What Materials Can the Markforged Mark Two Print?

Direct answer: the Markforged Mark Two currently lists four composite base filaments—Onyx, Nylon, Smooth TPU 95A and Precise PLA—and four continuous reinforcements—Carbon Fiber, Fiberglass, Aramid Fiber (Kevlar®) and HSHT Fiberglass. The reinforcement is not a standalone filament choice: Eiger places it inside an eligible supported base and geometry. Markforged's April 2024 Mark Two datasheet says Nylon White where the current product page says Nylon, so confirm the exact supplied grade and current Eiger profile rather than treating those names as interchangeable.

The Mark Two is therefore a focused composite system, not an open high-temperature printer. Onyx FR, Onyx ESD, Onyx GF, Nylon White FS, Carbon Fiber FR, Carbon Fiber HT-A, PEEK, ULTEM, metals, generic third-party filament, pellets, resin and powder are not on the current Mark Two product-page list. A material's presence elsewhere in Markforged's portfolio does not make it Mark Two-compatible, and a nozzle or temperature number alone cannot add it.

Mark Two material compatibility at a glance

What the current Mark Two record actually establishes

The live Markforged page identifies the Mark Two as a desktop Continuous Fiber Reinforcement system. It lists a 320 × 132 × 154 mm build volume, a precision-ground composite bed, 100–250 µm layer resolution and two media classes: composite base filaments and continuous fibers. The April 2024 datasheet describes fused filament fabrication plus continuous filament fabrication, a second-generation extruder, out-of-plastic detection, a 100–240 VAC input and 150 W power rating.

Those are system boundaries, not permission to extrapolate. The current product page's material section is the controlling short list. The broader Markforged material catalog includes products for other machines, including flame-retardant, ESD, glass-filled and high-temperature grades. Portfolio membership does not establish a Mark Two profile, compatible wear hardware, safe feed path, print surface, warranty state or useful part.

The product page also says the removable bed can be replaced with 10 µm repeatability. That is a manufacturer system claim, not a promise that every printed dimension repeats to 10 µm. Polymer shrinkage, moisture, layer orientation, fiber placement, geometry, calibration and measurement method remain part of any tolerance claim. Qualify the actual part and process.

Base filament and continuous fiber are two different decisions

Every Mark Two job begins with a supported base filament. That base forms shells, infill, small features and the material surrounding any reinforcement. A continuous-fiber spool does not replace the base and cannot be printed alone. Eiger must generate a fiber path inside geometry large enough to accept it, and the printer uses a separate reinforcement system to place that path.

This distinction matters at quotation time. Asking whether the machine "prints carbon fiber" could mean chopped carbon inside Onyx, or continuous Carbon Fiber routed through selected regions. Onyx changes the base polymer throughout the part. Continuous Carbon Fiber creates directional reinforcement only where it is placed. A buyer should define load direction, stiffness, impact, temperature, weight, fasteners, surface, cycle count and failure consequence before choosing either.

Continuous reinforcement does not make a printed part isotropic or automatically equivalent to machined aluminum. Holes, bosses, thin ribs, sharp corners, unsupported transitions and small features may have little or no room for fiber. Loads still cross polymer layers and fiber-to-polymer interfaces. Inspect the actual sliced layup, then test representative parts and assemblies in the intended orientation and environment.

Onyx is the default structural base, with moisture and abrasion limits

Markforged describes Onyx as a micro carbon-fiber-filled nylon. The hardened extrusion system is part of why the Mark Two can process it repeatedly; it is not evidence that every abrasive third-party composite is supported. Use the current Markforged spool and Eiger path unless Markforged provides a written alternative.

The nylon base is moisture-sensitive. Sealed storage helps preserve a dry spool but does not prove that a wet spool has recovered. Follow the current material-specific storage and drying instructions, log time outside controlled storage when the job matters, and watch for surface change, bubbles, stringing, inconsistent flow and dimensional drift. The nylon drying-versus-storage guide and nylon-composite drying guide explain why prevention and recovery are separate decisions.

