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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dachopper
Guess what.... all skips happening on parallel moves..... ! Strange
I you sure that this is not binding up or overtuned
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Re: The Dreaded X axis stepper error.
I am positive it is not mechanical, if I leave spindle turned off, it does not skip. If I turn spindle on and run job in the air, it jams under no load, and if I try to force it to jam, I can't, so it's 100% electronic interfere
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dachopper
Guess what.... all skips happening on parallel moves..... ! Strange
what do you mean by this
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Re: The Dreaded X axis stepper error.
It;s the type of Cut the machine is doing when the skipping happens. Its a a sideways X movement with vertical Z at the same time, repeat x 1000
Doesn't seem to skip doing a normal constant Z level manoeuvre....
Now I must be 3.5 hours into this next cut, so far no issues.
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Re: The Dreaded X axis stepper error.
Given the 'zapping' I would be checking you do have a good earth. The normal easy test is one of those plugin testers with LEDs on, but given you're down under, I'm not sure what would be available. It's also worth running the machine at the same time as having the tester plugged into the next nearest socket, just to make sure a good earth remains with things under load.
If you don't have a good earth, then the various filtering capacitors typically found in mains connected electronics (VFDs especially), can cause a voltage build up, which will earth through the nearest thing, which can be the person in contact.
You may need to install a new earth rod, or figure out why you've got a poor earth.
(does Australian power use L,N+E, or a centre tap L,L,N/E? to get 110V and 220V?)
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1 Attachment(s)
Re: The Dreaded X axis stepper error.
This is so frustrating, so I had another 4-5 skips / jams on the x and z axis doing this parallel job, so I reduced the speed, and the acceleration by 50% , still jamm, turned off the spindle, no jam. Put the spindle power plug and spindle / vfd cable earth on separate circuit ( not going through control box ) still jam.
Then I disconnected the spindle earth ( which runs inside the vfd cable so is probably a massive noise carrier, from the spindle and IE from the machine, and so far no jams.Attachment 22535
This ground cable was effectively attaching the vfd noise onto the machine. Since the stepper motors are on the machine, they are then subject to the effectively AC pulse made by the VFD earth, and by the vfd cable shielding.
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Update:
So disconnecting the VFD ground wire from the frame got me much further into the cut, infact the two medium sized parallel ops finished correctly without any issues, then I ran the really big one, it had a single skip 80% through. So now I'm thinking because the frame is now not grounded as I removed the spindle ground, I'm thinking of running a separately shielded spindle / Z block ground, to get rid of the static or whatever build up is occuring. Could Cat5 cable be useful in that scenario? I'm just trying to find a way to let the noise / static discharge without inducing any further issues...
Nick
So
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Re: The Dreaded X axis stepper error.
I think you may need to add ground wires between the various parts of the machine, to ensure everything is grounded.
I've just noticed in your photo, that you're using aluminium extrusion, which will be anodised, and anodising is a brilliant insulator.
Did you try running the machine with the VFD cable screen connected at both ends (and check that with it connected, there is continuity between the spindle body and the VFD earth point)?
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Re: The Dreaded X axis stepper error.
Hi MC,
I measured the voltage that the shielding on the VFD cable produced when the Spindle was turned on, it's was straight to a 40 Volts AC signal, between the shielding, and the CnC frame. When I connected that shielding to the frame, the steppers went ape shi*T. Motors were stuttering and I could " hear" the motors struggling to just run normally. Now, the machine wasn't grounded at this stage, but that was the effect of attaching the noise directly onto the frame of the machine.
I then unattached that end of the shield, and tried to attached what i thought would be a suitable ground ( it was an unused wire from inside the VFD shielded cable ) Big mistake - now this wire WAS on the Earth ground at one end, running through the VFD cable, and attached to the Z axis / stepper motor mount at the other end. I think all I did, was make a big long antenna inside the VFD cable, which even though it was grounded, was helping to turn the machine into another noise generating machine.
Then I got desperate after about 5 jams in 10 minutes, so I undid the " VFD " ground wire from the spindle / Z block and this made a big difference, but now the machine is not grounded any more.
So I am going to run another two grounds, one from the machine frame to house ground ( which is the same as the start point, but from a different socket) , and another shielded cable up the cable tracks and onto the spindle/ z block, which will then go to the other house ground.
I keep reading about these star grounds, but the fact is the VFD cable is creating an AC type noise signal, and If I run that into my electronics enclosure base plate, what is stopping it going straight back up my Stepper controller shielding which is connected to the same base plate? hence I'm connecting these two at a different socket of house earth, in the hope it weakens before reaching the base plate again.
I don't think Im going to connect the VFD cable screen back up to the frame, it just seemed to make the situation far worse.
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Re: The Dreaded X axis stepper error.
The entire point of the VFD cable screen is to absorb the EMI from the VFD cables, and drain it to earth. Due the VFD cables carrying a fast switching AC signal, an AC signal will be generated in the screen.
The fact that there is a voltage present, tells me that's it not correctly grounded. And also that connecting it to the machine frame makes things worse, tells me the machine frame isn't grounded correctly. If the screen was correctly grounded, then there should be negligible voltage in it, as it should be getting drained to earth without causing any problems.
Which brings me back to my earlier question, are you sure your power supply earth is correctly earthed?
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Re: The Dreaded X axis stepper error.
Quote:
Which brings me back to my earlier question, are you sure your power supply earth is correctly earthed?
This is what I mentioned several posts back but you make a good point re the anodised stuff so as M_C has said ground each part ie Z plate to gantry to machine frame to Star point
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Re: The Dreaded X axis stepper error.
