Automotive Engineering - August 2022 - 15

COVER STORY
Sandy Munro (center) with Munro electrification director Tom
Prucha and Rivian teardown manager Susan Smith.
underneath. The assembly workers responsible for marrying
the body and chassis modules at Normal have a needlessly
tough job, one that could go much more smoothly
with design changes, Munro and Smith concluded.
" There are places on this vehicle where subsystems
A nearly stripped R1T cabin reveals electronic controller locations, NVH mastics
on the floorpan and the innovative HFH cross-car beam.
are tagged, then organized on display boards for further analysis.
Engineers on laptops at an adjacent table were busy calculating part
cost and labor hours using Munro proprietary software.
Smith and Munro compared their initial observations about the
Rivian with their assessment of the Tesla 3 early in its 2018 teardown.
" The Model 3 had fit-and-finish issues galore, and issues inside the
cabin. The Rivian has no fit-and-finish issues whatsoever, " Munro
said. " It's far superior to where Tesla was at the same stage of that
company's production, relatively speaking. Of course, Rivian's overall
[manufacturing] volumes currently are much lower. "
" What I'm seeing is a really well-made vehicle, " Smith commented.
" Fit/finish is first-class. Paint is beautiful. However, my impression is the
R1T is very difficult to build. The design and engineering do not lend
themselves to manufacturability. It looks to be a bear to assemble. "
Looking into the teardown vehicle's increasingly skeletal body
structure, the experts highlighted the various areas in which Rivian
has much to learn about DfM. They pointed to excessive sealant applications
and evidence of a lot of hand finishing and manipulation of
the sealants and adhesives. Smith noted places that could enable
water intrusion. NVH countermeasures, particularly bake-on mastics,
appear to be more extensive than those used in other EVs. " The designers
clearly wanted to ensure a quiet cabin, so may have gone a
bit overboard to hit their interior dB targets, " Smith said.
A troubled marriage
While the R1T displays commendably tight body-panel gaps and tolerance
consistency in all areas visible to the customer, it's a different story
AUTOMOTIVE ENGINEERING
are being married, such as in the body decking operation
and in introducing the IP into the front structure,
where the operators must literally squeeze in between
the sections to connect up the harness wires during the
marrying process, " Smith explained. " It looks possible
to accomplish at a slow assembly-line rate. " However,
she cautioned that Rivian's ability to ramp up to its projected
line speed at Normal (and at the recently announced
second plant in Georgia) will be hampered by
gaps that are excessively close in critical areas.
" They've got to get their tolerances to where the assembly
workers will have freedom to assemble this vehicle
fast and without error, " she noted. " On this current
design, everything is too close. In the decking process
they're dealing with extremely small clearances. This
unecessarily complicates the assembly process. "
Added Munro: " Body marriage on the R1T appears to
be really, really tough, " he said. " Besides rethinking
some of the tolerances, I'd probably put electrical connectors
in different places versus where they are now.
As it stands, this is not a vehicle design that allows operators
to get their jobs done in a hurry. " He suggested
that with minimal modifications, his team could " take a
significant amount of labor hours out of the vehicle. "
Other observations from the early phase of Munro's
R1T teardown: The design of the " gear tunnel " closures
unfortunately has a protruding corner - like a blunt
spear - that can be a leg-bruiser when the doors are
deployed. The truck has an overabundance of bracketry,
the functions of which could be consolidated to
save complexity, labor time, cost and weight, Munro
reckons. Smith noted that in some areas of the Rivian's
body structure, the weldments are overly massive.
August 2022 15
BOTH IMAGES: LINDSAY BROOKE
Automotive Engineering - August 2022

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