[mcArch]

Pete, thanks for the input on the Z axis & ball screw . . . I was staying away from the ball screw for cost reasons for now, maybe in the future. If I take that 1071# & div. by 28 (the 28:1 decrease) I still get 38.25# which I should not get to near with the router. Maybe I can take some weight out of the Z carriage by thinning up the plates & angles, they don't need to be quite that heavy. I plan to use either (interchangable) router or plasma on the table. Would love to see the image of your router table. Shoot it to me in an email, [email protected]. I'll check out the Nook specs. Thanks.

-mike

[Jeep07]

Canadamaxx,

I agree, nice plasma table, good design, simple but effective. I am working on a cnc router, but it needs to be more accurate than a plasma, hence a somewhat different approach.

I would like to inject into the group, if anyone is looking for a plasma cutter, check out www.parkermetalworking.com. He is located in the US Indianapolis I think, or around there. I have one of his 40 amp plasma cutters, it is rated for 5/8" plate but will cut shorts of 3/4". This is one sweet machine, and the price is under $700 US. This sort of compares to the Miller plasma, that sells for about $2500 US, and is rated for only 3/8" plate. My unit is smaller than my computer case and weighs in at 22 lbs. It will work on both 115V or 230V, and switches automatically between them if you change the plug. It is a handy machine for remote work, as it can run off an small generator or even up to 250 ft on an extension. I have it wired to 220V using a 14/3 gauge cord. It also needs shop compressed air at 70psi.

I did some testing with this little machine, and I have cut up to 1/4" plate, and it did a beautiful job. I cut some painted aluminum siding, about as fast as you would draw a line with a ruler and pencil, and the cut was so good and clean that the paint did not even get scorched.......

To cut the heavier materials, you will need some of the optional heavier duty contact points, so if you buy this machine get a bunch of spare stuff as I dont think you can buy anything locally that will fit it, but he will ship Fedex overnight if you get in a jam I would imagine.

Parker has other options for equipment as well, for example a combination DC tig, stick and plasma cutter for $2500 US, and this package is available in AC/DC as well, if you need to weld aluminum.

Pete,
Calgary......
[email protected]

Have you used one of the Cut40's on a plasma table? I have a Cut40 but for my table I plan on buying a thermal dynamics unit for reliability and a non HF start.

Thanks.

[mcArch]

McArch, your z motor only needs to lift the torch and what ever it is attached to. I would recommend you revise your z drive to use a ball screw from Rick at homeshopcnc. It takes too much torque if you use a threaded rod......If you use a ball screw, you only need a small stepper motor. For example the Nook ball screws used by homeshop only require .035 in lb of torque to move (raise) 1 pound. So therefore a stepper motor that has 600 oz in of torque, which equates to 37.5 in lb of torque will lift (37.5/.035) 1071 lbs. The efficiency of a ball screw is about 90% and you get about a 28 : 1 increase in force using a ball screw. These numbers are from the Nook spec sheets if you want to check yourself.

Pete

On further investigation & a little calculating Pete, I think I'll take your advice & use a ball screw & nut from homeshopcnc for the z-axis drive, I think I can adapt the ends with my lathe to either a pillow block or end bearing from Mcmaster, either that or I was thinking of adapting it to fit a tapered bearing (Front wheel bearings from my old camaro) for end mounts . . . just because I have a few here that I could use & they are great for sustained loads over time. I've used them for a few other things like oversized door (like 9'square & about 550#) pivot hinges.

On a different note, anyone have any plus's or neg's about using a Miller Spectrum 625 Plasma machine on a CNC table? I plan on adapting this unit to the table & have it so I can change it out for a router.

Going is slow but is progressing, we started making additional space for the table & sifted through the steel drop pile that we'll make the table from. We are working on it only one day a week but hope to finish it by end of the year.

A couple of pics, Thanks for a great site.

[millman52]

Canadamaxx,

I agree, nice plasma table, good design, simple but effective. I am working on a cnc router, but it needs to be more accurate than a plasma, hence a somewhat different approach.

I would like to inject into the group, if anyone is looking for a plasma cutter, check out www.parkermetalworking.com. He is located in the US Indianapolis I think, or around there.
Pete,
Calgary......
[email protected]

Hey Pete,
Not to hi jack the thread. I dropped an email to parkermetalworking.com asking for information on their plasma rigs. What if any extras if any they carry, machine torch, is it plasma machine usable?

