Is water jet as awesome as it seems? Should I consider getting one?

My experience is with CNC milling mostly but some turning. Recently a job came up with a 24" x 24" x .625" plate (like a flange, all pockets were through holes) with four 4" x 4" pockets, some bolt holes, a 3" diameter pocket and four 1" x 12" pockets. I estimated the milling time of this at about 30 minutes give or take 5 and it was a little bigger than what we could do in one setup so I suggested the local waterjetter. The water jet ended up being the cheapest route and made the plate well enough. They said it took them about the same amount of time.

This really opened my eyes to a new possibility. I'd like to run a business that would run very little inventory of parts and mostly raw materials. This business would sell maybe 20-50 of a certain water jet cuttable part in a year and in about 50 different varieties each selling 20-50 per year and each made out of the same steel or aluminum plate thickness.

Could I basically take a DXF for these parts, run it quickly through a cam program and just cut them basically as we sell them? Is it really that straight forward? No fixturing required for flat plates?

I've just spent the summer working on a process that uses a waterjet.

For flat plates, yes it is just that easy. The control software will recommend pressure and feedrate for a given material and thickness, as well as set draft compensation. You can use a few pieces of steel or lead to rest on the plate to keep it from shifting around.

The maintenance on the machines is killer though. Seals wear out, everything is coated in a layer of abrasive, and the tank starts to stink.

The time I spent around the machine this summer has opened up a whole new realm of design for me. It really changes the way you think about doing things. The ability to go from CAD to parts in a few minutes is fantastic for quickly-evolving projects and prototyping as long as you can justify the cost.

Henry

Henry's right, I've ran and worked on a waterjet for the past three years, they are extremely versatile machines. We've cut everything from 6" thick stainless to 3" thick walnut, as well as 2" thick granite. The majority of the time though we're cutting 1/8" - 3/8" stainless or aluminum. About the only material that I've seen it really struggle with was a ceramic that was laminated with copper on either side. Programming is very simple and rarely requires any tweeking, many of the steps are semi-automated in the CAM software. As Henry also mentions, they are fairly maintenance intensive; many of the parts tend to be machine specific – expensive and only available from the manufacturer. I usually explain to people that they’re faster than EDM but slower than plasma; more accurate than plasma but not as accurate as EDM and can cut a much wider range of materials than either plasma or EDM.

How often do the nozzles and parts wear out? How much do they cost? Say I was running a 60 hour/wk shop and at capacity of the machines, how much of the work week should be planned for downtime?

Yes you should consider getting one.They are great when they are working, but they are expensive to keep running. Constant maintenance and parts availabilty from only a few sources. You are not going to plug it in and have the money start rolling in, but if you are serious and do not give up easily you can invest your time and money into one and make more money easier than you ever will CNC milling. But some days you will think that the waterjet is going to drain you dry.They really are awesome but that comes with a big price.

If you plan on sticking with just metals you should look into high definition plasma cutters. Like 80k will you a nice one and I am pretty sure it can go up to an inch thick. The kerf is much less than older style plasmas.

The little bit I know of them (Omax), they offer a maintenance contract that will cover most headaches.

This was from experience at least 3-4 years ago. May have changed since then.

this came up before. I remember some people saying they CONSUME about $50/hr in wear and grit. so if you can charge $100/hr for your work, pay an operator and still have some profit, ok......

I hope someone chimes in about that figure.

Yes depending on the up front installed cost of say $100K to $500K, and the machine configuration, figure $50 to $75/hr in direct operating expenses not including labor cost or lease payments, and cutting for customers based on a retail rate of $150 to $300/hr.

As an internal R&D resource, and for certain kinds of manufacturing operations where expensive materials simply must be cut without a heat affected zone, it's an awesome tool. Once you adapt to designing fabrications made from 2-D cuts in sheet and plate, you can make a first item with essentially no programming or tooling or setup cost, and make 1 each of 100 different items in a row all with no changeover cost. Depending what you are doing, it's a powerful tool, a game-changer.

On the other hand, I don't think it's such a great idea to buy a waterjet and expect to suddenly start operating a profitable job shop. At least not if you expect to compete based on price.

As for down time, if you planned to run a machine for a 60hr week, the throughput would justify a preventive maintenance approach. Given a couple hours/wk of regular service and one day/month of major maintenance, i.e. doing preemptive rebuilds based on operating hours instead of fixing things when they break, you could expect pretty reliable operation for the life of the machine - like 20,000 hours for one of the premium machines.

We've used a combination of cnc controlled oxy-acetylene, plasma, laser and water-jet cutting in our little job shop for years--sub-contracted work only; we don't own any of them. All have their strengths and weaknesses and if you're planning on getting into the business I think it's important to understand what each does best.

Oxy-acetylene is almost always going to be the cheapest but the trade-off is that accuracy and finish will the worst. With the right equipment it will handle plates up to 12" or more. Hi-def plasma is more accurate than a hot torch but I've never been a big fan of the finish and, of course, plasma struggles with thicker plate. We use more laser-cutting than anything else in our shop--accuracy and finish are superb but it's generally pricier than plasma and 1" thick is about the limit for any machines around here. Because we're usually working with 14 GA to 1/2" plate the combination of accuracy, finish and cost makes it the best choice for most of our work. We use some water-jet but it's always more expensive--because it runs slower--than plasma and laser. Finish and accuracy are super--probably the best of the bunch--and of course you get "zero" heat warpage or impact so for some materials it's the only way to go. We have 2 or 3 local shops that do water-jet cutting and where they all thrive is making super accurate cuts in the thicker materials that plasma and laser can't touch.

