary, discrete X, Y, Z data points and is referred to as a point cloud. The number of points making up the point cloud is typically based on the size of the part, features to be measured and the required resolution (point density) to capture these features. With the object's point cloud representation and specifically developed inspection software architected to process the robust part definition, industry is obtaining more thorough part and assembly

inspections with enhanced trouble shooting and root cause analysis capabilities.

Inherent benefits of the non-contact white light solution over traditional contact digitizing systems such as CMM's are throughput, inspection thoroughness, flexibility, portability and an almost unlimited size capability i.e. full scale C130 aircraft. The process is also capable of delivering traditional CMM measurements with CMM style reports as well.

The intent of this white paper is to present the effectiveness and flexibility of non-contact structured white light digitizing in multiple industry segments via various digitizing scenarios and inspection results for objects ranging from small precision parts (machined parts or turbine blades), typical automotive components (machined and stamped components to full body in whites), and up to extra large objects (full scale vehicles and aircrafts).