Automotive Engineering - December 2022 - 29

COMPUTED TOMOGRAPHY FEATURE
" CT inspection at both raw and
finished-product development
stages lends huge insights into
CAD design, mold design and
the casting process itself. "
straightforward and can be fully automated. The data
generated encompasses the product in its entirety.
Improving yields, reducing cost
What is an optimal way to use CT scanning software
for improving the total efficiency of casting a variety
of automotive metal components? Several leading
OEMs and suppliers combine inline and at-line inspection
during production. Raw castings and finished,
machined castings are candidates for either, mostly in
random or predetermined lots.
Examining raw castings prevents process faults and
mold design errors from carrying over into production.
Examination of post-cast, cleaned, machined and
treated heads allows teams to understand metallurgical
changes derived from the finishing steps. It's important
to realize that CT inspection at both raw and
finished product development stages lends huge insights
into CAD design, mold design and the casting
process itself, as well as the final variations that can
occur in the " as-manufactured " product.
Conducting a software analysis of the scan in the
beginning and later periods essentially permits continuous
process control. Companies can determine,
based on the complexity of the analysis, whether parts
should be taken out of the running production or inspected
as they are made.
Are the inspection costs worth the savings? Again,
post-processing a sub-spec raw cast part that gets
rejected downstream is as costly or more so than creating
the initial casting. Consider, too, that poor-quality
parts can make their way to the consumer, causing
recalls and damage to the company's brand. There are
countless examples of warped heads and poorly
sealed gaskets that led to warranty claims and recalls.
From 6% to 2% scrap rate
One large automotive OEM using CT analysis software
during cylinder-head production discovered immediate
gains and rapid return-on-investment. Using select,
at-line inspection methods for aluminum DOHC heads,
the OEM went from a disappointing 6% scrap rate (at
the raw casting stage) to just a 2% scrap-and-reprocessing
rate. For gravity casting, this is an excellent
AUTOMOTIVE ENGINEERING
Wall thickness analysis is especially critical for cast parts. Mold and part
design, along with material and process variations, can lead a component to
fall short of its specification. CT software analysis provides deep insights into
all stages of development, helping ensure final quality and higher yields.
Layout of a
typical inline
inspection station
featuring Computed
Tomography.
production yield. Moreover, the resulting statistical information
taught a great deal about the process drift and interdependency of
each juncture of head design and manufacturing.
Since its implementation of CT software analysis, this manufacturer has
better-utilized machining and post-processing resources. Bottlenecks
have been removed. The company has saved energy, labor and all costs
associated with upstream design and downstream manufacturing. CT
analysis contributes to total cost reduction and quality improvement.
Are the CT equipment and software acquisition costs worth it?
Automated inspection is the way to free valuable employees and
their knowledge to solve future growth and innovation challenges.
Capture productivity and quality - and let automation handle the
repetitive inspection tasks. Every group in product development can
benefit from the information gained.
Johannes Mann is director, global industry processes,
at Hexagon's Manufacturing Intelligence division.
December 2022 29
BOTH IMAGES: VOLUME GRAPHICS
Automotive Engineering - December 2022

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