Point Designs reduces prosthesis design time from 3 hours to 30 minutes with Freeform Dynabots

A well-fitting and functional prosthesis is crucial for a person with limb difference – but manufacturing one is tricky. A range of materials, skillsets and fabricators are required to make one device through a process that is time-consuming, meticulous and laborious. 

Recently, a new picture has started to emerge. 3D scanning and 3D design software are gradually enabling simpler and faster production methods that rely less on physical models. At the forefront of this approach is Point Designs, a US-based manufacturer of rugged prosthetic fingers. The devices are 3D-printed from titanium and feature an innovative ratcheting mechanism, which is coupled with custom silicone solutions and 3D printed nylon sockets.

The ratcheting mechanism already represented a significant advancement as it restored finger flexion and opposition. But Point Designs wanted to go further. They planned to bring the production of the custom socket in house so that clinicians wouldn’t have to coordinate work with multiple suppliers to get a prosthesis for one patient.

 

Challenges of traditional fabrication methods in orthotics & prosthetics 

Leading this effort was Chris Baschuk, MPO, CPO, FAAOP(D), a Certified Prosthetist Orthotist and Point Designs’ Director of Clinical Services since 2022. He came to the company with a deep understanding of the advantages additive manufacturing had to offer the orthotics and prosthetics (O&P) profession. 

“Manufacturing a prosthesis the traditional way involves a physical plaster positive model on which you do a composite lamination. You create a lay-up of fabrics like carbon fibre, fiber glass, and others over the positive model. Then you use a vacuum bag over the top of that to inject resin, and you do a wet lamination,” Baschuk says. 

 

For a partial hand prosthesis, the prosthetist then has to build the part of the hand that is missing using foam and other materials. Next, they glue the mounting brackets for the fingers in place in the correct alignment and carry out another lamination over the top. 

Finally, they remove the plaster from the positive model. Because hands with injuries have many complex geometries and curvatures, it’s impossible to pull the prosthesis off the model. Instead, the prosthetist has to break the plaster model with chisels and hammers and cut the material, exposing themselves to carbon fibre and plaster dust.

“It’s a very tedious and laborious process that can take many hours. If something is wrong – for example, if the alignment of the finger brackets is off – all the work you’ve done to that point goes in the garbage. There’s no way to remedy that,” Baschuk explains.

No wonder many prosthetists don’t fabricate arm or finger prostheses themselves. Their  facilities and tooling are set up to fabricate leg prostheses, which are considerably bigger than arms or hands. Working on a smaller scale with the same tools, such as a hand prosthesis, usually gives disappointing results. 

 

Additive manufacturing advantage

Scale is not an issue with 3D printing and Freeform. “Additive manufacturing enables you to design a prosthesis to a submillimetre accuracy. At Point Designs, as manufacturers who make hundreds of prostheses yearly, we can make sure that all the devices that we’ve produced share similar characteristics and functionality. That’s all possible because we use Freeform,” Baschuk says.

An essential to this process are Dynabots, a tool for automating design tasks. “We just need to identify the general shape and boundaries of the device and, using the Dynabots and the workflows, we end up with a consistent product, independent of who designed it. That’s why Freeform is so valuable: regardless of who does the work, the prosthesis is consistent and meets our technical specifications,” he says. 

 

Hybrid CAD and sculpting process

The process that Point Designs developed is a hybrid of traditional and digital manufacturing methods. 

The innermost portion of the prosthesis, which is made of silicone material and goes right up against a person’s skin, is fabricated manually. A prosthetist sends Point Designs an impression, which is a negative model of a hand. Then, Point Designs makes the positive plaster model from the impression and customises the silicone over the top. In this process, the team integrates unique features such as threaded anchors, zippers and straps as specified by the prosthetist and in the colours that the patient picks.

Next, the team switches to a digital workflow. They 3D scan the custom silicone and bring the data into Geomagic Freeform. A designer models the socket of the prosthesis inside the software which is then additively manufactured.

The signature rugged duty digits are added to the sockets in two phases. First, the team creates a diagnostic prosthesis for the customer to test. The fingers for the diagnostic fitting and the socket are sent unassembled to the prosthetist, who will glue the fingers to the socket while the patient is wearing it to achieve the desired alignment.

The prosthetist returns the assembled diagnostic prosthesis to Point Designs. The team will scan it to capture the alignment and replicate it in Freeform by using the CAD models of the fingers. The alignment of the CAD models is entirely automated with Dynabots.

In the final stage, it’s critical to ensure the fingers have enough clearance to spring back automatically. If something in the socket prevents the fingers from extending entirely, they will not return into the open position.

Aligning the digits inside Freeform makes it easier to prevent collisions. “Sometimes, when customers send back the diagnostic device, we notice that they’re not working properly. In Freeform, we can verify that we have the clearance necessary and prevent issues with the fingers hitting the prosthesis,” Baschuk explains.

Doubling down on Dynabots

In addition to finger alignment, Point Designs uses Dynabots in a range of tasks. “A prosthesis that might take a designer two to three hours on their own will take them half an hour or 45 minutes with Dynabots. It’s a huge time saver. For our diagnostic sockets, from importing the 3D scan of the silicone to the start of printing, it takes under 10 minutes because of the Dynabots,” Baschuk says.

The automation also makes training new staff in Freeform simpler. A person with basic experience in CAD can confidently be producing prostheses in a few weeks. All the devices and designs are still checked and signed off by certified prosthetists to ensure they comply with clinical standards.

Feeling the design difference 

These workflows and technologies allow Point Designs to create lifechanging products. One patient who has experienced its benefits is Jeff Soelberg, who had three digits amputated.

Soelberg was one of the early recipients of Point Designs’ additively manufactured prostheses after being fitted with several traditionally manufactured ones. The switch was a game-changer for Soelberg. The new socket had a lower profile and was lighter and more flexible than the ones he previously wore. Because of the intentionally designed added flexibility of the socket, he was able to go from wearing his prosthesis only a couple of hours at a time to wearing it for more than 12-14 hours a day. 

“I’ll never go back to wearing a traditionally manufactured prosthesis again,” Soelberg says. The innovation in 3D design, modelling, and printing that Point Designs has adopted has been transformative.

Freeform plays an important part in design execution by enabling variable socket thickness and the creation of engineered meta-materials. The patients feel the difference, and they don’t want to give it up. “We’ve had several of our customers’ patients say they don’t want to wear a traditionally manufactured prosthesis ever again because it cannot replicate the functionality of the prostheses we create with Freeform and additive manufacturing,” Baschuk concludes.