No one ever bothered even caslling or returning an email.

BTW. Very nice looking job on the table canadamaxxer. Have any more photo updates?

[Pete Stenabaugh]

Millman / McArch

The Miller 625 is really only rated for 1/2" material and you will find that it retails for approx $2500. Compare that to the Parker unit, rated for 5/8", but will cut short piece of 3/4" for about $700 - where do you wanna spend your money......sure the Miller is good equipment, and it has some features that the Parker doesnt, but it aint worth that much. The amount you save would almost build you a table.....

Parker has all the equipement and supplies you need, although like other manufacturers, you will likely need to get your spare from him. He is good to deal with, I have talked with him on the phone on occasion and he seems to be a great person. Try giving him a call, I think his phone number is on the site, and I think he lives in the southern mid us someplace.

His standard torch on the 40 amp unit that I have, has an angled head like anyone else's unit. You will have to design up a small saddle for it to be clamped into. The handle is very light, maybe 1/2lb or less in weight, and the trigger acutates a switch that is clamped to the torch handle.

The only thing you would need is a longer stinger, and this is one thing I was going to contact him about, but have not gotten around to doing yet.

If you can find out if he can supply a longer stinger, like maybe 25ft for a plasma table, also get a price, and post it here on the forum for us.....

His supplies are fairly well priced, and with a cnc setup, you wont go through many consumables, only the copper tips which are about $5 ea as I recall. You should almost never need to replace the ceramic cone, although the standard setup comes with a spare cone and a few tips to get you started.

Pete

[Pete Stenabaugh]

McArch, if you go to the Nook web site, you can download some cad drawings of their ball screw bearing assemblies, plus 3D models as well, to get an idea of how they do it. there are a few options you can do, but you will need opposite facing annular thrust ball bearing at one end to absorb the thrust of the ball screw, and with the bearing lightly loaded you wont have any end movement of the ball screw. Then a single floating bearing on the other end to secure the ball screw. You should only need a single ball nut for the plasma, because if you have the max of about .004" backlash on the ball screw, that wont hurt you for plasma cutting, but then again if you are using Mach 3, you can eliminate the backlash in Mach.

Pete
Calgary

On further investigation & a little calculating Pete, I think I'll take your advice & use a ball screw & nut from homeshopcnc for the z-axis drive, I think I can adapt the ends with my lathe to either a pillow block or end bearing from Mcmaster, either that or I was thinking of adapting it to fit a tapered bearing (Front wheel bearings from my old camaro) for end mounts . . . just because I have a few here that I could use & they are great for sustained loads over time. I've used them for a few other things like oversized door (like 9'square & about 550#) pivot hinges.

On a different note, anyone have any plus's or neg's about using a Miller Spectrum 625 Plasma machine on a CNC table? I plan on adapting this unit to the table & have it so I can change it out for a router.

Going is slow but is progressing, we started making additional space for the table & sifted through the steel drop pile that we'll make the table from. We are working on it only one day a week but hope to finish it by end of the year.

A couple of pics, Thanks for a great site.

[mcArch]

Great stuff Pete, thanks. I did download the 3d dwgs of the ball screw, I got some bearings from reidsupply.com & they have nearly all of their parts abailable as 3d downloads. I am using the Miller 625 unit because I have it already, my brother's unit. If it ends up being an issue with my brother needing his Miller too much I will definitely look into getting one of the Parker units. How important is torch height control, I don't think I need to worry about it for what I'm doing & the thc units are way too expensive.

Is that thrust bearing you are talking about adjustable? What would be the difference in using that as opposed to a tapered bearing set & fitting it with an adjustable plate to set the preload against the rod assembly? I'll draw what I'm talking about & post it so you can see what I'm talking about.

