Wazer introduces the first desktop water-jet cutter | Hacker News Reader

Wazer introduces the first desktop water-jet cutter

spectrum.ieee.org

266 pointsdevy137 comments

For anyone who needs things waterjet cut (or other methods) there are a lot of metal fab shops out there, and you can get things cut cheap enough. The last water jet job I had done in a 24 hour rush was $140 for a 1 sq ft piece of aluminum 1/4" thick. It was shaped with a couple holes in it, not complex, but $140 is a long way from $6000.

For speed, this thing is slow (fine for hobby use) and you may find that other processes are more appropriate - especially if you cut a lot. I have a HD Plasma that can cut 1/4" steel plate at 282 inches per minute; compare that to the 0.4" on this machine. While my machine was $60,000 and thus 10x more money, it does cut 700x faster ..... and I am going to the Fabtech show in Vegas this week because I need to go even -faster- . http://www.fabtechexpo.com/

Dreaming of a Kinetic machine with dual torch heads ... http://www.kineticusa.com/products/production-spindle-drilli...

Or maybe a 6KW fiber laser ... (this video is not sped up!) https://www.youtube.com/watch?v=B3gMM5VSQUE

Fabtech is one of those trade shows where something under a few hundred thousand dollars seems cheap!

I totally lost my respect to IEEE as a "serious organization" when I saw they were advertising [1] their start-up event with the title "Everything you know about startup success is wrong"

1: http://postimg.org/image/cz2rbvifz/

Are you a mechanical engineer by training? I'd like to learn more about hw fabrication.

The speed of the Waser was the first thing I paid attention to upon hearing about it so long ago - I'm sure it'd be great as a toolshop or hackerspace tool, or perhaps even educational, but there's no way I could use this commercially to complement existing laser and CNC capabilities, so I'll just keep outsourcing.

A shame, as I'd really like to get on the first rung of water-cutting - it's an incredibly versatile tool.

Your 6Kw fibre laser video has me looking at my own laser machine quite ruefully :)

> but $140 is a long way from $6000.

Which is apples to oranges of course. One instance compared to a tool to make many. I have a startup that needs 12" by 12" plates (quite a coincidence) in small production quantities with various holes and slots. I've been studying CNC milling but this would be much simpler and possibly cheaper.

The difficult thing in water jet cutting, historically, was the development of nozzles that can withstand the abrasive fluid. These parts have to shoot a jet of fluid which can cut through steel and ceramic; but themselves cannot be easily cut by the passage of that fluid.

I'd be concerned about the life of the nozzles and the cost and availability of replacement parts.

All of the hydraulic components in a waterjet are subject to wear: hoses, connectors, etc. The nozzle is considered an item that you simply have to replace regularly, kind of like windshield wipers on a car.

The pump is one of the larger and more expensive components of the waterjet cutting system and also tends to fail at inconvenient times.

How would a failure ever be at a convenient time? :)

Think about a bomb that ticks down to 0 and doesn't go off. That would be awfully convenient.

That's actually pretty bad because you have no idea whether it's still going to explode. Like a firework that does nothing after the fuse burns into the casing.

The alternative is worse for everyone but the bombers. I very much prefer to have a bomb in the mall that might explode any moment to one that actually just did.

Well, as a student that makes martian rover analogues for University Rover Challenge (7th place, woooo) I can attest that there is failure at the most inopportunate time.

Our unis water jet crapped out right before we were to have final parts cut on it before sending them for competition. It was massive PITA

It happens when you turn it on since a sensor or self-test detects it. Failure was inevitable but conveniently prevents you from wasting time and money on that run. I know this kind of thing can happen with some kinds of equipment but can't speak to if these could detect failure early. Works with many types of equipment, including computer software and hardware.

I wonder if you replaced the abrasive material with a ferrous material could you direct the stream with magnets? I guess the material would first have to be charged. And would the water flow follow the [hypothetically] focused stream of ferrous material? I need some coffee.

Like a water-jet rail gun?

Actually I didn't think of that. I was thinking more of a magnetic nozzle. But yeah if you can steer a fluid with embedded magnets you should be able to accelerate a fluid with embedded magnets, right? :) or maybe not. I have no idea.

Not a bad idea, but ferrous metals aren't very hard. Garnet abrasive is very very hard.

What if we used just enough ferrous metal as a kernel inside a grown crystal of garnet that the metal is sufficient to magnetically levitate the grain of abrasive; perhaps even extremely fine metal dust embedded within the grown crystal's matrix. Then could we pass the resulting metal-enhanced garnet abrasive grains through a Gatling rail gun?

Furthermore, since garnet has specific refractive properties different from other materials, could we pass all ferrous grains through an extremely high-speed discriminating chamber that looks for these properties in each grain, and magnetically directs the garnet grains back to the abrasive holding bin to vastly increase the recycling, while all other ferrous material goes a separate bin (for waste or other recycling purposes)?

