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- เผยแพร่เมื่อ 5 ก.พ. 2024
- In this video I explain what killed my spindle and how you can prevent it happening on your machine, especially if you are an occasional CNC Router user.
In order to prevent damage to your CNC Spindle or for that matter your CNC machine as I also mention some good practice for it's use, you'll find the information in this video useful. Hopefully preventing you from suffering the same misake we did and the subsequent expense.
#CNC #CNCMachining #CNCRouter #CNCFlatbed #CNCSpindle
Back in the 80's and 90's, some commercial CNC shops with a specialty of making high precision components would keep their machines running cutting paths during hours when the machines weren't making parts. This kept the ball screws, bearings, lubricant, etc. at normal operating temperatures, thereby minimizing the impact of thermal expansion.
Your procedure will not only keep the spindle in good condition but will also improve the overall accuracy of the machine by improving repeatability of positioning. Warming up the entire machine is a good practice, even though it is a bit of a nuisance. I recommend writing a simple program to exercise the spindle and drive system. Start off with slow spindle RPM and feed rates, increasing over the course of several minutes as the system warms up.
And since forever, grinding machines are left on all day, so the spindle bearings stay warm and on tolerance for clearances, etc.
Is this because your shop is cold? Mine is in a finished basement that’s heated year round.
No, you should run in your spndle each time regardless. You may not have to go through the breif warm of the electrics that I do, but that is due to humidity where I am coupled with the cold. The spindles though should follow this.
Also, I didn't make it as clear as I should have done in the video, if you only use your machine occasionally, you should do this routine regardless kif you need to use it at least a couple of times a month.
This is very very cautious. Perhaps warranted, but, your problem could likely be solved by letting it run at low speed for a few minutes or so before starting. These things come up to temp very quickly, and they never really get "hot". What you're trying to avoid here is hitting the spindle with load while it's cold, because the cold lubricant in the bearings isn't in-spec until it warms up to operating temps. You may also consider a program where the machine makes a large, slow circle for a few laps so your steppers aren't stone cold when they start working, for the same reason. Also it gives you a chance to make sure the machine is running right before putting work in it.
In terms of ramp up/down, again, as long as you're dialing it up/down slowly, you're fine. You want to avoid slamming a ton of power at a spindle all at once, because it'll take time to catch up, during which it is mostly producing heat in the windings. The same goes for ramp down, because it's on a VFD, the VFD slowing the spindle will cause it to electronically brake, which again, just produces heat. Not the end of the world, just easy to avoid with a few seconds of time.
Depending on your VFD, you can likely program in a short warmup cycle, and a ramp up/down cycle, that'll simplify all of the above. A couple seconds is all you really need there, or about a casual dial turn.
Also you mentioned that you have a Vevor spindle setup here, and, it would probably be best to not run it at maximum speed, you can probably realize some additional longevity at 80% or so. Yes that'll be slower overall, but, not a ton slower.
The other thing to consider is making sure the whole machine stays clean. It makes sense to have a vacuum system with a cyclonic separator on these, and that's possible to retrofit as well. That keeps them and the shop much cleaner. You still have to clean everything, just, less. Keeping the moving parts clean will extend their life alot.
Thanks for response, very detailed, really appreciate you taking the time.
On the spindle warm up, as stated I'm performing the instructions listed in the manual for that spindle, which may well be OTT.
I do mention the stepper warm up and the reasons why I now do this manually, previously I did automate which I know most do and it's fine, I now like to listen the machine as it's warming and pick up any issues as it's moving. I found a loose screw in an awkward position doing it manually that was in a not easy to check on routine daily inspection. It took several minutes of listening and moving to narrow down. All about pesonal preference.
Intersting and a very good point on the top speed, something you won't read in a manual! As you say, won't make a great deal of difference to cut times, great tip, I'm definately going to adopt that one!
Next video is going to be an opinion review on the Vevor spindle as I've used it for over 12 mths now.
Totally agree on the cleaning, which I mention this on the previous vid about lubrication.
