CNC Plasma Cutter: Post Purchase Costs

[lnex1357]

The Aluminum Falcons (FRC 2168) are working on proposals for a number of grant opportunities that we have have identified. One of the proposals in the works is being generated to support the purchase of 4' x 4' Torchmate CNC plasma cutter package. I know there are a number of teams who have purchased and are successfully using these systems from Lincoln Electric. In order to properly estimate the grant amount request, I am working to estimate a number of costs assosciated with purchasing and owning the said system. My questions to those teams that use the Torchmate or an equivalent system are:

What are the costs beyond the purchase of the machine and tooling you have expereinced, i.e. installation & setup cost (electric drop/water line for water table), gas rental, etc?

What have users experienced in terms of operational cost i.e. gas usage, tool & tip replacement, power consumption etc?

I have searched through a number of machining forums to see what peoples experience in industry are and have complied a rough set of cost figures. These numbers however are based on a machine shop usage level and not an FRC build season and off season usage level.

Your experiences and feedback are greatly appreciated.

[colin340]

no idea on cost

But just a warning that my team has never had great luck cnc plasma cutting parts in aluminum. If your team has a good fixture making background and a great welder then maybe. Otherwise your cash would be better spend on a full size Bridgeport with DROs

best of luck

[Samwaldo]

we (a fellow CT team in Brookfield) JUST got one. Team 1099 worked with the school to get a giant grant to get the Plasma cutter, a laser cutter, A 3D printer, new wet belt sander, and a few other things.

We got a slightly larger one (5' x 5' if I recall correctly) Torchmate CNC plasma cutter. We just finished constructing the table last week and still need to attach the cutter. Theirs alot of extra thing you need to buy. For instance we are setting up a whole new computer next to it, and got a wood router to attach to it also.

I'm not quite sure how much just the plasma cutter + accessories cost because some money came from the grant and some from the tech yearly budget.

If you have any questions i can pass them along to the Tech teacher though.

[MrBasse]

Originally Posted by lnex1357

What are the costs beyond the purchase of the machine and tooling you have expereinced, i.e. installation & setup cost (electric drop/water line for water table), gas rental, etc?

What have users experienced in terms of operational cost i.e. gas usage, tool & tip replacement, power consumption etc?

I'm going to assume that you have a computer to run this with...

Consumables are not too noticeable, as there aren't a lot of consumables. Gas is simply compressed air, so cost there is just getting a compressor. We have a refrigerant dryer as well to keep our plasma cutter free of moisture. Tips are the most commonly changed parts we have, with our machine operating for 1-2 hours per week we change tips every three to four months. Tip cost will depend which machine you will have, we use a Hypertherm 1600 and replace all parts but the outer shield when we open it up. On average it costs us $15-25 depending on what kind of tips we use. Power consumption isn't an issue for us as we are in a public school so power is free to us. You could figure it out by using the wattage on your plasma cutter and determining run time to get a rough estimate.

Without knowing where you are and what the general rates are for contractors in you area, the question of costs for drops for water and power are going to be unknowns for me. Ours was around $300 to get hooked up including a ground stake drilled through 12" of concrete. However we had ample 220VAC supplied right next to our machine already.

Our machine is a PlasmaCAM and people will tell you all day long that plasma is no go for this and no good for that, but it all depends on what you expect out of the machine. Plasma cutting materials for us has been fantastically successful because we use it for precision on our shapes and for layout on our holes and cutouts. We built our shooter using it this year for 1/8 inch aluminum and had no issue whatsoever. We had to drill out a few holes to be 1/4 inch but that was just because they were so small. Anything 3/8" and up the plasma does a fine job. Plus for our thicker sheet metal parts we use it to perforate the material so it is easier to bend and that has been hugely successful as well. We also used it for the seat pan on our electric car using 3/16 aluminum with perforations and that was a one cut and perfect fit operation.

[magnets]

Personally I don't like plasma cutters for FRC applications. They aren't super accurate (compared to waterjets), and they are expensive and a pain to run. Our team has a CNC router that can cut aluminum (shopbot 4' x 4'), a cnc 3 axis mill, and a really old bridgeport with a DRO.

We make 70% of parts on the bridgeport, 25% on the shopbot, and maybe 5% on the cnc mill.

If you don't have a good bridgeport with DRO/a good lathe, get one of those first.

Cutting sheet aluminum on a cnc router isn't totally ideal, cooling/lubrication is a little trick, and the parameters take a bit to get dialed in, but there is a massive amount of flexibility. We make things out of foam, plywood, and HDPE all of the time.

If you already have a bridgeport/lathe/other cnc machine, you could invest in a plasma cutter, but it depends on your team. Come up with a spreadsheet that shows you if the machine can save you money in the long run compared to sending parts out to be machined.

