SLS for Orthotics and Orthopaedic Devices: Materials and Workflow

Selective laser sintering (SLS) supports the production of custom orthotic insoles, finger orthoses and selected prosthetic components by combining complex geometry with batch manufacturing. Choosing between PA11, PA12 and TPU starts with the function of the part: the support it must provide, the deformation it must accommodate and the conditions in which it will be used.

The experiences of Dutch companies LutraCAD and Artus3D show how this approach works in practice. LutraCAD uses the Raise3D RMS220 to produce custom insoles in batches, while Artus3D manufactures prosthetic cosmetic covers and finger orthoses on the same SLS platform. Together, the cases provide a practical starting point for understanding material selection and the workflow from digital design to finished part.

Why do orthotics manufacturers use SLS 3D printing?

Orthoses and orthopaedic devices are highly individual products. A custom insole must reflect a person’s foot geometry and required support zones, while a finger orthosis may need to restrain one movement without unnecessarily restricting another. Traditional manufacturing methods—including CNC milling, thermoforming and manual finishing—remain important, but highly varied orders can involve repeated setups, material removal and hands-on adjustments.

SLS forms parts by selectively sintering layers of polymer powder with a laser. The surrounding unsintered powder supports the geometry during fabrication, which generally removes the need for separate support structures. This allows manufacturers to work with contoured surfaces, thin walls, openings and locally reinforced regions while placing multiple unique designs in the same build.

For an orthotics lab, the practical advantage lies in linking personalized design, build preparation and batch production. Geometry and wall thickness can be adjusted in CAD, orders can be grouped into build jobs, and repeatable settings can be managed through a digital process. SLS is particularly useful when a company handles many different designs but wants to manufacture them in planned batches rather than one part at a time.

Case study: LutraCAD scales production of custom insoles

Based in the Netherlands, LutraCAD develops software for designing custom insoles, shoe lasts, midsoles and related orthopaedic products. The company had explored material-extrusion printing and other additive processes while serving customers who also used traditional milling. As demand grew for rigid-support insole shells with refined surfaces and thin sections, LutraCAD adopted the Raise3D RMS220 SLS system with PA11 powder.

Custom PA11 orthotic insoles produced using the Raise3D RMS220 SLS system

How PA11 fits the insole design

Custom insole shells need to provide support while allowing selected areas to flex. LutraCAD chose PA11 for its combination of toughness, elongation at break and compatibility with thin-wall designs. By varying local thickness in the digital model, designers can tune how different regions bend while retaining the intended support geometry. Material properties and geometry therefore work together: the same polymer can produce different structural responses when its shape and thickness change.

What batch production looks like

According to the published Raise3D case study, LutraCAD produces 20–25 pairs of custom insoles in a single RMS220 build. Jobs can run overnight, reducing the need for frequent operator intervention during the build. After depowdering, the printed shells receive their required covering before being prepared for delivery. The result is a production pattern designed around batches of individual models, rather than continuous manual attention to each insole.

LutraCAD also compared the material use of SLS with its experience of milling, where as much as 80–90% of a starting material block can become machining waste. SLS builds the intended geometry from powder, and a proportion of unused powder can return to subsequent builds under the appropriate refresh and handling rules. The quoted 80–90% figure describes waste in the milling process, not a measured percentage reduction delivered by the RMS220.

Case study: Artus3D manufactures prosthetic covers and finger orthoses

Artus3D, based in Ridderkerk in the Netherlands, works in digital design and manufacturing for orthotics and prosthetics. Its RMS220 implementation highlights two different production demands: relatively large prosthetic cosmetic covers and compact finger orthoses. Both applications use PA11, but their design objectives and build arrangements differ substantially.

Prosthetic cosmetic covers

A prosthetic cosmetic cover sits over a prosthesis to improve its appearance and, depending on design, provide exterior protection. It is different from the primary load-bearing prosthetic structure. These covers often involve large, curved surfaces, so the printer’s available build volume, part orientation and material toughness play an important role in production planning.

SLS-printed prosthetic cosmetic covers and orthopaedic components produced by Artus3D using PA11

Artus3D reports that the RMS220 can produce at least four large prosthetic cosmetic covers per batch, including a bilateral set in one overnight build. The company also describes a one-day production cycle for the relevant parts. These figures capture Artus3D’s particular workflow and product mix, and offer a useful benchmark for evaluating similar applications.

Finger orthoses

Artus3D also makes small finger orthoses designed to prevent overextension while allowing controlled movement. In these devices, thin walls and the geometry of the restraint determine how stiffness and flexibility are distributed. PA11 provides a material basis for the required balance of structural support and deformation. Because the devices are compact, Artus3D reports that hundreds of small parts can be nested within one build; the achievable quantity depends on the actual design and packing arrangement.

