3D printing allows for the creation of durable parts and prototypes by depositing material layer by layer. Choosing the right filament is crucial for attaining maximum strength for your application. The strongest materials are characterized by high tensile and flexural strength, resistance to impacts, and stability under load.

With a wide range of materials now available for fused deposition modeling (FDM) 3D printers, identifying the best option for strength can be challenging. Factors like layer adhesion, temperature resistance, printing difficulty, and expense must also be weighed. This guide examines the top 10 Strongest 3D Printer Filaments choices available today.

1. Carbon Fiber Reinforced Filaments

By far the strongest 3D printer filaments utilize carbon fiber reinforcement. Tiny carbon fibers are embedded in the filament, providing a significant boost in tensile strength, rigidity, and durability. The carbon fiber dramatically outperforms non-reinforced materials.

Common base plastics that are combined with chopped carbon fiber include:

• ABS – Acrylonitrile butadiene styrene is a rigid thermoplastic known for its high impact resistance. The addition of carbon fiber enhances the strength and temperature resistance further.
• Nylon – One of the strongest unfilled polymers, nylon gets even better strength when reinforced with carbon fiber. It offers excellent wear resistance.
• PETG – Polyethylene terephthalate glycol-modified maintains good impact strength but has only moderate rigidity unless combined with carbon fillers.
• Polycarbonate – Already an excellent choice for durability, polycarbonate becomes extremely strong and rigid when carbon reinforced.

Carbon fiber filaments do have some tradeoffs, including abrasiveness on nozzle tips, less flexibility, and difficulty printing small detailed features. Proper drying is also critical to prevent splintering of the carbon fibers. Overall though, the exponentially better strength makes these the best choice where high loads or impacts are expected.

2. Nylon

For unreinforced materials, nylon ranks at the top for strength. This engineering thermoplastic offers the best mix of rigidity, durability, and resistance to bending stresses and mechanical wear.

Nylon’s precise properties differ slightly by variety:

• Nylon 6 – Great for parts that require some flex and resistance to cracking under load. It has high impact strength.
• Nylon 6/6 – With outstanding tensile strength and modulus of elasticity, this is the toughest nylon variant. Perfect for components needing the ultimate in stiffness.
• Nylon 12 – Offers excellent chemical resistance and layer bonding even without heated bed. Not as strong as 6 or 6/6 but easier to print.

The main challenges with nylon involve its tendency to absorb ambient moisture leading to bubbling and cracking issues during printing. Proper drying and storage is mandatory. An enclosed printer and heated bed are also recommended for best interlayer adhesion.

3. Polycarbonate

For an unreinforced material with temperature resistance up to 130°C, polycarbonate is as strong as it gets. It offers an unmatched combination of tensile strength, impact resistance, and durability.

PC is the plastic used for bulletproof glass and CDs. Parts printed in polycarbonate exhibit high stiffness and can withstand heavy loads and abuse without fracturing. The thermoplastic softens gradually under heat rather than melting completely, further enhancing high-temperature performance.

Despite poor UV resistance causing yellowing, polycarbonate’s extreme mechanical properties make it one of the strongest materials for 3D printing. Just be prepared for stringent printing requirements including a heated chamber and well-tuned hotend capable of 260-280°C temperatures.

4. ABS

A long-time workhorse 3D printing material, ABS maintains good strength-to-cost ratio. It possesses high impact resistance, toughness, and moderate flexibility when printed properly.

While not at the level of advanced polymers like nylon and polycarbonate, ABS strength exceeds basic PLA plastic across the board. At 100% infill, tensile strength of over 40 MPa is possible.

The main advantage of ABS is how easy it is to print compared to high-performance materials. Adhesion can still be challenging but is manageable on heated glass print beds. Just take measures to limit cooling-induced warping.

For strong parts on a budget, choose ABS filament with a minimum 20% infill and utilize a larger nozzle for faster prints. The material can be sanded and polished easily for smooth finishes.

5. PETG

PETG combines the durability and temperature resistance of PET plastic with the improved impact strength of glycol-modified formulations. Among amorphous plastics, it hits a sweet spot for strength and printability.

While still below ABS and nylon in raw strength, PETG compensates with superior layer bonding to prevent cracks and splits under load. Optimal infill level is 40-60% for rigid and durable finished components.

PETG’s ease of printing is a major advantage. Warping and shrinkage are minimal, and any standard build surface works reliably. Strong parts can be achieved hassle-free even on unheated print beds.

6. High-Performance PLA Materials

Standard PLA is no strength champion, but modified PLA filaments have emerged to boost stability and toughness significantly. These include:

• PLA Alloy – Blended with rubbers for flexibility and impact resistance rivaling ABS. Layer adhesion improves.
• PLA/PHA – PHA bioplastic enhances thermal properties and tensile strength beyond basic PLA.
• Carbon Fiber PLA – With 5-15% chopped carbon fiber, achieves 60% higher strength and rigidity than original PLA.
• HT (High-Temp) PLA – Adds heat deflection stability up to 100°C for stronger performance under load at higher temperatures.

