In Fall 2023, we launched FX10 as a next generation composite printer. We promised modularity, but didn’t specify what modularity meant. Now, we can clarify. The modularity we were promising was Metal FFF capability – making FX10 the first industrial printer capable of printing composite and metal parts. FX10 was designed from the ground up to bring this dual capability to customers. In this blog post, we’ll talk about what it took to create the first industrial metal and composite 3D printer, and what it means for you as a potential user.

Process Comparison: Composite and Metal

Before we talk about FX10 itself, let’s talk about the two complementary processes that it marries to print both metal and composite: FFF + CFR, and Metal FFF.

Markforged’s composite printers use a dual process: Fused Filament Fabrication (FFF, also known as FDM) and Continuous Fiber Reinforcement (CFR). FFF is an industry standard 3D printing process in which thermoplastic-based filament is heated and extruded through a nozzle in discrete layers to create a part. CFR is a secondary process that enables FFF 3D printers to reinforce parts with continuous fibers. CFR uses a second extrusion system for long strand continuous fibers. Continuous Fibers are laid down in-layer, replacing FFF infill. Resulting parts are significantly stronger (up to 10 times stronger than any FFF material), and can replace aluminum parts in-application.

Markforged developed a process known as Metal FFF to print near net shape metal parts with no metal powder exposure. Metal FFF is a three step process, as detailed below.

1. Print: A specialized FFF printer prints a filament made of polymerized metal powder (similar to MIM feedstock). In the printing process, the polymer is melted and extruded, with the metal powder along for the ride. Parts are printed with same-material rafts and supports if necessary, which are separated from the part by a Ceramic Release material printed through a second nozzle. The resulting “Green Parts” are scaled up ~20% to account for shrinkage later in the process.
2. Debind: Green Parts are immersed in a debinding solvent, which dissolves the polymer binding material. After debinding, parts are known as “Brown Parts.”
3. Sinter: Brown Parts are sintered in a specialized furnace, turning them into fully metal parts. During printing, the part shrinks roughly 20%.  Metal parts printed with Metal FFF are near net shape accuracy and typically have open cell infill.

Bridging the Gap

To build a metal and composite FFF printer, our engineers had to clear one existential stumbling block – the fundamental incompatibility between polymer filaments and early metal filaments. Polymer filaments are simple, but have one requirement: sealed material pathways to limit moisture exposure. Early metal filaments had the exact opposite problem: they were so brittle that they needed special treatment to print at all, including no sealed tubing between spool and print head. This issue made developing a dual capable machine nearly impossible.

To solve this incompatibility, we went back to the drawing board with Metal FFF filaments. Instead of brittle filaments closely mirroring Metal Injection Molding feedstock, we formulated our own polymer binder optimized for 3D printing. The resulting “Flexible” filaments were easier to handle, all but eliminated nozzle jams, and most importantly could be routed through feed tubes without breakage. Our first flexible filament was Copper (released in 2020). We followed that up by re-releasing 3 of our most popular steels (17-4PH v2, H13 v2, D2 v2) in the last two years. 316L stainless steel will be released next year after FX10 metal capability comes online.

Flexible metal filaments were the key technical enhancement for the FX10

While flexible filaments solved the fundamental problem with building a dual system, our engineers still needed to find a way to build a reliable system designed to print to very different media. To do that, they built the most modular machine we’ve ever created.

How it Works

FX10 is designed with the understanding that metal and composite filaments require completely different hardware to get material from spool to part. To enable this, we took the key elements of the print engine and made them swappable (listed below).

1. Print Head: Composite and metal each have a dedicated print head – both with two nozzles. The composite head has a plastic nozzle and fiber nozzle, while the metal head has a nozzle for metal filament and a nozzle for ceramic release material. The print head can be removed and swapped with only two screws.
2. Material Routing Block: The material routing block, located on the back of the machine, receives four feed tubes (one from each spool bay). On the composite block, these tubes are routed into a single outlet to feed to the print head. On the metal block, they are routed to two outlets: one for metal filament, and one for ceramic release material. The block can be swapped by removing a single screw.
3. Material Tubes: Dedicated material tubes ensure no cross contamination between metal and composite filaments.

The FX10 print head can be swapped by removing just two screws.

