Anyone have a plasma cnc and router cnc?

[ej4]

I've been reading here for awhile with the intent to build up a machine starting in the next six months or so.

I am an avid woodworker with a well equipped wood shop, but like to weld as well and seem to find small metal projects more and more. I'm on the fence as to whether I'm better off with a router CNC or plasma CNC for a first build. I really want to include a rotary axis for either machine I build (want to make wooden vise screws, or be able to do pipe cutting).

I think I'm pretty clear on the reasons for not making an all-in-one machine, due to optimizations for the respective tooling. I'm also working in a garage shop, so either machine would be fairly small - maybe 3x4 or 4x4. Would probably be a steel frame build either way w/ servos.

For anyone who has both or has built both, any thoughts on tradeoffs or things you discovered that you'd have done differently? or which you'd suggest building first?

I'm leaning toward a plasma, since it seems like it would open up some possibilities for metalworking projects (I don't own a mill or lathe). But a router table would seem to be more immediately useful. argh.

Any thoughts from you experts?


Thanks!

[Mike 1948]

Originally Posted by ej4 I've been reading here for awhile with the intent to build up a machine starting in the next six months or so. I am an avid woodworker with a well equipped wood shop, but like to weld as well and seem to find small metal projects more and more. I'm on the fence as to whether I'm better off with a router CNC or plasma CNC for a first build. I really want to include a rotary axis for either machine I build (want to make wooden vise screws, or be able to do pipe cutting). I think I'm pretty clear on the reasons for not making an all-in-one machine, due to optimizations for the respective tooling. I'm also working in a garage shop, so either machine would be fairly small - maybe 3x4 or 4x4. Would probably be a steel frame build either way w/ servos. For anyone who has both or has built both, any thoughts on tradeoffs or things you discovered that you'd have done differently? or which you'd suggest building first? I'm leaning toward a plasma, since it seems like it would open up some possibilities for metalworking projects (I don't own a mill or lathe). But a router table would seem to be more immediately useful. argh. Any thoughts from you experts? Thanks!

I'm no expert by any means, just a hobby shop type. I have a 4 x 4 plasma/router which was made by the now infamous, out of business DynaCNC. It runs both ways by taking the MDF bed and router mount off the Z and adding a hand torch mount for my Cutmaster 52 and support slats. I also have 3 stainless steel 15" x 45" two inch deep pans I fill with water for a rudmentary water table. They rest on the cross frame(where the mdf bed was) and fit under the metal support slats for plasma cutting. They dont catch all of the dust but do a fair job. Speaking of that "dust" do NOT put your control computer in the same room with your plasma cutter unless you have a very good capture system. That black electrically conductive crap gets into and on everything, just ask my "first" $800.00 computer, 3 months old and POOOF. I live in So. Wisconsin so I cut metal in the warm months with the garage door open, and cut wood in the winter with everthing closed. It actually works quite well and is a welcome change with the seasons.
As for software I use the Vectric's Aspire and PhotoVcarve for wood, Sheetcam for metal cutting. Mach3 is my control sofware which plays well with all my software.
Well all that said, I would build one machine with 2 different mounting heads, with a little planning it will give you the best of both worlds.

Good luck
Mike

[ej4]

Thanks for the input, Mike. Building an all-in-one has me feeling like I'd end up with a machine that wouldn't do either function well, but I like the idea of what you describe, where I could switch back and forth.

Being new to CNC and the design of such, I think focusing on one or the other might be more successful for me.

From what I gather, the tradeoffs are between higher accel/lower accuracy of a plasma, vs. lower speed/higher accuracy of a router, as well as the loads of a router being higher. I don't have enough knowledge yet to balance it all in an appropriate design. I do recall a build here where they had build it so they could have tooling on both sides of the gantry.....

I was considering one of the new fanless PC's for a host to avoid the dust/debris issues. I'd expect them to have plenty of compute power, but IO might remain the issue. More research to be done.

Thanks for the ideas, and I'd be interested in anyone else's comments or thoughts as well.

