3D printing flexible, rubber-like parts used to be a challenge—but not anymore. Today, a range of flexible materials suitable for 3D printing lets you create everything from squishy toy parts to durable automotive components. Whether you’re a hobbyist making a custom phone grip or a manufacturer designing medical devices, this guide will help you pick the right flexible material, understand its properties, and avoid common mistakes.
1. First: Understand Shore Hardness—The Key to Flexible Materials
Before choosing a flexible 3D printing material, you need to know Shore hardness. It’s the standard scale for measuring how soft or rigid a flexible material is—think of it like a “softness score.” Without this, you might end up with a part that’s too squishy (e.g., a phone case that bends too much) or too stiff (e.g., a toy that doesn’t flex).
The 3 Main Shore Hardness Scales
There are three scales to know, each for different types of flexible materials:
- Shore OO Scale: For extremely soft materials (like gel insoles or squishy toys). Scores range from 0 (super soft) to 100 (still soft but firmer).
- Shore A Scale: The most common scale for 3D printing. It covers materials from very soft (e.g., rubber bands) to semi-rigid (e.g., some phone cases). Scores go from 0 (soft) to 100 (semi-rigid).
- Shore D Scale: For hard rubber or semi-rigid plastics (e.g., PVC pipes or hard phone cases). Scores range from 0 (hard rubber) to 100 (rigid plastic).
Important Overlap: Shore A vs. Shore D
Sometimes, a material’s hardness can be measured on both scales. For example, Shore 95A is equal to Shore 50D. This is useful when comparing materials—if one brand lists Shore A and another lists Shore D, you can still tell they’re similar.
Below is a quick reference to help you match Shore hardness to real-world feel:
| Shore Hardness | Feel | Example Use Case |
|---|---|---|
| Shore 30A | Very soft (like a stress ball) | Squishy toy parts |
| Shore 50A | Soft (like a rubber band) | Flexible phone grips |
| Shore 80A | Firm (like a car tire’s sidewall) | Durable automotive gaskets |
| Shore 95A/50D | Semi-rigid (like a hard phone case) | Rigid but flexible enclosures |
2. Top 5 Flexible Materials Suitable for 3D Printing
Not all flexible materials work with every 3D printer. Below are the most popular options, their best use cases, and which technologies (FDM, SLS, MJF, DLS) they work with—based on data from Xometry, a leading 3D printing service.
1. TPU (Thermoplastic Polyurethane)
TPU is the most versatile flexible material for 3D printing. It’s part of the thermoplastic elastomer (TPE) family and works with FDM, SLS, and MJF printers.
Key Properties of TPU
- Hardness Range: 10 Shore OO to 72 Shore D (most 3D printing TPU uses Shore 50A to 95A).
- Mix of Plastic & Rubber: It’s flexible like rubber but durable like plastic—can bend, stretch, and bounce back.
- Other Benefits: UV-resistant (doesn’t fade in sunlight), hydrolysis-resistant (works in wet environments), and easy to print.
Popular TPU Types for 3D Printing
- TPU Polyurethane 88/95A (MJF): Made for HP Multi Jet Fusion (MJF) printers. It has high tear strength and great detail—perfect for end-use parts. For example, a sports gear brand uses this to print flexible shoe soles; the soles are durable, stretchy, and hold their shape for months.
- SLS Flexible TPU/TPE: Designed for Selective Laser Sintering (SLS) printers. It’s corrosion-resistant and UV-stable, making it ideal for automotive parts (like gaskets) or shoe components. A shoe company in Italy uses SLS TPU to print custom shoe midsoles—they’re lightweight and absorb impact well.
- FDM TPU: Works with FDM printers (the most common home/office printers). While FDM TPU is cheaper, it has lower quality than SLS or MJF TPU (visible layer lines). It’s great for prototypes, like a hobbyist printing a flexible toy car tire.
