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3D Printing Prosthetics Today – Repeatable, Predictable, Scalable

Plaster Reigns Supreme for more than Half a Century

Plaster has been the predominant medium for prosthetic socket design and fabrication due to market familiarity and its ability to deliver repeatable, predictable results.

Unfortunately, it takes valuable time to cast a patient, allow the cast to set, remove the cast, mix and pour plaster, fill the cast, let the plaster set, then remove the plaster based positive model from the cast. Proponents of casting note that it allows them to manipulate the shape of the patient’s limb to influence socket design. The focus is distributing the patient’s weight to optimize comfort, fit and function. Though substantial, the level of effort and duration of the overall process is well known with little variability.

Modifying in plaster is labor intensive, time consuming and messy, but the tools used are the same ones taught in formal educational settings and subsequently used in residencies. Pulling a check socket is a relatively straightforward process once a modified positive model has been created. Heat the plastic sheet until it is malleable, pull the sheet over the plaster model, then vacuum form against the model to shape the plastic until it hardens.

Even today, plaster remains the primary shape capture and design medium taught in all accredited masters programs in the US, with minimal instruction on digital mediums used for prosthetic socket design and fabrication.

Enter Digital

CAD/CAM is not new to the Orthotic and Prosthetic industry. That said, a lot has changed since its introduction in O&P nearly a quarter century ago. Now, with the advent of lower cost scanning options, CAD/CAM software for design and fabrication instructions, and 3D printing to automate the fabrication process, many in the industry are transferring the skills they honed within a plaster medium and applying them successfully to a digital environment.

In the past, 3D digital scanners, CAD/CAM software and fabrication equipment were cost prohibitive. The costs of these components have dropped significantly over the last few years. Smartphones have evolved with apps that make it easy to 3D scan a patient’s limb, which at one time, required expensive scanners.

CAD/CAM software used to require dedicated computer servers to run on and came with expensive licensing fees to use. Now there are web-based software options.  Some are associated with central fabricators.  Others are included with fabrication equipment for those that prefer the control inherent with in-house fabrication.

Fabrication equipment is now more affordable than ever.  A manufacturing grade 3D printer can be purchased for a fraction of what many paid a few decades ago.

Solution complexity has been a barrier to entry for many, even more so than cost. With push button, pre-configured options with solutions level training and support now available, anyone with an interest can harness the potential that digital fabrication options provide, without having to invest in the extensive trial and error self-taught learning that early adopters had to endure to achieve high-quality sockets.

Getting to Fabrication that is Repeatable, Predictable, Scalable

The process of getting to the right combination of settings to be able to consistently fabricate a device is expensive and time consuming. Each time one setting is adjusted, other settings must be held constant with test prints are required.

These settings include:

  • Nozzle and printer bed temperatures,
  • Flow rate,
  • Fan speed,
  • Nozzle size,
  • Layer height,
  • Layer width,
  • Printer speed.

Optimizing these settings is the largest barrier to digital fabrication.

To counter this issue, preconfigured slicing profiles enable users to easily convert their digitally designed device into a 3D printable check socket with the click of a button.

These profiles provide predictable results by optimized, tested, verified settings. Since the same settings are applied each time, the results are easily repeatable as they are optimized for a target application. For check sockets, this means that the 3D printed devices are strong and clear, suitable for dynamic fittings.

Implementing in-house digital fabrication through preconfigured profiles greatly simplifies the process. Users of these profiles benefit from extensive development effort to fabricate check sockets that print reliably. Because little manual effort is required to manage the print process, fabrication be scaled up using existing resources.

Since the barriers of up-front cost and complexity have been greatly lowered, it is now a great time to revisit digital fabrication.  Contact us for a free trial of Rapid Plaster, our CAD/CAM software, so that you can see firsthand what we describe in this post. Also ask us about a free trial for a scanning app, that could be used with Rapid Plaster to design your first check socket, all with no cost to you. For a nominal fee, you could even have a check socket 3D printed then mailed to you so that you could perform a full solution evaluation with very little out of pocket. Beside a little time to learn, what have you got to lose? Maybe more importantly, what have you got to gain!