I kind of wonder what problem this would be solving? It sounds magnificently cool, but also expensive. In the long run, I have great hope for fiber lasers becoming cheap enough for a home-version. Maybe a home-grade 1kw. Seems more practical than worrying about recycling sand.

I do love the idea of a Rail gun cutter, though - just not sure how it could really help cut things.

I'm thinking in terms of resource-constrained use cases, like on an aircraft carrier or further out, deep space exploration. Until this thread, I had always assumed a laser cutter would be just as good, but didn't realize some of the unique advantages of a waterjet cutter.

Rail guns work by passing a current through the projectile, which would boil your abrasive carrying fluid, unfortunately.

Perhaps he meant Gauss rifle or coilgun. I remember building one when I was younger, I wish I had thought of experimenting with ferrofluid.

I don't think this would work because the particles are free to move within the water stream. Say you used something like a magnetic pinch ( https://en.wikipedia.org/wiki/Pinch_(plasma_physics) ) to focus the stream... my hunch is that all you'd achieve is to compress the iron particles with little or no compression of the water since the iron is just floating in the stream.

It's a good idea though.

That would be something of an advantage, no? The metal particles would be mixed with water still, pulling along some of the stream. The tighter the "beam" of metal particles, the better - presumably that allows a more precise cut.

No, because you also need to increase the pressure of the water for it to cut. The nozzle increases the pressure of the water by constricting a constant flow into a smaller area, which increases the kinetic energy of the water and the abrasive particles.

A magnetic pinch would (I expect, I only really covered them a bit in a plasma physics course so I'm not an expert) basically pull all the suspended iron particles out of suspension and compress them into a thin rod, without actually compressing the water very much. My hunch based on semi-informed knowledge is that it just wouldn't do much to actually cut anything, but I could be wrong.

The other problem is that magnetic fields also produce a lot of heat in a conductor. The metal particles that clump up would probably sinter together or even melt. On top of that, it'd take a lot of power to run... pinches aren't super efficient.

Interesting idea. If the water were conductive -- say salt water -- then I don't see why you couldn't steer it with magnets. The trick would be to keep an electrical current running through the jet.

At normal fluid pressures -- the classic example being peeing on an electric fence -- it's hard to get much current flowing since there's so much empty space between droplets. But at thousands of PSI, is that still true?

Water is dipolar (the oxygen atom 'pulls' harder on the electrons it's sharing with the hydrogen atoms, so the middle is negative and the ends are positive). It can be controlled by both electrostatic and magnetic fields, no salt needed.

Electrostatic, sure. You can deflect a stream of water from a faucet by holding a comb near it. But magnetic?

This sort of thing was actually used for water propulsion system:

https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive

The hardness of the material is critical. Ferrous material sounds like metal, which could just melt/spatter on impact. Probably not make a good cutting medium.

Is the wear of the nozzle still relevant considering the wear of the pump? I can imagine that the historical problems are due to turbulence in the system and we can simulate that adequately these days. Or do the abrasions inside the system dominate?

The nozzle and hose are easy to exchange, and a replacement part with predictable wear is a plus from the manufacturers/investors perspective. I'd wager that the pump is the problematic part here.

Yes, the nozzle wears at mostly a steady rate, while pumps, with their moving parts, seals, etc. can fail suddenly.

Though they have less of a problem pumps pushing 7000-15,000 psi mentioned elsewhere on this thread instead of the 60,000 to 90,000 of traditional waterjet cutting machines.

Waterjet operator for about a decade here (OMAX). The nozzle slowly and unevenly wears until such a point as you decide it's hurt precision enough that you want to replace it. Everything else on the machine wears out in sudden and near random fashion. Replacing pump parts is done more just because if anything in there fails, you end up with something catastrophic failing. The regularly replaced pump parts are mostly just little gaskets and fittings, but they're pricey anyway. With 50k PSI going through little stainless pipes, sometimes something gets cracked, at which point you get fog shooting across a room out of a hole so small you can't find it with a microscope. Most failures besides the nozzle end up destroying at least three parts. I'm not sure how much of this would hold true at the much lower pressure used here.

Thank you for your insights.

Going a little off topic here: The failure mode you described reminded me of the horrible accidents that sometimes happen while maintaining high pressure oil systems in industrial machines. The smaller the hole, the worse the incident - human flesh and skin does not pair well with a thin, high pressure stream of fluid. I spare others the details, it's not pretty.

Do you think that a 'personal waterjet' poses more dangers to the operator than machines like a band saw or drill press?

Same danger. A personal water jet will cut your finger off just like a bandsaw. If it can cut metal, it can certainly cut YOU!

I tried to avoid painting a mental picture. I'm not talking about cutting here but rather the things that happen when fluid is injected under your skin and into your body.

Amputation of extremities is not the worst case scenario :-/

Well, when I see someone using a bandsaw, they're usually running a piece of wood through it with their hands near the blade. Cuts seem relatively likely, severity seems moderate.