TPU Pros & Cons
| Pros | Cons |
|---|---|
| Works with FDM, SLS, and MJF printers | FDM TPU has visible layer lines |
| Affordable (cheaper than DLS resins) | Not as soft as gel-like materials (Shore OO) |
| Durable (resists wear, UV, and water) | Can be tricky to print with FDM (needs slow speeds) |
2. Flexible TPE (Thermoplastic Elastomer)
TPE is similar to TPU but often softer. It’s best for SLS printers and is great for parts that need high elasticity.
Key Properties
- Hardness Range: 30 Shore A to 80 Shore A (softer than most TPU).
- Elasticity: Bounces back quickly after stretching—like a rubber band.
- Other Benefits: UV-stable and hydrolysis-resistant (works outdoors or in wet areas).
Use Case Example
A automotive parts manufacturer uses SLS TPE to print flexible gaskets for car doors. The gaskets seal out water and noise, and they last for years without cracking—even in extreme temperatures.
3. DLS FPU 50 (Flexible Polyurethane)
FPU 50 is a semi-rigid flexible material for DLS (Digital Light Synthesis) printers (a type of resin printing). It’s tougher than TPU and great for parts that need to handle repeated stress.
Key Properties
- Hardness: Similar to Shore 80A (firm but flexible).
- Strength: High tensile strength (resists stretching) and fatigue-resistant (handles repeated use).
- Detail: Can print features as thin as 0.25mm (great for small, precise parts).
Best Use Cases
- Snap-on fits (like a battery cover that clicks into place).
- Strain elimination parts (like cables that bend without breaking).
- Small circuit brackets (holds electronics securely but flexes if dropped).
Comparison to TPU
FPU 50 is more durable than TPU but less flexible. For example, if you need a part that bends often (like a phone grip), TPU is better. If you need a part that’s firm but can handle stress (like a circuit bracket), FPU 50 is better.
4. DLS EPU 40 (Elastomeric Polyurethane)
EPU 40 is a super soft resin for DLS printers. It’s like a gel and is perfect for parts that need to be squishy.
Key Properties
- Hardness: Shore 40A (very soft, like a stress ball).
- Feel: Squishy and elastic—bounces back after being squeezed.
- Limitation: Only for skin contact (not for mucosal contact, like inside the mouth).
Use Case Example
A wearable tech brand uses EPU 40 to print soft wristband liners for fitness trackers. The liners are comfortable against the skin and don’t irritate even after all-day wear.
5. DLS SIL 30 (Silicone-Polyurethane)
SIL 30 is a silicone-like resin for DLS printers. It’s soft to the touch and biocompatible (safe for skin contact)—great for medical or wearable parts.
Key Properties
- Hardness: Shore 35A (soft, like a silicone wristband).
- Biocompatibility: Safe for long-term skin contact (>30 days) and short-term mucosal contact (<24 hours).
- Other Benefits: Tear-resistant and easy to clean.
Best Use Cases
- Wearables (wristbands, headphone pads).
- Medical devices (soft grips for surgical tools, skin patches).
- Baby products (soft toy parts that are safe to chew).
3. Cost Comparison: Flexible Materials for 3D Printing
Cost is a big factor when choosing a flexible material. Below is a breakdown of unit costs for different materials (from Xometry’s quotation engine) to help you budget. Prices are in Euros (€) for a standard small part (e.g., a phone grip or small bracket).
| Material | Technology | Unit Cost (1 Piece) | Unit Cost (10 Pieces) | Unit Cost (100 Pieces) |
|---|---|---|---|---|
| TPU Polyurethane 88/95A | MJF | €29.95 | €12.37 | €11.41 |
| Flexible TPE | SLS | €25.84 | €23.24 | €21.41 |
| DLS EPU 40 | DLS | €212.44 | €48.82 | €48.82 |
| DLS FPU 50 | DLS | €436.53 | €100.31 | €100.31 |
| DLS SIL 30 | DLS | €632.56 | €159.24 | €159.24 |
Key Cost Takeaways
- Cheapest Option: Flexible TPE (SLS) or TPU (MJF) for small batches.
- Best for Bulk: TPU (MJF) has the biggest price drop when ordering 100 pieces (from €29.95 to €11.41 per unit).