Onyx can be printed without continuous reinforcement for fixtures, covers, brackets and prototypes where its base properties are enough. Add continuous fiber only when the load case and geometry benefit. More fiber is not automatically better: unnecessary rings can add time and cost, while poorly placed fiber can miss the load path or crowd critical features.

Nylon versus Nylon White is a grade-confirmation gate

The current Mark Two web page lists "Nylon." The current F-PR-2027 datasheet, revised April 30, 2024, lists "Nylon White." Markforged also markets a separate Nylon White FS grade elsewhere in its portfolio. Those labels should not be collapsed into a single promise. Before quoting color, compliance, mechanical behavior or availability, confirm the exact spool name, part number, Eiger profile and current Mark Two compatibility.

A compatibility statement never makes a printed part food safe, medical safe, pressure safe or certified for a regulated application. Surface porosity, wear, cleaning, contamination, geometry, additives, process records and the exact standard scope still apply. Use traceable material and representative finished-part evidence when compliance matters.

Precise PLA and Smooth TPU 95A serve different jobs

Precise PLA gives the Mark Two an explicit lower-cost base option for models, checking fixtures and form-and-fit work. It should not inherit Onyx's chopped-fiber description or the structural claims attached to a continuous-Carbon-Fiber layup. If a part will see heat, sustained load, impact, chemicals or outdoor exposure, define that environment and select from evidence rather than assuming the desktop composite printer makes PLA suitable.

Smooth TPU 95A is the product page's explicit flexible option. The 95A hardness is important: it does not establish support for 90A, 85A or very soft TPU. Flexible parts fail by tear, notch growth, creep, compression set, heat, abrasion and layer separation as well as simple tensile load. Test the actual wall thickness, bend radius, clamp dwell and environment. The current compatible list also does not say that continuous fiber can be embedded in TPU; require a visible Eiger pairing before promising it.

Choose the reinforcement by failure mode, not by headline strength

Continuous Carbon Fiber is the stiffness-first option. It can be valuable for long fixture arms, load-bearing brackets and parts where deflection controls usefulness. The datasheet's tensile figures are explicitly continuous-carbon-fiber data and approximate. They are not blanket values for Onyx-only parts, every layup, every direction or a finished assembly.

Fiberglass is a supported general-purpose reinforcement. It may fit jobs that need more stiffness or strength than base polymer without the same performance target as carbon fiber. Aramid Fiber (Kevlar) is often considered where impact and toughness matter, while HSHT Fiberglass is the higher-temperature fiberglass lane. Those category descriptions guide a shortlist; the exact datasheet, base pairing, Eiger path and representative test decide the part.

Fasteners and load introduction deserve special attention. A reinforced plate can still fail by bolt pull-through, bearing, splitting, layer separation or creep around a clamp. Add radii, washers, inserts, local thickness and fiber paths based on the actual load. Do not use unqualified printed parts for lifting people, pressure containment, vehicle control, critical electrical insulation, fire barriers or other high-consequence service.

What is unsupported or a poor fit

The current Mark Two list does not include PETG, ABS, ASA, polycarbonate, polypropylene, generic nylon, third-party PLA, other TPU hardnesses, PEEK, PEKK or ULTEM. It also does not include Markforged's Onyx FR, Onyx ESD, Onyx GF, Nylon White FS, Carbon Fiber FR or Carbon Fiber HT-A. Some of those materials exist in the current portfolio, but the portfolio page spans several printer families. Treat them as unsupported unless the current compatibility matrix, Eiger and Markforged support all identify the Mark Two path.

Metal filaments belong to Markforged metal-capable systems and downstream debind-and-sinter workflows. Pellets, vat resin, powder, wire and paste use different feed or process architectures. If those are core requirements, the Mark Two is the wrong platform. The FX10 material router, FX20 material router and AON3D Hylo material router show different industrial capability boundaries.