With a waterjet like the one I use, you would generally have a computer moving the nozzle and not even have a reason to be near the nozzle. It also sounds like a jet taking off. I seem to remember the water speed being something like mach 3 exiting the nozzle, but don't trust my math on that. Cutting is done under water most of the time, which muffles most of the sound and splashback.

On the other hand, I carry a card that tells medical professionals how to treat me if I arrive with a waterjet injury. Waterjets don't work great on laminated materials, because when they hit a transition between materials, they tend to send their energy horizontally. This is also true if it goes through skin and hits bone. It basically shoots you up with water, air, and abrasive, which travels along or in your bones. I've never even come close to injuring myself with the nozzle, but it would absolutely be more scary than a bandsaw.

The closest I've come to injury was one day when I felt an eerie sensation of wind on my skin. I grabbed a piece of paper and tracked it down to a 1/4" stainless water line. I backed away and ten seconds later it was a white cone of fog from a leak that was visible for about 15 feet without even feeling wet. The moral of the story is don't feel around for leaks.

I heard stories about injuries you can get from high pressure leaks from hydraulics guys. By all accounts they absolutely horrifying. They would have their flesh detached from their bones and oil basically soaking into their flesh so that it becomes necrotic later on. Plus they're said not to hurt immediately, doesn't help with treatment. Makes me glad I don't work on hydraulics that's for sure.

I've looked at the examples of things they cut with that thing [0] and the amount of time and abrasive needed to cut even a single knife blade out of steel is quite shocking:

>Cut time: 118 min. | Abrasive used: 39 lb.

I presume this abrasive sand, garnet, is non-recyclable? Yikes!

Imagine how many bags of sand you'd need to cut a whole sheet of metal!

[0] https://www.kickstarter.com/projects/1294137530/the-first-de...

It apparently can be recycled:

http://www.thefabricator.com/article/waterjetcutting/reusing...

(I guess it won't be worth setting up recycling for most users of this machine)

They say $0.30-$0.60 a pound (and I see lower prices suggested elsewhere), so the cost isn't astronomical.

That's an interesting link! However, like you said, you need specialized equipment to recycle it so this is not something that hobbyists or users of this machine will use since the cost will probably be more or less the same as the cost of a new bag of sand.

And you're still left with the huge amount of time it takes for it to cut steel. Commercial waterjet systems can cut that blade I mentioned in seconds. Wazer took 2 hours.

I think all these hobbyists and small shops that are considering this technology should beware of the cost. Suddenly, that seemingly high cost of commercial waterjet providers doesn't seem that high at all to me!

AFAIK garnet isn't recyclable, but it's also pretty much just sand (non-toxic, though the material you're cutting might make the resulting slurry something to avoid).

To put the amount of material in perspective, the large table waterjet in the shop that I work at recently had its annual cleaning, during which over 1.5 tons of garnet mud was removed (we do use it regularly, but we're far, far from a high-volume shop). To cut a single knife blade ours would probably use less than a pound of garnet, but then again our machine cost several hundred grand.

As for time, that is indeed pretty high, but it's comparable to what you'd expect from commercially-available 3D printers. DIYers wouldn't be discouraged there.

For me, the biggest reservation is that 4mm of steel seems quite shallow, if indeed that is the maximum depth.

(Note that I just started working at this machine shop two months ago, so I'm hardly a real expert here. :P )

Thanks for an excellent overview and for confirming my assumptions. I've seen commercial waterjet machines in action when I visited a tool factory when I was in high school and those machines were amazing... they were cutting through plates of steel like it wasn't even there.

As for garnet, yeah, it's sand but it's finely meshed and I'm guessing you need a strongly abrasive sand. Unless you're near some beach with that type of sand, you'll have hard time finding something optimal.

I just don't see why any DIY-er would want this want this machine given how expensive and time-consuming the whole process is. Unless you're rich or working for some rapid-prototyping place, you're much better off paying commercial guys for cutting your blanks for you. Anyway, feel free to correct me if you think my reasoning is wrong since I'm no expert.

  > you'll have hard time finding something optimal

I wasn't intending to imply that one could use any old sand in the machine, only that disposal shouldn't be unduly bad for the environment (unless your recycling comment was intended to focus on the economic aspect rather than the environmental aspect).

Taken in the context of being a first-generation device, I don't think this is a bad product at all. First-generation 3D printers were way less polished than this appears to be (though of course I haven't used it myself). It remains to be seen how much maintenance it will require, but even current-gen 3D printers seem to manage to break down once a week or so, so again I don't think DIYers will be deterred there. :P And in particular, I think hackerspaces with a decent amount of cash but with scant floorspace might find this product compelling (our waterjet is easily the single largest tool in the shop). This might also appeal to folks with personal shops who can't justify the enormous expense of a full-size waterjet, who might purchase this out of sheer novelty. AFAICT it won't appeal to rapid prototypers, because prototyping in acrylic (or wood) via a laser cutter is already so much faster than waterjetting (unless you need your prototypes to be metal, in which case you already own a full-sized waterjet).