Water-jet has a place but do your research and determine whether there's enough of a market for the kind of work it does best. I don't think you'll do too well competing against laser and plasma in the thinner materials but if you can find work for it in the thicker and specialty materials you should do fine...

A place near me makes good money cutting out holes in bathroom tiles for fancy inserts when he's not cutting metal. Uses a lot less garnet and keeps the hired help on his toes coz it cuts them quick.

TurboFabSupply said:

My experience is with CNC milling mostly but some turning. Recently a job came up with a 24" x 24" x .625" plate (like a flange, all pockets were through holes) with four 4" x 4" pockets, some bolt holes, a 3" diameter pocket and four 1" x 12" pockets. I estimated the milling time of this at about 30 minutes give or take 5 and it was a little bigger than what we could do in one setup so I suggested the local waterjetter. The water jet ended up being the cheapest route and made the plate well enough. They said it took them about the same amount of time.

This really opened my eyes to a new possibility. I'd like to run a business that would run very little inventory of parts and mostly raw materials. This business would sell maybe 20-50 of a certain water jet cuttable part in a year and in about 50 different varieties each selling 20-50 per year and each made out of the same steel or aluminum plate thickness.

Could I basically take a DXF for these parts, run it quickly through a cam program and just cut them basically as we sell them? Is it really that straight forward? No fixturing required for flat plates?

Click to expand...

Your probably not old enough to remember when someone put a optical line tradcer on a torch and the tracer followed whatever line was drawn... And then N/C came along and same fellows tossed away the tracer and used the N/C. Then CNC was developed and that became the new kid on the block... and now it's what Water Jets?... ok... Now dont get me wrong about all the new fangled things...I was a part of designing, building, and selling them to users...Then I bought several of them myself...

What I see and want to ask you is... Is there enough demand for the additional capacity that your new machine will create?... or will it add to the capacity in the way that customers will now have the advantage and the owners of these machines will now joining the race to the bottom in the pricing of their work?... I dont know...but it's happened with turning and milling cnc, it will happen when the next generation of plate cutter come along...

Think I'd wait for a LukeSkyWalker lazzer beam Clean cutter myself...

+1 to all the comments regarding maintenance and upkeep, as well as upfront costs. One thing I didn't hear mentioned is that you will need some way to keep your waterjet isolated from your CNC mills... unless you like the idea of having very fine, very abrasive dust all over everything. Depending on the size of your shop and the waterjet, this might mean no less than an addition to the shop, adding to the up-front costs.

IMO, unless you're sure you can keep a waterjet running, they're like boats. You think you want a boat, but you don't. What you really want is a buddy with a boat.

John
Sounds like you've owned more than a few boats
so have I

I get lots of my products water and lazer cut, for a brief moment I thought I wanted my own but after a little research I discovered that letting someone else maintain and make payments on the machine was a bargain. The shops here in Tucson compete for work they are willing to eviserate each other just to keep the machine running even if it is barley making a profit or operating at a loss. I have them put my jobs as fill in on the sides of plates and whenever they need work, I cant believe how little they charge.

Actually, that's a great point that cuts both ways. So you start thinking you want a boat, and then discover it's way better to have a close friend with a boat.

And then you realize, no, actually, it's worth having your own boat. Or not.

Same thing applies to box trucks, waterjets, etc. etc.

Something else to contemplate - what is your customer base and contact pool like? Waterjet shops seem to thrive on serving a much more diverse set of customers. Stone. Yep. Wood. Yep. Plastic. Yep. Metal. Of course. Do your circumstances enable you to pursue these markets? Or are you doing R&D or art where cutting wood on monday and stone on tuesday both with very short turnaround is super valuable?

OP talks about a family of parts cut from plate. ANY of the CNC plate cutting technologies can do that. But of course, if you want, say, gaskets to go with them, your gas-axe won't be so handy.

can a laser do aluminum? I heard the reflectiveness from the aluminum messes up the laser. Is this true?

Lasers are very effective in aluminum within a certain thickness range. This range has probably increased since the last laser I was involved with hit the market.... back then you didn't want to try anything thicker than 1/4". As I recall dross was more of an issue as well, compared to other materials. That said, that Trumpf Trumatic could FLY through 1/8" 6061 sheets. Outpaced the waterjet by about three to one.

Average thickness is probably 5/16"-1/2" with a lot of 6061 and mild steel thrown in there. This machine's intended purpose isn't so much a job shop as it is a manufacturer of niche products in small volumes that I don't really want to inventory. $50/hr operating/maintenance cost not including machine payments or operator costs is pretty high though. For CNC Mills that's probably be down around $35 for aluminum.

TurboFabSupply said:

Average thickness is probably 5/16"-1/2" with a lot of 6061 and mild steel thrown in there. This machine's intended purpose isn't so much a job shop as it is a manufacturer of niche products in small volumes that I don't really want to inventory. $50/hr operating/maintenance cost not including machine payments or operator costs is pretty high though. For CNC Mills that's probably be down around $35 for aluminum.

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I was a waterjet operator around 2004-6ish, I just made the tool paths (all sketches from an artist that we converted to vector) and loaded the machine. $50/hr seems high to me, but I've been out of the game for awhile now.

+1 what everyone says on the maintenance, the maintenance cycles are frequent, but the machines themselves are reliable and can have high up-time.

As mentioned their strength compared to all the other CNC plate cutters is really the ability to do a large variety of materials, from cutting gaskets, to stone, to tile, to titanium. If you do go a waterjet route, become good friends with a laser cutter, as the two tools really compliment each other.

I don't know what the market is for sheet metal cutting job shops is. Most of the guys I knew ran brakes, or sand blasters, or powder coating too so they could do net parts and add more value.