Spindle Speed Controller Question

[A_Camera]

I see you did not answer this point.

I did answer indeed...

"Air cooled = less installation work, simpler machine, less possible problems, less space, zero risk for leakage causing problems, no chemicals to handle, simpler motor, less risk for electrical problems..."

Now, the point is if you realize you need a water cooled you can pretty easily upgrade, but if not than you get the above advantages. OK, this way you may get a spindle over, but so what? You can always use it as spare or just simply sell it on to the next one. The important thing in my opinion is to get the right VFD and the right power. A new motor is no big deal.

Similar to buying anything else, camera, car, house or whatever else. You may buy something you think is going to work well for you, get experience and realize that you need some other feature, or more space or power so you simply buy or upgrade to a new one.

I did not say you could install a cooling system for £3.

No you did not. But why quote such a price, like if it was the major part of the cooling system? I mean, I didn't even brought up saving or costs as argument, you did that, because you assumed that my reason for air cooled was money saving, which is not.

Yes it is your opinion and having reread all your other posts with opinions I will not be replying again to this one.

Fine. So you mean that the only one who can have a valid opinion is you? You must be joking...

[njhussey]

Similar to buying anything else, camera, car, house or whatever else. You may buy something you think is going to work well for you, get experience and realize that you need some other feature, or more space or power so you simply buy or upgrade to a new one.

I think Clive's point is that normally as you state above you learn by experience....however the whole point of coming on a forum is to use the experience of others to shorten the learning curve...therefore why buy something that others are saying (yourself included) you'll replace later?

[A_Camera]

I think Clive's point is that normally as you state above you learn by experience....however the whole point of coming on a forum is to use the experience of others to shorten the learning curve...therefore why buy something that others are saying (yourself included) you'll replace later?

I am NOT saying that an air cooled spindle must be replaced. It can be the case, but not necessarily and in my case not likely that I will need to replace it.

There is no "one size fit all" solution, regardless who claims that. Points and experiences valid for one person are not necessarily valid for everyone else. I don't claim that everyone should use air cooled spindles, just that it works FOR ME, as well as for many others, and most arguments for using water cooled spindles are pretty lame. Considering most of us are amateur CNC users and DIY builders, using our machines very irregularly and for short periods every time I regard water cooled systems overkill. This may change in the future, nobody knows, not even I. If I'd start using my CNC more professionally and much more often than I am ready to pay the price of upgrade. This is one of the fun points of DIY engineering. Just like my first CNC had unsupported curtain rods and a pretty weak design as well as a 400W DC motor (which I am still using) even though I knew about the weak points, I decided to build it that way to start with, KNOWING that if I continue with the hobby I'll upgrade it, some parts will be thrown away or become unused. My version one was successful enough, used it for a year and made me more money than I expected initially and motivated an upgrade. So I did the work, which meant new, redesigned frame, supported rails, proper ball nuts and ball screws, new power supply... and so on, as well as VFD (Bosch, not cheapo Chinese) and a motor. I read a lot about other peoples experiences and opinions because I wanted to know, but I am an adult, so I made my own choice because only I know what my needs are. Not everyone needs water cooled systems, both systems have advantages and disadvantages and we learn mostly by our own experience. Asking about others experience is valuable, listening to what others have to say is also valuable, but that does not mean we have to follow every word of it. We have SEVERAL choices and reasons why we decide to go one way or the other, but just because somebody is going a different route or recommends a different solution or an alternative he/she is not stupid or ignorant and must not be flogged alive for having a different opinion.

No, I am not saying that an air cooled spindle must be replaced by a water cooled one, what I am saying is that it has many advantages over a water cooled one and that not everyone needs water cooling. What I am also saying is that water cooling MAY be necessary if you run a professional work shop and use the machine practically 24/7, but that's a totally different subject.

BTW, aren't you one of those who built spindles from scratch? Did you regret it? Why build one when you can buy a ready made? I am joking, don't answer those questions, because I really understand even those who build motors or rewind existing motors to improve or modify them. However, I would never do such thing but I understand it is an interesting experience and very cool in my opinion. I mean, you of all people should understand my points.

[JAZZCNC]

No, I am not saying that an air cooled spindle must be replaced by a water cooled one, what I am saying is that it has many advantages over a water cooled one and that not everyone needs water cooling. What I am also saying is that water cooling MAY be necessary if you run a professional work shop and use the machine practically 24/7, but that's a totally different subject.

Why do assume because It's hobby most machines are run for short periods at time.? Just because you may doesn't mean others do.! . . Infact I can tell you thru my experience of building machines for Hobby people which are used in vastly different walks of life it's actually very common for machines to be run for extended periods in Hobby use. Single Jobs that take 8-10hrs cutting 3D models in very abrasive model board or MDF moulds etc. On large 3D Jobs this can 24hr+
Yes they may not do this every day or every week but at least they can if they wish to and not worry about killing there spindle. Which isn't the case with Air cooled spindle. Run it for 24hrs none stop at 24000rpm and it will Die.!!