While cost-effective, high-strength PLA filaments generally lag behind advanced materials like nylon and polycarbonate on maximal load bearing capabilities. But large 3D models benefit from faster print speeds than more difficult materials allow.

7. Composite Wood Filaments

Wood-based composites like Wound Up and ColorFabb contain up to 40% recycled wood fiber in a PLA matrix. The cellulose filler enhances stiffness and resistance to bending stresses significantly.

These materials contain no actual wood; rather, pulverized cellulose is used as a strengthening additive. Parts feel similar to wood but with the temperature resistance of PLA plastic.

The wood-based layers bond tightly for good interlaminar rigidity. Just use higher infill levels (40-60%) and slower print speeds to capitalize on the improved strength properties.

8. Glass-Reinforced Filaments

Similar to carbon fiber, fine glass fibers can dramatically augment the structural properties of a 3D printing material when used as filler. Strength improvements of 200-500% are attainable.

PLA, nylon, and PETG benefit the most from glass reinforcement. The fibers increase tensile and flexural strength as well as max load capacity. They also add rigidity and creep resistance under heavy loads over time.

The challenge with glass-filled filament lies in filament quality control. Poor dispersion of the glass particles can cause nozzle clogs and uneven extrusion. When produced carefully though, glass reinforcement rivals carbon fiber for boosting part strength.

9. TPU (Thermoplastic Polyurethane)

For applications requiring flexibility, elasticity, and resistance to dynamic rather than static loads, TPU is the strongest choice. The dense plastic has hardness levels from 85A to 95A shore.

At 100% infill, TPU can withstand over 3000 bending cycles without any compromise in mechanical performance. This makes it ideal for functional components like hinges and latches that need to flex repeatedly without cracking.

While rigid plastics are stronger under direct tensile loads, TPU withstands regular cyclical stresses and impacts better. The excellent abrasion resistance also makes it a good choice for RC car tires needing durability.

10. Metal-Filled Composite Filaments

Composite filaments infused with tiny metal particles like bronze, copper, stainless steel, and iron provide enhanced structural rigidity and load capacity. Tensile strength can double that of non-filled materials.

A primary benefit of metal fillers is their density. The increased weight of printed parts improves stability. Applications like drone frames and 3D-printed molds see the most gain from metal reinforcement.

On the downside, abrasive metal particles in the filament tend to wear down nozzles quickly. Hardened steel nozzles are a must. The composites also have lower maximum print temperatures than their base plastics normally allow.

Key Considerations When Choosing a Strong 3D Printer Filament

While this guide ranks the top materials for strength, the optimal option depends heavily on your specific application and property needs:

• Tensile Strength – Maximum resistance to pulling/tearing stresses. Nylons score highest.
• Impact Strength – Ability to resist fracture from sudden impacts or forces. TPU and reinforced PETG are best.
• Flexural Strength – Resistance to breakage when bent. Carbon fiber variants excel here.
• Modulus of Elasticity – Measure of stiffness and resistance to variable loads. Highest with carbon fiber or glass-filled materials.
• Fatigue Strength – Ability to endure cyclical stress applications without failure. TPU has outstanding fatigue life.
• Creep Resistance – How well a material resists deforming permanently under high loads over time. Polycarbonate and nylon are superior.
• Interlayer Bonding – Critical for translating infill strength to total printed part. Nylon and PETG bond layers tightly.
• Print Difficulty – Advanced high-strength materials require more optimized printers and dialed-in settings.

Carefully balance the design strength needs versus printability when selecting a filament. Reinforced materials deliver the most impressive mechanical properties but require expertise to print successfully.

Tips for Getting Strong Parts From Your 3D Filament

Follow these best practices to ensure you maximize the strength potential of your chosen material:

• Print with 100% infill whenever possible for solid internal structure.
• Use at least 3 solid top/bottom layers for greater resistance to shear and compressive forces.
• Align the load direction with the print layers for best tensile and flexural strength.
• Minimize overhangs and angles below 45° to improve interlayer bonding.
• Slow down print speed for a more precisely extruded bead path.
• Print with a larger nozzle (0.6mm+) to eliminate small weak points and voids between layers.
• Use a heated print bed and enclosure for better adhesion with challenging materials like nylon and PC.
• Dry filament properly before use and store in a sealed container with desiccant.
• Replace nozzle when you observe changes in extrusion quality or under-extrusion.

Follow the manufacturer’s guidelines for optimal print bed and hotend temperatures. Test your printer’s settings with a new material on a benchmark print before attempting your final part.

Leverage Strength Where It’s Needed Most

One final tip – conserve material by using stronger reinforced filaments only for the high-stress sections of a print. For example, use PETG or ABS for the main body and switch to carbon fiber reinforced supports and connection points.

Choosing the right filament material is the first step to maximizing part strength. Match the material characteristics to your loading needs, then refine the print settings until layer bonding is optimized. With the strongest plastics and composites now available on the desktop, impressive resilience is attainable with the proper techniques.