The Low-Cost Ankle Foot Orthotic (AFO) heralds a shift in development focus from our 2021 developed award-winning long-leg brace exoskeleton toward better affordability—“low-cost mold production”— and market entry in compliance with Japanese standards.

The biggest hurdle for CFRP products is the cost of producing molds. The need for various molds to accommodate user-tailored sizes and shapes in adaptive equipment and orthotics creates high initial costs which are ultimately added to the unit price. Thus, our key project theme was “low-cost mold production” by integrating digital technologies into design and manufacturing.

Joint Development Partner

Miura Medical Engineering and Design (Miura-ikou Design) Co., Ltd.

As a manufacturer of adaptive equipment and orthotic devices for children, Miura Medical Engineering and Design supervises orthotic device production and coordinates with medical professionals and end-users to ensure that product development aligns with the market and user needs. As cast taking and orthotic fitting requires the involvement of a Certified Prosthetist/Orthotist (CPO), our key development focus is to facilitate efficient access to data after cast taking, simplify manufacturing flow, and deliver the product within a favorable time frame.

＞ Company website

＜ Our Mold Development Concept ＞

While CFRP products have a reputation for being expensive, these costs are born from not just the materials but also from the complex manufacturing processes and high volume of manual labor involved, particularly in prototyping and small-lot productions, which impedes our ability to lower costs. For bespoke mass-customized products such as orthotics and prosthetics, the cost of producing molds significantly influences the price. Thus, our central development focus was on “low-cost mold production.”

– Design –

In conventional mold design and modeling, creating a functional easy-to-use mold demands specialized experience and know-how of the CFRP product including the size, form, design limitations, demolding capacity, and constraints of MC machining tools. Each mold is unique to the product. The Graphical Algorithm Editor (GAE) replaces these complex manual processes with algorithms and automates CAD design and process planning of Ankle-Foot Orthoses.

< Previous Process >

#1 Process Design

#2 Mold Milling

#3 Sheet Cutting

#4 Limination

#5 Finishing

Algorithmization

＜ New Digital Process ＞

Integrated New Process - Seemless

#1 Process Design

#2 Mold Printing

#3 Sheet Cutting

Process Design Algorithm

Same Process

#4 Limination

#5 Finishing

– Manufacturing –

1) Leveraging 3D Printers to Shorten Production Times, Reduce Costs, and Address Environmental Concerns

Conventional methods of bonding block materials and cutting female molds presents environmental and productivity issues including excess waste from block materials and cutting powders and the added time and costs of disposing of molds after use. With 3D printers, we can dramatically reduce industrial waste and cut down production time.

*3D printed molds are crushed and re-pelletized after use, recycling resources and contributing to a circular economy (currently under development).

– Manufacturing –

2) 3D Printer Mold Materials

Conventionally CFRP products are produced using the autoclaving method, whereby the resin is cured using high temperatures and pressure. This method offers stable production of high-quality products and is commonly employed for aircraft industry components. As the orthotics industry does not require the same high-end precision of aircrafts, we could construct molds from inexpensive general-purpose plastics using molding processes that don’t require thermal or high-pressure curing.

– Results –

1) Reduced Production Time and Costs with 3D Printers

(addresses environmental issues)

  • Reduced costs by about one-tenth (10%) compared to conventional autoclave prototype molding.
    *Also achieves product cost reductions due to the elimination of expensive autoclave equipment and facilities.
  • Direct modeling enabled shorter production times.
  • Reduced production time by two-thirds (33%) compared to conventional autoclave-compatible prototype molds.
    *Conventional molding process: Primary processing of block material—material adhesion—MC machining—surface treatment—demolding—mold completion.

【Other】

  • 3D scanner-based casting enables online ordering from prosthetic limb and orthotic device manufacturers, speeding up the entire process from the time of initial request to manufacturing.

– Mold Fabrication: Example Case –

Adding pigmentation during the resin impregnation process eliminates the need for final coating, lowering costs while allowing users to select product colors according to their preferences.

Automotive wrapping film application in vivid pink (example)

Black carbon pattern finish (example)

Lavender-blended pigment finish (example)

Solid blue pigment added finish (example, finished product)