I've posted a few photos from out first day really constructing the table, I have it on 8" casters to keep the shop versatile, but have some simple levelers designed out of some left over 1" allthread. The main rails are 4"sch.40 pipe, 9' long with the supports about 16" in from each end to reduce deflection. I am an architect & am used to deflection tolerances like .2" for that 72" span, L/360. But for this I need a much tighter tolerance. With that 4" pipe I have about a .005" deflection at midspan under a 130# load which I think is pretty close for what the gantries will be. I will likely put a truss stiffener under it to get that down. The more important issue I suppose is that deflectcion/displacement at the cutter head, the plasma will not likely deflect at all except at acceleration/decelleration, but with the router head on, it will have lots of resistance, especially cutting wood & plastics. The gantries I have not gotten into deflection calcs yet, but may need to stiffen those some. Today I',m working on the Xaxis gantry, maybe I can get it up & rolling on the pipe rails.

Will post more pics when I can. I have some time lapse that I will try to compress to fit on the site, if not I'll put a link to them on my site.

Cheers

[Jeep07]

The chinese cut 40's are High Frequency start units which "could" interfere with the electronics on a CNC.

On another note I have dealt with Parker Metal Working and they are really cool guys. I ordered some consumables from them and talked to them about my crappy cut 40 plasma cutter. If I was gonna buy Chinese I would buy from them. However I bought a new Thermal Dyn unit and while it costs a lot more I think it was money well spent as I now enjoy using the plasma cutter again and have some confidence in it.

[Pete Stenabaugh]

The Parker units are built off shore, but they are designed by Parker in the US and they are then built to his specs, so I dont think you can place these units in the same catagory as another unit that is designed / copied by China and then built by them.

Parker is a very good place to deal with and it is hard to beat his price, reliability and service. Try getting a Chinese import fixed.....

Pete

The chinese cut 40's are High Frequency start units which "could" interfere with the electronics on a CNC.

On another note I have dealt with Parker Metal Working and they are really cool guys. I ordered some consumables from them and talked to them about my crappy cut 40 plasma cutter. If I was gonna buy Chinese I would buy from them. However I bought a new Thermal Dyn unit and while it costs a lot more I think it was money well spent as I now enjoy using the plasma cutter again and have some confidence in it.

[Pete Stenabaugh]

Mcarch, no the bearings are not 'adjustable' per se, what you need to do is to thread the end of the shaft with a fine thread and then use either a regular bearing locknut with a lock tab washer, or a pair of locknuts against each other. You can also use a locking nut like a nylock, but they do have a tendency to come loose a bit with all the back and forth action. The easiest is to use one of the first two options. All you need to do is to put light tension against the bearing to remove all backlash. The tension must be light or the bearing will not last long. You will also need some sort of dust cover to protect the bearing from dirt - especially important with a router. Tapered roller bearings are open by design so you need a felt dust protector for them. One the other hand it may be possible to purchase an annular thrust ball bearing that is sealed. This is the easiest way to go. Reid sells such a bearing made by INA. It is their part number INA-1150 thru 1180. The standard bearing number for these is 32002RS thru 3206RS. Either number can be crosses by any power transmission supplier for you. The bearings are about $30 or so. These are annular thrust bearings and will take thrust in both directions. This is the way to go......

In the bearing blocks that Nook uses, they use 2 single thrust bearings back to back, that is more work as you have to bore the holes from 2 sides rather than one hole with a bit of a lip at the bottom to hold the bearing outer race.

If you use the single bearing, you need to do the same thing on the bottom to prevent the ball screw from moving, which is why Nook uses 2 single thrust at one end, and a single floating bearing at the bottom that can move as a result of thermal expansion, but the bore size is critical to prevent movement side to side - only size on size, no tighter for the bottom bearing, maybe .0005" loose at the most.

If you are using these bearings on the Z, then you can use standard single row bearings such as a 6001 or 6002 as the axial loading is quite light for a plasma. These bearings are only about $6 or so and are designed to take light axial loading only, but fine for plasma, maybe even ok for a router if you use a larger size perhaps, but for a router, I would go with a proper bearing.

For the plasma, I would consider using the THC control. This is controlled by Mach 3, but I dont know if you require anything special for hardware apart from the torch. This is something that I have not gotten into yet. You might want to post a question on the Mach 3 user forum regarding that to get some good answers.

A few thou deflection in you table is nothing for plasma. You shouldnt get any deflection using schd 40 pipe, at least not from the gantry. Your gantry does not have to be heavy duty, you are only moving a plasma torch that weighs under a pound.....with no side loading. The entire gantry can be made from aluminum tubing.....or very light 1" square x .063 wall steel tube. The lighter the faster and easier it will be to move, and the smaller the motor you could use, although I would stick with about 900 oz in Nema 34 motors.

