Direct answer: FLSUN currently calls PLA, PETG and TPU ideal materials for the S1 Pro; ABS, ASA, PA, PC and PET satisfactory; and carbon/glass-fiber-reinforced PLA capable. The older S1 FAQ names a wider set that also includes PVA/HIPS support materials plus PA-CF/GF, PET-CF/GF and PPA-CF/GF. Treat those as two model-specific manufacturer records, not one unlimited family promise.
Both machines have a fully enclosed delta layout, a 350 °C hardened-steel nozzle, a 120 °C bed, a textured PEI plate and a filament-drying compartment. Those features make the family unusually broad, but the enclosure is not an actively heated chamber: FLSUN says the original S1 can reach about 50 °C only when the nozzle and bed are heated and the machine is closed. Exact grade, drying, feed route, chamber stability, surface, ventilation and finished-part proof still decide the job.
FLSUN S1 family material compatibility at a glance
| Material group | Verdict | Decision that matters |
|---|---|---|
| PLA | Straightforward; ideal on the current S1 Pro list | Use an exact profile; filled, foaming, silk and high-flow PLA can change cooling, wear and flow limits. |
| PETG and TPU | Ideal on S1 Pro; condition dependent | Dryness, spool drag, feed path, hardness, cooling and PEI release remain grade-specific. |
| ABS and ASA | Satisfactory; environment conditional | The closed shell helps, but there is no active chamber heater. Part footprint, drafts, surface, cooldown and ventilation can veto the job. |
| PA, PC and PET | Satisfactory on S1 Pro; strongly grade conditional | Recovery drying, sealed handling, chamber stability, build interface and representative-part qualification are part of capability. |
| Carbon/glass-fiber PLA | Capable on the current S1 Pro list | The hardened nozzle addresses wear, not every grade's minimum nozzle diameter, moisture, particle size or clog risk. |
| PA-CF/GF, PET-CF/GF and PPA-CF/GF | Named by the older S1 FAQ, not the current Pro tier table | Keep the claim model-specific and require an exact grade, current profile, drying process, nozzle and chamber proof. |
| PVA and HIPS support | Named in the S1 FAQ; workflow conditional | A single-nozzle machine needs a practical change strategy; pairing, moisture, purge, bonding and removal govern usefulness. |
| PP, POM, PVDF, PEEK, PEI/ULTEM, PPS and unlisted specialties | Unsupported or poor fit by default | Temperature overlap does not establish manufacturer support, surface compatibility, chamber control or safe processing. |
What the current S1 Pro record actually establishes
FLSUN's current S1 Pro specification page is the strongest family source because it does more than list temperatures. It identifies a closed chamber, 0.4 mm hardened-steel nozzle, 350 °C hotend ceiling, 120 °C build-plate ceiling, textured PEI plate, active-heating dry box and three material tiers. It also lists HEPA plus activated-carbon filtration. The tier language matters: “ideal,” “satisfactory” and “capable” should not be flattened into “all equally easy.”
The official S1 Pro wiki adds PLA, PETG, TPU, ABS, ASA, PVA, PET, PA, PC and PLA-CF, and says the Pro added another feed port for filament that cannot fit inside the filament box. That creates a useful ownership decision. Use the integrated dry-box route when the spool fits and the required drying conditions are appropriate; use the external port when spool size or geometry requires it, while providing separate dry handling when moisture-sensitive material is involved.
FLSUN's live US product JSON still identifies the S1 Pro as the exact current product and supplies the official hero used here. It does not add a more precise material table, so this guide does not convert its generic “wide range” language into new capability claims.
How the original S1 differs from the S1 Pro
The original S1 remains documented on FLSUN's current site and wiki, but its FAQ is broader than the Pro's current tier table. It names ordinary low-temperature materials, support materials and several fiber-filled engineering families. The S1 wiki also calls its nozzle hardened steel and suitable for composites. Those are manufacturer statements with scope, not independent proof that every formulation will run with the same setup.
