LPBF, DED or WAAM: which additive manufacturing process is suitable for which part

"Metal 3D printing" is an umbrella term that covers processes that don't compete with each other. They differ in a single variable that affects everything: how much material they produce per hour. Producing quickly and producing finely are incompatible, and everything else stems from this tension—maximum size, minimum detail, finish, and price per kilogram.

The short rule, before the details: If the part fits in a shoebox and has internal geometry, LPBF. If it measures more than half a meter, DED or WAAM. If it consists of thousands of small, identical units, binder jetting.

The four processes

Process	How the material is supplied	Size range	Detail	What it's for
LPBF	Laser-fused powder bed, layer by layer	Up to about 300–500 mm per side	Finest: features below one millimeter	Complex geometry, internal channels, lattices
DED	Powder or wire supplied and melted on-site, with a moving nozzle	Meters	Low: requires machining afterward	Large parts, reloading, and repair of existing components
WAAM	Wire fused by electric arc, like automated welding	Meters, the largest of all	Coarsest	Very large and inexpensive parts per kilo, with little detail
Binder jetting	Binder that bonds the powder; then sintered in a furnace	Small and medium	Good, with nuances	Long runs of small parts

What really decides the election

Size matters above all else. If the part doesn't fit within the building volume, there's no point. Cutting it and reassembling it later usually destroys the advantage you were trying to achieve.

The internal geometry is only resolved by the powder bed. Channels that follow a surface, lattices, closed cavities: LPBF, and no other. Directed deposition processes deposit material from the outside with a nozzle, and a nozzle cannot fit where it doesn't.

The deposition rate determines the cost per kilo. WAAM deposits kilos per hour; LPBF, tens or hundreds of grams. For a thirty-kilo part, that's the difference between one shift and two weeks.

The finish determines how much work comes next. DED and WAAM produce a preform that almost always needs to be machined entirely. If your part required a smooth surface throughout, that machining negates the advantage.

Binder jetting has a specific drawback: the part comes out "green," is sintered in the kiln, and shrinks in the process, typically by around 20 percent. This shrinkage must be compensated for in the design and is not entirely uniform. However, for long production runs, it is unbeatable in unit cost.

The most misunderstood case: DED to repair

DED has an application where it doesn't compete with anyone and which almost never appears in comparisons: adding material to an existing part. This includes reloading a worn blade, rebuilding an eroded area, and repairing a mold.

The question isn't "What manufacturing process should I choose?" but rather "Should I repair or buy new?" And the math is usually overwhelmingly in favor of repair when the original part is expensive or has a long lifespan. If you have expensive components that wear out in a specific area, that's the conversation worth having before any other.

When the answer is "none"

For the sake of honesty, because this is also a choice:

Long series with simple geometry. Casting, stamping, or machining are significant advantages.
Solid part with no internal geometry. There's nothing to add.
Non-weldable material. None of the three fusion processes will work: if it cracks during welding, it will crack.
Tight tolerance on all faces. You'll have to machine it anyway.

Three questions and one decision

What is the maximum height? Above half a meter, opt for LPBF.
Is there any geometry that cannot be machined? If so, LPBF is the only option.
How many per year? Above a few thousand, consider binder jetting or conventional processes.

Those three answers resolve most cases. The ones that remain on the borderline are the interesting ones, and those deserve a discussion with the relevant information in hand.

Where are we

We manufacture LPBF machines, so that's our natural response, and we're not going to pretend to be neutral. What we do is say so when your part doesn't fit: if it's two meters long or an overlay on an existing component, our machine isn't the right tool, and we prefer to say so sooner rather than later.

If your part does fall within the range, the quote calculator gives you a cost estimate, and at the open days you can bring it in and see it being manufactured.

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What's inside a powder bed printer, in what is a metal 3D printer. What parts you shouldn't manufacture using LPBF even if it's possible, in five parts you shouldn't print. And the comparison with machining, which is usually the real alternative, in print or machine.