components, the customer returned to ask
if NCAD would be interested in producing
the entire Blackhawk tail pylon mock-up.
The pylon frame substructure was to be a
weldment approximately 14 ft. tall, made
of 2- by 2-in. 6063 aluminum square tube
(see Figure 2). It was to be skinned in T-52
sheet. Machined parts were specified as 6061
aluminum. The catch was they wanted it
completed in 90 days. The simulator manufacturer knew that at that time NCAD
did not offer in-house welding, but was
also aware of Porter’s extensive welding
and fabrication experience.
Previous NCAD projects had resulted in
relationships with skilled, local welders, one
of whom Porter hired. Additionally, Porter
purchased a Lincoln variable-frequency
power supply. The right approach to fixturing, however, remained unclear.
“We are a Solid Works house and wanted
to leverage the performance of welding fixturing via intelligent use of CAD. The idea
was to optimize welding setups and add
value to the Blackhawk project now, while
positioning us to recoup our fixturing
investment on future jobs. But what kind of
fixturing could do that?” Porter said.
He discussed this reasoning with his
welding supply house, which put him on to
the Demmeler modular fixturing system
from Bluco Corp., Naperville, Ill.
FIGURE 1
A customer approached NCAD to manufacture a mock-up of the Blackhawk UH-60 tail pylon.
CAD-friendly Modular Fixturing
According to Porter, the Bluco system
offered two key benefits, making the decision to bring welding in-house easier.
“The system is modular and reusable,
eliminating the cost of nonrecurring fixturing. And it’s set up in SolidWorks—our
preferred modeling platform—enabling us
to define the fixture and the completed
weldment before the job even hits the floor.”
Fixturing is developed virtually by
bringing together 3-D models of the finished
weldment within 3-D models of the fixturing
(see Figure 3). Fixturing models are developed utilizing tools Bluco provides. The
precision of the fixture elements provides
datum points that facilitate determination of
design issues or shortcomings, in either the
weldment or fixturing models before real
metal is committed. This reduces mistakes,
material costs, and wasted time and motion.
