31 October 2018

Customer Story: A new life with 3D-prosthesis

October 31, 2018

30 years ago, Chris Casteel suffered a heavy blow of fate. Today, with support from BASF, he stands up for those who experienced the same.


It was a warm and sunny day on August 26, 1988. Then 24-year-old Chris Casteel decided to hop on his motorcycle to drive to work. At this point, he did not know that his life was about to change forever.

As he was driving on a winding road on River Drive in Detroit, US, he saw two students inside a car, who looked distracted while driving towards him.

“I realized they were over the line and I remember locking up the brakes,” Casteel remembered. The car struck him nearly head-on hurling him into one of the curbs. The young motorcyclist blacked out for a few days after his left leg had been amputated due to serious injuries.

Birgit Hellmann
Global Sustainability Communications

Today, 30 years after the accident, Casteel is a through-the-knee amputee who wears a prosthesis and he is paying it forward by helping others to walk again. As a board-certified orthotist and board-eligible prosthetist, Casteel helps patients from all walks of life to be mobile again post-limb loss.

The amount of time it takes to make a prosthetic takes days. “For us to manually hand-cast someone, create a plaster model, modify it, pull a test socket, it takes a few man hours,” he said.


With the new 3D-printed prosthetic socket, this process will be abbreviated in the future. As the owner of Anew Life Prosthetics and Orthotics, Casteel recently teamed up with BASF and Essentium Inc., a 3D-printing and material development company, to convince his patients of this revolutionary prosthetic. In the first instance, BASF delivers the polyamide Ultramid B, then Essentium strengthens it with short carbon fibers. The intermediate is processed into customized prosthetic sockets by 3D printing.

What makes this socket stand out among traditional carbon sockets is that it is lightweight but tough and more flexible. “It’s one thing to hear about it, it’s another thing to actually feel and touch it,” Casteel said, while holding the socket in his hand. Whereas he himself has not gotten around to testing the socket just yet, he has already fitted about 50 of his patients with it. The process entails Casteel scanning the patient and then Essentium printing the prosthetic for each one. The patients try on the test sockets first at Casteel’s office, so that their bodies adjust to the fit. Later, they are fitted for a definitive socket, made with BASF’s Ultramid polyamide. “This material keeps the prosthetic strong anywhere between three to five years”, according to Josh Lawson, Head of Marketing at Essentium. Traditionally manufactured prosthetic sockets typically last less than three years.

Chris Casteel

Additive manufacturing, another name for 3D printing, also eliminates human errors, ensuring the socket fits correctly the first time. This means that the amount of time it takes to fit someone for a prosthetic limb is reduced by 50%. Also, while old sockets are non-adjustable, the new material can be heated up post-3D printing and adjusted accordingly to fit the patient comfortably. So, if the patient grows, loses or gains weight, the prosthetic can be changed and fitted to his or her present size. “3D printing is really an innovation for the future. It’s going to expand exponentially and we’re trying to be on the leading edge of that,” said Charles Tazzia (N-PMN/ND), Senior Technology and Business Scout, Performance Materials (PM), who was responsible for bringing the three parties – BASF, Essentium and Chris Casteel – together.

Tazzia is proud of the result of the collaboration with Casteel: “It’s rare that we get the opportunity to see our materials actually change people’s lives so positively. And that’s why this work with Chris has been so rewarding.”

Last Update 15 June 2020