TL;DR: empowering DIYers is good, even if initial appeal is limited, and hopefully subsequent generations of the device will improve the economics.

You can basically use any old sand as long as it's meshed within spec for your machine depending on what you're cutting.

If you use silica sand, you get silica dust and silicosis.

With garnet, you can recycle it on site and their some companies that will buy and recycle your abrasive to resell. That being said, garnet sand is cheap as shit and it's more expensive for most shops to recycle. I've heard that factories making backhoes and the like cutting lots of like 1/4 inch plate will because they're using just so much that it makes sense to recycle on site. All that being said, the sand will go round and be a less effective abrasive after a few uses.

According to their specs page, the 118 min was for blade, bolsters, inserts, etc, for a total of 9 pieces. So, figure maybe 45-60 mins for knife blade itself? Still long but less so...

Odd that they don't want to let anyone know the operating pressure. They seemed to spend an inordinate amount of song-and-dance dodging the "whats the pressure" question.

It is odd. That was my first question, having used a more traditional (==much larger) one.

I have trouble figuring how the cutting speeds claimed jibe with the overall weight of the device. Not calling it out, just saying based on their numbers, that seems like quite a lightweight tank for the kind of pressure used for cutting, for instance, stainless steel.

I'm also kinda wildly interested how they keep vibration down, given the operating pressure, etc

I wouldn't be surprised if its what a standard pressure washer can do (3k PSI) as they claim to use parts from "other industries".

I doubt the pressures are much above 10k PSI as there isn't the power to generate those pressures with a reasonable flow from a standard US outlet.

Using gpm=(hp x 1715 x efficiency)/psi and allowing for 90% pump efficiency along with max 1.93 hp continuous from a 15A 120VAC receptacle, we can simplify the pumping-water-with-a-North-American-receptacle equation to gpm=3000/psi. So 10k psi outputs only 0.3 gpm, 3000psi outputs 1gpm, and 2000psi spits out 1.5 gpm (the latter of which matches the output from the top electric pressure washers).

And since they said that it uses 10-20% the water of a standard shower head...

A modern shower head uses about 2gpm, so we are talking about 0.2 to 0.4gpm. That would give us a pressure of about 7500 to 15000psi using your equation.

This is much more realistic. 3k psi will struggle to cut a cake.

As someone used to metric, this is probably the msot confusing comment chain I've read yet o.O

You don't measure cutting force in cakes?

For those that need it in metric, a cake is roughly equivalent to a scone...

At least in the UK, Her Majesties Customs and Excise tried to measure it in biscuits (which require 17.5% greater cutting force than cakes), but Mcvities prevailed in the courts.

We measure cutting force using a very old baguette held at the Bureau international des poids et mesures.

That sounds like the worst case to me. They are doing their demos with 7500 psi from an outboard pump and thinking that it's going to be a minor detail that can be worked out after the kickstarter succeeds to generate a workable pressure from 15A 120v.

If they told us the pressure they're using for their demos, some smarty with a slide-rule might call them on getting that from a normal wall outlet.

Based on one of the examples on their website (the knife), I estimate that we can cut around 27 times faster on a professional waterjet machine.

Given equivalent running costs, this means that 2 hours of runtime on a pro Flow or Omax machine is equal to the price of the entire Wazer.

In other words, the $6000 you spend on the Wazer will buy you a LOT of complete parts from on online service like Big Blue Saw.

Latency is a major advantage of this stuff. Do 10 examples on this as you iterate a design then 1,000 on a professional device. Even if it is really slow, you can probably use different materials and or thinner materials.

As other comments pointed out there seems to be an issue with max pressure it can produce. If it has to be run for hours on end it might actually be cheaper to get a local place to do it...(Not even considering the costs of maintenance and consumables, just power and initial price)

I've had parts made on a crappy waterjet once and we just tossed them all out due to extreme taper (Although the company was a massive piece of shit too, used the wrong material)

If you go that route, just get a laser cutter and use acrylic for prototypes.

The "I wish I had that" recently was for some custom one off parts for a recumbent tandem trike. The part did exist as a standard manufactured part... in Germany. There is also an online bike shop with no inventory that probably does what you describe... and at that time had a backlog of two weeks.

This was for one part - a custom gear. Yes, a professional machine can do that in no time flat for less than the cost of the Wazer. No, the professional machine can't do that in the same time it takes to make the part and it was actually faster to order from Germany in this case than to try to find time on a professional machine shop somewhere.

Sure, if you're going to make hundreds or thousands of the parts - thats great. But if you want one or two... not so much. Especially if that has the timeframe of "today" on it to fix that gear to go out cycling this afternoon.

Our rush service typically gets parts delivered to the customer within 3 days. Regular orders ship in 7-10 days.

As far as finding a shop that can take your order quickly, try a search for something like "waterjet cutting online ordering".

The Wazer's speed makes it difficult to get a part done in a single afternoon. As I mentioned elsewhere, you'd probably be better off with a small CNC milling machine. But do you really want to own either for only occasional use?

