Cold metal fusion 3D printing is an emerging metal additive manufacturing process that routes around many of the cost and throughput constraints that have limited LPBF adoption. Rather than melting metal powder with a high-powered laser in an inert atmosphere, CMF uses existing SLS infrastructure to print polymer-coated metal feedstock, then converts those green parts into dense metal components through standard debinding and sintering steps — the same downstream workflow used in metal injection molding.
The result: metal parts produced at SLS speeds, on SLS equipment, without the overhead of a dedicated laser powder bed fusion system.
What Is Cold Metal Fusion?
Cold Metal Fusion (CMF) was developed by Headmade Materials as a process that bridges the gap between metal injection molding (MIM) and additive manufacturing. The name reflects the core mechanism: the metal is never melted during the print step. Instead, the laser fuses the polymer binder coating each metal particle — the same mechanism as standard polymer SLS — producing a “green” part that holds its shape but has no structural strength yet.
That green part then goes through the same downstream steps used in MIM:
- Debinding — solvent or thermal process removes the bulk of the polymer binder
- Sintering — a high-temperature furnace cycle densifies the metal particles into a solid, near-fully-dense part
The Feedstock
The feedstock is the key enabler. Metal powder (typically in the 10–40 µm range) is coated with a thermoplastic binder system, producing a free-flowing granular material that handles identically to polymer SLS powder. This means existing SLS machines — EOS, Farsoon, Sintratec, and others — can run CMF feedstock with minimal modification, which dramatically lowers the barrier to entry for shops that already operate SLS equipment.
The binder is engineered to flow and fuse under laser energy at SLS-compatible temperatures while remaining stable enough to hold powder together in the green state. It also prevents metal particles from sintering during the print step — which is what keeps the process “cold” relative to laser powder bed fusion.
How CMF Compares to LPBF
LPBF melts metal powder directly with a high-power laser, layer by layer, in a tightly controlled inert atmosphere. It produces parts with excellent mechanical properties and fine feature resolution, but comes with real operational constraints:
- High capital cost for dedicated LPBF machines
- Inert gas atmosphere (argon or nitrogen) required to prevent oxidation
- Support structures required for overhangs, adding post-processing labor
- Lower throughput: continuous-wave laser melt rates are inherently limited
- Strict powder handling and safety requirements, especially for reactive metals like titanium
CMF shifts the “hard” metallurgical work from the print step to the sintering furnace. During printing, the equipment is running a standard SLS cycle — no reactive atmosphere, no high-power laser pointed at bare metal. Practical implications:
- Lower machine cost: repurpose existing SLS equipment or buy SLS hardware instead of a dedicated LPBF system
- No support structures: parts nest in unpacked powder, same as polymer SLS
- Higher throughput: build chambers pack densely with parts
- Simpler operation: no metal powder in the laser path reduces safety and ventilation requirements during the print phase
The tradeoff is post-processing dependency. CMF parts require debinding and sintering, adding time and furnace equipment to the workflow. Sintering also introduces shrinkage — typically in the 15–20% range volumetrically — that must be compensated for in part scaling before printing.
CMF vs. Metal Binder Jetting
Metal binder jetting is the closest process analog: both print green parts from metal powder, both require sintering, and both eliminate support structures by building in a powder bed. The differences lie in the print mechanism.
Binder jetting deposits a liquid binding agent via inkjet print heads. CMF fuses polymer-coated particles with a laser. This gives CMF some practical advantages:
- Better green part strength: fused polymer binder produces a more robust green part than inkjet-deposited binders, which simplifies handling before sintering
- Finer feature resolution: laser spot sizing can resolve smaller features than typical inkjet arrays
- Existing SLS compatibility: binder jetting requires dedicated hardware; CMF runs on machines many shops already own
Binder jetting retains advantages for very high-volume batches, and some systems offer inline debinding that reduces cycle time. Both processes are maturing, and the right choice depends on part geometry, batch size, material, and existing equipment.
Available Materials
CMF feedstock has been validated across several metal alloys:
- 316L stainless steel — corrosion resistance, biocompatibility, broad industrial use
- 17-4 PH stainless steel — higher strength, suited to mechanical components
- Ti-6Al-4V — low density, high strength-to-weight ratio, aerospace and medical
- Copper — high thermal and electrical conductivity
Sintered densities for validated materials typically exceed 99% of theoretical density, with mechanical properties comparable to wrought or MIM equivalents. Material development is ongoing, with tool steels and additional alloys in the qualification pipeline.
Design Considerations for CMF
Because parts sinter after printing, CMF design rules differ meaningfully from LPBF:
Shrinkage compensation: Parts are printed oversized by the expected shrinkage factor. Uniform cross-sections produce predictable shrinkage; sharp density gradients or non-uniform wall transitions can cause warping.
Minimum wall thickness: Constrained by green part strength and the ability of the binder to hold thin sections through handling and debinding. Generally thicker than LPBF minimums.
Internal channels: Possible, but require debinding path planning to ensure binder can escape without trapping.
Surface finish: As-sintered roughness is comparable to as-built LPBF. Secondary operations — machining, polishing — achieve the same end-state as with LPBF parts.
Where CMF Fits in the Metal AM Landscape
CMF is well-positioned for:
- Shops with existing SLS infrastructure wanting to add metal capability without a second machine class
- Medium-complexity geometries that don’t require the tight dimensional tolerances of LPBF
- High-mix, low-volume production where nest packing and no-support printing accelerate throughput
- Cost-sensitive programs where LPBF economics are difficult to justify
It is less suited to ultra-thin walls, parts requiring very tight post-sinter tolerances without secondary machining, or programs where sintering furnace lead time is a bottleneck.
Cold metal fusion 3D printing adds a credible third path for metal AM alongside LPBF and traditional selective laser sintering-derived approaches. It doesn’t obsolete LPBF — the two processes have different resolution and tolerance floors — but it meaningfully lowers the barrier to metal AM for organizations that already operate SLS equipment and want to produce functional metal parts without acquiring a separate machine platform.