I did some cleaning up of the table last night. The gantry moved smoothly the entire length afterwards, so I'm not really sure what bound it up for years before that. But it did remind me of another thing I hated about this table, which was adjusting the roller bearings. At this point I am leaning toward replacing that system with linear rails on just the y-axis. Assuming they just bolt on to the table, it will require minimal modification to the table and raise the gantry up maybe half an inch, but my motors are mounted in slots and can be adjusted to compensate for that. I think this is also wise just because my motors are so small and weak that it will reduce friction. I will need longer than the ones you linked though, as my table is 10' long. I don't see longer ones listed. Can they be added end-on-end together?
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What to do with old plasma table
- Thread starter patooyee
- Start date
I did some cleaning up of the table last night. The gantry moved smoothly the entire length afterwards, so I'm not really sure what bound it up for years before that. But it did remind me of another thing I hated about this table, which was adjusting the roller bearings. At this point I am leaning toward replacing that system with linear rails on just the y-axis. Assuming they just bolt on to the table, it will require minimal modification to the table and raise the gantry up maybe half an inch, but my motors are mounted in slots and can be adjusted to compensate for that. I think this is also wise just because my motors are so small and weak that it will reduce friction. I will need longer than the ones you linked though, as my table is 10' long. I don't see longer ones listed. Can they be added end-on-end together?
CarterKraft
Red Skull Member
I don't think that style is meant to join.
From what I have seen joining any of the rails is problematic, I'll do some looking but 10' is real big boy shit...
SomeGuyFromOlympia
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adding more rack to your table is one of the first things I noticed
I added more rack, and can get a full 10' sheet on it, it is tight, but I can get it in there
CarterKraft
Red Skull Member
Here's some "jointed" 3500mm rails
2 pcs SBR20-3500mm Jointed LINEAR RAIL SHAFT ROD with 4 SBR20UU Block Bearing | eBay
2 pcs SBR20--3500mm jointed linear rail. Each 3500mm will be jointed by 2000mm and 1500mm. 4 pcs SBR20UU. Aluminum support rail with pre-drilled holes for ease of mounting. The shaft is case hardened.
www.ebay.com
More rack? I can get a 10' sheet on it as it is. I never could cut it though because of all the binding on the far end of the table. It was nice not to have to shear a 4x8 sheet to get it on the table though.
CarterKraft
Red Skull Member
Is the table square, it's not clear to me why your carriage is binding.
Maybe they are adjusted too tight?
It's not clear to me anymore either because it seems to be travelling all the way just fine now. It's been over a decade since I used it, so some of this I'm going to have to recall as I go along.
There's a longer version of this story, but the short version is that sections of the roof collapsed in a shop I was renting. Weather and flooding was allowed to come and go in there for over a decade until I was recently able to build my own shop and move in. I was unable to properly fabricate anything during that period. I'm now going through ALL my tooling, cleaning it up, and getting it properly functioning so that I can someday fab again. This table is part of that process.
CarterKraft
Red Skull Member
There is a dude on plasma spider that builds single y motor tables and he's built/sold 8+ at this point and he says there's no problem with them so you'll need to take all this in to determine what's going on.
If the motors are in fact "tiny" then that might be the actual problem, not enough power for the weight of the gantry to drive 2x axis'
Any measurements of the motors?
Nema 34 or nema 23?
I would expect a 34 on that drive specifically
If the motors are in fact "tiny" then that might be the actual problem, not enough power for the weight of the gantry to drive 2x axis'
Any measurements of the motors?
Nema 34 or nema 23?
I would expect a 34 on that drive specifically
According to my randomly googled link here ...
Stepper Motor Sizing and NEMA Standards List - Oyostepper.com
www.oyostepper.com
... they are 23's.
Bacho
Yellow Skull
I have 23s on mine, they do all right.
I’ve been thinking about springs on some of the rollers. Make it a little bit more forgiving towards less than perfect tracks.
I wonder if the linear rails might be overkill
I’ve been thinking about springs on some of the rollers. Make it a little bit more forgiving towards less than perfect tracks.
I wonder if the linear rails might be overkill
CarterKraft
Red Skull Member
I didn't realize this was a 10' table... That does change things as the rails in that length are much pricier.
