The first industrial application of CT scanning for metrology in America involves aluminum casting. Josh Schradin, one of the 3D scanning specialists at Exact Metrology’s Cincinnati facility, recently completed a CT scanning project involving aluminum castings measuring approximately 12" x 6" x 6" and weighing 10 to 15 pounds.
The company’s new Metrology Grade GE v|tome|x 300 CT Scanner, with Nanofocus Tube (180 kV/15 W) and Microfocus Tube (300 kV/500 W), is equipped to “look inside” aluminum to a wall thickness or total amount of material of 6 to 7 inches or steel to a wall thickness or total amount of material of 1 inch.
For this particular job, which represents the first use of CT scanning for metrology in America, the client was interested in wall thickness inspection as well as porosity and void analysis. The blue paint visible in some of the images was applied by the customer to indicate stress areas where leaking or breaking was suspected. Schradin performed three stacked scans, each taking only about 30 minutes, to capture the entire casting. The result of the scans revealed the voids (legitimate holes) and highlighted the most serious problem areas in red-to-pink shadings.
In addition to offering the only method to get 3D views inside a part, another primary benefit of the Exact Metrology CT scanning is the true dimensional data provided in a non-destructive test manner, i.e., without cutting up or otherwise destroying the test object.
The workpiece (casting) was rotated 360 degrees in the x-ray beam’s path, with multiple readings from various angles being taken. Once the CT grayscale images were converted into voxel-based 3D point clouds, Schradin was able to generate a CAD-to-part comparison for the customer.
To see videos on this new scanner’s capabilities, search: “VG GE casting analysis with CT hi-res at Exact Metrology” on YouTube.