FLSUN S1 Pro 3D Printer Review: Blazing 1200mm/s Speed Meets 350°C High-Temp Precision

The FLSUN S1 Pro represents a significant leap forward in delta-style 3D printing technology. This innovative design fundamentally changes rapid prototyping capabilities by maintaining exceptional print quality even at remarkable speeds. Delta configurations have always offered theoretical speed advantages, but the S1 Pro actually delivers on this promise with practical, usable results. By suspending the extruder from three arms in parallel rather than using the traditional Cartesian movement system, the printer achieves faster, more precise positioning with less inertia. Professional and enthusiast printing needs have traditionally required different equipment, but the S1 Pro effectively bridges this gap. Professional users benefit from the speed, precision, and advanced material handling, while enthusiasts gain access to capabilities previously reserved for industrial machines. What truly distinguishes this printer is its groundbreaking 1200mm/s speed capability. Most consumer and prosumer printers operate between 60-150mm/s, making the S1 Pro potentially 8-20 times faster. This dramatic speed increase transforms production timelines, enabling rapid iteration of designs and significantly reduced wait times for large prints.

Build Volume and Its Practical Applications

The massive Ø320mm x 430mm build volume provides exceptional versatility. This cylindrical print area accommodates large engineering components, full-size prototypes, or multiple smaller parts simultaneously. For context, this volume is approximately 34 liters, surpassing many competitors in its class by 30-50%.

Nozzle Technology and Temperature Capabilities

The hardened steel 0.4mm nozzle represents an optimal balance between detail and speed. While seemingly standard, the steel composition resists wear from abrasive materials like carbon fiber composites. The 350°C maximum temperature capability exceeds most competitors by 50-100°C, enabling proper extrusion of high-temperature engineering materials.

Acceleration Performance

The 40,000 mm/s² acceleration specification is particularly significant for delta printers. This acceleration rate allows the printer to reach top speeds almost instantaneously and maintain them even during complex geometries with frequent direction changes. In real-world printing, this translates to consistent extrusion rates and layer quality even on intricate models.

Build Surface Technology

The textured PEI build plate with 120°C maximum temperature provides excellent first-layer adhesion while allowing easy part removal after cooling. This temperature range supports even high-temperature materials like polycarbonate, which typically requires bed temperatures of 100-110°C for proper adhesion.

Structural Integrity

At 41kg, the S1 Pro's frame delivers substantial mass and rigidity. This weight might seem excessive, but it serves a critical purpose: minimizing vibrations that would otherwise cause ringing artifacts at high print speeds. The solid construction maintains precision even when the printhead is moving at maximum velocity and acceleration.

The S1 Pro supports an extensive range of materials beyond basic filaments. From standard PLA for quick prototypes to engineering-grade materials like polycarbonate and nylon, the printer handles virtually any 1.75mm filament on the market. The 350°C high-temperature extruder is particularly noteworthy as it unlocks professional-grade materials that typically require temperatures between 250-340°C. This includes polycarbonate (260-310°C), carbon fiber composites (240-280°C), and high-temperature nylons (250-300°C), materials that many sub-$5000 printers simply cannot process reliably. Complementing the thermal capabilities, the built-in filament dry box system actively preserves material quality during printing. Hygroscopic materials like nylon and TPU rapidly absorb atmospheric moisture, which causes popping, stringing, and structural weaknesses. The integrated dry box addresses this issue directly at the source. Temperature stability across long print sessions shows minimal variation, typically less than ±2°C at the hotend and ±3°C at the build plate. This consistency ensures excellent layer adhesion, particularly crucial for materials like ABS and ASA that are sensitive to thermal fluctuations.

Smart Features and Automation Systems

Auto-Calibration Technology

The full-auto calibration system eliminates one of the most frustrating aspects of 3D printing: manual bed leveling. Using precision sensors, the printer maps the build surface and compensates for any irregularities automatically. This process requires no user intervention and ensures consistent first layer adhesion across the entire build area.

AI Monitoring Capabilities

The integrated AI monitoring system provides real-time camera feedback with intelligent error detection. The system can identify common failure modes like "spaghetti" prints, debris accumulation, and layer shifts. When issues are detected, the printer can either alert the user or, in some cases, pause the print automatically to prevent material waste.

Zone Heating Efficiency

The smart zone heating approach divides the build plate into two regions: an inner circle (Φ220mm) and an outer ring (220-320mm). This division allows the printer to selectively heat only the areas needed for a particular print, reducing power consumption by up to 40% for smaller objects. The system maintains precise temperature control in the active zones while allowing inactive areas to remain cooler.