I wouldn't consider the ones you just posted to be cost prohibitive, it's just a matter of whether they are worth it.
I think I'm going to stick with what I've got for now, as it's the same amount of labor to do later as it is now.
Tonight's shop project is to add some bracing to the table to make it more rigid. I need to figure out these controls soon though so I can get them coming.
CarterKraft
Red Skull Member
I think that's a good plan you have to fix electronics no matter what so start there once you get a functional table then you can worry about the axis guides.
SomeGuyFromOlympia
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some of the pictures look like you can get some more rack in there
I have enough rack I can shoot that gantry right off of the end of the table
In the past I used CandCNC for my motion controller on the plasma table.
www.candcnc.com
Little pricey but has built in THC and awesome tech support. Sheetcam also has a awesome post processor and additional features built in to help with torch dives in the corners.
CandCNC – CNC Control Electronics
www.candcnc.com
Little pricey but has built in THC and awesome tech support. Sheetcam also has a awesome post processor and additional features built in to help with torch dives in the corners.
CarterKraft
Red Skull Member
That gantry is beefy as hell!Weldered some scrap metal to the table today. Rigidity was increased tenfold I would say. I think I'm at a stopping point until I get controls and torch mount figured out now.
Lots of weight to accelerate there.
SomeGuyFromOlympia
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this is fact
Mine is 5'+ and OP should be close to that
it does not like quick directional changes
CarterKraft
Red Skull Member
Its not the end of the world but the LinuxCNC guys were targeting pretty high G accelerations to get better resolution around sharp features and it was sort of explained to me the heavier you make the gantry the worse your G rating will be while accuracy of the tool head will be higher. But it was explained that higher tool accuracy is relative when cutting with a flame, speed and positioning is superior.this is fact
Mine is 5'+ and OP should be close to that
it does not like quick directional changes
Not the gospel just what I gathered.
I am trying to keep my gantry light, I may put the motors on the frame when I convert to rails.
SomeGuyFromOlympia
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it isn't a big deal here as I rarely cut anything less than .25 mostly its .5 and 1.00
where I really notice it is when the kid or family wants that artsy fartsy sign made for some ones new house
what is OP cutting?
CarterKraft
Red Skull Member
Agreed, if the table IPM is limited then the effects will be less obvious but if the controller has more sophisticated velocity controls it might show up in some sharp details.
As already stated, I spent this afternoon bracing the table and doing a little tuning and squaring. I got the gantry rolling more freely than it ever has before. I'm still not impressed with the roller bearings though. I did just a tiny bit of grinding nearby and some of the dust got on the table. It wouldn't roll freely like this again until I wiped it clean. It is what it is for now I guess.
I was wrong about the size of the table. It is over 10' long, but I guess that's just to make space for the gantry frame to go all the way to the 8' mark. It is only 4.5' wide though. I thought I remembered putting some 5x10 aluminum on it at one point a long time ago but I guess I was wrong.
I rarely cut up to 3/8 steel. 95% of everything I do will be 1/4" or thinner. My torch is rated for 3/4" (I think) and, if I take my time, I have done 1" before. (Hypertherm Powermax 1000.) I don't do this for a living. If I have to cut slower because of my gantry weight, it doesn't really affect me at all. No matter how slow it goes, it'll be better than hand-cutting.
I was wrong about the size of the table. It is over 10' long, but I guess that's just to make space for the gantry frame to go all the way to the 8' mark. It is only 4.5' wide though. I thought I remembered putting some 5x10 aluminum on it at one point a long time ago but I guess I was wrong.
I rarely cut up to 3/8 steel. 95% of everything I do will be 1/4" or thinner. My torch is rated for 3/4" (I think) and, if I take my time, I have done 1" before. (Hypertherm Powermax 1000.) I don't do this for a living. If I have to cut slower because of my gantry weight, it doesn't really affect me at all. No matter how slow it goes, it'll be better than hand-cutting.
Have you tried putting wipers in front of your gantry rollers?
No. That's not a bad idea. Are you saying there is a product specifically made for that or just suggesting that I fab something?
I'm sure somebody make something, but easy enough to fab up some mounts for some stiff-ish brushes to sweep the rails in front of the gantry as it moves.
