Discover why PSU (Polysulfone) is redefining high-performance 3D printing in medical, aerospace, food, and industrial applications.
What is PSU (Polysulfone)?
PSU, or polysulfone, is an amorphous, high-performance thermoplastic engineered for extreme environments. Commercialized in the 1960s, it’s known for its heat resistance, dimensional stability, and exceptional clarity. Chemically built on aromatic rings, ether linkages, and sulfonyl groups, PSU resists radiation, oxidation, and thermal degradation—making it ideal for sterile and rugged applications.
Where Is PSU Used?
From space helmets to dialysis filters, PSU is trusted by industries where failure isn’t an option:
- Medical: Used by GE Healthcare, Medtronic, and Baxter for surgical instruments, blood filters, and sterilization trays thanks to its biocompatibility and autoclave resistance.
- Filtration: 3M and Pall Corporation use PSU in ultrafiltration membranes due to its performance in hot, chemically active water environments.
- Food & Beverage: Found in Keurig brewers, coffee dispensers, and milking machines—PSU is FDA and NSF compliant for repeated contact with hot and acidic substances.
- Automotive: Trusted by Bosch and Valeo for sensor housings and fuel system components where heat, vibration, and chemical exposure are routine.
- Aerospace & Defense: Used in aircraft ducting, electrical insulators, and even space equipment for its flame resistance and low smoke toxicity.
Technical Specs at a Glance
- Tensile Strength: ~70 MPa
- Flexural Strength: ~106 MPa
- Glass Transition Temperature: 187–190°C
- Heat Deflection Temperature (HDT): ~175°C @ 1.8 MPa
- Max Continuous Use Temp: ~160°C
- UL 94 Rating: V-0 (flame retardant)
- Water Absorption: 0.2–0.3%
- Dielectric Strength: ~17 kV/mm
Why Choose PSU for 3D Printing?
PSU stands out for its unique blend of performance properties:
- Resists deformation under high heat and humidity
- Inherently flame retardant and self-extinguishing
- Transparent, strong, and chemically resistant
- Does not degrade in steam or autoclaves
- Comparable to PEEK in performance—but easier to print
How to Print PSU Successfully
Printing PSU requires precision, but it’s surprisingly forgiving for a high-temp material. Key printing parameters include:
- Nozzle Temperature: 360–370°C
- Bed Temperature: 140–160°C
- Chamber Temperature: Minimum 90°C, ideally 140°C+
- Drying Requirements: 3–4 hours at 130–160°C before printing (critical!)
- Best Layer Heights: 0.1–0.2 mm
Use a vacuum oven or a quality filament dryer to prevent moisture-induced bubbling and poor surface quality.
Real-World Performance Tests
Thermax™ PSU isn’t just specs—it’s been tested against propane torches, universal testing machines, and microscopic failure analysis. Here’s how it performs:
- Flame Resistance: Self-extinguishes in ~5 seconds after 3600°F torch exposure
- Tensile Strength: Over 2,000 newtons in XY axis prints
- Z-axis Weakness: Still performs well, though layer lines remain the weakest link
- Microscopic Inspections: Confirm excellent layer bonding and minimal material degradation
Is PSU Right for Your Application?
If your project demands heat resistance, sterilizability, clarity, and durability—Thermax™ PSU deserves a spot in your filament arsenal. Whether you’re prototyping medical tools, producing high-temperature manifolds, or building flame-retardant housings, PSU delivers professional-grade results straight off an FDM printer.
Final Thoughts & What’s Next
As testing expands with pressure vessels, paracity, and advanced chemical immersion trials, PSU is proving to be more than just a niche material. It’s a versatile, durable alternative to more expensive polymers like PEEK—without sacrificing printability.
Expect more data-driven reviews, stress tests, and materials comparisons in the future. For engineers, designers, and manufacturers looking for that perfect balance of performance and printability, PSU might just be the hidden gem in your next high-temp build.
Ready to try Thermax™ PSU for yourself? Browse 3DXTech materials at Vision Miner and take your prints to the next level.