In addition to the three components of the print engine, there are a few ancillary parts that need to be swapped – including the print sheet, purge bin, and spool holder. The full changeover takes about 15 minutes of work, after which the machine conducts a calibration routine lasting around an hour.

With FX10, you can fully transition between metal and composite printing in less than two hours. Metal printed parts still need to be Washed and Sintered using the same ancillary machines that Markforged offers.

The End Product

FX10 is available in two configurations: Composite and Metal + Composite. The composite configuration comes with the printer, while the Metal + Composite configuration comes with the printer (in composite configuration), the FX10 Metal Kit, the Wash-1, and a Markforged sintering furnace. A user who purchases a composite only FX10 can acquire metal capability by purchasing the Metal Kit, Wash-1, and a sintering furnace. A customer with existing Markforged Metal FFF capabilities (via the Metal X) can purchase an FX10 with a Metal Kit to upgrade their metal capabilities.

FX10 will be compatible with all of our existing flexible metal filaments: 17-4PH v2, Copper, H13 v2, and D2 v2. In addition to our legacy materials, we are releasing one new filament exclusively on FX10: 316L stainless steel. This highly corrosion resistant stainless steel is useful in food and beverage, maritime, and other industries.

FX10 Metal and Composite Applications

As the first FFF printer capable of both composite and metal printing, FX10 is the first device capable of covering the full range of manufacturing applications. Industrial metal and composite 3D printing are highly complementary, and play off each other’s strengths.

Composite Excels At

1. Large Parts: Metal FFF has part size constraints inherent to the sintering process. If a part has dimensions larger than 15 cm, composite printing is typically a better solution.
2. Designed Compliance: Composite and plastic parts can be designed to yield or bend under loading, ideal for many fixtures.
3. Non-Marring Surfaces: Composites are non-marring, which is absolutely necessary when handling fragile materials.
4. Low Cost and Fast: Comparatively to Metal FFF’s 3 step process, composite printing can yield parts faster and cheaper than metal.
5. Tighter Tolerances: While metal can be post machined, composite machines offer far tighter tolerance as-printed than metal.

Metal Excels At

1. Strength and Hardness: Composites are strong, but stainless and tool steels offer strength only achievable with metal. Likewise, metals are orders of magnitude harder than composites as printed, and some can be further hardened.
2. Heat Resistance: For parts operating in environments above 200 ºC, metal is the only option.
3. Abrasion Resistance: Along with being hard (and hardenable), metal offers far superior abrasion resistance for parts subject to repeated
4. Machinability: Metal parts can be machined to tight tolerances or mirror surface finishes.
5. Heat and Electrical Conductivity: Copper provides unique heat and electrical conductivity for parts with specific requirements.

Composites solve many problems, but sometimes you just need metal.

These highly complementary strengths bear out in three ways: shared applications, unique applications, and hybrid applications.

In some applications like end of arm tooling, composites and metal excel for different reasons. Composite EOAT can be non-marring grippers and vacuum tools, while metal EOAT are typically production grippers used in high-volume production applications. Having both technologies available expands an application space to a greater variety of parts.

In other cases, a specific property of composite or metal enables an engineer to access a specific application. For composites, a quality example is factory aids: the huge suite of brackets, mounts, guides, and fixtures required to effectively run a production line. These parts are consequential, but benefit from the low cost and speed of composite printing. Simply put, they don't need to be metal. On the metal side, high temperature tooling like brazing fixtures can only survive if printed in metal.

Finally, hybrid applications enable engineers to harness the complementary benefits of metal and composite in a single assembly, creating highly optimized tools that offer enhanced performance. A perfect example of this is end of arm tooling with composite tool bodies and metal wear pads. In these tools, composite tool bodies are low cost, strong enough, fast to produce while metal wear pads offer hardness and abrasion resistance. By using both materials, a tool can be customized for a specific application in ways that no other manufacturing technology can achieve.

The Bottom Line

FX10 was already an excellent, category-leading machine as a composite only machine. The addition of metal turns it into a truly transformative piece of manufacturing equipment: the first FFF machine credibly capable of fabricating metal and composite parts on factory floors. As the first industrial metal and composite 3D printer, we believe it’s the most versatile tool for your factory floor. If you’re interested in learning more, talk to one of our 3D printing experts.