OmioCNC report

[NickB00]

You would think that Omio machines would be running at 48 Volts then, being a better quality chinese unit?
How would you check this anyway? I agree if its running at 24V it may be skipping a bit.

IMHO, fix mechanical issues first, then look everywhere else....
Sometimes Chinese machines don't run the steppers at their optimum voltage.
At stepper can run at 48 V and yet they only use a 24V power supply.
The closer to max voltage you run, the more positive each' step' is and least chance of missing any.

[dharmic]

1. Open the case for the controller.
2. Read the "24V out" label on the power supply inside

The only time I've had skipping on my machine with the supplied 24V supply is when I've been an idiot in toolpath design. It's enough even for fairly aggressive work on aluminium if everything else is ok. Also bear in mind if you're going to push things that hard, the machine will flex more meaning cuts become less accurate, chatter gets worse, etc, etc, etc.

[NickB00]

If thats the case then, I know I am not pushing mine hard at all..

1. Open the case for the controller.
2. Read the "24V out" label on the power supply inside

The only time I've had skipping on my machine with the supplied 24V supply is when I've been an idiot in toolpath design. It's enough even for fairly aggressive work on aluminium if everything else is ok. Also bear in mind if you're going to push things that hard, the machine will flex more meaning cuts become less accurate, chatter gets worse, etc, etc, etc.

[NickB00]

So you replaced the power supply to fix the problem? I cannot believe the factory supplied one set on fire? You really must have been overloading it, or maybe the tight spots were really hard to push through,and so brute force has now saved the day. Go figure!

My PSU was at fault for a few unexpected gdhdkdksndhdjsk (I could swear just thinking about it)

I do have a few tight spots along the travels but the stock PSU just wouldn't deliver the power to move over them, until it eventually set on fire. Replaced with an 800w 48v supply and all problems magically disappeared. Well they didn't, the underlying issue is still there but doesn't cause any trouble now at all.

The few issues I do still have, which are very rare, are interference/ground loop or some other Harry Potter type wizardry which I don't really understand. They're few and far between and particularly since I've got this skyfire the OMIO is only doing very simple and basic stuff now so I've opted to just live with them.

Also the X axis ballscrew was seriously overtightened on mine from factory and loosening that off a bit made the whole thing a lot smoother. But the damage to the keeper bearing had been done, still not got around to swapping it yet.


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[dharmic]

Overloading will just pop the fuse. He got a crappy power supply - actually from dim memory there was a litany of sadness that came with that machine, must have been a Friday Afternoon Special

[Mmpie]

So you replaced the power supply to fix the problem? I cannot believe the factory supplied one set on fire? You really must have been overloading it, or maybe the tight spots were really hard to push through,and so brute force has now saved the day. Go figure!

Mine was just a duff piece of crap. It was 36v not 24v too. The tight spots weren't that tight they should have caused it any issue, I can turn the screw over them by hand but it does go from silky smooth to needing a bit of persuading in places. Some of my bearing carriages have ball bearings missing and one is quite sticky and doesn't rotate as freely as the others which doesn't help. Yes it set on fire.

Replacing it wasn't a magic fix for all my problems but it solved the getting stuck one with no further intervention required.


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[NickB00]

Yeah I recall reading that he got a lemon, or a Monday Morning got the Blues version! sad .

Overloading will just pop the fuse. He got a crappy power supply - actually from dim memory there was a litany of sadness that came with that machine, must have been a Friday Afternoon Special

[Mmpie]

Overloading will just pop the fuse. He got a crappy power supply - actually from dim memory there was a litany of sadness that came with that machine, must have been a Friday Afternoon Special

It certainly was, though on balance I got a really good spindle and set of ballscrews/nuts that actually repeat with great accuracy and negligible backlash (has to be measured on a metric hundredths indicator), so it's six of one and half a dozen of the other.

Most of my frustration was in the really poor assembly of everything but and afternoon stripping it all down and redrilling/retapping holes solved that


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[NickB00]

Mmpie I remember your old posts nearly put me off getting one, but you persevered and conquered! Most people would just given up considering all the issues you had with yours. Omios we got your money and now dont give a crap after sales service didnt help either!!

I too am wondering if my 2 sort of tight spots on the x axis (which have now loosened up a bit) are creating my back to job home error in the x-direction after a job completes. I noticed that my finishing pass runs on a slight angle and not square to the job which mucks things up a bit, is related to the homing error as well or tightness in the x shaft or bearings issue. Can you get replacement bearings and carraiges for these machines from Omio??

