OmioCNC report

[extent]

I run out of rigidity long before I run out of power, only ever around 30% load on my 800w spindle. 1/4" is the largest "normal" size you can run in the ER11 without a reduced collet, and that will happily run at 24k with carbide. The only reason I would consider a larger spindle would be to get a larger collet to use a wider selection of edge finders and indicators, as a lot of them are larger than 1/4". The rigidity just isn't there to run something like a micro flycutter where you need really low speeds. I'm tempted to try a 3/8 inserted endmill, but since I couldn't increase my MRR any I just haven't bothered

I don't think the number of bearings impacts TIR any, but it should provide longer life with abuse. If you're planning on cutting metal I would personally stick with a 4 bearing spindle as a rule, though I'm sure a 3 bearing spindle will cut just fine.

[doogle]

javanree, Mmpie, extent.. thanks for your responses and advice.
I finally stopped deliberating and ordered the damn thing, and went with the 800w 4-bearing spindle.
Now I wait. Well, now I start looking at dial test indicators, end mills, replacement cabling etc. etc.
Cheers!

[RCaffin]

4 bearings sound good.
Infinite are the ways of spending more money.

Cheers
Roger

[Mmpie]

Anything to think about when speeding the motors up? With my new PSU my machine seems happy to whizz the X and Y around simultaneously at 6000mm/min, do I need to change the acceleration, add heatsinks etc? Or just change the max speed and it's good to go?


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[dharmic]

I'd have a play with acceleration too, see if you can push it up. Max speed is all well and good for sweeping across the table; short rapids can be limited by the acceleration (ie doesn't get up to speed before it has to slow down again).

[Mmpie]

I think my spindle bearings have gone. This is a bit of a kick in the balls as it hasn't been abused, hasn't seen all that many hours of use and only had two very minor crashes. It's making a whooshing noise, almost like there's a fan attached to it, much louder with a tool chucked in the collet but still audible without.

https://m.youtube.com/watch?feature=...&v=9fFBzx-IGqY

I guess new bearings will cost more than a new spindle. New 2.2kw? 3kw? Take the whole thing to the scrapyard where it belongs and buy an old hurco instead? Thoughts?

Edit: it's been suggested to me that the nowforever VFD could be a culprit. I'm not sure about that, else everyone would likely be moaning about dead spindles after a few months.

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[RCaffin]

I listened to the video, but I can't say it sounded all that bad. So the bearings whine a bit - they usually do at high speed.

Try spinning the spindle by hand - disconnected from VFD. If it feels lumpy or gritty, then you have a problem. Otherwise, try working a few drops of oil into the bearings and see what that does.

Cheers
Roger

[Mmpie]

I listened to the video, but I can't say it sounded all that bad. So the bearings whine a bit - they usually do at high speed.

Try spinning the spindle by hand - disconnected from VFD. If it feels lumpy or gritty, then you have a problem. Otherwise, try working a few drops of oil into the bearings and see what that does.

Cheers
Roger

Thanks Roger, I'll give that a go. Yes it's hard really to pick up on the video. Much noisier and clearer in person. There isn't any noticeable play on the shaft but it does definitely feel tighter to turn by hand and doesn't spin as freely, so it's on borrowed time I think.

Edit: just played the video on my phone, the whooshing sounds more like an air blast. In person actually that whooshing noise is far louder than the spindle motors electrical turny noise.

Do you know anything about the VFD being a potential killer? I'm quite interested to find out. I had a look at proper VFD's and ones capable of running these spindles actually aren't too badly priced. I'm wondering if it's worth an upgrade anyway?


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[Mmpie]

Well I took it apart and dropped a little oil in the bearings, it's a three bearing spindle. Definitely the bottom two that are on their way out, you can feel them clunking. Not actually any run out or play at the tool yet, and I need to get something finished so will cross my fingers and hope for the best for today. They are noisy though and oil didn't make any difference whatsoever.

So it's a new spindle job. Undecided on more of the same or something completely different. The only UK based seller I can find sells the unit as a spindle/Huanyang VFD pair so it's either buy another crappy VFD which I don't need, chance it on eBay and hope for the best or buy one from one of the well known Chinese sources on alibaba and wait ages for it to arrive. Or spend a bit (3 times) more on something a little better with proper support and warranty like a teknomotor.

Or as I suggested yesterday just weigh the lot in, have it melted down and turned into something decent and buy an old hurco/Bridgeport etc. which poses it's own problems.

