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Implementation
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View
Manufacturing Plan
(document 2 of 3)
Click the link above to view a piece
of technical writing simulating an informative memo
describing my proposed manufacturing plan for the
Eagle Claw. It is directed toward a team of managers
and engineers at Ossur Prosthetics
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Machining the pylon:
I needed a 30mm OD tube
to slide into the Ossur tube clamps, donated by Hanger Prosthetics,
that would connect to the top and bottom of the leg. I cut
a 1-3/16" OD tube to the correct length with a band saw,
faced and chamfered the ends, and turned the part down to
30mm OD using the tailstock and steady-rest to prevent it
from vibrating.
Machining the foot:
I first cut the rough shape
of the foot with a band saw. Then, I aligned and strap-clamped
the part to a rotary table mounted on a Bridgeport mill and
proceeded to cut the outline of the foot with a 3/4"
end mill. I then drilled the four-holes pattern on the center
of the foot. Finally, I rounded the toes and heel with an
1/8" radius corner-rounding end mill. |
Final
machined foot (before bending)
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Detail
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Bending the foot:
Bending 1/4" thick aluminum
precisely and repeatably is not an easy task. It requires
a lot of force and a fixturing method that allows controlled
bending. I constructed two sets of fixturing blocks - one
set for the front toe and one set for the side toes. Each
set consists of a concave and a convex block, which I cut
using the band saw. For each toe, I positioned the flat foot
in a vise, between the fixture blocks, and locked it in place
with clamps, a spacer, and a retaining block. I then tightened
the vise as hard as I could, which forced the foot into the
desired shape. |
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Aligned
and ready for bending
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Bent into
the desired shape
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Detail
of setup
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Machinist
in action
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Finishing:
I removed imperfections from
the foot and leg with sandpaper and sent the finished parts
to PK Selective, a metal plating company in Santa Clara, which
hard anodized these parts to protect them from scratching. |
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The
foot has been successfully bent,
and has suffered minimal damage
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Rubber tips:
I covered the toes of the
Eagle Claw in rock-climbing shoe rubber to enhance their ability
to grip rock ledges. I drew templates of the toes with SolidWorks
and used an exacto knife to cut the toes. I glued the rubber
tips to the foot with quick-set expoxy.
SolidWorks
template for rubber tips
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