Mine was just a duff piece of crap. It was 36v not 24v too. The tight spots weren't that tight they should have caused it any issue, I can turn the screw over them by hand but it does go from silky smooth to needing a bit of persuading in places. Some of my bearing carriages have ball bearings missing and one is quite sticky and doesn't rotate as freely as the others which doesn't help. Yes it set on fire.

Replacing it wasn't a magic fix for all my problems but it solved the getting stuck one with no further intervention required.


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[Mmpie]

Your machine likely isn't square full stop. Mine was out quite a bit. X to Y was out by a mm or 2 over the X travel and the Z was higher on one side than the other because the holes for the gantry beam were lower on one side. It was too much for a redrill and retap so I shimmed one side of the gantry with folded aluminium foil to make it sit even.

Squaring the machine is easy just time consuming. You will need a precision square, 1-2-3 block or other instrument with flat ground surfaces and a good 90 degree angle, a test indicator, a hammer and an hour or so. The problem is when doing the bolts back up it will move so once you get it in place you need to keep going round tightening each bolt a little bit at a time whilst checking your angle as you go. I had to drill the holes out for the gantry side arms on that big bottom beam that runs under the bed to get enough movement. Don't go too crazy trying to get it perfect as it will move anyway, but not by a massive amount.

If you ever need spare bearing carriages or whatever probably quicker, cheaper and easier to just get them off eBay or aliexpress.


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[dharmic]

The machine being out of square and flexy was why I ended up getting that tooling bed machined up on a big bridgeport, so I had a reference to squish the frame to. Even then I used a coke can's worth of shimming to get it level.

[Sterob]

Even then I used a coke can's worth of shimming to get it level.

You were lucky......

I had to shim my Gantry up ~2.6mm so it stopped deflecting the ballscrew.

Here's a before pick:


A vid of a test run afterl lots of rooting around......lol

https://www.dropbox.com/s/iurv76psuc...mming.mp4?dl=0

[dharmic]

Damn...

That's nuts!

[NickB00]

So are you saying my bed is not square to the spindle? Have not checked that. I can see that it could cause out of whackness (hows that for a technical term?) both in the X and Z axes and I suppose a less pronounced error in the Y. I hope I dont have to square the machine as you mention, it sounds like a bit of a nightmare to keep it square whilst doing up the bolts. My bench moves around a bit and is not as sturdy as what I thought, so maybe that is inducing some vibes and errors too. Somehow I think you are right, the out of squareness in X and Z axes may be where the problem lies.
cheers..

Your machine likely isn't square full stop. Mine was out quite a bit. X to Y was out by a mm or 2 over the X travel and the Z was higher on one side than the other because the holes for the gantry beam were lower on one side. It was too much for a redrill and retap so I shimmed one side of the gantry with folded aluminium foil to make it sit even.

Squaring the machine is easy just time consuming. You will need a precision square, 1-2-3 block or other instrument with flat ground surfaces and a good 90 degree angle, a test indicator, a hammer and an hour or so. The problem is when doing the bolts back up it will move so once you get it in place you need to keep going round tightening each bolt a little bit at a time whilst checking your angle as you go. I had to drill the holes out for the gantry side arms on that big bottom beam that runs under the bed to get enough movement. Don't go too crazy trying to get it perfect as it will move anyway, but not by a massive amount.

If you ever need spare bearing carriages or whatever probably quicker, cheaper and easier to just get them off eBay or aliexpress.


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- - - Updated - - -

ditto!

Damn...

That's nuts!

[NickB00]

Impressive fix there Mmpie!!

You were lucky......

I had to shim my Gantry up ~2.6mm so it sttopped deflecting the ballscrew.

Here's a before pick:


A vid of a test run afterl lots of rooting around......lol

https://www.dropbox.com/s/iurv76psuc...mming.mp4?dl=0

[dharmic]

I guess it's 50/50 these machines' frames aren't made in a bigger CNC, aren't made in a workshop full of jigs etc, but are made by a guy squatting out the front of his house with an electric pistol drill. A fairly skilled guy, but there are limits to what we humans can do consistently. Seems like most machines are within a millimetre or so (of course there are exceptions). For what most people do with them it's good enough, almost, good enough at least to make it not worth stripping down and trying to clean up at least. The biggest pain for me wasn't so much X and Y, as Z variance across travel. When you're working on 2mm sheet, a 0.5mm variance over what should be a single depth step, well, it's pretty nasty.