Have you seen the table design that has been posted by canadamaxx? Really good design ideas there......

I hope you are not planning on building this table to be able to switch between router and plasma......... bad idea.....it wont work properly. Build the plasma, then build a router separately. These are different animals and have totally different requirements. The router has to be rigid, accurate, perfectly flat, fast, and of reasonably high precision. The plasma does not.

If you havent already, email me personally at [email protected] and I will send you a solidworks drawing of the cnc router table I am designing. This unit once finished will rival and exceed, I think any standard commercial unit out there and it will do things that most cannot do....... It should cost you about $7000 tops for materials to build a table that will cut 49 x 97 x 12. The table will also be able to be moved up and down about 16" for increased capacity for a large object - just a plus from the design. I dont have it finished yet, just no time right now, about 2/3 done.

Pete

Great stuff Pete, thanks. I did download the 3d dwgs of the ball screw, I got some bearings from reidsupply.com & they have nearly all of their parts abailable as 3d downloads. I am using the Miller 625 unit because I have it already, my brother's unit. If it ends up being an issue with my brother needing his Miller too much I will definitely look into getting one of the Parker units. How important is torch height control, I don't think I need to worry about it for what I'm doing & the thc units are way too expensive.

Is that thrust bearing you are talking about adjustable? What would be the difference in using that as opposed to a tapered bearing set & fitting it with an adjustable plate to set the preload against the rod assembly? I'll draw what I'm talking about & post it so you can see what I'm talking about.

I've posted a few photos from out first day really constructing the table, I have it on 8" casters to keep the shop versatile, but have some simple levelers designed out of some left over 1" allthread. The main rails are 4"sch.40 pipe, 9' long with the supports about 16" in from each end to reduce deflection. I am an architect & am used to deflection tolerances like .2" for that 72" span, L/360. But for this I need a much tighter tolerance. With that 4" pipe I have about a .005" deflection at midspan under a 130# load which I think is pretty close for what the gantries will be. I will likely put a truss stiffener under it to get that down. The more important issue I suppose is that deflectcion/displacement at the cutter head, the plasma will not likely deflect at all except at acceleration/decelleration, but with the router head on, it will have lots of resistance, especially cutting wood & plastics. The gantries I have not gotten into deflection calcs yet, but may need to stiffen those some. Today I',m working on the Xaxis gantry, maybe I can get it up & rolling on the pipe rails.

Will post more pics when I can. I have some time lapse that I will try to compress to fit on the site, if not I'll put a link to them on my site.

Cheers

[mcArch]

Thanks for all the info Pete, I suppose I'll be ok with the plasma, as for the router, I am planning on switching back & forth, I'll just have to find its limitations & eventually I'll be able to build a second, improve it, and have a dedicated table for each. We'll have only about $1000 in this table when all is said & done. That's not counting the steel for the pieces because it's from my drop racks. This will get me started at least, I have calculated under a 50# horizontal load at the router tip (excessive I think) I will only have .035" deflection at the same point. That's with the configuration as it is in the photos. I still have to make a cover for the tapered bearings you see on the Z-axis ball screw & make an oiling & closure system for the Y & X threaded rods.

The entire gantry with the Z carriage, router & motor only weighs about 120#. The Z by itself with the 8# router only weighs 35#. So I think I should be ok with 400oz.in. motors, do you think they will have trouble moving the Y & X? I don't think I need alot of speed, 100ipm at the most.

[Pete Stenabaugh]

I am not too sure about the motors for the X and Y, however, if you have decided to use Nema 34 motors, then it is easy to up size the motors without having to make adapters to change from Nema 23 to 34. Nema 34 is the way to go for the same price on the motors......

Using a ball screw for the Z is good, you will have lots of torque from that, and you would be fine with a 400 motor on the Z.

The 400 on the X and Y may be fine, depending upon your drive ratio. I think though that you will likely want to have more than 100 ipm speeds. You may be able to cut fine at that speed, but you will want something like 400 ipm or so to go from corner to corner in rapid, with out having to go for coffee in the mean time. With the plasma, the force on the system is the same regardless of cutting or not, so keep that in mind. I would recommend at least using 900 stepper motors on the X and Y, gear them about 3 or 4 to 1 (from the motor to the final drive shaft) and you will have lots of power.