[Mike 1948]

Originally Posted by ej4 Thanks for the input, Mike. Building an all-in-one has me feeling like I'd end up with a machine that wouldn't do either function well, but I like the idea of what you describe, where I could switch back and forth. Being new to CNC and the design of such, I think focusing on one or the other might be more successful for me. From what I gather, the tradeoffs are between higher accel/lower accuracy of a plasma, vs. lower speed/higher accuracy of a router, as well as the loads of a router being higher. I don't have enough knowledge yet to balance it all in an appropriate design. I do recall a build here where they had build it so they could have tooling on both sides of the gantry..... I was considering one of the new fanless PC's for a host to avoid the dust/debris issues. I'd expect them to have plenty of compute power, but IO might remain the issue. More research to be done. Thanks for the ideas, and I'd be interested in anyone else's comments or thoughts as well.

You use different setting files(called "xml" files)in Mach 3, one setup for Router speeds and feeds, and one for the plasma portion. It give the best of both worlds.

Mike

[Torchhead]

The one thing MACH cannot change is the mechanics. The final drive ratio dictates the amount of torque you have at a given speed. You either have to overbuild/overisze one or the other to get a machine that does both tasks equally well....but that is not to say you can't compromise and get a machine that will do both functions but maybe not as good as separate dedicated machines. The 'overbuild" approach says you build the gantry rigid enough for routing and slinging a 3 HP PC router around and pushing a 1/2 mortise bit into solid oak and then you pick motors that will have plenty of torque and speed for plasma cutting sharp corners at high feedrates ...aka Servos.

Your venture parallels mine a lot but about 10 years later. I was a woodworker and built furniture, but got interested in the mid 90's with metalworking and bought myself a mill-drill and a 12 X 36 import metal lathe. I never really put the two crafts together and got so enthralled with the precision of metalworking I neglected the woodworking for a long time (BTW learning to be a machinist has made me a better woodworker!). In 2000 I decided I wanted to build a CNC table and a mixed use table sure made sense to me at the time. i made all of the standard mistakes. My first table was servo's (because I found them surplus) and long ballscrews (because they came with the motors). Once I switched from hobby mode to business mode in 2002 and decided to build a business around CNC cutting, I learned several things real quick;

1. People will pay the same price for a decorative cut and painted piece of 20" square steel as they would for a 20" wood carving but I could do the steel in about 1/10 the time. No brainer.

2. My table was poorly engineered. It was two slow for plasma (fastest I could get was about 160 IPM before lead whip on the ballscrews started to cause bad vibrations.) It took me about 30 to 45 minutes to swap back and forth (and do the clean-up of wood chips to stop the shop fires the plasma can set) and the table NEVER seemed to be in the right setup. I finally decided to just make it a plasma only table even though it was better suited for router.
3. The amount of volcanic dust from plasma cutting is so nasty that you don't want it near you woodcutting equipment. Even with a water tray and cross ventilation the grit gets everywhere. The smoke off the torch is vaporized metal and drifts and settles on any exposed surface.
4. You seldom end up doing what you think you will with the machine. I understand the limited space aspect in a small shop BUT unless your shop is detached from your house Your plasma cutting days will be short lived unless you live alone!
5. You need to cut bigger stuff with plasma. it's not very useful for small delicate cutting (kinda like carving with a chain saw). Conversely most routing projects 9unless you build cabinets commercially) are small and can be done on a 2 x 2 oe 2 x 3 machine.

6. The story goes full circle and now I can own any kind and size of table I want. We use router tables, an engraving table-top machine, CNC mills, rotary axis and I just ordered a new 5 x 5 plasma table. Guess what: I built it it's own room far away from my other equipment and the people that work for me!

7. In the end you may find a lighter gantry table for plasma with smaller stepper motors and smaller drives/electronics dedicated and optimized for plasma with a separate smaller router table built for that purpose will not be a lot more money. I guess I would equate it to having separate wood working tools like a joiner and tablesaw VS the All-in-one ones I see in the wood magazines.

The most important thing is you build something. Not matter what it is you will find things that you will change the next time.

TOM caudle
www.CandCNC.com

[ej4]

So, what you're saying Tom, is that my wife is going to be really unappreciative of the plasma CNC sharing the garage with her laundry closet.... I see.

