CJ Howard
We love a 3D printing success story, and this next case is certainly one that fits into that category.
In 2002, at the age of just 17 CJ Howard was diagnosed with osteosarcoma, an aggressive bone cancer that is commonly found in teenagers or young adults. After Chemo, CJ’s leg had to amputated below the knee; you’d think that’d be quite the blow to the keen runner. But CJ is different than most he simply saw the amputation as another physical challenge.
His life is a super active one; not only is he an incredible runner (6 months after picking up running again he ran 5K in 18 minutes!!!) but he’s a mountaineering enthusiast. Climbing presents a huge challenge for prosthesis as many of the techniques required are all about the foot; finessing cracks, balancing on small toe holds, or gripping on sloping cracks.
CJ Howard was not happy with his standard artificial foot at all when it came to climbing, specialist-climbing shoes tended not to fit and wore out quickly. Luckily, his climbing partner, Mandy Ott, was a former mechanical engineer at a major aerospace company in the US. She used a CAD package on her laptop to design what Howard described as an aggressive climbing prosthesis with a downturned toe that looked like a banana. Best of all, there was no need to use a shoe at all.
The foot was made from titanium alloy powder using an EOS direct metal laser sintering (DMLS) machine at Morris Technologies, an Ohio firm that specialises in additive manufacturing.
Ott said, “I never even thought about fabricating the foot using traditional subtractive machining techniques… because they would have resulted in seams in the foot or nuts and bolts sticking out, which would not have worked well for climbing."
Manufacturing started by uploading the digital CAD data of the prosthesis to Morris Technologies, where the model was printed in the EOS system using commercial grade Ti64 powder.
Fabricating the approximately 150 x 75 x 50 mm, smooth-edged foot took about 40 hours. The finished 2.25 kg prosthetic was a single-piece construction, of high strength and stiffness, hollow to minimise weight and with no seams or fasteners. It was stress relieved to cure the metal and ensure material strength.
Finally, to create the combined foot and shoe, it was coated with a rubber used for the soles of climbing shoes. The artificial leg, a solid titanium rod, connects to a socket on the prosthesis and to Howard’s stump.
He climbs as much as three times a week with his new prosthesis in northern Californian sites, such as the granite of Tahoe’s Lover’s Leap, the single-pitch trad routes of Phantom Spires, Luther Spires, the crevice and chimney systems of nearby Sugarloaf, and the dome and crack routes in Yosemite.
The plan is to design a triangular shaped foot for pure crack climbing and another with less downturn for more slabby conditions. Howard said, “It’s like changing tyres on a race car – you just switch your foot for different climbs.”
