> We tapped in some friends in the additive manufacturing industry, who said it wasn’t quite like any metal 3D printing they’d seen before. Their best guess is that Apple’s using a binder or aerosol jet process in addition to some after-printing machining.

I’m curious who they talked to. I’m no expert but this photo [1] looks like laser sintering. It’s got the telltale melt pools and the laser scanning direction from hatch passes

Maybe Apple has figured out economic electron beam melting at scale?

[1] https://valkyrie.cdn.ifixit.com/media/2025/09/20111617/USBC-...

▲

noahchen 3 days ago | parent | next [-]

The video mentions a patent for the 3d printing tech. I think it's this one https://www.patentlyapple.com/2023/08/apple-inherited-a-3d-p...

To sum up, it uses an inkjet to spray binder to metal layer by layer.

▲

dogma1138 3 days ago | parent | prev | next [-]

This indeed does not look like any sintering MLS or otherwise surface I’ve seen which looks like this https://assets.newatlas.com/dims4/default/0c9b8ea/2147483647...

Edit closed surface finish I’ve seen is indeed of a Laser Assisted DED here is a research published this year https://www.sciencedirect.com/science/article/pii/S221486042...

▲

Kevinwu0710 3 days ago | parent | next [-]

Good reference right here.

Just because Apple is using space-grade titanium (likely Ti-6Al-4V) for the new Watch case doesn’t necessarily mean the same material or process is being used for the USB-C housing. As mentioned in the video, the scratch resistance of the watch case appears to be higher than that of the USB housing. This could be due to differences in surface finishing, post-processing, microstructure, or even different base materials. Scratch resistance generally correlates with hardness, which in turn scales with yield strength of the material.

Regarding the manufacturing method, based on the sectioned images and visible layer patterns, the USB housing does appear to be additively manufactured, likely SLM or DED, not binder jetting. However, those optical images alone don’t provide enough evidence to pin the exact AM process used. The visible "fish scale" surface texture could result from either Directed Energy Deposition (DED) or Powder Bed Fusion (PBF/SLM) since fish scale morphology is a result of remelting of the previous deposited tracks. Without cross-sectional images showing the interface between the housing and the substructure, it's hard to tell whether the part was printed directly onto the assembly (DED-fashion), or printed separately (SLMEd) and then soldered on. Even some additional simple SEM images that reveals the microstructure at 50 micron scale would give more information since DED and SLM have inherently different cooling rate that gives different grain morphology and pattern in sub-micron scale.

Worth noting that while DED has advanced enough to achieve relatively fine resolution today, DED Titanium typically exhibit higher ductility and lower strength/hardness compared to PBF, due to its beta-phase dominated microstructure as opposed to the alpha dominated structure + martensitic phase in PBF. A scale bar on the optical images would’ve helped estimate melt pool size or hatch spacing, giving more insight into the process used. As it stands, we can speculate, but more detailed characterization is needed to be 100 % sure. Cheers

▲

spott 3 days ago | parent | prev [-]

Could it be post processed by milling?

	▲	dogma1138 3 days ago \| parent [-]
		No this isn’t a milled surface this looks like DED/DMD as you can see the individual melt pools but at a much finer scale then I’ve ever seen.

▲

metal_am 3 days ago | parent | prev | next [-]

Looks like spot melt laser powder bed fusion (L-PBF). Electron beam doesn’t make sense for something on a smaller scale like this; it wouldn't have the resolution. Spot melt is interesting. Renishaw is the only manufacturer I’m aware of that uses a pulsed laser vs continuous wave (and I’m not even sure if they’re still doing that for their newer machines). I would’ve guessed it would’ve been printed on a Farsoon since it’s in China. I just wish the images had scale bars to give a little more info.

▲

huflungdung 4 days ago | parent | prev [-]

Those friends could have been managers or sales or HR. Not necessarily engineers. And to save face they are just parroting fab methods they heard in passing.

Obviously not DED or binder jetting, and anyone who knows metal printing would see that instantly. DED has the resolution of a hot glue gun, laying down thick beads of molten metal that could never produce such a fine, intricate lattice - it's built for large-scale, rapid deposition, not delicate internal structures. Binder jetting is even more of a non-starter; you're essentially gluing powder together and then sticking it in an oven to sinter. That process leaves behind a distinctly porous, slightly grainy microstructure because the particles are fused, not fully melted, which looks nothing like the smooth, continuous, and fully dense solidified strands you see in this micrograph. This image screams high-precision, localized melting, which is the exclusive domain of powder bed fusion techniques like SLM or DMLS.

	▲	huflungdung 3 days ago \| parent [-]
		[dead]