The most defensible family rule is simple: use the exact model's current record. For an S1 Pro, start from the current ideal/satisfactory/capable table. For an original S1, preserve the FAQ's broader list but qualify the exact spool, profile, nozzle diameter, conditioning, surface and chamber behavior. Do not use the original S1's PPA-CF/GF line to silently expand the S1 Pro table, and do not assume a Pro purchase makes the older S1's AI or feed arrangement identical.
Both use a delta build envelope with the maximum cylindrical height lower at the outer edge than at the center. Material selection does not remove that geometry boundary. For a cross-machine example of how model-specific limits should be routed, compare the Bambu Lab P2S material guide, then qualify the S1 job's actual footprint and height.
PLA, PETG and TPU: the practical baseline
PLA is the easiest starting material for visual models, organizers, fixtures and dimensional prototypes. Keep the enclosure behavior in mind: a fully closed hot chamber can be counterproductive for some low-temperature PLA jobs, especially tall prints or small features that need cooling. Use the exact profile and observe the manufacturer's ventilation and door guidance rather than assuming “enclosed” always means “keep it sealed.”
PETG is a strong everyday route when toughness and moisture resistance matter more than PLA's easy stiffness. It still absorbs moisture, can string and may bond too aggressively to some smooth surfaces. Follow the textured PEI and filament instructions, and use the PETG drying-versus-storage guide to separate recovery drying from ordinary sealed storage.
TPU is ideal on FLSUN's Pro table, but hardness changes the feed decision. A result with mainstream 95A does not qualify a softer grade. Moisture, spool drag, the internal or external feed route, retraction and unsupported geometry can cause buckling or inconsistent flow. The TPU drying guide helps distinguish a wet-spool symptom from a mechanical feed problem.
ABS and ASA: enclosure helps, but it is not active chamber control
FLSUN places ABS and ASA in the S1 Pro's satisfactory tier. That is appropriate: the closed shell reduces drafts and helps retain heat, but the S1 FAQ explicitly says there is no cavity-heating function. Its roughly 50 °C statement is a maximum reached when other heaters are at their highest and the machine is enclosed, not a regulated chamber setpoint promised for every job.
Wide ABS or ASA parts can still curl, split or release as room conditions, bed contact and cooldown change. Follow the exact grade's surface and chamber instructions, keep the machine away from drafts and qualify representative footprint. The ABS and ASA printer guide is the better route when recurring large engineering-material work is the purchase decision.
Filtration is not a universal exposure guarantee. FLSUN's HEPA and activated-carbon system is a useful machine feature, but filter state, leakage, room volume, material and operating temperature all matter. Use source control and suitable room ventilation under current equipment and material safety instructions.
Nylon, PC, PET and composites need a complete process
PA, PC and PET are satisfactory rather than ideal on the Pro table. That is a useful warning against temperature-only reasoning. Nylon may need recovery drying before the integrated box can maintain it. PC formulations vary widely in bed, chamber and adhesion needs. PET is not automatically interchangeable with PETG. Use the exact grade's technical and safety data, then qualify a representative part after full cooldown.
For nylon, the nylon drying-versus-storage guide explains why a maintenance box is not always a recovery dryer. Keep a prepared spool sealed through a long print and track exposure during changes. When engineering composites dominate the workload, compare purpose-built options in the nylon and carbon-fiber printer guide.
The hardened 0.4 mm nozzle is meaningful for abrasion, but “hardened” is not universal composite approval. Check the filament maker's minimum orifice, particle size, drying cycle, print temperature and surface. FLSUN's current Pro table specifically names carbon/glass-fiber-reinforced PLA; the original S1 FAQ separately names PA-, PET- and PPA-based composites. Preserve that distinction.
Filled material can improve stiffness while reducing impact behavior or changing layer-direction strength. Sanding, drilling and cutting can create dust. Control dust under the safety data and suitable PPE, and never infer a structural rating from the fact that a spool printed.
