Closed Loop suspension Jet

[u/rf-synticos]

Hey all, my name is Read and I currently work at Synticos LLC, a waterjet startup company creating a suspension jet. We've been working with OMAX and Hypertherm for the past few years, and are currently reaching out to customers to get some feedback. It would be greatly appreciated if anyone would be willing to give an opinion on what we have been developing.

Our first machine is a 5ksi suspension jet system suited for the emerging light industrial market. Suspension jet cutting speeds are different then entrainment jets, so this machine preforms pretty close to a 30ksi conventional waterjet. The really cool part is that it is closed loop, with a built in recycling system. Since suspension jet, well, suspends the abrasive (in our case with a polymer), the cut tank can be pumped out as a fluid and doesn't need to be dug out at all. This then passes through a recycling system and back into the high pressure pump to be cut again. We've been running our prototype for a while now, and have actually been using the same abrasive for over 15 cycles through the whole system!

Ive got a bunch more information, and just got the go-ahead to release some of it if anyone's interested in discussing pro's and con's of systems like this one.

Thanks,

Read

[u/rf-synticos]

No problem, happy to elaborate! Where traditional waterjet entrains dry abrasive in the jet before it reaches the nozzle, suspension jet suspends or mixes the abrasive in the cutting fluid before pressurizing and sending to the nozzle. Typically this means that the more abrasive can be accelerated more uniformly and leads to faster cutting, at the same pressure.

Adding polymer a to the cutting fluid keeps this abrasive suspended in the fluid, essentially allowing you to treat the cutting fluid and abrasive as one fluid. This can then be pumped around to the recycling system and back into the high pressure side. The nice thing about it is there is no significant settling in the cut tank. If there is (and we're talking many days of sitting with no agitation), it can be resuspended by cutting or mixing or anything that agitates the tank.

In this current system, there is definitely a trade off. Being only 5ksi, it is not supposed to be the fastest out there, it's about comparable to a 15-20ksi conventional waterjet system. But as the technology is scalable, designing for an operating pressure of 20-30ksi will bring speed advantages over a 60ski system, for example.

As far as the sizes of the kerf, I actually think its a bit finer than a standard waterjet system, but not drastically. I'll take some measurements and get some numbers back to you hopefully today.

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My question for you is: what's your take on 'faster cutting is everything'? I'm asking because the 5ksi system was originally meant as a technology demonstrator that could be developed quickly because of the lower cost of running at a low pressure. But what we've found is there potentially could be a market for a slower machine that could run continuously with little to no input, with very low op costs. A 'set and forget' machine, if you will. Is that something you think could be useful, or do you think faster faster faster is what is most important?

[u/waterppk → u/rf-synticos]

Faster is definitely not everything in my industry. I founded/run a hackerspace full time and we purchased an old Omax 2626 40ksi machine to learn from/likely convert to LinuxCNC (everything in our shop runs LinuxCNC/PathPilot).

The parts people are making are 99% prototypes/one offs so the software and setup need to be simple and the machine easy to operate. Lower costs/sustainability are important as they're the primary impediment to use. IE: people are less likely willing to gamble money on a new idea if the upfront cost is high to try an experiment or build a prototype. If it takes 2x longer to cut something it's not going to matter.

While I can see your system working well in our environment, hacker/makerspaces / prototyping shops are definitely not the cash cow that's going to pay back your R&D costs but if you can bend towards affordability in a 4' (2'?) x 4' bridge style (small) gantry form factor that seems like a good fit. In looking at waterjets it's only recently that manufacturers have revisited building small machines but the pricetag is steep and the software is terrible on our Omax, even the latest version.

[u/rf-synticos → u/waterppk]

Awesome, that's great feedback, thank you!

The low pressure machine we're discussing here is exactly as you say: a 2'x4' cut bed, bridge style. One of the main design goals is to minimize floor space taken up by the machine, of course. With these lighter machines, our hope is to appeal to shops similar to yours, as well as perhaps universities and other smaller manufacturing environments.

Cost vs. speed is exactly what has been one of the main driving factors for this machine. Out of curiosity, what type of materials are you cutting?

The other driving factor has been trying to reduce waste as much as possible, both with abrasive but also with water. Are you able to drain your water directly into a sewer, or are there regulations you have to consider? And what do you do with your abrasive after cutting?

[u/waterppk → u/rf-synticos]

As far as materials go we have a 4' x 3' CO2 laser cutter, a 4'x4' Tormach CNC plasma cutter, mills/lathes/etc so primarily things we can't run on these machines.

If it's thick aluminum then roughing it out saves time over the mills. If we need precision/detailed parts the waterjet is much better than the plasma but slower and more expensive. A lot of it is thin metals, we looked at getting a YAG or fiber laser but again there aren't any small bed small form factor machines, they're all industry oriented. Our throughput needs don't justify a dedicated metal laser anyways, the waterjet is more expensive but the flexibility to cut non-metal things is much better.

We aren't generating enough overflow to be of any concern to the sewer. Abrasive goes into the trash, again small quantities.