NeXT Cubes - Explosive Formed or Die-Cast

[NeXT]

Some Polish museum decided last night to say that Cube cases were formed using explosives because it was "to provide the accuracy and structure that satisfied Steve Jobs."
This reeks of RDF. Also It's been spoken for years that the cases are die-cast. Just because it's a magnesium alloy does not mean it wasn't possible in the mid-80's. GRiD did it. The cube case is actually three pieces that internally screw together.
Anyways I challenged them on this assumption and they come back with an excerpt from a memoir written by "Michael Darius". They didn't cite the book and I quickly checked and cannot find a book written by anyone with that name pertaining to Apple, NeXT or Steve Jobs.



All I can assume is that the casting process where the alloy is blown into the casting has been RDF'd into using explosives to shape it. Is there any other evidence behind this?

 

[krebizfan]

Michael Darius does have a Twitter feed and steady stream of Medium articles. On the other hand, he describes using Apple IIs in grade school so he was unlikely to have been old enough to have worked at NeXT during the cube's development. Given how NeXT was bragging about all their innovations with the arsonist's friend the cube, if there was any truth to the story, several column inches would have been devoted to it in all the introductory articles.

 

[NeXT]

Exactly, but I take Tweets with even less trust than Wikipedia.
If this is something that's true and I'm wrong about it being die-cast (I do make mistakes) this is new to me and I've been fiddling with NeXT hardware for quite a while.

 

[Eudimorphodon]

Sounds like utter BS to me. The case looks nothing like what explosive forming is usually used for, IE, turning sheet metal into smooth *rounded* shapes, and it’s also smooth on the outside and rough/unfinished on the inside, *exactly* like you’d expect for a cast product.

 

[krebizfan]

I would trust him with information about Apple in the 90s, especially if it related to UI design. One tends to know things about one's own job. I imagine it would be necessary to ask one of the former NeXT engineers to find out what the actual truth was behind the story being related. I wouldn't have been too surprised if one of the prototypes was explosively formed. The costs involved and time needed for each unit makes it seem very unlikely for any production units to be explosively formed even with the very few cubes that were made.

 

[Eudimorphodon]

I would be a modicum less skeptical if anyone could actually point to something shaped even remotely like a Cube made with explosives. Again, the process is used to make things like rocket nose cones and other aerospace parts, *not* boxes. The NeXT case has a lot more in common with an engine block, things which are very much *cast*.

 

[Eudimorphodon]

… I mean, seriously, this is pure RDF garbage unless someone can trot out a photo of this amazing explosive forming rig that creates *razor sharp corners* from… what, a metal box with *rounded* corners?, that’s lowered into it… and ends up textured like a casting on the inside despite explosive forming being a technique for shaping *sheet* metal.

No one has ever accused IBM ThinkPads of being “explosively formed” despite many models of them using Magnesium alloy cases.

 

[resman]

From NeXT's own brochure it's die cast: https://www.nextcomputers.org/NeXTfiles/Docs/Hardware/nextcube.pdf

 

[NeXT]

Okay, so I'm not going crazy. Thank you resman. I've been searching on and off all morning and was starting to get a little frantic (don't like it when I discover I called someone out incorrectly) when I was finding mentions of it being die-cast but nothing official. The spec sheet has it set in granite, so unless it was some one-off prototype thing, it was without a doubt die-cast.

 

[Eudimorphodon]

The spec sheet has it set in granite, so unless it was some one-off prototype thing, it was without a doubt die-cast.

Again, I call complete BS on the claim in its entirety, unless there was a prototype that looked *nothing* like the cast cube that actually shipped. There's *nothing* about the construction of the NeXT cube that even remotely suggests explosive forming would be an appropriate technique for making it. The plates in a waffle iron are more complex than the NeXT cube and they cast just fine.

Edit: Here's a paper from *2015* talking about the feasibility of using magnesium alloys with explosive forming techniques. Take a look at the test articles: they're essentially shallow bowls. You don't make cubes with explosive forming.

 

[NeXT]

NeXT Sphere.

 

[resman]

Yeah, I wouldn't think magnesium and explosions would be a good combination.

So even die casting may not come without issues. From what I've read, the Apple ///'s aluminum base was tricky enough to require a manufacturer fluent in engine blocks.

 

[Eudimorphodon]

There certainly *is* some special sauce involved in casting magnesium; apparently the most common method involves a system that uses a pump/piston that’s fully submerged in the molten alloy to rapidly force-fill the mold instead of just pouring it in, because magnesium alloys are really bad about prematurely crystallizing if not kept uniformly hot during the injection process… but “explosive forming” this is not. Maybe the author of the tweet read something that implied the process was ”exciting“ and extrapolated in completely the wrong direction. But still, dumb, and bad.

 

[NeXT]

Hence my suspicion that "explosion" was misinterpreted with the process where the hot metal is "blown in" (IE injected at high pressure) at such a speed there isn't enough time for it to unevenly cool while travelling through narrow cavities and passages.

Edited: Also for archival purposes, here's a photograph of the inside of a cube. The steel rods that run front to back are what keep the three pieces of the case together.

 

[Eudimorphodon]

Yeah, I would imagine it's something like that. Maybe I got a little over-prickly about the (dumb) mistake, but alas my patience is tragically limited when it comes to garbage RDF propaganda.

It's painfully obvious it's plain cast pieces when you see the inside of it like that. Cast magnesium isn't magic, and in fact there are significant downsides to it; it natively has poor corrosion resistance, it tends to need a lot of machining/cleanup, and at room temperatures it's more brittle than aluminum. It was a "choice" to make the case out of that, and maybe a defensible one, but considering what a debacle NeXT's hardware business turned out being in the end one has to ask the obvious questions about whether wasting money on perfecting a novelty like that as opposed to just making it out of bent steel and plastic was really a good use of company resources.

 

[resman]

...

It's painfully obvious it's plain cast pieces when you see the inside of it like that. Cast magnesium isn't magic, and in fact there are significant downsides to it; it natively has poor corrosion resistance, it tends to need a lot of machining/cleanup, and at room temperatures it's more brittle than aluminum. It was a "choice" to make the case out of that, and maybe a defensible one, but considering what a debacle NeXT's hardware business turned out being in the end one has to ask the obvious questions about whether wasting money on perfecting a novelty like that as opposed to just making it out of bent steel and plastic was really a good use of company resources.

Um, *stevejobs*. Surprising it wasn't powder coated in diamond dust.

 

[tech58761]

Excuse the dumb question, but what is "RDF"?

I would assume that the 'injection molding' process used to form these case pieces had to be similar to what was used on the old hot-metal typesetting machines (i.e., Linotype, Ludlow, etc).

 

[krebizfan]

Excuse the dumb question, but what is "RDF"?

I would assume that the 'injection molding' process used to form these case pieces had to be similar to what was used on the old hot-metal typesetting machines (i.e., Linotype, Ludlow, etc).

RDF refers to "Reality Distortion Field" in this case.

The stories of the development of NeXT indicates they had so much money they could try experiments to create the perfect computer case eschewing restrictions from budget or practicality.