- Most Expensive: DLS resins (FPU 50, SIL 30) are for high-end parts (like medical devices) where quality matters more than cost.
4. How to Choose the Right Flexible Material for Your Project
Follow these 3 steps to pick the best flexible material for 3D printing:
Step 1: Define Your Part’s “Feel” & Function
Ask yourself:
- How soft does it need to be? (Use the Shore hardness guide to match feel to use case.)
- Will it be used outdoors? (Choose UV-resistant materials like TPU or TPE.)
- Will it touch skin? (Pick biocompatible materials like SIL 30 or EPU 40.)
Example: If you’re making a flexible phone grip that’s used outdoors, Shore 50A TPU (MJF) is perfect—it’s soft, UV-resistant, and affordable.
Step 2: Check Your 3D Printer Type
Not all materials work with all printers:
- FDM Printers: Use FDM TPU (cheapest but lower quality).
- SLS Printers: Use SLS TPU or TPE (durable, no support structures).
- MJF Printers: Use MJF TPU (high quality, great for bulk orders).
- DLS Printers: Use DLS resins (SIL 30, EPU 40, FPU 50) for high-detail, soft parts.
Step 3: Set Your Budget
- If you’re on a tight budget: Go with FDM TPU or SLS TPE.
- If you need high quality for a small batch: Choose MJF TPU.
- If you need medical-grade or super-soft parts: Invest in DLS resins (SIL 30 or EPU 40).
5. Real-World Case Study: Flexible Material in Action
A small startup in Berlin wanted to create a custom flexible dog toy (a squishy bone that’s safe for chewing). Here’s how they chose the right material:
Step 1: Define Needs
- Feel: Soft (like a rubber chew toy) → Shore 40A.
- Safety: Non-toxic (safe for dogs to chew).
- Durability: Resists tearing (so dogs can’t destroy it quickly).
Step 2: Choose Material & Printer
They used Shore 40A TPU (FDM) because:
- It’s non-toxic and durable.
- They had an FDM printer (no need to buy new equipment).
- It was affordable (€30 for 1kg of filament—enough for 50 toys).
Step 3: Result
The startup printed 50 toys, tested them with local dogs, and got great feedback. The TPU toys lasted 2–3 months (longer than store-bought rubber toys) and were safe for chewing. They later scaled up to MJF TPU for bulk orders, cutting the unit cost from €1.50 to €1.10.
Yigu Technology’s View on Flexible 3D Printing Materials
At Yigu Technology, we believe TPU is the best starting point for most users looking for flexible 3D printing materials—it’s versatile, affordable, and works with most printers. For hobbyists, FDM TPU is great for prototypes; for businesses, MJF TPU offers the best balance of quality and cost for bulk orders. We also recommend SIL 30 for medical or wearable projects, as its biocompatibility and soft feel meet strict safety standards. Our team helps clients optimize designs for flexible materials—recently, we helped a fitness brand adjust their wristband design to use less TPU, cutting material costs by 20% without losing flexibility. The key is matching the material to the part’s function, not just picking the cheapest option.
FAQ:
1. Can I print flexible materials with a regular FDM printer?
Yes! Most regular FDM printers can print FDM TPU, but you may need to adjust settings:
- Slow down the print speed (20–30mm/s instead of 50mm/s) to prevent stringing.
- Use a flexible filament guide (to avoid tangles).
- Lower the retraction (1–2mm instead of 5mm) to keep the filament from breaking.
2. How do I know if a flexible material is UV-resistant?
Check the material’s spec sheet! Most TPU and TPE materials list “UV resistance” as a property. If you’re unsure, ask the manufacturer—for example, Xometry’s TPU 88/95A spec sheet clearly states it’s UV-resistant, making it safe for outdoor use.
3. Is there a flexible material that’s safe for food contact?
Yes, but options are limited. Look for food-grade TPU (some brands offer this). For example, a few manufacturers make TPU that’s FDA-certified for food contact—great for printing flexible ice cube trays or food storage lids. Avoid DLS resins (like SIL 30 or EPU 40) for food contact, as they’re not designed for this use.