The related question would be "what is your minimum order?' That's where a personal water cutter may work better for some. The occasional use is indeed a question - and how much additional things may be done or prototyped. How many jury-rigged parts are on the trike that could be done better with the proper custom part. And if it's worth doing a one off order for a gear or bracket that is 2"x4".

Minimum is around $90 for material and cutting, unless we're having a sale, in which case it drops to around $10.

If you order 1 part, wouldn't you at least want to order 1 spare, 1 for your friend, and 1 experimental variation? This helps drop the per-part cost.

A typical order is around $200. I estimate that this would buy you cutting time equivalent to 20-30 hours on the Wazer.

That minimum order is significantly higher than the price of the part from Germany... even with shipping. And with the gear, one spare isn't that useful... and the parts for the trike ( http://www.terratrike.com/tandem.php ) tend to be a bit specialized - I don't know anyone else who has one (mine is similar though has different parts and such because its a folding http://www.terratrike.com/traveler.php ). In the past, my father has gone to the machine shop where he used to work for custom parts - but the people who he had favors with to get some time for non-academic projects have nearly all retired.

Yes, it is certainly cheaper to have an industrial cutter if you know what you're making and making them in lots that cost a few hundred dollars. If you are after making a part rather than a half dozen... that minimum order and turn around time (do it on Saturday, have it on Sunday?) make it less interesting for some applications.

Huh, another puff piece about a crowdfunding project on an IEEE blog. Is this a trend?

https://news.ycombinator.com/item?id=12950781

Looks pretty cool, but it seems like it would be impractical to use regularly for small things due to the hassle of purchasing, storing, and disposing of large quantities of abrasives. (I wonder if higher-pressure commercial machines consume less abrasives?)

My point of comparison is that I own a 45 watt laser cutter from Full Spectrum [1], which I'm pretty happy with. The machine is kind of expensive, but the cost of operating it is very low. Just have to keep the mirrors properly aligned and clean, and top off the water bucket and scoop out dead bugs from time to time. The main operating expense is the material, and I can get 1/4" or 1/8" birch ply for under a dollar a square foot. I can't cut metal or glass or ceramic or stone though, which is where a water jet would come in handy. Another advantage of a water jet is that you don't have to vent smoky exhaust. (Fortunately, I live in the top floor of an apartment, and if anyone notices they probably think I'm running a barbecue.)

[1] http://fslaser.com/Product/Hobby

Is it possible to cut metal with a more expensive laser cutter?

Yes, but in most cases you'd be looking at industrial-scale machines. Better find a smaller local shop and send them a .dxf, they'll have better access to raw material anyways. Buying sheet metal in small quantities is expensive and a pain.

Small laser cutters are really fun though. Other interesting materials (besides wood) that can be laser cut with good results are acrylic and delrin. Delrin has great mechanical properties but can't really be glued effectively. Acrylic cracks easily but has the advantage of being easily "welded" with some solvents (acetone can work in a pinch but isn't the best, dichloromethane is great but requires most safety precautions).

Sure, but it takes a lot of power to do it and the price goes up really fast.

I think once you get over about 100 or 150 watts it's possible to cut thin metals. To cut think plate steel takes a lot more. Since I've just got a 45 watt machine, I don't have any experience with metal. (I have been wondering if I can cut copper foil tape with 45 watts, but I haven't done the experiment yet.)

There are other considerations besides wattage, though. Different wavelengths are better at cutting different things. I've also heard of releasing pure oxygen at the point where you're cutting helps. (Even low-end laser cutters typically use an air compressor to blow smoke out of the way and, paradoxically, prevent the material from catching on fire.)

Reflectivity can also be an issue. I know someone who runs an industrial laser cutter and they avoid brass because too much of the light just reflects back and tends to damage the machine.

I've used an industrial OMAX and it consumes a lot of abrasive as well it's just the nature of the technique.

This was on kickstarter here: https://www.kickstarter.com/projects/1294137530/the-first-de...

It is a little pricey, but pretty cool.

Very cool, but the price of the abrasive seems high; why does it have to be disposed of instead of reused?

Probably because it is full of bits of whatever is being cut and can't easily be filtered after a run.

Depending on the material being cut there are might be ways. If the weight densities of the abrasive and the material differ enough we can try simple density separation. If the abrasive isn't magnetic while the material is, we can use magnets to do the same. In both cases, the big question would be how much impurities in the abrasive can the machine tolerate. If machine is somewhat tolerant, and impurities do not threaten its mechanisms, these simple methods can be economical for small businesses working with specific materials.

That struck me as well. The abrasive cost looks to be the killer there.

Lets say you only cut steel. Then the steel particles could be filtered out with magnets. I suppose its much more common to want to work with steel than glass or ceramics.

Nobody I've heard of recycles garnet. It is considered part of the cost of operation.

If you only cut steel you should be buying a plasma cutter.

