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Comment by Animats | Hacker News Reader

It's neat, but there aren't answers to many important questions:

- How fast is this process? All videos are sped up.

- Is the resulting material close to isotropic, or is the layer to layer bond weaker than the longitudinal bond. That's the usual weak point of 3D printing. Heating up the previously laid down area with lasers is a good idea, because it gets you away from trying to weld a hot thing to a cold thing. That never gets a really good bond.

- How much laser power does this take? They say "small" lasers, but don't give the power level. Probably over 100 watts each on stainless steel.

The interviewer doesn't seem to know enough about metalworking to answer the right questions.

A modest sized machine for this would be useful. Would have liked to have had one in the TechShop days.

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In general, fully automated systems do not require persistent human labor, and thus only the cost of the machine/consumables/space/power constrain fabrication capacity.

Generally these systems are likely slower than mature subtractive CNC Mills.

"Is the resulting material close to isotropic"

Some processes hit above 98% density, but for hobby level machines it is rarely above 90% (3 cubic inches of 316L a day on a 120v 1kW max outlet.) The oxide inclusions may be an issue in some materials, but it depends on your use-case and process.

Best of luck =3

Well if the machine is slow enough it may not make enough products throughout its lifetime to pay back for its investment cost.

A key difference with additive manufacturing is it allows internal geometry/manifolds that are difficult or impossible using traditional fabrication methods.

Metal is always expensive, but hollow parts are not as weak as one would expect. =3

the integration kit specs say 1000w 9 x 450nm diode lasers.

I can't tell if that's 9x1000w diode lasers, or 9*111W diode lasers.

Given the 2kw-5kw average power need they quote, i'm guessing it's the latter.

I highly doubt it's 9kW, that would require some crazy cooling.

The lasers are at the other end of the fiber optics feeding the print head.

It takes about a 1KW laser to cut stainless steel sheet. A 100W laser is about right for plastics and wood. I suspect each laser is about 1KW, but they are not all turned on at the same time.

That's an expensive system.

Sure, but then i also see: "Cooling:Water-cooled deposition head. Chiller lncluded"

(spelling error in original :P)

the deposition head is where the lasers are.

An even better question is what are the metal's granular properties like? Most metal prints are fairly isotropic, but their strength compared to a machined sample is significantly worse.

You can probably do annealing / hardening / tempering of the printed part to improve its mechanical characteristics.

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