I'd also look at slipping a strip of sheet metal or something between the cutting surface and rails to try to deflect anything getting kicked up off the table. Doesn't look like you have a ton of clearance under the gantry, but I'd bring something right up as close to the gantry as possible.
A few z axis actors I'm looking at:
openbuildspartstore.com
openbuildspartstore.com
Curious as to functional differences of roller wheels vs linear bearings?
100mm/200mm/300mm CNC Linear Slide Rail Guide 23 Nema Stepper Motor Ball Screw | eBay
Specification Material: Aerospace Aluminium Process: Anodic Oxidation Model: GGP Assembly Required: No Color: Black Accuracy: 0.03mm/0.001in Ballscrew Diameter: 12mm/0.47in Lead: 4 mm/0.16in Speed: 40-100 mm/1.57-3.94in/s Horizontal Load: Max.20kg/44.09lbs Vertical Load: 10kg/22.05lbs Motor...
www.ebay.com
V-Slot NEMA 23 Linear Actuator (Lead Screw)
SHOP NOW - Pre-Packed Bundles - NEMA 23 Linear Actuator Bundle ! Fast Shipping from U.S. - Genuine OpenBuilds Parts - #1 Open Source Hardware
C-Beam Linear Actuator
SHOP NOW - C-Beam? Linear Actuator Bundle - Pre-Packed Bundles - CNC Machines - Linear Actuators & More! Fast Shipping from U.S. - Genuine OpenBuilds Parts - #1 Open Source Hardware
Curious as to functional differences of roller wheels vs linear bearings?
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CarterKraft
Red Skull Member
The linear bearing style uses bearing blocks with built in wiper seals which in theory would prevent debris from fouling the "track" like you are seeing on your X/Y axis. They are more precise as well but the down side might be they are more susceptible to damage from debris.A few z axis actors I'm looking at:
100mm/200mm/300mm CNC Linear Slide Rail Guide 23 Nema Stepper Motor Ball Screw | eBay
Specification Material: Aerospace Aluminium Process: Anodic Oxidation Model: GGP Assembly Required: No Color: Black Accuracy: 0.03mm/0.001in Ballscrew Diameter: 12mm/0.47in Lead: 4 mm/0.16in Speed: 40-100 mm/1.57-3.94in/s Horizontal Load: Max.20kg/44.09lbs Vertical Load: 10kg/22.05lbs Motor...www.ebay.com
V-Slot NEMA 23 Linear Actuator (Lead Screw)
SHOP NOW - Pre-Packed Bundles - NEMA 23 Linear Actuator Bundle ! Fast Shipping from U.S. - Genuine OpenBuilds Parts - #1 Open Source Hardware
C-Beam Linear Actuator
SHOP NOW - C-Beam? Linear Actuator Bundle - Pre-Packed Bundles - CNC Machines - Linear Actuators & More! Fast Shipping from U.S. - Genuine OpenBuilds Parts - #1 Open Source Hardware
Curious as to functional differences of roller wheels vs linear bearings?
The most common is linear bearing rail, SGR style, they are easy to work with as well because the front and rear mounting planes are co-planar to each other. Basically transfer the bolt pattern each part to the mount plate and bolt it down for a "linear stage"
This style is pretty nice, you will need a "floating" torch unless you are only going to use ohmic sensing which the MyPlasm/Promo supports.
I am not up on the newest news where it's OK to go ohmic only. I think ohmic is a nice feature but I'm not sure if it is a good compliment to use with floating head or if its good enough in all conditions to not have floating.
(ohmic allows the cutter to "sense" the surface to be cut through resistance from the torch tip to the work, basically like a touch probe on a cnc mill but for plasma. It's faster and doesn't require any force to push on thinner sheet. )
A breakaway/magnetic torch mount is preferred. Switches on the torch mount will trigger cycle pause if the torch is hit so big jobs don't get ruined from a torch strike sliding the steel etc.
View attachment 1709907320812.webp
View attachment 1709907405068.webp
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CNC Plasma Table Z-Axis with Precision Linear Rail and Floating Head THC | eBay
Z-Axis for CNC Plasma Table with Precision linear rail and floating head. Motor Mount: for Nema 23 (Not Included). Motor Mount: for Nema 23 (Motor Not Included).
www.ebay.com