If the work is mainly open-market PLA, PETG or ordinary prototypes, a simpler platform may be a better economic and operational fit. See the Bambu Lab P2S material router. If the requirement is nylon or chopped-carbon-fiber filament without continuous reinforcement, compare the nylon and carbon-fiber printer guide before paying for a CFR workflow.

Surface, storage, software and maintenance are part of compatibility

Use the current Markforged bed preparation, adhesive, removal and cleaning instructions for the exact base material. A precision-ground composite bed is not a universal surface for arbitrary polymers. Confirm the selected material and fiber are visible for the Mark Two in the current Eiger organization before ordering production inventory.

Fiber routing tubes, nozzles and feed components are wear items. Inspect and replace them on the manufacturer's schedule, especially when surface, dimensions or fiber placement change. Keep material identity and lot records for qualified jobs. After a software, material, nozzle, bed or maintenance change, run the representative acceptance part again rather than assuming the old result transfers.

Electrical, fire, ventilation and dust boundaries

Install the Mark Two on a stable surface with the clearance, ambient conditions, network controls and 100–240 VAC supply specified by Markforged. Keep the power path grounded and suitable for the local circuit. Do not bypass covers, sensors or interlocks. Heated equipment and polymer processing require housekeeping, manufacturer-approved maintenance and an appropriate fire response plan; do not leave a process outside the supervision permitted by the current instructions and facility policy.

FFF can release ultrafine particles and volatile compounds, and filled polymers can create fine polymer or fiber dust when sanded, drilled or cut. Use source control or local exhaust based on the material, task, occupancy and applicable workplace assessment. Avoid dry sweeping; use controlled cleanup and task-appropriate eye, skin and respiratory protection. NIOSH's safe 3D-printing guidance is a useful control framework, while Markforged's current safety data and machine instructions govern the exact product.

Buyer and owner decision

• Buy the Mark Two when desktop scale, Onyx or the other listed bases, and one or more of the four listed continuous fibers solve a recurring, qualified job.
• Choose the Onyx Pro or another simpler route when fiberglass reinforcement is enough and the additional Mark Two fiber choices will not be used.
• Move to FX10, FX20 or another industrial platform when the required grade, build volume, automation, environmental control or production workflow sits outside the Mark Two's current list.
• Choose an open-material printer when supplier freedom, third-party grades, PC, PP, PEEK, PEKK or ULTEM is the primary requirement.
• Pause for written confirmation when the exact Nylon/Nylon White grade, base-and-fiber pairing, Eiger option, compliance claim or application certification is essential.

For a defined part, start with the material-selection checklist, use the custom-printing service FAQ, request a GoodPrints quote, or use the JC Print Farm route when external production is more sensible than machine ownership.

Bottom line

The Mark Two is a capable but deliberately bounded desktop composite system. Its current base list is Onyx, Nylon, Precise PLA and Smooth TPU 95A; its current continuous-fiber list is Carbon Fiber, Fiberglass, Aramid Fiber (Kevlar) and HSHT Fiberglass. Confirm the Nylon-versus-Nylon-White grade and every base/fiber pairing in current Eiger. Treat every other polymer, specialty Markforged grade and feed technology as unsupported or confirmation-required rather than inferring capability from heat, hardness or brand adjacency.

Official sources checked

• Markforged Mark Two product page for current compatible materials, build volume, process, bed and system claims.
• Markforged Mark Two F-PR-2027 datasheet for the April 2024 material names, electrical input, power, process and approximate-property caveat.
• Markforged materials catalog for the portfolio-wide base-versus-continuous-fiber distinction and the materials that require printer-specific confirmation.
• Markforged material compatibility matrix for execution-time printer and material confirmation.
• NIOSH: Approaches to Safe 3D Printing for source-control, ventilation and exposure-reduction boundaries.