Custom finger orthoses designed to limit overextension while allowing controlled movement

These applications demonstrate why a single SLS platform can serve different orthopaedic product categories. Larger cosmetic components use the build volume in one way, while small orthoses benefit from high packing density. Their functional requirements remain distinct, so the same printing method does not imply the same design or inspection criteria.

How to select PA11, PA12 or TPU for orthotic devices

Material selection begins with the role of the finished part. A support shell may prioritize dimensional stability and stiffness; a thin orthosis may need a controlled amount of bending; and a liner or cushioning element may depend on elastic recovery. PA11, PA12 and TPU offer different approaches to these requirements. The material examples below are engineering selection guidance; the two published RMS220 customer cases specifically identify PA11.

PA11: toughness for thin and flexible-support designs

PA11 is a polyamide whose toughness and elongation at break make it a useful candidate for thin-wall orthoses and other parts that need some deformation capacity alongside structural support. In Raise3D’s PA11 Black Powder data, typical X-direction values are 53.97 MPa tensile strength, 41.17% elongation at break and 1,691.37 MPa tensile modulus, tested according to ISO 527-2. LutraCAD’s insole shells and Artus3D’s finger orthoses are practical examples of how PA11 can be applied to different geometries.

PA12: general-purpose structural stability

PA12 is another widely used SLS engineering polymer. It is a suitable starting point for parts where dimensional stability, housing geometry and general structural performance are central requirements. Raise3D’s PA12 Black Powder lists typical X-direction values of 50 MPa tensile strength, 9% elongation at break and 1,791 MPa tensile modulus, also under ISO 527-2. The data illustrate different material behaviors, although wall thickness, build orientation and loading conditions remain important to the behavior of a finished device.

TPU: flexibility and cushioning

Thermoplastic polyurethane (TPU) is useful when a design calls for elastic deformation, cushioning or a soft contact component. Potential applications include flexible insole structures, cushioning elements and liners. For components that also require defined structural support, manufacturers may evaluate a nylon shell combined with a separately produced flexible element. The outcome depends on the selected TPU grade, geometry, wall thickness and loading conditions.

For parts exposed to repeated flexing or compression, material screening should lead into component-level testing. Cyclic loading, dimensional recovery and durability are more informative for service life than a single tensile figure alone.

The SLS workflow: from digital design to finished orthotic part

An effective production workflow connects the intended function of the device with the geometry, material, build job and finished-part checks. The steps below combine the digital-production practices described by LutraCAD and Artus3D with standard engineering controls that a manufacturer can adapt to its product and quality requirements. For a closer look at how printing, external cooling, powder recovery and surface finishing work together, Raise3D’s RMS220 SLS production workflow provides an example of an integrated manufacturing system.

Raise3D SLS production ecosystem, including the RMS220 printer, Build Unit 220, C220-P Cleaning Station, and B520 Blasting and Polishing Station

Step 1: Capture geometry and define the product requirements

Production starts with a clear definition of the product’s function and the geometry it must fit. A custom insole design may begin with a 3D foot scan and specified support regions; a finger orthosis requires the relevant anatomy, fixation points and intended range of movement; a prosthetic cosmetic cover requires the outer shape and interface details of the existing prosthesis. The information collected guides the design rather than serving as a substitute for functional assessment.

Step 2: Design and refine the CAD model

Designers turn the measurements or scan data into a manufacturable model, adjusting contact surfaces, thickness, edges, openings and attachment features. Changing local thickness can tune the bending response of an insole, while a finger orthosis may use carefully placed openings to guide movement. This is also where the intended role of the printed object should be recorded: a prototype for fit checks, a mold or manufacturing aid, or a component intended for direct use. These categories call for different acceptance criteria.

Step 3: Choose the material and prepare the build

Once the material and design are defined, the model moves into slicing and build planning. Both customers use Raise3D ideaMaker for RMS220 print preparation. At this stage, the team checks geometry, selects print settings, chooses the part orientation and nests multiple items in the build volume. With customized parts, clear identification and traceability are also important so each printed component remains linked to its correct order.

Step 4: Print, then cool the build

During printing, the laser consolidates selected areas of each powder layer to form the parts. Material condition, process settings, geometry and orientation all influence the finished result. Once the job is complete, the removable Build Unit 220 allows the powder bed and parts to be transferred from the printer to the C220-P Cleaning Station for cooling and subsequent processing. Both case studies describe overnight builds as a practical way to organize production, leaving subsequent handling and finishing to the next stage.

Step 5: Depowder, finish and assemble

After cooling, parts are recovered from the powder bed using the C220-P Cleaning Station, which supports part extraction and powder recovery. Any remaining loose powder, including powder trapped around openings or internal features, is then removed. Depending on the product,  post-processing may include blasting with the B520 Blasting and Polishing Station, as well as edge finishing, cleaning
and assembly. LutraCAD describes adding the required covering after depowdering its insole shells; other orthoses may require fastening elements, contact liners or connections to existing components. Finishing requirements should be considered during design so that powder and tool access are practical.

