[doogle]

Thanks for the response Mmpie. They're both max rpm of 24000... but do you mean the speed at which they achieve their rated power? I don't know if that's different between the two spindles.
I was wondering about performance at lower rpms though, and how that might affect me. That's interesting to know about lower rpms on the 2.2kW spindle though. Although from what I've read, these spindles are just not meant for drilling in the same way the spindle on a mill would be.

I suspect I'm making a mistake in thinking (/hoping) of the X4-800L as just a smaller X6-2200L... obviously the spindle and steppers are lower powered on the X4... but it's sounding like the difference in mass (and maybe even other construction factors) might affect things to the point where 800W is enough, and whichever spindle I have I'll have a significantly more difficult time with aluminium and steel than on the X6. Hmm.. I'm starting to think that maybe having the X6 (well, X6 in an enclosure) dominating my small home office might just be the solution!

[Mmpie]

There isn't really any mass in these machines, if the X4 has profile rails and a smaller framework it could actually be a more capable machine. If both are 24k rpm I would definitely go for the 1.5kw option as it should I believe have more oomph at lower revs.

The spindle can 'drill' perfectly fine. It's once you get to around 8mm diameter or so, they want to be spinning quite slow, and the spindle just doesn't have enough torque at lower rpms to push the drill through at a matching feed rate, so you either have to kill the feed or increase the RPM. I choose the first option, but both make a horrible noise and I'm sure aren't very good for the spindle or the drill bit or the nicest hole. 6mm and below it will drill perfectly well no problem.

I don't think stepper power is an issue, they're specced to move the machine. Unless you plan on recycling them for a bigger beefier build or adding considerable mass there would be nothing really to gain from higher powered ones IMO. Maybe a bit of speed.


Sent from my iPhone using Tapatalk

[doogle]

if the X4 has profile rails and a smaller framework

Profile rails and linear guides are just two names for the same thing, right? It has those. What do you mean by smaller framework?... Just that it's a smaller machine?

If both are 24k rpm I would definitely go for the 1.5kw option as it should I believe have more oomph at lower revs.

The torque at lower rpm was the reason I asked about the option of upgrading the spindle in the first place. But then the fact that the 1500W spindle has fewer bearings made me wonder if that was the right approach. I guess it comes down to the tradeoff between torque and number of bearings, and which aspect is likely to be more important. In your opinion do you think the extra power of the 1500 spindle is worth it at the cost of fewer bearings? Then again I really haven't been able to find anything concrete on the practical difference between 2 and 4 bearings in a spindle, so I have no idea how much of a difference it'll make.

I'm sure aren't very good for the spindle

That's pretty much what I was referring to with my previous statement, rather than whether they can drill... but then that's just what I've read, so I don't have any experience to back me up. But yeah, these spindles do seem like they can be coaxed into doing various things they're not designed for. Maybe not tapping though.

I'm going to stick with the stock steppers so I only mentioned them for the comparison between the 2 machines. In terms of speed, I'm probably more likely to see an improvement there by switching to a different controller and/or drivers. Something I'll consider down the line, but the more turnkey approach works for me for now (rewiring and sorting out grounding and also building an enclosure is enough for me to deal with at first).

Cheers

[Mmpie]

Without looking I would assume OMIO use the same extrusions just cut to different lengths across all their machines, obviously the same gear in a smaller set up is going to be mor rigid. The profile rails (fixed square type) are the big improvement on this as you know so if the X4 have them and the working area is enough then it's a good choice.

Having read a lot of machine building threads over the past few weeks I have seen a lot of very knowledgable people have purposefully chosen to use the 1.5kw spindle. If there is a drawback to it it wasn't enough to put these people off. If you intend to work with aluminium and hard plastics I think the extra power will be of far more benefit to you.

Worst case the spindle needs replacing, the spindles on their own aren't particularly expensive at all and you can just plug a new one in. You get the 800w and find you need more power then you have to buy a new vfd and spindle as well as probably set it all up properly and get it to talk to Mach.

Just my 2p's worth.


Sent from my iPhone using Tapatalk

[RCaffin]

Assuming your reply was a jovial sarcastic reference to my post about the rails.
Mainly a reference to the tilted off-centre poorly-tapped holes.

Cheers
Roger

[Mmpie]

Assuming your reply was a jovial sarcastic reference to my post about the rails.
Mainly a reference to the tilted off-centre poorly-tapped holes.

Cheers
Roger

It was my day off and I had just woken up. For some reason I had thought you'd quoted my post about the rails in your reply.

Just thought I'd clear that one up


Sent from my iPhone using Tapatalk

[javanree]

My X4-800 came with a VFD which could also handle the 1.5kW spindle , I doubt anything needs to be changed, just plug n play. From all the pictures and movies, I've seen the control box for X4 and X6 contains pretty much the same.
Both spindles can't go much below 6000 rpm and then already torque is lacking. In reality I never go much below 10k rpm for milling.

I've never encountered a lack of HP on my machine with the 800W spindle, with a 6mm mill I can plough through MFD just fine. It's usually the lack of stiffness of the frame that's limiting me, not the spindle.
The reasons I chose for the 800W spindle : I didn't want watercooling, I wanted the 4 bearing model due to better runout numbers and since I wouldn't use the extra power I'd just be moving more mass, limiting my rapids and acceleration and perhaps causing more sagging of the bridge (which is flimsy)
Unfortunately the poor steppers are now what's limiting me most...

[doogle]

Mmpie:

Yeah I'd seen a 1.5Kw spindle described as the sweet spot between 800w and 2.2Kw.
As you say, I'll have the option of changing spindles later if needed. But as javanree said, it seems the VFD delivered with the 800w is rated for 1.5kw anyway. The diameters are different... but starting off with a larger mount might be handy (maybe).

javanree:

Ah, so it is the case that the higher number of bearings means less runout? That's kind of what I was looking for... ie. what the difference in number of bearings makes in practice. I've seen conflicting statements elsewhere that when someone says '2 bearing spindle' that actually means 3 bearings (suggesting the matched pair is counted as one bearing)... so not sure whether the 1.5kw is really 2 bearings or 3.
I've been looking at various videos of people cutting aluminium on smaller routers with both 800w and 1.5kw spindles... but since there are so many other variables that I'm not sure how useful that is. Have you been relatively happy with your machines performance with cutting aluminium?
Do you think you'll upgrade the steppers? Have you upgraded the controller or drivers?

[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?


Sent from my iPhone using Tapatalk

[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.

Sent from my iPhone using Tapatalk

[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?


Sent from my iPhone using Tapatalk

[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.

Sent from my iPhone using Tapatalk

[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.


Sent from my iPhone using Tapatalk

[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