Materials
PA11 nylon orthotics: how laser-sintered shells compare
Most custom orthotics in Australia are still made one of two ways: a polypropylene sheet heated and vacuum-formed over a model of the foot, or a block of EVA foam milled to shape. ORTX makes shells a third way, by selective laser sintering (SLS) of PA11 nylon. This guide explains what that changes for the device and for the person wearing it.
What PA11 is
PA11 (polyamide 11, often called Nylon 11) is an engineering polymer made from castor-bean oil rather than petroleum. It is used where parts must flex repeatedly without cracking: automotive fuel lines, sporting goods and prosthetic components. In SLS, a laser fuses a bed of PA11 powder one thin layer at a time, so the shell is built directly from the digital design with no mould, plaster positive or offcut sheet.
Why it suits an orthotic shell
- Fatigue resistance: our PA11 material is tested beyond four million bend cycles, so the shell keeps its shape and its correction instead of slowly flattening.
- Stiffness where it is wanted: thickness can change across one shell, rigid under the medial arch and more forgiving at the heel or lateral border, from a single prescription.
- Thin and light: an SLS shell does not need the bulk of milled foam, so it fits more shoes, including tighter work, school and football boots.
- Exact geometry: the shell is printed from the scan and the script, so posts, skives, apertures and heel cups are where the prescriber put them, with no hand-grinding drift.
- Repeatable: the design is stored, so a second pair or a replacement matches the first.
Compared with polypropylene and EVA
Vacuum-formed polypropylene is proven and inexpensive, but its thickness is the same everywhere and its final shape depends on the positive model and the technician. Milled EVA is comfortable and easy to adjust, but foam compresses with wear and the correction fades over months. A sintered PA11 shell sits between the two: rigid enough to hold a correction for years, thin enough for everyday footwear, and adjustable in the design rather than on the grinder.
Comfort layers still matter. A PA11 shell can carry an EVA or Poron top cover, sulcus or full length, when the prescriber wants cushioning on top of the control the shell provides.
Who prescribes them
Fully custom ORTX orthotics are made to a podiatrist's or physiotherapist's assessment and script. If you think you need orthotics, start with your clinician. Clinics can see how to order on ORTX Pro.
Health professionals
Order fully custom orthotics, made in Brisbane, through ORTX Pro.
Go to ORTX Pro →