The splint comes out lighter, breathable, washable, and shaped to the exact anatomy of the patient.
This guide walks through the materials, design rules, and safety protocols for modern custom orthotics.
- A 3D printed splint is a custom orthosis made by scanning a body part, designing a shell in CAD, and printing it in a skin-safe material.
- PETG and PLA are common for learning projects, but neither is certified for medical skin contact.
- For patient-facing work, use biocompatible materials like Siraya Tech Blu resin (ISO 10993-5 and 10993-10 certified) or ISO-certified TPU.
- Design rules matter more than material. Ventilation holes, padded contact zones, and proper thickness prevent pressure sores.
What Is a 3D Printed Splint?
A splint is a rigid or semi-rigid shell that holds a body part still so it can heal or rest. A traditional splint is made from plaster, fiberglass, or thermoplastic sheets that a therapist heats and molds by hand. It works, but it is bulky, heavy, and hard to clean.
A 3D printed splint replaces that hand-molding step with a digital workflow:
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Scan the patient's arm, hand, or ankle with a 3D scanner or phone app.
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Design a custom shell in CAD software like Fusion 360 or Meshmixer.
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Print the shell on an FDM or resin printer in a skin-safe material.
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Finish with straps, padding, and any hinge parts.
According to a review in the International Journal of Biomedical Engineering, this digital approach can cut the delivery time for a custom orthosis from multiple clinic visits to a single session, because the splint is designed from scan data rather than hand-shaped on the patient.
The Mayo Clinic has also reported that 3D-printed splints are lighter, water-resistant, and more breathable than plaster or fiberglass splints.
The catch is that a 3D printed splint still has to meet the same safety standards as any other medical device. Material, print settings, and design all need to be right or the splint can cause pressure sores, irritation, or even slip out of alignment.
The Common Uses for 3D Printed Splints
Published case studies and clinical trials have looked at 3D printed splints for:
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Wrist and hand splints for carpal tunnel, wrist sprains, De Quervain's tenosynovitis, and post-surgery rest.
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Finger and thumb splints for trigger finger, mallet finger, and arthritis.
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Ankle-foot orthoses (AFO) for drop foot and stroke recovery.
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Cervical collars for neck instability.
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Scoliosis braces for spinal curvature in teens.
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Wearable braces for sports injuries like tennis elbow.
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Animal splints for veterinary use on dogs and small pets.
Of these, wrist and hand splints are the most common starting project because the design is small, the print time is short, and the anatomy is relatively simple to scan.
Best Materials for 3D Printed Splints
| Material | Stiffness | Skin Contact Cert | Weight | Durability | Best For |
|---|---|---|---|---|---|
| PLA | High | None | Light | Low (fails in hot cars, breaks under load) | Student prototypes only |
| PETG | Medium-high | None | Light | Medium | Non-medical prototypes |
| ABS | Medium-high | None | Light | Medium | Prototypes, not skin contact |
| Nylon (PA12) | High | Some grades certified | Light | High | AFOs and load-bearing splints |
| TPU (flexible) | Low (flexible) | Siraya Flex TPU: ISO 10993-5, 10, 23 | Light | High | Living hinges, straps, padding |
| Biocompatible resin | Very high | Siraya Blu: ISO 10993-5, 10993-10 | Light | High | Rigid wrist and finger splints |
| SLS nylon | High | PA12 medical grade certified | Light | Very High | Clinical AFOs, scoliosis braces |
Rigid Shell, Flexible Shell, or Hybrid?
There is no single best design for a 3D printed splint. The right choice depends on the injury and the body part. Here are the three main types.
Rigid shell
A solid plastic or resin shell that fully immobilizes the body part. Used for fresh injuries, post-surgery recovery, and anything where movement is not allowed. Usually printed in Blu resin or nylon.
Flexible shell
Printed entirely in TPU, the splint bends and breathes but provides less support. Used for arthritis, mild sprains, and long-term wear where comfort matters more than rigidity.
Hybrid (rigid shell plus flex lining)
The pro move. A rigid outer shell holds the shape, and a TPU or silicone inner layer sits against the skin to prevent pressure sores.
Research published in Biomedical Engineering describes exactly this approach using a 3mm PLA shell with a 1mm medical-grade silicone inner lining to avoid pressure ulcers.
Most commercial 3D printed splints are hybrid designs for this exact reason. The skin-contact side is soft and breathable, the outside is stiff and strong.
Design Rules That Prevent Pressure Sore & Failures
Material is only half the battle. Proper design prevents common issues like sweat-induced rashes or pressure sores.
- Ventilation: Aim for 30% to 40% open surface area using Hexagonal or Voronoi patterns.
- Thickness: Wrist splints should be 2.5mm to 3mm; finger splints 1.5mm to 2mm.
