Post By Ries
Post By Ries
Looking into a CNC Plasma table. HELP
Can anyone tell me what they have and what all is involved? Tips, tricks and what not... Looking at a 4 x 4 table. We are looking at making little parts, such as tabs for brackets to bolt to. Little stuff that we have been making on the mill, but looking now to mass produce several at a time.
Need more info to make an intelligent response.
what metals will you want to cut, in what thicknesses, in what sheet sizes.
how many parts per week/month/year?
personally, I would not consider a machine without auto torch height compensation.
Max 1/4 inch. More in the 10 gauge range. Cut probably one 1- 4 x 4 sheet per week. Not a ton of work, just checking to see if it could be justifiable.
In that case, you should be able to get away with one of the Home size machines- Plasmacam, Torchmate, or similar.
They are lightly built, and use small power supplies, and will do what you want, probably for well under ten grand new.
The cutting table and the plasma cutting power supply are two separate things. Some of the home size machines use hand torches, others require machine torches. A machine torch will generally run you around $500 more, but its tougher and longer lived. I would recommend either Hypertherm or Thermal Dynamics for a power supply. Jim Colt, who works for Hypertherm, but maintains a pretty unbiased view, should check in here soon with his two bits.
Real industrial systems are much sturdier, and cost much more. But if you arent slamming 4x10 sheets of 1/2" plate on with a forklift 4 times a day, you can use a home grade machine.
But I would still hold out for auto torch height.
Have you looked at farming them out for laser cutting? If there stock parts and you can be flexible + order a decent qty it can work out pretty cheep. Cut quality can also be massively better too.
The downside of plasma is hole quality.Regardless of what salesmen tell you good hole quality costs money and I doubt I`d want to invest at that level in a 4 x 4 table.
If OTOH you are prepared to do holes as a second op then investment comes down dramatically so it`s a question of will the customer stand the drop in quality from machining to plasma.
As suggested might be worth getting quotes for lasering.
For that limited quantity - I wouldn't even consider buying a plasma. They make a huge mess in your shop, set off all your smoke detectors and have considerable cost in consumables.
We have 3 really good laser cutting vendors who typically turn parts around in 1-3 days depending on how busy they are and I can't compete with my plasma table for cost or cut quality.
We use our plasma for MUST HAVE parts same day . . . otherwise, our local vendors take care of us with a phone call and e-mail of a DXF file. (plus, they can bend and form parts that we cannot with our limited equipment)
I get lots of parts lazer cut, it is so cheap that there is no way you will pay for the machine. Do what you guys do best and let someone else absorb the cost of the machine. I used to have one I had an Esab ESP150 it never made me a nickle I also had a small hypotherm I think it was a 1000 it was a great machine but still never paid for itself. I hated the big mess and the fussing with the dang thing. I just jump in the truck and go get my parts now, the holes are all perfect and I dont have the skeletons laying all over the place. The people I sold the machine to are now selling it because they are getting all the stuff lazer cut.
I think whether or not it is worth it depends on several factors.
First, you need to price outside cutting shops in your area. This market is bizarrely regional- in some areas, there are lots of laser shops and few contract plasma shops, in others there are tons of waterjet shops and few lasers- it just depends on where you are, and how many of each there are, as to how competitive they will be.
I have a shop near me that does both laser and waterjet in the same shop, and when I get quotes, they always do waterjet cheaper- but that may be the materials I am cutting, and the thicknesses, for their two particular machines.
Second, it depends on your tolerances- as mentioned, laser is the best for accurate holes, waterjet next best, then plasma. If you can get by with the relatively sloppy tolerances of plasma, its the cheapest, either in house, or outsourced. I have done projects where I needed lots of relatively big parts in 1/8" aluminum- 8' x 3', say, and found that a plasma shop with a 12' x 40' table was far and away the cheapest in my area.
Third, it depends on your quantities per part, degree of complication, and how far in advance you can plan.
I often have cases where I need ONE very complicated part cut, and the programming time alone to send it out would be prohibitive. Or, I have cases where I design and cut a part, to test it, find I need to modify the design, cut a second one, change it again, then cut 4. To pay to outsource stuff like this is usually not worth it, so I have a 4x8 plasma table in the corner. Its fast, and flexible, to cut oddball stuff. But the tolerances arent that great, I punch or drill holes in a second op, usually.
If you know you are going to be constantly needing very small quantities right now, it might be worth it to have in house plasma. If you usually do the same things over and over again, it might be cheaper to outsource.