Ok - I thought I would put some closure in here..... The random X and Z axis ' jams' were 100% due to electrical interference from the spindle control wires.
I had unshielded control cable, with shieleded stepper cable
Then I tried shielded control cable but mistakingly placed the machine earth inside the Spindle power cord, and in doing so charged the entire machine up with a generated AC signal.
Then I earthed the frame + spindle + spindle shielding + stepper motor shielding seperately to house earth, and finally, no issues !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dachopper
Motors are NEMA23 381oz/in 3.5A Single Shaft Stepper Motor KL23H2100-35-4A, 0.9 degree.
Power supply is PS-10N68 - 1000W 68V Power Supply running 4 of the above steppers, ( two of the motors would have been on 50% current hold ) when the other motor stalled also.
Nema23 running on 68V???
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dazp1976
Nema23 running on 68V???
Nothing wrong with that. Most of us run NEMA23 size motors on about 68V. More volts, better performance. The motors are happy enough - mine have been running like that for about 7 years now. As long as your driver can take it (and again, that's why a lot of us use 80V drivers) there's no problem. Just tweak the max current settings on the drivers so that the motors don't overheat.
Somewhere there is a guideline formula (originally from the Gecko people, I believe) that suggests that around 50V is the optimum. Firstly, this is a guideline and not a hard-and-fast rule, and secondly, it's wrong anyway. Go by other people's experience!
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Re: The Dreaded X axis stepper error.
Agree. My steppers have been running at 68V on 80V drivers for several years too.
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
routercnc
Agree. My steppers have been running at 68V on 80V drivers for several years too.
If I'd figured that out before, I'd have got the 570oz nema23 on 60v for the AMAT25 rather than the nema34 on 60v I have.
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dazp1976
If I'd figured that out before, I'd have got the 570oz nema23 on 60v for the AMAT25 rather than the nema34 on 60v I have.
It's not that simple.
A 450oz Nema 34 rated at 6 amps will usually easily outperform a 570oz Nema 23 rated at 5 amps.
Inductance plays a large role. And typically, smaller nema 34 low inductance motors can spin much faster than large Nema 23 motors.
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dazp1976
If I'd figured that out before, I'd have got the 570oz nema23 on 60v for the AMAT25 rather than the nema34 on 60v I have.
Horses for courses and You've got the right motors and voltage for that machine. Routers are a different animal so extra torque higher up speed curve helps.
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
Ger21
It's not that simple.
A 450oz Nema 34 rated at 6 amps will usually easily outperform a 570oz Nema 23 rated at 5 amps.
Inductance plays a large role. And typically, smaller nema 34 low inductance motors can spin much faster than large Nema 23 motors.
Ger, I think you got your motor sizes mixed up there...
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
JAZZCNC
Horses for courses and You've got the right motors and voltage for that machine. Routers are a different animal so extra torque higher up speed curve helps.
Bloody hell Dean where have you been :encouragement: Nice to see you back
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
Clive S
Bloody hell Dean where have you been :encouragement: Nice to see you back
Got to get back on the horse some time Clive.:cheerful:
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
JAZZCNC
Horses for courses and You've got the right motors and voltage for that machine. Routers are a different animal so extra torque higher up speed curve helps.
They don't give the speed I was hoping for but that may be down to the resonance I seem to get. It won't help. The inductance for them shows 4.1.
Looking at curves though the torque is equal between the 23 & 34 at 400rpm and over.
The 34 do however give very good acceleration so it's not all bad.
Spindle rpm will likely only allow 600mm/min anyway with 8mm 3flute.
Still an unfinished project.
The machine is more or less built, oil system is in, enclosure has minor snagging issues. Really I just need to finish the coolant system and I'm ready for first chips.
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dazp1976
They don't give the speed I was hoping for but that may be down to the resonance I seem to get. It won't help. The inductance for them shows 4.1.
What drives are you using.?
4.1Mh isn't bad for nema 34 from that i guess it's 8 wire motor wired in parallel. If it's a 4 wire which are often wired series I'd expect much higher inductance so would question that 4.1 figure.?
Sent from my SM-T580 using Tapatalk
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
JAZZCNC
What drives are you using.?
4.1Mh isn't bad for nema 34 from that i guess it's 8 wire motor wired in parallel. If it's a 4 wire which are often wired series I'd expect much higher inductance so would question that 4.1 figure.?
Sent from my SM-T580 using Tapatalk
I did wonder that. These ones:
https://www.ebay.co.uk/itm/German-Sh...72.m2749.l2649
https://www.robotics.org.za/85BYGH450D-008
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Re: The Dreaded X axis stepper error.
Quote:
Originally Posted by
dazp1976
Think Those 860ma drives are analog version which are junk and will be holding those motors back massively. Replace with digital and you'll get different machine.
Regards the motors it looks like they could be parallel wired version but the datasheet on web site doesnt match the spec so I'd still be suspicious.? All the 4 wire they show have high inductance.!
Sent from my SM-T580 using Tapatalk
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Re: The Dreaded X axis stepper error.
I found your post researching what seems to be a very similar issue. During the "event", a stepper makes an alarming high pitched noise. Large numbers of steps are lost. An axis often moves at a slower rate during this. No mechanical binding ever found afterwards. Re-home the machine and it might run perfectly the next time.
We share a very similar sounding setup. UCCNC running through UC400ETH. Same manf VFD if not exact model.
Last evening it occurred again several times. I have not checked for stray AC voltage but will do that today.