Fail-Safe Features

The combination of filament detection and power loss recovery features provides robust protection against common print failures. The filament sensor detects both run-outs and clogs, pausing the print until the issue is resolved. Similarly, the power loss recovery function allows prints to resume precisely where they left off after a power interruption, saving hours of print time and material.

Firmware Advantages

Running on Klipper firmware, the S1 Pro leverages the processing power of a dedicated computer to calculate optimal motion planning. This approach delivers superior kinematics compared to traditional microcontroller-based systems. The OTA (Over-The-Air) update capability ensures the printer can receive new features and optimizations without complex manual firmware flashing procedures.

When evaluating speed versus quality, the S1 Pro maintains impressive detail integrity up to approximately 600mm/s for most models. Between 600-900mm/s, some minimal quality reduction becomes visible on fine details and overhangs. At maximum speeds of 1000-1200mm/s, the printer still produces functional parts, though with some visible artifacts on complex geometries. The vibration compensation technology proves particularly effective at speeds above 400mm/s. Without this feature, rapid direction changes would create ringing artifacts (ghosting) around corners and details. The implementation effectively counteracts these mechanical resonances by predicting and adjusting for them in real-time. Noise testing confirms the manufacturer's claim of ≤55 dB during standard operation. Even at maximum speeds, the printer rarely exceeds 58 dB, remaining quieter than many conventional printers operating at one-fourth the speed. This is particularly impressive considering the rapid movements of the delta mechanism. Temperature consistency during 12+ hour print sessions shows exceptional stability. The hotend maintains target temperatures within ±3°C even during rapid extrusion at maximum speeds, while the bed temperature variance remains within ±2°C across the heated surface. Benchmark comparisons reveal print time reductions of 60-80% compared to leading competitors when printing identical models. A complex 150mm tall engineering part that requires 9 hours on a conventional printer completes in approximately 2-3 hours on the S1 Pro at high speeds while maintaining comparable quality.

User Experience and Interface Design

The 7" color touchscreen provides an intuitive interface with responsive controls and clear visual feedback. The menu structure logically organizes functions into print, prepare, control, and settings categories with minimal sub-menu nesting, reducing the learning curve for new users. While the FLSUN Slicer V2.0 is optimized for this specific printer, the S1 Pro maintains excellent compatibility with popular alternatives including PrusaSlicer, Cura, and Simplify3D. The printer accepts standard G-code files and supports all common 3D model formats (STL, OBJ, AMF, 3MF). Initial setup requires approximately 30-45 minutes from unboxing to first print, significantly faster than most kits and only slightly longer than pre-assembled Cartesian printers. The calibration process is largely automated, requiring minimal user intervention beyond following the on-screen prompts. Maintenance accessibility is well-designed, with the extruder assembly easily removable for cleaning or nozzle changes. The linear rails and motion components are accessible without major disassembly, facilitating regular maintenance of these critical systems. The learning curve presents a moderate challenge for absolute beginners but proves quite manageable for users with basic 3D printing experience. Most users report feeling comfortable with basic operations within 1-2 days and mastering advanced features within 1-2 weeks.

Environmental Considerations and Workshop Integration

The closed chamber design creates a controlled printing environment critical for temperature-sensitive materials like ABS, ASA, and polycarbonate. This enclosure maintains ambient temperatures 15-30°C above room temperature during printing, preventing warping and layer separation in high-temperature materials. The integrated HEPA and activated carbon filtration system captures up to 95% of ultrafine particles and reduces VOC emissions from melting plastics. This feature is particularly valuable for indoor environments, though supplemental ventilation remains recommended for extended printing with high-temperature materials. Power consumption analysis shows peak usage of approximately 750W during initial heating, settling to 350-450W during printing depending on chamber and bed temperature settings. The zone heating feature reduces this consumption by 15-40% for smaller prints. With dimensions of 550mm x 595mm x 1030mm, the printer requires substantial dedicated space. The height dimension is particularly important to consider, as the unit requires approximately 20cm of additional clearance above for filament loading. The printer works best on a solid, stable surface like a workbench or dedicated printer stand. Workshop compatibility is enhanced by the relatively low noise output, though positioning away from drafts or temperature fluctuations improves performance with sensitive materials. The printer's self-contained nature means it doesn't require extensive external infrastructure beyond power and network connectivity.

The FLSUN S1 Pro represents a significant evolution in desktop 3D printing technology, combining industrial-grade speed with exceptional versatility. While its premium price point places it beyond casual hobbyists, the dramatic time savings and expanded material capabilities deliver genuine value for professionals and serious enthusiasts. The full-auto calibration and smart features remove many traditional 3D printing pain points, while the robust construction ensures consistent results even at maximum speeds. For those who value their time and require both speed and precision, the S1 Pro stands as one of the most compelling options in today's market.