Another Dead Mill Spindle

As per topic, now on our 2nd Mill spindle in 1 year, This one went very quickly having only been replaced 6 months ago, was machining some very small features using a 0,6mm B/nose @ 12000rpm when it suddenly got very hot and the bearings siezed, managed to get some coolant thro the spindle nose to cool it down (was using Air on the machnining ) but you can now feel the bearings when you spin the spindle by hand. Still able to do turning at the moment, just waiting on Mazak to get back to me :(

Hi Dan,

Would you mind telling us the current status or how this subject was resolve? Any recurrence? Or is it a machine design issue? We run our spindle too at 11000rpm and your posting it here is a red flag for us to watch out. TWO mill spindle in 1 year even with the warranty is..something.. Is it IG300-IV?

Thanks,
itubal

Hi, We have been thro' a total of 7 or 8 spindles now, although the last one lasted just over a year, we limit our machining to 11k and don't do any big cuts, as most of the time it is used for small ball nose cutters down to 0.4mm. The machine is a Integrex 200-IVs.

It seems that the first batch of spindles that we went though must have had some sort of quality issues as the last one was a lot better (although a year is still far too short) and I am just hoping that the current one will last forever :)

Dan

Hmm..interesting but yes I agree that one year is a vey short life for spindle. Save for a machine collision, ours should last for awhile since it takes only just about a minute/ cycle @ 11Krpm for engraving. We usually run with thru-coolant and should help keep spindle temp manageable.
I also wish spindle to last forever, just a wish though..
Thanks again..
itubal

Mechanical design is a fickle thing, and in machine tools even more so considering the wide range of applications they can be used for. You might find that the spindles simply don't like the consitant high speed / light loads as they've probably been designed against a duty cycle that considers predominantly much higher loads. In my experience these spindles are quite robust.

I know in my experiance,the only time weve had to replace a spindle or had problems with one is when its been crashed. We have both the new direct drive spindles (matrix integrex) and the older style (640mt integrex). ive done some very heavy milling and turning with both and have had no issues, unless the machine was crashed.

Well I can honestly say that only one of the spindles was crashed (and we paid for that one) as for the rest we just had a mixture of front and rear bearing failures, we did explain to mazak exactly the kind of work we would be doing and were assured that the spindle would cope with the high speed/light load, however nowadays i just limit the spindle to 10k and touch wood everything seems ok..

Dan

well we just had our first spindle replaced after 4 years and 5 months of use, never crashed or over loaded. it was working perfectly one second and the next it just seized, literally. it had just completed an engraving operation and had moved out to the tool change position and as it put the brakes on to slow down, it made a horrible grinding and clunking noise and came up with the alarm "feedback system malfunction". when we checked it to find out what happened, we couldn't even rotate the spindle by hand, it wasn't even warm so we think something other than bearing failure was the problem. maybe the armature exploded? it looks as if i have had a good run compared to other users, the average looking at this forum being probably about eighteen months. great money spinner for mazak doing all of the R & R's. our replacement was a second hand re-built exchange unit as they didn't have a new one in stock even in japan, which was our preferred option. $18000.00 for the privilege plus 3K to install. the "new" spindle is nowhere near as quiet as ours was and i'm now looking forward to joining the eighteen month club with rest of you lucky guys.

by the way if you read this Stuart, thanks for the heads up with instructions for the removal and replacement of the spindle that you emailed me earlier, it probably saved me about a days downtime and over 1000 bucks in bills from the tech installing it, as i had it all ready to simply remove when they came here.

mazak japan had a survey out regarding 12,000 rpm couple years ago. they were inquiring who was using these spindles at max speed all the time or most of the time. not sure about the outcome or the purpose.

gofastjohn

what rpm do you run your spindle at and what is the duty cycle? would you consider that there is a problem with spindle bearings lubrication? what type of spindle i.e. capto, BT40?

thanks