- Smoothed Edges: All contact edges must have at least a 2mm fillet to prevent rubbing.
- Relief Zones: Cut dimples into the design where bone sits close to skin (like the ulnar head).
Print Settings & Post-Processing
Settings vary by material, but here are tested starting points for the most common options.
Table 2: Slicer Settings for 3D Printed Splint Parts
| Setting | PETG Shell | TPU 95A Lining | Biocompatible Resin Shell |
|---|---|---|---|
| Nozzle temperature | 235°C | 225°C | N/A (LCD resin printer) |
| Bed temperature | 80°C | 50°C | N/A |
| Layer height | 0.2mm | 0.2mm | 0.05mm |
| Walls/perimeters | 4 to 5 | 3 | Solid print |
| Top/bottom layers | 6 | 4 | Solid print |
| Infill | 40% gyroid | 20% gyroid | 100% |
| Print speed | 50 mm/s | 25 mm/s | Per resin profile |
| Cooling fan | 40% | 100% | N/A |
| Post-process | Sand 220 to 400 grit, round edges | Peel supports carefully | IPA wash, UV cure, bake per biocompatibility guide |
The Splint Design Workflow in 6 Steps
Here is the real-world process from scan to finished splint, based on published clinical and maker workflows.
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Scan the body part. Use a 3D scanner (Revopoint, EinScan, or Structure Sensor) or a phone app like Scaniverse. Capture with the limb in the splinted position, not a relaxed position.
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Clean the scan in Meshmixer or Blender. Remove noise, close holes, and smooth rough areas.
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Design the shell in Fusion 360, Rhino, or a parametric splint generator. Add ventilation, relief zones, and strap slots.
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Export an STL and load it in your slicer.
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Print the shell. For rigid parts use PETG, nylon, or Blu resin. For flexible parts use TPU.
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Post-process and fit. Sand edges, add padding, install straps, and fit on the patient. Watch for pressure points for the first hour of wear.
For students and beginners, the PrintLab educational workflow suggests making a physical mockup with plastic wrap and painter's tape first.
Wrap the body part, mark the splint outline with a pen, cut the mockup off, and use that as a reference for the CAD design. It is a great way to understand shape before touching software.
FAQs About
Can you 3D print a splint at home?
Yes, you can 3D print a splint at home using a standard FDM or resin printer. Wrist, finger, and small ankle splints print on most hobby machines. The tricky part is making one that is actually safe for skin contact and fits correctly. For anything more than a learning project, you should work with a licensed clinician and use a skin-contact certified material like ISO 10993 rated resin or TPU. A homemade splint should never replace medical care for a real injury.
What is the best material for a 3D printed splint?
For rigid wrist and finger splints, a biocompatible resin like Siraya Tech Blu (ISO 10993-5 and 10993-10 certified) gives the best mix of stiffness, detail, and skin safety. For flexible parts like living hinges and padding, ISO-certified TPU is the top pick. PLA and PETG are fine for learning and prototyping but are not certified for medical use. Clinical splints are often printed in SLS nylon (PA12) at service bureaus because of its strength and proven biocompatibility.
How much does a 3D-printed splint cost?
A DIY 3D printed wrist splint costs around $2 to $15 in material depending on the plastic. Add a 3D scanner and printer and the total per-splint cost runs $30 to $60. Clinical 3D printed orthoses from service providers usually run $150 to $400 depending on complexity and follow-up fittings. Traditional commercial thermoplastic splints retail around $75 to $200, so the 3D printed version is often cheaper once the equipment is paid off.
Are 3D printed splints FDA-approved?
Some 3D-printed splints are FDA-approved when made by companies that have cleared specific products through 510(k) clearance, such as ActivArmor and Xkelet. Most maker projects and general-purpose splints are not FDA-approved.
How long does it take to 3D print a splint?
Printing a wrist splint typically takes 4 to 10 hours depending on the printer, layer height, and infill. Finger splints print in 30 to 90 minutes. An ankle-foot orthosis can take 12 to 20 hours because of the larger size. The full workflow including scanning, design, printing, and post-processing usually takes 6 to 24 hours from start to wearable splint. Thermoformed plaster casts are faster for the first fitting (about 40 minutes) but do not produce a custom digital file you can reprint if the splint gets lost or damaged.
Final Thoughts
3D printed splints represent a major crossover between hobbyist technology and medical value. When done correctly, they are lighter, more breathable, and more customizable than traditional casts.
Always remember: a splint is a medical device. Use your maker skills to provide better design, but always consult a professional for clinical applications.
Recommended Products
- Rigid Shells: Siraya Tech Blu Tough Resin (ISO 10993 Certified).
- Padding & Straps: Siraya Tech Flex TPU Filament Collection.
- Cleaning: 95%+ Ethanol or IPA for biocompatible post-processing.