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Comment by adrianmonk | Hacker News Reader

If my memory can be trusted, then it can be done with a high-pressure water jet. As a kid, my class took a field trip to a factory that did this. I remember being fascinated by the idea that water could cut.

EDIT: No need to trust my memory:

https://wardjet.com/waterjets/water-only

https://textilelearner.blogspot.com/2015/07/fabric-cutting-b...

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Incidentally, this was a long time ago (~1980?), and another thing we saw was a computer whose operator explained that to boot it up, they had to go through a sequence involving toggle switches on the front panel. Someone commented that it sounds impossible, and the operator said it gets easy after a while.

They also had some stations for design work with basically a drafting table and a mouse-like device with a ~12 key keypad on it and I think a glass with a reticle, presumably for aligning with points on a blueprint or something like that.

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We had a waterjet at the granite shop we worked at for cutting stone slabs. Even after years of working there, I'd still just sit and stare at it sometimes fascinated.

That thing was always a hassle with maintenance though and sometimes things on the intensifier would explode....

Programming it was pretty cool. Different than the routers I programmed. We had a camera system rigged up that could take photos of the slab. The cad files were then loaded in and dropped and arranged on the stone.

The guy that did it at our shop was really good at matching everything. Connecting the veins for pieces that needed to be joined or mitered.

A friend operates one at a granite shop. They use a software that maps the surface and then uploads it to a webapp that lets the customer choose the pattern layout.

One thing I found interesting about water jets is that you absolutely do not want to be cut by one. The force is strong enough that it can inject the abrasive garnet into your bloodstream. The machine I actually came with instructional tags to pin to the shirt of anyone headed to the ER.

>A friend operates one at a granite shop. They use a software that maps the surface and then uploads it to a webapp that lets the customer choose the pattern layout.

That would have been pretty cool. One of the biggest holdups to our schedule used to be waiting for customers to confirm layouts before cutting. They always come into the shop to verify.

We used old unsupported software called stonecam from Park Industries. Only one guy still working there had any experience with the software. We ended up having to recalibrate the camera on the machine while I was there. It involved manually configuring variables in text files with variable names written in a mix of German and English. Apparently the software was written by one German guy who vanished some time ago who never told anyone else how it all worked completely.

They'd switched to officially supporting AlphaCam a while ago. We had licenses for our two routers for alpha cam but they were ten grand a piece and the boss was holding out as long as possible before switching the waterjet over.

>The force is strong enough that it can inject the abrasive garnet into your bloodstream

Oh wow had no idea about that. I figured you absolutely did not want to get your body into the flow, but never heard that.

>I remember being fascinated by the idea that water could cut.

It doesn't. Water is a really poor cutting agent. The water is just used to propel abrasive garnet at high pressures. If there was a cheaper and better way to move the garnet then someone would have already done so without water.

Not entirely accurate. Certainly for metals, stone, and other hard materials the entrained abrasive is doing the cutting, but water-only waterjet cutting is used for a lot of things: foams, rubbers, plastics, fibrous materials, food, sensitive items like diapers and medical materials (because the pressurized water is inherently sterilized, and there's no blade to gum up and hold bacteria).

And what's really going to bake your noodle is there is an additive called...wait for it...SUPER-WATER that helps maintain stream coherence out of a high-pressure waterjet nozzle, allowing even more effective water-only cutting.

A person who worked on early PDPs for UNIX said he had memorized the toggle switches positions to enter the bootloader.

"Toggle these programs in at location 10000", literally there would be toggles to enter the machine location 10000 and the series of instructions that would be pasted into it.

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