You bring up some good points. The mechanics of the two styles of machines was my main consideration in trying an all in one. Yes, I think it could be balanced (obviously people have done it as you and Mike pointed out), but I'm not sure I want to go down that path on the first shot; I'd be worried it would create some expensive mistakes. I'm also not sure I could convince the wife of two machines, nor do I really have the proper space.

Thanks for the alternative viewpoint. I'm coming to the realization that I should probably go with the router due to practical reasons, but in my head I really was hoping for a plasma machine to do something 'new'. Well, I still have some time until I start work on it, so I may be able to come up with some alternatives yet....

[Torchhead]

Originally Posted by ej4 So, what you're saying Tom, is that my wife is going to be really unappreciative of the plasma CNC sharing the garage with her laundry closet.... I see. ....

My objective was not to discourage you from building your machine but to let you in on a couple of the "Dirty Little Secrets" of plasma cutting. It's not something that I would do in a small shop that had other operations (be it woodworking, machining or laundry) going on. While plasma cutting is exciting and has lots of uses it's got limitations and downsides that need to be understood.

1. it's not a precision process
2. It's designed to cut primarily sheet metal and only in 2D
3. It does not do a good job on cutting small holes or tiny features
4. It's nasty, loud and generates lots of sparks and smoke
5. It will set things on fire
6. It is harder to do in a lot of ways than 2.5D routing
7. It can cause eye burns like any arc welding/cutting process
8. It generates levels of EMI and RFI that could effect you or your close neighbors electronic equipment.

My advice is to either find a buddy that has a plasma cutter (even a manual one) or a local welding shop that could give you a demo and go see it for yourself (take dark glasses). When you are there stand back and note the amount of sparks, smoke (vaporized metal) and back side "dust" that is generated. Then decide if you want that in your shop and around your woodworking equipment and work area.

Some controls will allow you to easily field upgrade to a plasma and Torch Height Control. If you build the router and later decide to come over to the world of fire and smoke, then it can be a low cost and (relatively) painless experience.

Since this is not going to be a production machine it does not have to be perfectly optimized for the job(s).

There are other "Dirty Little Secrets" but you have enough to mull on for now (:')

TOM caudle
www.CandCNC.com

[ej4]

Nope, you're not discouraging at all. I appreciate the comments coming from experience.

I got hooked on the plasma idea through a community college welding class I took. They had an ancient monster CNC that only 1 guy knew how to use and he gave me a rundown on it so I could use it.

It had some sort of eye tracer (??) so I drew the outline of my project on a sheet of butcher paper in black marker, and it traced it automatically, then switched over to metal and voila, 20 minutes later I had a metal blank cut out; very slick and quite a teaser.

[tulsaturbo]

I built mine originally as a dual purpose plasma / router machine. I am limited on space in my shop so the size of the machine was critical. I finally decided on a 3' x 3' sized machine as being a good size for me but its all relevant on what you plan to create (size wise) on your machine.

Because I am running a bunch of different projects, it was simpler to have a seperate machine for each task, although a dual purpose machine is cost effective and very doable. As far as plasma is concerned, it is a very dirty job when it comes to cutting metal. The best thing I ever did was make a water table for mine. I had to literally roll the machine outside to cut and get away from the dust but not anymore. Now the dust is virtually nil.

Link to Youtube videos:
YouTube - ShopDroids's Channel

Here is a picture of my RouterBot and PlasmaBot with project log links on the zone:

My RouterBOT - CNCzone.com-The Largest Machinist Community on the net!


My PlasmaBot - CNCzone.com-The Largest Machinist Community on the net!

[ej4]

Hi Tulsaturbo -
Interesting build. I remember looking through your build awhile back, but now I bookmarked it. I like the way you have the x motors vertical to save some space.

I was thinking through a way to put them horizontal 'inboard', under the table, rather than 'outboard' like many builds; it seems like it would save a good foot of extra real estate. I haven't come across any builds like this yet...maybe there's a reason..... (water table is one...but maybe I can figure something out). Vertical may be another option I should be considering.

Looks like you have an effective design without overbuilding it. I've been considering doing a minimalist build to get it off the ground, and then using said machine to fabricate parts for a 'real' machine, like the bracketry and mounting supports like you've got.

Thanks for the ideas.