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[extent]

I can't see any reason why the VFD would have any effect on the bearings. I really like my Hitachi vfd, no regrets there at all. I'd consider the extra crap vfd that comes with it just part of the cost of doing business, it's still cheap even with the extra bits you don't want.

When I was looking for toolchange heads it was kind of annoying because all of the suppliers I found were in Europe (Germany, France, Czech) and almost all of them refused to ship to the US for some reason. So even if you can't find anything in the UK there must still be something closer than china for you.

If I had the space I'd drop the router for a bridgeport and do a cnc conversion in a heartbeat, at least for the kind of cutting that I do. But getting a replacement spindle is a pretty cheap and easy fix, and if not cheap then you can be sure to be getting a nice jump up in quality.

You could also just replace the bearings, though I'd probably get a 4 bearing spindle before worrying about maintaining it.

[Mmpie]

I can't see any reason why the VFD would have any effect on the bearings. I really like my Hitachi vfd, no regrets there at all. I'd consider the extra crap vfd that comes with it just part of the cost of doing business, it's still cheap even with the extra bits you don't want.

Me either, something about not regulating power properly and getting to hot, but I have a temp sensor on mine and, despite it never getting hot, have always kept an eye on it.

When I was looking for toolchange heads it was kind of annoying because all of the suppliers I found were in Europe (Germany, France, Czech) and almost all of them refused to ship to the US for some reason. So even if you can't find anything in the UK there must still be something closer than china for you.

Wouldn't a proper bt30 spindle be nice, even if still used manual it would save a ton of time at every change!

Finding a supplier isn't difficult, plenty of them, but to reduce the gamble I'd prefer to use someone who's done the homework and found the right Chinese factory to source them from, as they're made by hundreds of people to varying standards.

If I had the space I'd drop the router for a bridgeport and do a cnc conversion in a heartbeat, at least for the kind of cutting that I do. But getting a replacement spindle is a pretty cheap and easy fix, and if not cheap then you can be sure to be getting a nice jump up in quality.

You could also just replace the bearings, though I'd probably get a 4 bearing spindle before worrying about maintaining it.

One of the many problems. Along with having to set the 3 phase lines back up, getting it here, knocking out a wall and rebuilding it to get it in, then the inevitable problems an old and likely abused machine will probably have. Etc.

I looked at replacing the bearings, that is not a cheap option at all. God knows how they turn these spindles out at these prices, is all I can say. I'm really interested in getting a vector VFD now though, having spoken to someone about them and seen the benefits it can bring, at around £150 whichever option I take it seems it would be silly not to. I am liking the idea of this ER25 teknomotor spindle but it's 4x the price of a Chinese. But - you pays your money...

I'm looking at changing all the framework to either welded steel or at least thick heavy duty aluminium profile at some point in the near future, so maybe an upgrade to the spindle wouldn't be so much overkill.


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[RCaffin]

BT30 is definitely nice, although truth to tell, most of the time my BT-30 is holding an adapter for an ER25 collet chuck. Yeah, manual tool changes - but they are SO much cheaper than an ATC ...

Cheers
Roger

[Mmpie]

BT30 is definitely nice, although truth to tell, most of the time my BT-30 is holding an adapter for an ER25 collet chuck. Yeah, manual tool changes - but they are SO much cheaper than an ATC ...

Cheers
Roger

Yes, very true. But at least BT30 gives you the option of setting all your tools up prior to a job and changing the whole toolholder in seconds, rather than manually removing the collet, cleaning everything and loading up another one and having to set the Z height every time.

Just a shame a BT30 spindle costs more than this entire machine

Back to the OMIO, engraving mild steel, small ball mill or spot drill? I'm thinking carbide spot drill and taking quite a few passes.


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[dharmic]

I've "engraved" mild steel using the D-bits that came with it. Quotes because it was actually a fine milling operation down about 1.5mm deep. Went through a few cutters as I sussed feeds and speeds but turned out nicely.

Once you get down to that 1mm diameter sort of range you can run the spindle flat out so you have torque aplenty (and much less need for it) so the only thing left to worry about is balancing the feed against the RPM for a decent chip size.

[Mmpie]

Cheers. I have a carbide 6mm spot drill already which I'll probably try to use, or just use up those tiny bits that came with the machine. I'll only be going 0.25mm deep or so, just replacing a rusted chassis number.


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[Mmpie]

Wel I made my first big costly mistake today and took my eye off the machine for as long as it takes to write a text message. I was making a batch of the same part using a tried and tested toolpath, and somewhere during that time the chips had started welding to the bit along a distance of about 20mm. All of a sudden the machine just went silent and stopped dead, no bogging down or skipping, just blink of an eye and goodnight Vienna.

