Measurement technology such as CMM surface scanning is
excellent for detecting the external geometry of production parts. But with
advanced manufacturing technologies like metal additive manufacturing, is it
enough to only measure the external dimensions of a part?
Not only can additive processes build internal structures such
as cooling channels or lattice support structures that are inaccessible to most
non-destructive testing methods, but the process of metal additive—whether
it’s a welding-based or powder-based system—affects the metallurgical
qualities of the part in ways that are not a problem with conventional,
subtractive techniques.
With billets, sheet or block material stock, you can count
on the fact that the metal is of consistent quality, and that in most cases the
machining process won’t change those qualities very much. Building metal up one
particle at a time is a completely different story. Inclusions, porosity and
other problems must be detected to ensure quality. That’s where CT inspection
comes in.
Based on the same technology as medical CT inspection, the
power level and scan time of industrial CT differs due to the wider range of
materials, shapes and sizes of scan subjects. In medicine, all people have
generally the same shape and size, and the parameters of the scan are set up
for the human body.
However, in industrial CT, the subject could be a large
automotive engine casting, or a complex aerospace manifold. The scanning power
must also overcome denser metals, from aluminum to materials typically used for
shielding against such radiation. A gold or gold-plated part could require
intense power to penetrate.
CT scanning is highly accurate and provides an unparalleled
level of data, but it can be very costly to implement. Jesse Garant Metrology
Center provides a service performing CT part inspection so that manufacturers
can avoid the investment of a CT machine.
For more information on industrial CT scanning and their
other services, check out this article.