I do have a cyclone fitted but as most of our cutting is aluminium, we create chips not dust, the chips go into recycling. I create more dust from the alu on the fibre wheel cleaning & deburring, that has it's own cyclone. We don't cut wood or MDF that often but it's essential then. HDPE though is a whole other story.
My water-cooled spindle manual recommends that if the spindle has not been used in days to start at 3,000 rpm for 20 minutes and increase by 3,000 rpm every 20 minutes. That's beyond a 2 hour warm-up sequence. Even for the first use of the spindle, yes, that degree of caution seemed a bit much. The spindle had been sitting for who knows how long, and the bearings did not sound healthy upon initial startup, so I did comply with the instructions. By the end of the warm-up sequence the spindle sounded perfectly normal at all speeds.
For an air-cooled spindle, running it on a low speed for too long could be problematic, as the cooling airflow may be insufficient for the amount of heat that needed removal.
@@r2db If you're not using the machine regularly, it is worth turning it on just to run that warm up process every now and againl I'd recommend at least twice a month.
@@siukcnc Agreed, running some kind of warm-up is likely going to prolong the life of the spindle. If it continues to sound normal while operating at the slowest speed, I am thinking of halving the time to 10 minutes per increment, or just a bit over an hour for the full exercise routine. For the daily warm-up I have yet to settle upon a specific plan, but I am thinking 15-30 minutes including the motor axes, possibly including some fixture to check squareness of all axes. I have been in the process of an entire electronic rebuild (and partial mechanical one), so it's not going to get a ton of use for the immediate future.
@@r2db Makes sense when you think about it. One other comment suggested it's the slower speed at the start that needs to be the longer one, increments can reduce in time, hope that helps reduce your warm up a little.
Can't you automate the warm-up process with some G-code?
Most industrial machines will warn you if the machine hasn't been used for a period of time, few hours, etc and prompt you to run a warmup program. this slowly ramps the spindle arm up over 15 minutes or so.
If you have the spindle controlled by the g-code software then yes you could automate it all. I've never connected the spindle as I like the flexibility of adjusting the speed on the fly via the know on the VFD. I used to run a roadrunner path at the start , which was non cutting machine op to warm the steppers. I didn't pay attention to the machine as it was running something I do more now.
@ashpalmer1365 sadly most CNC routers don't have anything like that.
Alot of VFD's can do it all by themselves.
@@jttech44 Interesting, I didn't see that in the manual but there is a lot of settings I didn't look at.
i dont really think you need to max speed while warming up the spindle, Im using a hiteco 11kw spindle which max out at 24k rpm,
i go 1000rpm for 4-5mins then 5k for 2-3 mins then 10k for another 2-3mins and at last i set it to 15k rpm for another 5 at least. 15k is the rpm im mostly working on btw.
Also never forget to lub the spindle axle every month or so with a metaflux paste spray (if you have access ofcourse).
The previous spindlle didnt last for long since i was working almost always at max RPM which is 24k, and the lub the "technician" told me to use was WD-40... AAAND yeah this destroyed it.
Possibly every manufacture suggestions variations in their manual. I use the popular Vevor 2.2kw, which mentioned full speed for 2-3 mins, which is much less than the initial 10m at slowest speed.
Thanks for your contribution, very much appreciated.
WD-40 is terrible for use as a lubricant because it leaves a residue that hardens like varnish on the surface. I once had to repair the spindle brake systems on 12 CNC machines where the shop supervisor had been filling the reservoir with WD-40. The spindle brakes began locking up due to build up of residue.
Manufacturers recommend certain lubricants for a reason, but this guy thought WD-40 was a miracle lubricant. A repair bill of several thousand dollars and lost revenue while the machine tools were unable to make parts taught him otherwise.
@@gaiustacitus4242 I missed that in the original post but yes, as per my previous video on CNC lubrication WD40 is a no no, other than for those who love to squirt it on parts they're cutting. I prefer to avoid that also,