It is, as motion guru says, dirty. And noisy. Plasma produces brown, sticky smoke, that coats the inside of your walls and roof with rust colored grime that is basically "rust dust". It also scatters hot sparks which cool to become something very like grinding dust. A water table helps a lot, but thats another thing to build and maintain- it needs cleaning periodically, which is a very filthy job, and refilling pretty often. A water table does not mean you dont also need good dust collection for the machine too- I use both an electrostatic smog hog type machine with articulated hose, and big fans to exchange all the air in that part of the shop.
Oh- and you will need a big compressor, with decent CFM, and a good water filter on it. I run a 7.5hp compressor with a 120 gallon tank, and it runs continuously when plasma cutting- its probably not really big enough. I would recommend a ten horse with at least a 120 gallon tank. A real ten horse, not a "home depot" ten horse.
If you need it, in house plasma can be a lifesaver, with custom parts right now.
I have cut a lot of really oddball stuff with mine that would have been very expensive to send out- welded together 4x8 sheets, which was one 4'x 16' foot piece, for example, I cut one end, then flipped it end for end, registered it, and cut the other end. Only one of em, with a very complicated pattern- woulda been a small fortune to have that cut commercially.
PS- I didnt know you were supposed to have smoke detectors in a welding shop.
Thanks guys. What is a estimated cost of a laser machine, or a water jet? We are talking small quantities, but the nearest laser shop I know of to me is over an hour and half away. I am thinking with a relatively low start up cost, we can pay for it soon enough without driving all over. R&D... We do a lot of it. After I get something made, they want to change it. And a lot of the time, the holes that are there, are nothing critical. Mostly tabs that they can bolt a bracket to to hold something small. They position it where ever they need it after it is bolted up. It just needs a bolt hole cut in it. Or two... Maybe to help pay for it we can make some fancy welcome signs too HA
You've gotten very good answers here.
Now it does appear you need to purchase the machine, as your lack of
Torchmate is now part of Lincoln electric, and has a package deal running
with a small (2' x 2' IIRC) complete with power supply, for I think $6,000.
I didn't think much of Torchmate, until I started troubleshooting
a 5' x 12' model (neighbors). it was $20,000 complete, and
has T.H.C., and the drive system (which I initially scoffed at)
isn't looking too shabby.
When we get the bugs out (he moved it to a diffferent shop, and
there are some loose wires somewhere) I'll try to report back.
When dealing with small parts the distance from a good laser cutting vendor should not be an issue. Drawings and files can be sent by email to almost anywhere and USPS has decent rates for it's flat rate shipping envelopes and boxes. We have a non-high def CNC plasma/torch with a shop built water table but only use it on large parts.
My desire to do all work in-house has me wanting to upgrade our equipment but the economics shows otherwise. The parts we get from a laser cutting vendor are accurate, clean and usually require no additional machining. We just did some parts that were laser cut from 1/8" P&O. I had the tap drill size cut for 8ea 10-24 threaded holes. All we had to do was chamfer and tap. If I did this job with my plasma the parts would require more cleanup as well as a secondary drill & tap operation.
Originally Posted by 3dracer
NEW prices for turnkey systems, just rough seat of the pants-
Home grade plasma, such as Plasma cam or Torchmate- $10k or under.
industrial grade Plasma, with 4x8 or 4x10 tables, dedicated computers, and bigger, better power supplies- $30k to $50k or so.
Hi-Definition Plasma, which is a Hypertherm power supply which can cut thicker materials, and does much tighter tolerances- add about $30k to the above industrial models.
Waterjet- good quality, respected US company, in at least a 4x4 size- figure $100k minimum, more like $150k to $200k for a 5x10. Of course, this can go up if you want the ones that compensate for kerf draft angle by automatically swivelling the head.
Laser- figure that they start at around $200k for real industrial models, and quickly head up towards a half mil, especially when you start adding auto sheet loading, scrap conveyors, and the like.
In addition, Waterjet and Laser have very high hourly costs- consumables, pump rebuilds, abrasives, abrasive disposal fees, new lenses, shielding gases, and so on. Basically, with either, you should be planning on at least one full 40 hour shift to pay for the machine. 2 shifts is better.
Now, of course, there are the occasional screaming deals- oddball used machines, and so on- but aside from the bone simple plasma machines, none of this stuff is cheap to run or maintain. Even if you happen upon some very cheap waterjet, the pumps still have a finite, pretty short, life in running hours before they need very expensive rebuilds.
These are not machines to jump into for fun, unless you have very deep pockets.
PS- dont forget the software costs. For in house plasma on a small scale, you can use the cheap programs. For job shop work, you need big, expensive programs with the ability to read a variety of files, and they tend to need upgrading regularly, at no small cost. A waterjet shop near me is losing more and more business, because they just cant, or wont, plunk down the ten or twenty grand it would take to upgrade their ten year old software. The new guys up the road, with current software, are getting more and more of their work, because the file sizes on modern stuff just keeps growing.