Try that with Air cooled Spindle and see how long it lasts.? The duty cycle alone eliminates Air cooled Spindle. The dust just Kills the bearings Fans etc in short period of time. Which in practice on long jobs often doesn't happens because the heat Kills them first.!
(Stopping the spindle for cool down period isn't an option either because it leaves tool marks on the work piece.!)

Now we come to the Simpler Part.? . . . Really 2 hoses connected to pump in bucket isn't exactly Complex or rocket science. Or Like Boyan says and what is actualy happening on my machine at moment due to robbing the pump for another Job is straight thru the hose pipe and out again.
Other than this there is no difference. The advantages of WC spindle with VFD greatly out weigh any slight None complexity of the cooling system. And for No or very little extra cost.

For anyone building there first CNC Machine then buying a Air cooled spindle costing same or few £$ or euros cheaper than WC is Dumber than Dumby recommending to do so.!

[A_Camera]

Why do assume because It's hobby most machines are run for short periods at time.? Just because you may doesn't mean others do.! . . Infact I can tell you thru my experience of building machines for Hobby people which are used in vastly different walks of life it's actually very common for machines to be run for extended periods in Hobby use. Single Jobs that take 8-10hrs cutting 3D models in very abrasive model board or MDF moulds etc. On large 3D Jobs this can 24hr+
Yes they may not do this every day or every week but at least they can if they wish to and not worry about killing there spindle. Which isn't the case with Air cooled spindle. Run it for 24hrs none stop at 24000rpm and it will Die.!!

Try that with Air cooled Spindle and see how long it lasts.? The duty cycle alone eliminates Air cooled Spindle. The dust just Kills the bearings Fans etc in short period of time. Which in practice on long jobs often doesn't happens because the heat Kills them first.!
(Stopping the spindle for cool down period isn't an option either because it leaves tool marks on the work piece.!)

Now we come to the Simpler Part.? . . . Really 2 hoses connected to pump in bucket isn't exactly Complex or rocket science. Or Like Boyan says and what is actualy happening on my machine at moment due to robbing the pump for another Job is straight thru the hose pipe and out again.
Other than this there is no difference. The advantages of WC spindle with VFD greatly out weigh any slight None complexity of the cooling system. And for No or very little extra cost.

For anyone building there first CNC Machine then buying a Air cooled spindle costing same or few £$ or euros cheaper than WC is Dumber than Dumby recommending to do so.!

ha... ha... ha... Why assume that EVERYONE uses his CNC in dusty environment for jobs which definitely classed as industrial work? Even if it is called "hobby" it is just as industrial manufacturing as any other professional work if you do such long runs. It's not me making assumptions, it is you and all the other people who lack imagination and can't understand that what suits your needs may not suit everyone else and what you may need may not be necessary or needed for others, and the environment you have around you may not be the same as everyone else have. That seems to be very difficult for some of you to understand.

Like I said before, if you use your CNC as an industrial machine, even if you have it as hobby, of course water cooled is to be preferred. If you run the spindle for 24hr+ jobs that in my vocabulary is called industrial use, and in fact, demands high quality parts, even for hobby and even if you have a water cooled spindle. If I would be planning for that kind of activity I wouldn't even look at cheap Chinese spindles at all, water cooled or otherwise.

As for 24h test run you propose, no, I am not going to test run my spindle for 24 hours non-stop at 24k RPM because such test is totally pointless, regardless of the outcome of it. Other than that, I think what most likely would fail is the bearings, and those bearings are the same in both water cooled and air cooled spindles if they come from the same factory. What I hear is that these spindles are NOT made for spinning at that speed, even if they can do that, because of the low bearing quality. I have no idea if that is true or not and not going to pull apart mine just to have a look. Also there are huge individual variations, some spindles die faster than others because of generally low QC. So, your proposed test of my spindle is totally pointless, but if you want you can send me one at your own cost and I can test run that one for 24+ hours and report about the results. In parallel, you could send me a water cooled one from the same factory with the same power so that I can run the two in parallel and see what happens. I can set up the water cooling necessary, have a pump I can use and all the necessary other parts for the cooling, so don't bother about that.

Other than that, I will use my spindle just the same way I want or need to. The longest run with my DC spindle was 1.5 hours work. It worked just fine and is still working. I expect the spindle I have now to last even longer and for at least the same length of jobs. I will not likely need to run my spindle at 24k RPM since I am currently pretty happy with 9-10k RPM, so even here, if I can double that to 18-20k RPM that's more than I need. Regarding the heat... well, don't worry about that, I am supervising the heat of not only the spindle, but also all my steppers, power supply and drivers. So far I have not seen heat as a problem the way I am using my CNC. BUT... if my air cooled spindle would die I would evaluate the reasons and if the reason is poor quality I will buy a new air cooled spindle of much higher quality and price and don't bother with the cheapo Chinese ones. But again, that's just me looking at my own use, need, environment and so on. Not necessarily the same or similar to yours and it may not suit you at all, but definitely suits me very well.