There's seemingly no power going to the spindle or motors, the VFD and PSU both seem to be completely dead, no USB connection to the PC. I've tried different fuses and cables to no avail. I'm guessing whatever happened has bricked the entire electric cabinet


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[Mmpie]

Looking around at what's available locally to get the thing back up and running ASAP. Will try change the VFD and PSU first, fingers crossed the drivers and motion card survived.

Thinking forward to the upgrades I had planned over time can I plug the OMIO stepper drivers into a 68v linear PSU? I see the drivers can't output to the motor with any more than 48v, but I can't see anything about input voltage. I don't know if this is a stupid question but worth asking if it saves me having to buy twice, particularly if the drives are dead and I have to replace them too but I already bought a 48v PSU. As I've already said before my knowledge of anything electrical is... well I don't have any.

VFD I'm looking at is a Bosch EFC5610. Somebody has one just down the road so I can grab it and get started straight away. £180 but has vector control and surely better than the Chinese crap, I'm hoping this could turn out to be money well spent and get a bit of extra performance from the spindle at lower speeds.


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[dharmic]

Did you know: King Midas of the fable had a brother Mmpie who had a similar curse, except everything he touched didn't turn to gold but instead a different kind of brown stuff?

:O

Not been having a great run of late, have you?

All I can suggest is approach this logically. Start at the mains plug and work your way through the system: is the PSU getting mains? (did you accidentally hit the e-stop and not realise? Is there a fuse hiding somewhere on or in the box that's popped?) Is the PSU putting out a voltage? Are the drivers getting it? Is the USB BoB getting power from the computer? Is it doing anything? Is the VFD getting power? and so on.

Hint: If the VFD display is dead that's telling me mains is not getting to your black box's guts.

Hint: Diagnose the issue first, with no thought of what to replace or remedy until you know what's wrong. Otherwise you end up chasing a red herring because that's what you have a fix for and, when it turns out not to be the problem (no matter how hard you tried to make it so) everything just gets sad.

[Mmpie]

Tell me about it! This is just my luck though, I'm used to it. Everything I touch turns to the brown sticky stuff, you're bang on the money there.

I agree and is exactly what I plan on doing bright and early. Tonight I'm just covering bases and finding locally sourced parts so that once the issue is found I already know what I need and who's got it so I can head straight out and get it without messing around finding who's got what. The stepper drivers and BOB don't seem to have any local retailers though so will need to order those online or go for a long drive. There is a little time pressure here, I need to get a one off part ready for a job by the end of next week, hopefully the local machine shop can squeeze it in!

I didn't have time to have a proper look at the symptoms as I had to rush off. In fact it happened right on the home straight, literally the last 30 seconds of a 16 minute toolpath! Talk about a good hard kick in the bollocks. The text message I was writing was "leaving now" which sort of tells you how fast it all happened, I think unless I had my hand on the estop I wouldn't have prevented it anyway. But yeah, I checked all the quick and obvious things, different fuse then different power cable, different USB cable, power off, power on, a gentle tap with the sledgehammer etc. There was no USB connection to the PC, nothing would move, the cooling fan on the box wouldn't power on, the cooling fan on the PSU wouldnt power on, the VFD display wouldn't come on. So I'm pretty certain both the PSU and VFD are dead. Last time when the original PSU died it was exactly the same although the VFD still worked then.

I'm just hoping the BOB and stepper drivers are all good, as figuring out what to put where and how to wire it all up and get it all working smoothly is sure to turn my relaxing weekend into a migraine inducing nightmare.

For what it's worth the plan for the future of this machine is to slowly but surely turn it to a steel framed fixed gantry. By the end I think everything bar the rails would have been changed, I want to go with closed loop steppers or servos purely for the fact so I can have the peace of mind that I CAN look away and be safe in the knowledge the machine isn't skipping steps and getting up to anything naughty whilst I'm not looking. Hence me asking about the 68v PSU.

Edit: I am assuming that 48v is also the max input current but I'm not 100% sure. It would be nice not to have to waste money on a 48v unit when I plan on changing it, and these drivers could well be dead as a dodo anyway.


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[Mmpie]

Well it could have been a lot worse. VFD is dead, the male IEC connection on the back of the box is somehow dead (not sure how, it's just a metal pin sealed in a housing... no sign of damage but no power coming through it) and the cooling fan on the box appears to be dead.

Everything else appears to be ok.

Apparently the Bosch VFD isn't really suitable for this application and I've been recommended some other complex looking thing at the same price instead.

Going to be a laugh programming this


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