This 100%. Water jet is great when you need to cut things that don't cut well any other way (tiles, glass,stainless steel, hardened tool steel). Otherwise, plasma, laser, router, mill, etc are all nicer and easier to work with.

Yeah, I'd love to have a water jet for making tools, but I've learned to live with the fact that these kind of things are better owned by someone else.

idk, plasma leaves a lot of slag and depending on the application requires substantial finishing work. mill is fine but has a limited work area (like this waterjet), and at least in my shop, cutter lifetimes aren't great. Thats probably because i don't have the best processes. Also holding down sheets well enough is a substantial hassle unless you're set up for a particular run. Metal routers are really noisy and are arguably more of a hassle than mills.

but I totally agree with your last point, its less convenient, but doing small to medium runs though a local water jet shop is pretty cost effective. Its mildly pricy but they will source standard material for you, and you pick up clean parts a day or two later. even ignoring maintenance - dealing with the up front cost, the consumable cost, and renting enough space to keep the thing is a pretty serious commitment. I have free access to a 4x8 cnc plasma gantry and I still send out quite a bit of work to the water jet place.

Abrasive cost and maintenance (because high pressure water lines are quite needy) are the biggest expenses.

I studied a bit the question, in the waterjet cutting industry nobody reuses it. Basically it becomes rounder after use. A bit like the difference between river sand and desert sand.

Among other things, it gets used up, it may become too fine to cut the kerf at that IPM, it may also have impurities, etc.

Depending on the abrasive, it's theoretically reusable, but that would be very hard to quality control (even assuming you separate it effectively from the material).

This is one reason waterjets often get used only when other ways of cutting are not effective.

Also note: for things like wood, you can probably water jet them without abrasive.

In principle it can be done, of course, but it wouldn't be economical. The abrasive sludge that accumulates in the bottom of the machine is full of large and small bits of various different materials, which complicates filtering. Even if you only cut a single material, you end up with significant amounts of abraded metal from the machine parts (slats, fittings, clamps, etc.). You would also have to spend a significant amount of energy evaporating and drying the sludge.

In any case, the main problem is that the abrasive garnet particles become decidedly less abrasive once they've been smashed into a piece of steel at 75000psi. Think of it like one of those tumblers you use to smooth and polish stones to make them pretty.

EDIT: As someone else mentioned, it's also a QC issue. Even with brand new abrasive, you sometimes get the tiniest bit of something the wrong size or weight and the solenoid feeder gets jammed and has to be take apart. Recycled sand and who knows what else would be a nightmare. Waterjets are enough work to keep running as it stands ;-)

Source: ~7 years of using an Omax waterjet cutter.

If you're curious how these things look like: https://www.youtube.com/watch?v=PCsoC3i7JYc (this is some other waterjet cutter obviously)

Looks amazing.

Great video!

This is a messy process, unlike laser cutting. The Kickstarter videos gloss over that. (They also avoid showing video of the thing cutting at actual speed.) The tank fills up with water and garnet sludge. A lot of sludge. They don't show cleaning out the tank.

I've used TechShop's Flow waterjet cutters a few times. They're way overkill for most TechShop jobs, being able to cut 4 inches of steel plate 8 by 8 feet. TechShop's people are looking at the Wazer. The big question is operating costs. If the Wazer goes through its consumables fast, it could be too expensive to run. It's useful to have a small waterjet, but it's not clear that a really slow waterjet is useful. Especially if it chews up more garnet per cut. Still, it could be great for thin sheet metal jobs.

I hope this thing ships. Remember GlowForge, the low-cost laser printer? That's been hyped for two years now, and holds the all-time Kickstarter pre-order record, $28 million, beating out the Pebble watch. But it hasn't shipped. Currently they're claiming they will ship by the end of December 2016.

The kickstarter page has a 'preorder' button. So did Kickstarter give up on the 'donate to fund artistic endeavor/get a premium' model, and just switch to selling things now?

Mmmmmm... gritty steak, my favorite.

Yeah, I would think the abrasives used in the cutter are not exactly food safe.

The meat looked frozen it would all probably wash off. Not sure if that stuff is toxic though.

Steak can probably be cut without an abrasive.

Cutting food is actually one of the number one uses for waterjet machines. Ever wonder how salad mix is cut without crushed edges changing color? Or how do you cut rice crispies without accumulating marshmallow on the knifes? Waterjets (without grit) are wonderful tools for cutting foods. Also, without grit they are unable to cut steel, so the waterjet will not cut through the bed. Degradation of the bed is a significant problem with steel cutting waterjet machines.

Food and other soft materials are cut without abrasives, using water only.

harder problem: cutting the steak in a shape so that after it's cooked it looks like the US.

Could probably train a network to look at the marbling and determine the deformation within decent bars with enough before/after shots. Might put some pounds on generating the training set though...