Yeah cross your fingers and pray your torchmate didnt get any crud in the gear rack because its in the cut zone or you dont have any dust on the cold rolled steel like we did everytime you have $$ on the table. Some of the worst engineering goes into those. Look at plasmacam and when you lean on it the torch wiggles. There are $2K junk tables on ebay that you may get a good part and then you may not even get it to run. There are old tables that cannot move out of their own way...cut at 100IPM max and rapid at 200IPM max..I know we had one as well. If you cannot travel at the mfgs speeds you will not be happy with the result. Hypertherm just released a slow speed for lower amperage...guess what its a joke you can get a nice part with a huge welded dross on the backside...I know we tried tons of settings. Stick to laser and farm out the work. Unless you want to putz with wasting money to make a couple signs youll be grinding all day steer far away from little cnc plasma cutters.
Originally Posted by digger doug
Also do not confuse Hi-definition with HYdef which is hypertherms sales pitch for their height controller. There is no Hi-definition plasma cutter its a myth but there is Hy-def hypertherm axis controls that they use with multi gas consumables and change the amperage as they cut. That height control is #1 right now but there are 2 others in the works that may make it #3...or so the sales pitch went.
Originally Posted by Ries
I've built my own cnc plasma and here's some pointers.
Hypertherm Powermax 45, 65, 85 or 105 with Duramax machine torch. These torches have new conical flow technology which increases arc jet density. Many users rave about the increased cut quality compared to the previous Hypertherm torches uses on the 1250 machine for example (although these earlier machines can be fitted with the Duramax torch, that's what I have done).
Initial height sensing before pierce. Example my table "touches off" to find top of material then retracts to a height (user programmed) before piercing. After a delay (user programmed) to allow the pierce to complete the torch comes down to cut height at a certain rate (user programmed). After a delay (user programmed) the torch height control takes over to precisely maintain the correct cut height.
NOTE: with plasma you want torch height control it your want good edge quality and longest consumeable life. The initial height sensing and piercing at a higher height also greatly reduce your consumeable costs.
With a Duramax torch, piercing at the correct height, and cutting at the correct controlled height the consumeable costs will be not bad at all for the number of parts you can cut.
I use Sheetcam to convert my cad files to gcode. It's great for the price, has good support on the forum, and has quite a lot of features (different types of lead ins and outs, looping on corners, chain cutting to minimise number of pierces, etc). You can download a fully functional version of Sheetcam but I think the amount of gcode is limited.
You will need clean, dry air, or start forking out for consumeables. Many uses report huge increases in cut quality and consumeable life when they get their air clean and dry.
There are methods to improve hole quality but you'll never beat laser (or drilling LOL). Sheetcam has a function to pierce only at hole centres so you can drill them out afterwards. I go one step further and modify the gcode at that point so the plasma just gives a blip and creates a little crater at the hole centre.
If you are happy to cut the hole with plasma then the cut speed can be reduced at the hole and the torch height control turned off just for that cut. Hypertherm has a PDF download on improving hole cut quality.
Refining cut quality is a matter of starting off with the manufacturer recommended settings then doing several test cuts at different parameters and find that sweet point for a given material and thickness.
Overall, cnc plasma is quite a learning curve. Many think it's simple when in fact it's more complicated than cnc milling. Lots of variables: feed rate, cut height, air quality, acceleration, cut amps, torch dive over gaps (with torch height control), etc. Many take the bullish approach but they won't get the quality that way (or consumeable life).
Actually HyDefinition is a Hypertherm trade name for its plasma that has a higher energy density arc (invented and patented technology from about 1992).....the name high definition is a generic name for this technology that basically means forcing the same amount of energy through a smaller nozzle orifice....for more energy density as measured in Amps per Square inch....narrower kerf, squarer cut edges as well as less dross formation. Early high definition plasmas were limited to 70 amps and 3/8" max thickness....today high definition plasma can go to 800 amps and 6 inch thickness. High definiton has never referred to a Hypertherm height control system. There is some new technology called True Hole that uses a Hypertherm high definition class plasma in a well orchestrated dance with the correct CAM software, a good quality height control, as well as a cnc machine with extreme accleration to achiev hole quality that has no taper, minimal metalurgicall effect, and minimall start stop kerf anomalies.
The CAM software reconizes hole profiles in the inputted .dxf drawing....and applies the correct lead ins, leadouts, plasma power levels, speeds, heights, process gasses (o2/o2) atomatically with no operator intervention or machine code editing. Many of the holes in steel plate are equivalent to drilling using this process....are much faster....and have a high tolerance to stress fracturing.
Jim Colt Hypertherm