[Mmpie]

I guess it's 50/50 these machines' frames aren't made in a bigger CNC, aren't made in a workshop full of jigs etc, but are made by a guy squatting out the front of his house with an electric pistol drill. A fairly skilled guy, but there are limits to what we humans can do consistently. Seems like most machines are within a millimetre or so (of course there are exceptions). For what most people do with them it's good enough, almost, good enough at least to make it not worth stripping down and trying to clean up at least. The biggest pain for me wasn't so much X and Y, as Z variance across travel. When you're working on 2mm sheet, a 0.5mm variance over what should be a single depth step, well, it's pretty nasty.

Some is machined. Having had my rails off the tool marks in the pockets they sit in are obviously machined. Same for the ball but mounts. Would suspect things like the holes in the end of the gantry plates are probably done manually with a jig, which are the holes I found didn't match on either side. One of them was actually at an angle maybe 5-10 degrees.

Nick, it's not a lot of work really it's only taking measurements and 6 bolts that need undoing/retightening and possibly some shims to get the z axis level across the gantry. It's not hard either just frustrating and slow paced. It's probably worth doing depending on what work you're doing and once it's done it's done, barring a crash I can't see it moving out of square by more than a .1mm/.2mm or so of its own accord. I have a fixture plate bed just like Dharmic's (I copied his idea) and using a h7 tolerance 6.2mm carbide drill I can still drill and align a big sheet/plate using easily loose fitted 6mm dowels in all four corners of the bed.

If you're just doing one sided wood carvings you probably won't notice much, if any difference unless it's really badly out of square but if you ever intend to cut from both sides the X and Y misalignment will show up really bad on your 2nd op chamfers and Z axis height will make getting a flat or semi accurately thicknessed part a tall order. And the bigger the part the more obvious the errors and the more features it will affect.


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[NickB00]

Hi Guys,
You would think these machines would be made in a factory and not on someones front balcony? Then again?
I have progressed a little further with the issues on my machine being not coming back to X=0 after a job finishes. Some minor slipping or skipping issues.

Mmpie I have done some measuring and found it all looks pretty square and within 0.1mm tolerance that me & my digital calipers will measure accurately.
I also checked my X Stepper motor coupling and found that the collar was a bit loose on the motor side. This would account for some slipping under force.
There was also a bit of black muck under the ballscrew end which I cleaned and retightened so maybe it was also slipping?

dharmic I have earthed the machine like you said and also have used a insulated USB cable and the screen has cleared up from being a little fuzzy, so thats good!

After all the checks and mods, I re-ran a Rough pass file (in mid air without the spindle running) to see if it came back to job zero and it did. I also ran the Finish pass
file in mid air and it too came back to job zero. So now I need to do the same again but actually carve a piece out so I can
check it under load and see if it returns to zero.

I am hoping that the X Stepper Motor loose coupler was the culprit causing skewed work due to slipping under heavy cut areas and losing job zero in X.
Will let you know when I get a chance. Maybe later this week? Work gets in the way...

Some is machined. Having had my rails off the tool marks in the pockets they sit in are obviously machined. Same for the ball but mounts. Would suspect things like the holes in the end of the gantry plates are probably done manually with a jig, which are the holes I found didn't match on either side. One of them was actually at an angle maybe 5-10 degrees.

Nick, it's not a lot of work really it's only taking measurements and 6 bolts that need undoing/retightening and possibly some shims to get the z axis level across the gantry. It's not hard either just frustrating and slow paced. It's probably worth doing depending on what work you're doing and once it's done it's done, barring a crash I can't see it moving out of square by more than a .1mm/.2mm or so of its own accord. I have a fixture plate bed just like Dharmic's (I copied his idea) and using a h7 tolerance 6.2mm carbide drill I can still drill and align a big sheet/plate using easily loose fitted 6mm dowels in all four corners of the bed.

If you're just doing one sided wood carvings you probably won't notice much, if any difference unless it's really badly out of square but if you ever intend to cut from both sides the X and Y misalignment will show up really bad on your 2nd op chamfers and Z axis height will make getting a flat or semi accurately thicknessed part a tall order. And the bigger the part the more obvious the errors and the more features it will affect.


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[dharmic]

Sounds promising, Nick - don't forget to lube the screw. The schmoo you cleaned off it will be a mix of oil/grease and sawdust. And yeah, the Y screw is a PITA to get to.

[Sterob]

Yes, well done Nick. Wow...haven't you learn't some stuff!!...lol