How does this compare to a co2 pump laser CNC? what conditions would water jet be preferable especially because it also requires high power consumption? Co2 lasers are cheap and pretty easy to build/ maintain. They also can put out enough power to cut steel. In my experience only special optical/thermal materials like borosilicate glass or certain plastics are not good with co2 because of heat build up/ stress and fracturing properties

CO2 lasers aren't great for many metals due to wavelength issues. Waterjets create essentially no heat affected zone. As an example, I've cut two inch thick black granite with a waterjet, and I'm not sure a CO2 laser would do more than scuff it. Silver seems to just reflect infrared lasers like a mirror. Some plastics make nasty fumes in a laser, but cut fine with water. When both technologies were in their earlier years, I would have taken a waterjet over a laser for most industrial uses. Now I think I'd lean more towards a fiber laser. I'm not sure how much more innovation there is left in the waterjet realm, but lasers seem to be continuing to get better.

Thanks that makes sense.

What cut edge quality can waterjet achieve? It seems it would be a factor of the abrasive material particulate size. Has pure waterjet been employed (the pressure requirements would be huge I would assume but doable). I've seen directed explosive blasts + water cut through cars :)

https://www.youtube.com/watch?v=gHJo956BtJM

It's interesting you bring up silver/ other IR reflective materials), as I know fiber lasers cut silver.

Here's a cool paper on it:

http://onlinelibrary.wiley.com/store/10.1002/latj.201390001/....

I actually worked on beta testing what was, around eight years ago, the most precise waterjet in production. It did indeed use very fine sand that seemed to get into everything. Keeping it from caking was the main challenge. Edge quality on an OMAX is a software setting (I love their software and use it for everything 2D and vector). Basically, the numbered quality settings allow you to prioritize what kind of edge quality you want. 1 gets you the bare minimum needed to get the parts to separate. 2 is fine, but a bit rough on the bottom. Picture that the waterjet pierces the material and then moves slowly, grinding the interior edge of the cut along the path. If you corner quickly, it flares out in the opposite direction. I think of it as being like cutting with a paintbrush. 3 is optimized for dimensional accuracy on the top of the cut. Despite the fact that the water stream spreads out as it goes, the top of the cut is wider than the bottom. This is due to ejecta cutting on the way back out of the cut, and the velocity being higher near the nozzle. Higher numbers are for reducing the taper of the cut, but generally reduce dimensional accuracy. There are also settings for cutting without abrasive, which are generally only worthwhile for something soft or edible, and settings for etching, which I found too loud and messy to mess with. There are also nozzles that will tilt as they cut, which allows you to move and corner quickly by countering the taper with tilt.

I do have experience with cutting precious metals with a laser. CO2 and fiber lasers may both be infrared, but it's a big spectrum. CO2 is a wavelength better suited for cutting organics, and doesn't have the fine focus or energy density available in fiber. I've used a 70 watt picosecond fiber laser for cutting silver and it actually cuts very nicely, but the problem is getting up to the initial threshold to affect it at all. Titanium, with it's low reflectance to infrared, low thermal conductivity, and high melting point, will cut with a power setting that won't leave a visible mark on silver with its opposite set of properties.

That was an awesome description. Thank you

That was the ugliest steak I think I've ever seen.

What's the advantage of water vs metal blades? Do metal blades not cut through glass/porcelain/etc well?

IANAWaterJetGuy, but I think a big draw is that (A) you can make arbitrary cuts and very turns and (B) less risk of shattering brittle substances.

https://en.wikipedia.org/wiki/Water_jet_cutter#Benefits

In addition to what others said, inside holes are a lot easier.

Waterjet & laser have cut through a small point that can follow any programmed 2D path and can start a hole in the middle of a sheet.

By contrast blades are often very restricted as far as shapes go. Imagine cutting a disk with a band saw. A wire saw can get closer, but you don't start a hole with one, and AIUI it's quite slow (a thin wire is fragile, you can't feed hard). Milling tools can likewise follow arbitrary paths but usually the tools are unnecessarily large for cutting a shape out of a sheet. So you have higher forces and need better clamping and waste more material. Tiny milling tools exist but again you run into issues with fragility & low feeds, high rpm requirements, coolant, tool wear, etc. And the depth of cut tends to be very limited. All of the said methods will leave burrs instead of a nice smooth cut.

The setup for laser cutting can be very very simple.

I was indeed picturing a mill setup. I guess the cost of the abrasive seems higher than the costs associated with material loss, coolant, etc at the hobbyist scale, but I'm also not particularly familiar with this domain.

The waterjet is especially flexible compared to a milling machine. The small kerf means you can create smaller features. There's no need to change tools depending on the material type. Chips are automatically blasted into the catch tank, instead of accumulating on the workpiece. Waterjets also typically have a much larger workbed compared to a milling machine, so you can load an entire 4x8 foot sheet and cut a bunch of different parts, or one big part.

I think you're right, though. For occasional prototype parts you're probably better off either ordering waterjet cut parts from an online service, or running them in a small CNC milling machine.

Well, if waterjet works anything like laser (we had a big one at work), then you just barely need to clamp the work. Gravity does its part, and I imagine the cutting force would be aligned with gravity, pushing the work into the table. So the setup really is simple and easy, and you can cut parts off the sheet and let them just drop.