Pete

[millman52]

mcArch,

Where's the updates & progress on your table??????

[mcArch]

Thanks for asking Millman, just been swamped lately getting drawings done for a house renov. & had a death in the family, should be able to post some more updated photos & info in next couple days.

Here are a couple photos from like a week ago, We have gotten the xaxis motor mounted, I want to make an aluminum plate to mount at the face of the motor for heat sink, this will work for now. The overall photo is before I made the chain guide & did not really work as the chain would vibrate too much & derail, the black nylon guides that I made on the lathe in their brackets work great though. I tested it w/ a dewalt drill on the drive rod & got it to nearly 2700 rpm, worked fine, a little wobble in the 3/4" allthread drive rods, but I think 2700 is probably a little faster than I will run it ever. Other than that, the Y is ready for motor mounting, then get the z mount ready.

more later.

-Mike

[millman52]

I tested it w/ a dewalt drill on the drive rod & got it to nearly 2700 rpm, worked fine, a little wobble in the 3/4" allthread drive rods, but I think 2700 is probably a little faster than I will run it ever. Other than that, the Y is ready for motor mounting, then get the z mount ready.

more later.

-Mike

Are you using servo motors to drive the table? Steppers won't do much more that 700 RPM or so, Depending on the size. Looks like you are planning on running them direct drive. Will that be fast enough to get the speed (inches per min.) you need form your table? If my math is right with steppers you'll only be able to get around 70 IPM max. Plenty for Ox/Fuel cutting but don't leave much for rapids.

[mcArch]

Hi Millman, Pete, I posted some new pics in the thread I started for my table:

Plasma/router table build progress
http://www.cnczone.com/forums/showthread.php?t=47615

We got the machine running now, the x only chugs along at like 12ipm cutting with the 3/4" dia router bit, have not turned the plasma on yet, next couple days will tell that. We had to do some fine tuning with my low cost bike chain drive, the sprockets are really too thin for alignment, but we were able to make the vinly lined guides & use a spring loaded tensioner underneath that just lets the chain ride on a small section of 1" pipe. It seems to work ok for now. We got another 400ozin motor to slave the x with on the other rod, but we didn't get the mount bolts aligned well enough yet, then the keyboard or something must have hit the y motor drive & it got toast, sowe unhooked the x-slave motor that we got & used that driver for the y & was able to get it back up & running at the slower speed at least. We still have to make an enclosure for the electronics, a better table surface for the monitor/keyboard, & a cover for the plasma while it's in router/dust mode. The threaded rods could use dust covers too.

We have a problem with the limit switches falsely tripping in Mach though, we could not get it to stay reset, so we just turned it off at the switch & it's working ok, just have to watch it like a hawk in case something goes wrong. I'd like to get that resolved, but have no idea what else to try, have tried all the stuff the mach manual & FAQ's suggest, nothing helps. I have all the switches set up where the circuit is closed until tripped, maybe that's backward? I cannot figure it out.

Working well overall, cannot complain for what we have into it . . . still lots to do, but I think it can produce at least.

Check out the pics in the other thread & reply there so as not to hijack canadamaxxer's thread here any more.

[mcArch]

How's your table coming Canadamaxxer? Had time to work on it lately?

[canadamaxxer]

Hi guys,

Sorry about the long delay. I have not forgotten about the project, I just had to put it on hold for almost a year....kinda sad but necessary.

I finally got back to it about a month and a half ago, and spent the first while redoing some of the quality issues that had been nagging me. I had some issues with parallelism on the x axis rail, and with an upward bowing of those rails as well. After some surgery with a grinder/zip disk as well as my plasma cutter, I got it surprisingly straight. I had to redo the setup of the rails and redo the gantry carriage setup to some degree so that I could get the skate bearings under some preload. I also had to to do some reinforcing on the drive shaft pillow block mounting.

I have the last of the parts I need coming via ebay, and once I get some tooling in for my mill, will be machining up my nema mount plates. Once that is done, this thing can start moving (at least x and y....still need the last parts for the z axis and the THC carriage).

I will post some pics in the next couple of days.

[canadamaxxer]

Here are some pictures of the progress. It's a little messy in the shop, so I hope guys can look past that.....

[millman52]

Welcome back maxxer