Raise3D C220-P Cleaning Station (left) and B520 Blasting and Polishing Station (right)

Step 6: Inspect the part and verify its function

Final inspection should reflect the part’s intended function. Insole shells require dimensional and fit checks alongside their defined support behavior. Finger orthoses call for assessment of restraint, movement and structural integrity; prosthetic cosmetic covers need attention to assembly interfaces, appearance and use-related durability. Where a product is intended for a regulated medical use or direct body contact, the applicable product and biological-safety requirements become part of the verification plan. A repeatable workflow closes the loop by feeding inspection findings back into the digital design.

What matters when choosing an SLS printer for orthotics

For a lab planning to introduce SLS, printer selection is best approached through representative parts rather than a headline speed figure. The build volume must fit the largest design and leave room for effective nesting; the material portfolio must support the required mechanical behavior; and slicing, cooling, powder handling and post-processing must work together as a practical production system.

The Raise3D RMS220 used by LutraCAD and Artus3D provides a reference point. According to the April 2026, Version 2.0 technical specification, the system offers a 220 × 220 × 450 mm build volume (about 21.8 L), a 75W infrared fiber laser at 1,064 nm, a 0.05–0.40 mm layer-height range and ideaMaker slicing.

Raise3D RMS220 SLS 3D printer used for custom orthotic and orthopaedic device manufacturing

LutraCAD uses this build area for multiple pairs of custom insoles, while Artus3D uses it for both larger cosmetic covers and compact orthoses. A manufacturer considering a similar system should run build-layout studies with its own CAD files, test representative parts and account for cooling, depowdering and inspection when estimating total throughput.

Where SLS delivers value—and what the production plan should include

SLS is well suited to businesses that handle substantial design variation, complex polymer geometry or batches of individually customized parts. LutraCAD’s insole production illustrates how the process can organize numerous personalized items into a single job; Artus3D shows how a facility can allocate the same equipment to both larger shells and many small orthoses. Digital build preparation makes it easier to plan these jobs consistently, while powder reuse—within material-specific processing rules—changes the waste profile compared with subtractive machining.

A sound production assessment still considers the full manufacturing cycle. Equipment and powder costs, build density, print and cooling time, depowdering, finishing, labor and inspection all contribute to the cost of a finished acceptable part. Where a device contacts the body or has a defined medical purpose, material suitability and the corresponding safety and regulatory assessment must also be covered in the product plan. Engineering material data are a starting point for design; product-level evaluation addresses the conditions of actual use.

Conclusion: a scalable route to personalized orthotic production

SLS brings geometry freedom and batch manufacturing together in a way that suits many customized orthotic and orthopaedic applications. LutraCAD’s PA11 insole shells demonstrate how separate patient designs can be processed as one RMS220 build, while Artus3D’s cosmetic covers and finger orthoses show the breadth of part sizes and functions a single SLS platform can address. These are production examples grounded in specific parts and material choices rather than claims about every device category.

For manufacturers evaluating SLS, the most productive path is to start with a clearly defined part, select the material around its mechanical needs, validate a representative build and establish a workflow that carries the design through finishing and inspection. That combination is what turns individualized CAD files into a repeatable manufacturing process.

Frequently Asked Questions

What 3D printing technologies do orthotics labs use for custom insoles?

Material-extrusion methods such as FFF/FDM and powder-bed methods such as SLS are both used to make custom insoles. FFF/FDM can be appropriate for prototypes and selected production tasks, while SLS is especially useful for thin shells, complex geometry and batches containing many different designs. LutraCAD’s RMS220 workflow, producing 20–25 pairs per build, is one documented example.

What SLS printer do orthopaedic device makers in Europe use?

Equipment choices vary by application and manufacturer. Two documented examples in the Netherlands are LutraCAD and Artus3D, both using the Raise3D RMS220 for different orthotic and prosthetic products. LutraCAD focuses on custom insoles; Artus3D prints prosthetic cosmetic covers and finger orthoses.

Is PA11 or PA12 better for orthotic devices?

PA11 is a strong candidate where toughness and controlled flexing are priorities, particularly in thin-walled designs. PA12 is worth assessing for structurally stable housings and support components. The best choice depends on the geometry, expected loads, orientation and required service performance, not just the material name.

Do SLS orthotic parts require post-processing?

Yes. The typical sequence involves cooling, part recovery, depowdering and any required finishing or assembly. Final-use products then move through inspection and checks matched to their purpose. For example, LutraCAD describes covering its insole shells after depowdering.

Can SLS produce customized orthoses in batches?

Yes. SLS can nest multiple unique designs in a common powder bed. This lets manufacturers consolidate jobs without making every part identical. LutraCAD’s multi-pair insole builds and Artus3D’s batches of small finger orthoses demonstrate this production model.