By contrast, milling tools will try to push the work in all directions depending on what kind of cuts you're taking at the moment. They will also try to pull the work (and if the work is loose, you can easily shatter tools). Of course the countering forces affect the tool and through it the rest of the machine, which needs to be rigid enough to take it. The workpiece and the part that will fall off must be clamped accordingly, and then you run into the issue of tool paths that would cross over your clamps, so you'll need the operator to re-clamp things in the middle of the job. And there are clearance issues when you try to operate small tools near clamps. It's definitely harder to set up, and more involving than a laser that just needs a path and then cuts it all up for you after you press play.

I don't know what exactly the state of the art of hobbyist scale machine tooling is right now, but I would be surprised if high speed (=> suitable for small tools and low forces) CNC mills were commonly available. Most hobbyist machines I've seen are neither rigid nor CNC, so you won't be easily cutting smooth & complicated shapes with them.

"Well, if waterjet works anything like laser (we had a big one at work), then you just barely need to clamp the work. Gravity does its part, and I imagine the cutting force would be aligned with gravity, pushing the work into the table. So the setup really is simple and easy, and you can cut parts off the sheet and let them just drop. "

Go hit part of something not flat to within a few microns with 75k psi of water and see if it vibrates :)

Also, unless your nozzle alignment is perfectly vertical, there is some sideways motion imparted.

(IE you are kinda right, but you still gotta do something)

Particularly for small pieces, it can be a pain in the ass. On the plus side, yeah, light clamping with c-clamps/etc works most of the time.

for fun comparison, check out EDM (https://en.wikipedia.org/wiki/Electrical_discharge_machining).

Now THOSE guys can cut metal precisely.

I would like to know how its possible to operate this thing without wearing down the nozzle as fast as you're cutting the workpiece. Is the grit fed down the center of a laminar flow of water so it never touches the metal of the nozzle?

The particles in the flow won't hit the nozzle much at all, since the average flow is tangential to the nozzle walls. Even if the flow is highly turbulent inside the nozzle, there is a boundary layer where the velocity becomes zero. However, when the flow impacts a solid object, the particles can't "keep up" with the fluid splashing away due to their inertia, so they hit the solid object at high speed.

Particles in turbulent flow are characterised by (among others) the Stokes number [1], which says something about how well the particles follow the flow. This depends e.g. on the particle size, roughness, and the density difference between solid and fluid.

I imagine they have tuned the Stokes number to an optimal tradeoff between cutting speed and nozzle/fluid line wear.

[1] https://en.wikipedia.org/wiki/Stokes_number

The nozzles do wear and are made of hard but brittle materials. Bumping the nozzle when joging the machine around is an easy 200 USD mistake to make.

The waterjet "jewel" is typically diamond, and the nozzle tungsten carbide. Both are very hard, and thus wear slowly. Though they do wear.

Waterjet has a small kerf, typically 0.04 inches, or 1 mm. It can go even smaller with specialized setups (microjet).

The waterjet cutting stream automatically cools the material as it cuts, leaving heat treatment intact. Waterjets can also cut through material that would too hard to machine with ordinary metal tools, like hardened tool steel, stone, etc.

I have some more information on the Big Blue Saw website: https://www.bigbluesaw.com/faqs/parts/how-does-waterjet-cutt...

I see this falling flat on it's face unless the table is easily expandable. Waiting a long time for a part is a much easier to deal with problem than constantly hitting the upper limit of what your machine can cut.

Tip: Make sure to turn your volume down before clicking the link.

Holy cow, the addition of a set of legs costs an additional $250?! Who the hell could ever justify such a price increase to save a bit of worktop space?

Custom options on small-run hardware is invariably quite high because of the cost to manufacture and the small end-market.

Compared to options on other machines out there it actually feels quite cheap to me (even in current GBP terms).

I'd not fault them for this.

why would you use a Rolex to show off your water-jet cutter? So many harder yet less expensive things to demo...

Seriously, why has it taken so long for me to be able to get a steak in the shape of the US?

Since the product doesn't actually exist yet they should perhaps say Plans rather than Introduces.

By "doesn't exist" do you mean "isn't for sale?"

What is the base of the cutter made out of? Does the water jet defuse before hitting the base?

There's typically a catch tank filled with water below the workpiece, which diffuses the stream pretty quickly. I've also heard of other materials being used, like stainless steel ball bearings.

very interesting, except for the destruction of a rolex watch.

As much as I appreciate the innovation, I'm not sure this would do well in places like California where water has become a bit more scarce than it once was.

This is the kind of numerically illiterate logic that now requires me to ask for a glass of water at a restaurant when I'm in CA.

There are probably 10+ orders of magnitude difference between the couple gallons used here and the billions of gallons used in agriculture, industry, etc.

Water isn't expensive at anything less than an industrial level, and using this will have 0 impact on the water shortage.

> numerically illiterate

innumerate :)

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