ETA's Friction Stir Additive Manufacturing machine deposits solid metal bar feedstock layer by layer — using thermomechanical deformation, not fusion. The result is fully dense, forged-quality metal parts in aluminium, copper, steel, titanium and unweldable alloys. Open floor. No vacuum. No powder hazard. Scalable to very large parts.
ETA's FSAM machine uses a hollow, rapidly rotating deposition tool. A solid metal bar feedstock is fed through the centre of the tool under controlled axial force. As the feedstock contacts the substrate or previous layer, the combination of frictional heat and adiabatic (plastic deformation) heating raises the material temperature to 60–90% of its melting point — the thermoplastic range.
At this temperature, the metal plasticises and flows — not as a liquid, but as a very viscous solid, like hot glass. The rotating tool stirs the material into the layer beneath it, creating a solid metallurgical bond as the spindle traverses. When the layer is complete, the substrate or machine head indexes down and the next layer begins.
Because the material never melts, there is no solidification — and therefore none of the defects that come with it: no porosity, no hot cracking, no solidification segregation, no residual stresses from thermal cycling. The deposit builds up with fine, equiaxed, dynamically recrystallised grains. Mechanical properties approach or equal wrought material.
ETA's FSAM machine is distinct from MELD-type systems in architecture, spindle design and feed mechanism — offering specific advantages in tool change time, feedstock magazine capacity and accessible work envelope for large-format builds.
Solid metal bar (square or round section) loaded into the hollow spindle. Multiple bars queued in the magazine for continuous operation without stopping.
Spindle rotates at controlled RPM while pressing the bar feedstock downward onto the substrate. Friction + adiabatic heating plasticises the interface region of the feedstock.
Plasticised metal flows out from under the tool shoulder, is stirred into the layer beneath by the pin geometry, and deposited as a new layer. The feed bar continuously advances as material is consumed.
Severe plastic deformation and rapid strain rates drive dynamic recrystallisation — breaking up and refining grains throughout the deposit. Results in equiaxed grain structure with superior mechanical properties vs. cast or SLM material.
Machine traverses the programmed toolpath for each layer. On completion, the machine increments Z-height and deposits the next layer. Near-net-shape preform is then CNC-machined to final dimensions.
Most metal AM processes melt the material. FSAM does not — and that one difference eliminates an entire class of defects while enabling materials and part scales that melt-based processes cannot handle.
| Property | FSAM (ETA) | SLM / LPBF | DED (laser/wire) | Casting |
|---|---|---|---|---|
| Melting involved | No | Yes — full melt | Yes | Yes |
| Porosity risk | None — 100% dense | Significant | Moderate | High |
| Hot cracking | None | Risk in high-strength alloys | Risk | Risk |
| Residual stress / warping | Very low | High | Moderate–high | Moderate |
| "Unweldable" alloys (AA7075 etc.) | Fully compatible | Very limited | Difficult | Cast only |
| Feedstock form | Solid bar / rod | Fine metal powder (hazardous) | Wire or powder | Ingot / liquid |
| Works in open air | Yes | Vacuum/inert chamber required | Inert gas required | Furnace / inert |
| Part size scalability | Very large (machine-limited) | Small–medium (chamber-limited) | Medium–large | Medium–large |
| Grain structure | Fine, equiaxed, recrystallised | Columnar, anisotropic | Columnar | Cast grain, coarse |
| Mechanical properties | Approaches wrought | Anisotropic | Below wrought | Below wrought |
| Repair / cladding on existing parts | Yes — fixture and deposit | Not practical | Limited | No |
High-strength aluminium alloys like AA7075 and AA2024 are classified unweldable — they hot-crack during fusion processing. FSAM circumvents this completely: no melting means no hot-cracking. Alloys previously restricted to machining from solid can now be additively deposited.
Metal powder handling requires ATEX facilities, vacuum chambers and extensive safety protocols. FSAM uses solid bar feedstock — it can run on an open factory floor. No inert atmosphere, no powder explosion risk, no vacuum pump maintenance, no sieving or recycle chain.
SLM machines are constrained by their build chamber — typically 300–600 mm in any axis. FSAM has no such limit. The part size is bounded only by the machine's travel envelope — which ETA configures to customer requirements. Navy hull sections, aerospace wing ribs, automotive structural frames — all feasible.
FSAM machines can be used for field repair: fixture an existing worn or damaged part, and deposit new material exactly where needed. The deposited region bonds metallurgically to the base part. No weld filler, no pre-heat, no post-weld heat treatment required in many cases. Ideal for extending the life of high-value components.
FSAM can change the feedstock mid-build — depositing different alloys in different regions of the same part to create a component that is, say, hard and wear-resistant on one face and tough and impact-resistant on the other. No joining step, no interface: a continuous, graded transition.
FSAM deposition rates are significantly higher than powder bed processes — consuming a 600mm feedstock bar in approximately one minute at production settings. For large near-net-shape preforms, this makes FSAM far more productive than laser-based methods and directly competitive with forging lead times.
FSAM has been demonstrated across a wide range of commercially important metallic alloys. ETA's process development lab can run feasibility trials on your specific alloy before machine delivery.
ETA's FSAM machines are configured to customer part size, material, build rate and process requirements. All incorporate ETA's in-house spindle design, IPC-based process control and real-time deposition parameter monitoring.
Compact FSAM machine for R&D facilities, universities, material labs and process development programmes. Suitable for coupon and small component builds, parameter mapping and material characterisation. Full process parameter logging and programmable toolpath. Ideal entry point for FSAM capability development.
Production-configured FSAM machine for near-net-shape preforms, large structural builds, defence applications and field repair depots. Large build envelope, feedstock magazine for extended continuous deposition, optional CNC sub-table for hybrid add-then-machine workflow. Scalable to very large custom configurations.
The ability to print forged-quality metal parts on demand addresses critical DoD and MoD supply chain challenges — cutting long forging and casting lead times, reducing foreign supplier dependence. FSAM is being used to produce armour plate, structural vehicle components, hull sections and flight-critical spares on-demand.
Aluminium and titanium structural preforms for fuselage frames, stringers, ribs and floor beams. Buy-to-fly ratios dramatically better than machining from plate. FSAM enables AA7075 preforms — previously impossible with any additive method — for next-generation lightweight airframe structures.
Aluminium alloy rocket body sections, propellant tank blanks and structural brackets — where alloy unweldability has historically forced machining from thick plate at enormous material cost. FSAM enables large, near-net-shape aluminium builds that cannot be achieved by any other additive process.
High-value components — aircraft landing gear, structural fittings, heavy machinery wear surfaces, marine shafting — repaired by solid-state FSAM deposition without the distortion, HAZ and metallurgical risks of conventional weld repair. Metallurgical bond to base material without melting.
Large-format aluminium superstructure components, hull stiffeners and bracket arrays produced near-net-shape without an oven or vacuum. FSAM's open-air operation and scale scalability make it uniquely suited to shipbuilding's large-part, low-volume production model.
Copper and copper-MMC electrical conductors, Al-Cu bimetallic structures for battery busbars, heat exchanger preforms with graded thermal conductivity. FSAM's ability to join dissimilar metals in a single build opens new design freedoms for EV power electronics and thermal management.
Tell us your material, part geometry and production goal. ETA will run a feasibility assessment and recommend the right FSAM configuration — or whether a conventional friction process is a better fit.