Product Introduction of UM420MT Metal 3D Printer

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  What matters before you send a file
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  How the UM420MT metal 3D printer builds a part
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  What two lasers change on the shop floor
• 4
  Gas flow, soot, and spatter control
• 5
  Materials and geometry the platform handles well
• 6
  From build plate to finished part
• 7
  When additive beats machining, and when it does not

The machine works by powder bed fusion. A recoater spreads a thin layer of atomized metal powder across the build plate, then a 500 W fiber laser melts a cross-section of the part into that layer. The plate drops by one layer thickness, powder is spread again, and the cycle repeats until the part is complete. The UM420MT metal 3D printer carries two laser and two galvanometer sets, so both halves of the bed can be scanned at the same time.

Layer thickness is usually 20–60 μm, and that number drives everything else. Thin layers give a smoother surface and better resolution on small features, but they take longer per part. Thick layers cut build time and are common for large, simple geometry. Laser spot size, scan speed, and hatch distance are set per material, not per part, because the melt pool behavior is a property of the alloy.

The atmosphere matters as much as the optics. The chamber is filled with argon or nitrogen and held below 100 ppm oxygen. Titanium and aluminum alloys are the strictest cases; reactive powder will pick up oxygen and nitrogen at higher levels, and the resulting part will show it in impact toughness rather than in a hardness test.

Build orientation is chosen before any of this runs. A face that sits on supports will be rough and slightly distorted, so engineers rotate the part so that critical surfaces face up or sideways. Holes printed horizontally come out oval. Threads smaller than M6 are usually printed undersize and cut afterward.

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  Powder layerTypically 20–60 μm, set per alloy and feature size.
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  AtmosphereArgon or nitrogen, oxygen held under 100 ppm.
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  Melt poolControlled by laser power, scan speed, hatch distance.

A single-laser machine scans the whole bed with one galvo head. As the part gets larger, the scan head has to reach further from center, and the spot distorts at the edges. The dual-laser layout in the UM420MT metal 3D printer gives each scanner a smaller working field, so spot quality stays more consistent across the full 420 × 330 mm plate. That is the quieter benefit, and it shows up in edge density rather than in cycle time.

The loud benefit is throughput. Two lasers working in parallel on separate regions of the same layer cut build time for large parts. Reported output for the platform is 5–50 cm³/h, and the spread is wide because it depends on part shape, size, material, and print parameters. A tall thin bracket and a solid block of the same volume do not build at the same rate.

Parallel scanning introduces one real risk: the overlap zone. Where the two scan fields meet, the second laser may remelt material the first one already solidified. Done correctly, the overlap is fully dense. Done badly, you get a band of porosity or a change in grain structure that only shows up after machining or in a fatigue test.

That is why overlap quality is verified with mechanical testing, not visual inspection. Tensile bars and density coupons should be positioned to cross the overlap band, then cut and tested. If your supplier cannot show overlap test data for the material you need, ask for it before releasing a production order.

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  Smaller scan fieldsEach galvo covers less area, so edge spot quality holds up better.
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  Parallel exposureTwo regions of one layer are melted at the same time.
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  Overlap bandMust be validated with tensile or density coupons, not by eye.

Inside the chamber, the laser does not just melt metal. It vaporizes a small amount of it and throws spatter off the melt pool. Those particles have to be swept away before the next layer is spread, or they end up embedded in the part as inclusions. Gas flow design is therefore a first-order quality variable, not a housekeeping detail.

The flow field is optimized so that the cross-flow over the build plate stays uniform from edge to edge. If flow is weak in one corner, soot accumulates there, laser energy is absorbed by the plume, and that region runs cold. The visible result is a part that looks fine on one side and has lack-of-fusion porosity on the other.

Filter condition changes over a build. As the filter loads with condensate, the pressure drop rises and flow drops. Long builds, or builds with reactive alloys, need the filter checked on a schedule rather than at the end. A machine that ran clean last week can drift out of spec this week with the same parameters.

For the operator, this means the UM420MT metal 3D printer is not a push-button system. Chamber oxygen, flow rate, and filter differential pressure are process parameters. They belong in the build log next to laser power and layer thickness.

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  SootAbsorbs laser energy and cools the melt pool locally.
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  SpatterCan be re-deposited as inclusions in the next layer.
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  Filter loadRaises pressure drop and reduces flow over a long build.

The UM420MT metal 3D printer runs cast steel, stainless steel, high temperature alloys, aluminum alloy, and titanium alloy. Those families cover a lot of ground. Ti-6Al-4V and Inconel are the classic additive alloys because they are hard to machine and easy to melt cleanly under argon. Aluminum is the opposite case: it reflects well and oxidizes fast, so it needs tight oxygen control and proven parameters.

Geometry matters as much as alloy. The process is strongest where the part has internal channels, organic load-bearing shapes, or conformal cooling that cannot be cut with a tool. A mold insert with curved cooling channels close to the cavity is a textbook fit. A flat plate with six drilled holes is not.

Small features have a floor. Walls thinner than about 0.4 mm, or holes below roughly 1 mm, become unreliable across a full plate because the melt pool is wider than the feature. Designers should either thicken these features or plan to machine them after printing.

Downward-facing surfaces always need support, and support removal leaves witness marks. If a surface has a sealing groove or a bearing fit, orient it up or sideways, or leave 0.3–0.5 mm of stock and finish it on a CNC. Hybrid workflow is normal here, not a compromise.

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  Good fitConformal cooling, internal channels, lattice and organic shapes.
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  Poor fitSimple prismatic parts, large flat plates, high-volume low-cost items.

A printed part is not a finished part. It comes off the plate attached to a build substrate, with support structures still on it, and with residual stress locked into the metal. The first step after the build is a stress relief heat treatment, usually done with the part still on the plate so it cannot warp freely. Skipping this step is a common cause of cracking during support removal.

Support removal is manual or semi-manual work. Cut-off is followed by grinding or wire EDM at the base. Then the part goes to a CNC for critical features: sealing faces, bores, threads, and any surface with a tolerance tighter than what the printer can hold. Additive holds roughly ±0.1 mm on well-supported features; ±0.005 mm belongs to machining.

Heat treatment also sets the final microstructure. HIP and solution treatment plus aging are chosen per alloy. Ti-6Al-4V gets stress relief and sometimes HIP to close internal porosity. Inconel 718 gets a two-step age. Aluminum alloys have their own schedules. The result is that the same printed shape can come out with very different mechanical properties depending on what happens after the build.

Surface finish as-built is rough, typically Ra 8–15 μm on downward faces and better on vertical walls. Bead blasting, tumbling, or machining brings it down. If you need Ra 0.8–1.6 μm, plan for a finishing cut, not a printed surface.

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  Stress reliefRun before support removal to limit distortion and cracking.
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  CNC finishingBores, threads, and tight faces are cut after printing.
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  FinishingBead blasting or machining to reach Ra 0.8–1.6 μm.