PVA, HIPS and unsupported materials
The older S1 FAQ includes support materials for PLA and PETG and names PVA and HIPS. On a single-nozzle machine, those materials are useful only when the change strategy and model pairing are practical. PVA is highly moisture sensitive; the PVA feed diagnostic covers moisture and clog symptoms. HIPS removal can involve solvents, which adds chemical, fire, ventilation, PPE, storage and waste requirements governed by the solvent safety data.
PP, POM, PVDF, PEEK, PEI/ULTEM and PPS are not established by the current sources used here. Some need specialized surfaces, actively controlled hot chambers, different nozzle materials or industrial exposure controls. The correct default is unsupported or poor fit—not “maybe” because the hotend reaches 350 °C. Select equipment with explicit manufacturer support or use a qualified production service.
Seven checks before a non-routine spool
- Exact model: decide whether the evidence belongs to the original S1 or the current S1 Pro.
- Exact grade: use current filament technical and safety data, not only a family name.
- Feed route: confirm spool fit, internal dry-box suitability, external-port geometry and drag.
- Nozzle: confirm material, diameter, wear state and the grade's minimum orifice.
- Environment and surface: verify PEI instructions, chamber stability, cooldown, ventilation and fire precautions.
- Conditioning: distinguish recovery drying from maintenance storage and protect the spool during printing.
- Acceptance: qualify dimensions, layer bond, creep, fatigue, heat, weather and chemicals in representative geometry.
If one check lacks evidence, the answer is “not yet qualified,” not “the temperature range overlaps.”
Safety and finished-part use limits
Operate the printer, dry box and filters under current FLSUN instructions. Maintain electrical and fire clearances, keep hot and moving parts guarded, and do not defeat cooling or safety paths. Do not leave a newly introduced high-temperature or composite process unattended until it has been safely qualified under the equipment instructions.
NIOSH's safer-3D-printing guidance treats ventilation and high-efficiency filtration as parts of source control. Follow the exact filament safety data, provide suitable ventilation, replace filters as directed and control composite or finishing dust. Odor is not an exposure measurement, and GoodPrints is not the final workplace-safety authority.
A printable object is not automatically suitable for food contact, potable water, medical use, pressure containment, mains electrical insulation, fire performance, vehicle-control duty or structural safety. Formulation, contamination, orientation, voids, creep, fatigue and post-processing can dominate service behavior. Start with the part's real operating conditions.
Buyer and owner decision
- Choose or keep either S1 model for fast PLA and PETG work where the delta envelope and integrated handling fit the job.
- Choose the S1 Pro when its current tiered record, extra feed port, active-heating dry box and current product/support route matter more than the older S1's broader FAQ.
- Use ABS, ASA, PA, PC and PET conditionally when exact-grade drying, surface, chamber stability and ventilation can be controlled.
- Keep composite claims model-specific: current Pro evidence clearly names reinforced PLA, while the older S1 FAQ carries the broader PA/PET/PPA composite language.
- Choose another qualified machine or service when an actively heated chamber, an unlisted high-performance polymer, traceability or controlled exposure is mandatory.
For a defined part, request a GoodPrints quote; for repeat production and broader equipment access, use the JC Print Farm route.
Bottom line
The FLSUN S1 family has real engineering-material range, but the two models do not have one interchangeable list. PLA, PETG and TPU are the S1 Pro's ideal lane. ABS, ASA, PA, PC and PET are conditional. Reinforced PLA is the current Pro composite claim, while the older S1 FAQ owns the broader filled-material list. Hardened hardware, enclosure and drying help, but exact grade, feed, surface, chamber, ventilation and finished-part qualification retain veto power.
Official sources checked
- FLSUN S1 Pro specification page for the current ideal, satisfactory and capable tiers, nozzle, bed, PEI plate, dry box and filtration record.
- FLSUN S1 FAQ for the original S1 material list, hardened nozzle and non-active chamber boundary.
- FLSUN S1 Pro filament wiki for the exact named materials and external feed-port route.
- FLSUN S1 Pro component wiki for the hardened-nozzle and enclosed-machine architecture.
- FLSUN US S1 Pro product record for current product identity and official imagery.
- NIOSH: Approaches to Safe 3D Printing for ventilation, filtration and source-control boundaries.