[mman1506]

We have a plasma cam(6x6?). You cannot use a water table for aluminium as it will collect poisonous gases released when plasma cutting that are heavier than air. We sometimes spray a little water on the collection table we have under it to prevent the dust through being blown into the air. Consumable consumption can change depending on what you're cutting and your operator but its not too bad.

As others has said I would recommend against getting a plasma cutter. It takes a lot of careful calibration to get mediocre results. It works ok for large low tolerance cut-outs and if you just make locating holes by piercing and drill them out you can get reasonable accuracy.

Most of the time are team skips the plasma cutter and uses a shear, band saw and drill press to do large pieces that cant fit on our CNC mill or a manual mill.

[BBray_T1296]

Our team usually gets our stuff laser cut by our local sponsor. Due to their scheduling and priorities, it takes them about 1.5 weeks to finish a part, even though it is only 1-2 hours of work (I worked there this summer). We have discussed getting some sort of small sheet metal cutting machine for quick prototypes and things. Thanks for providing useful knowledge.

[MichaelBick]

Originally Posted by BBray_T1296

Our team usually gets our stuff laser cut by our local sponsor. Due to their scheduling and priorities, it takes them about 1.5 weeks to finish a part, even though it is only 1-2 hours of work (I worked there this summer). We have discussed getting some sort of small sheet metal cutting machine for quick prototypes and things. Thanks for providing useful knowledge.

Look into getting better sponsors. Our first waterjet sponsor took about the same amount of time. We found a new one that returns parts within 5 days, usually much faster. We're looking to find more/faster machine shop sponsors too.

[techhelpbb]

Team 11 has a CNC plasma cutter.

Works great on aluminum for rough cuts.
Gets things down to size.
Allows for really fast testing of things if you don't mind the slop.
Don't expect finished work from it.
Works great for removing unnecessary material to lighten things up.

Team 11 also has: a Bridgeport, bandsaws, several lathes and the Haas TM-1P is now in the shop.
Not quite up and running but soon. There's a Haas lathe on the way.
Plus the Makerbot.

Nothing wrong with the CNC plasma cutter.
Just don't expect it to be the end all and be all of shop tools.
If you can reuse the X/Y for other things that's even better.
Say for example use a real Z instead of a mere up and down and fixture a shop router for some work.

One nice part about CNC plasma cutters is that they tend to be as easy to instruct as pen plotters.
So unlike some other CNC tools it really is possible to run a CNC plasma cutter without touching much G-code.

The Makerbots sort of share this ease of use.
Slic3r is really not something most people use in that work flow but it is there.
Slic3r often comes up with RepRap style printers.
Even at that most people don't manipulate 3D printer G-code at the starter level.

I think of these later tools as introductory tools for the lathes and mills.
It gets increasingly difficult to avoid touching G-code and encountering surprises during operations.

[Peter Matteson]

We have I believe the exact same machine and have been using it since 2012.
If you look at our 2012 robot you can see a robot made almost entirely on the cnc plasma cutter.
http://www.chiefdelphi.com/media/photos/37782

I can't talk to the electrical cost, as we replaced an existing welder which was already well ventilated. No new drops were needed.

We did the assembly installation ourselves.

We don't have any gas bottles to run the system we use our shop air, which we also already had.

The tips last a reasonable amount of time. We replace them when the plasma loses focus and they only cost a few dollars at the local welding supply shop. We use 3 or 4 per season at most.

The biggest thing is with trial and error you will learn how much finishing you need to do on other machines. We can do most of our drive train side plates on the Plasma cutter.

[Akash Rastogi]

Originally Posted by Peter Matteson

The biggest thing is with trial and error you will learn how much finishing you need to do on other machines. We can do most of our drive train side plates on the Plasma cutter.

With tips from the internet and through trial and error, 11 also completed both robots this year on a PlasmaCAM with some finish work on a CNC mill.

The shooter's sheetmetal was also cut on the plasma table, as well as all gussets on the frame. Small holes were finished off on a drill press with relative ease using jigs. I'll try to have one of the students who operates our machine post on here. I'm sure he would have the best feedback for you.

http://i.imgur.com/ybL2XiL.jpg
http://i.imgur.com/FlVBfQ6.jpg
http://i.imgur.com/8uyWIBp.jpg
http://i.imgur.com/d3XxHDy.jpg

Not sure if it was mentioned yet, but 11 has welding curtains set up around the machine for safety. May want to look into that.

Originally Posted by magnets

Personally I don't like plasma cutters for FRC applications. They aren't super accurate (compared to waterjets), and they are expensive and a pain to run.

While not as accurate, this is a pretty poor comparison. Additionally, we have had no issues with ease of use. As mentioned, kids run all parts on the machine pretty easily. The whole point of adding machines in-house is so you don't have to rely on sponsor resources. There are very few teams/schools who can afford waterjet system, which are immensely more expensive to operate, while plasma systems are relatively low cost and produce satisfactory work when dialed in correctly.