[milldoe]

I was wondering if anyone else has ever come across this problem. The technicians sure cant seem to help me out. After using any roughing endmill my spindle starts to build up a varnish on both the spindle taper and tool taper. This varnish is causing my tools to stick in the spindle. The tools are ejected with such force into the carousel the tools in the changer next to the pocket are getting knocked out of alignment, which when time to call these up they are being dropped instead of put in the head. Which this is not necessarily my concern my problem is why is this varnish building up. The tapers are not hot when ejected after a cut. The spindle load is only around 8-10%. Im having to m00 and eject each tool by hand then stick it back in in order to do a tool change on these tools. Ive had the service techs come out many times and they are all worthless. maybe someone else has had this issue before.

[HuFlungDung]

I think the 'varnish' is actually iron oxide, and the miniscule vibration of the tool in the socket creates it. The process is called 'fretting'.

They tell me that a spindle taper that is out of true is the main cause. If the tool shank cannot seat and make full contact, then the air gap provides wiggle room and the tool shank vibrates and creates the 'rust'.

So check the taper for nicks and dings. Sometimes a weak drawbar (broken springs) is the culprit, because it permits the tool to pull out slightly while heavy cutting is taking place. Again, wiggle room creates vibration space for fretting to occur. This makes the tool stick.

Perhaps a taper regrind is called for. There are travellers who do that kind of reconditioning on your machine. They also probably have the tools and knowledge to analyze the exact problem.

It could also be 'gunk' created from oil mixing with moisture in your shop air. That looks more like greasy grime than rust though.

[DareBee]

Milldoe

I have seen the same thing when doing heavy cutting.
Even with a brand new spindle and new holders.
Long runs of heavy cutting do not seem to be avoidable for this problem BUT when I keep the spindle and tools clean and spray a little dry teflon into the spindle I have alleviated the issue 95% of the time.

[milldoe]

im really not even sure if i would call it long runs, 10 minute cut times. my main issue is with a 1/2 carbide rougher cutting .450 depth and .1 on the side. only at 4.5 ipm. it is titanium though. i have found if i clean the bajesus out of everything it works good for about a day. i will take all the imput i can get on this thanks.

[billystein]

I am using 1" ruffers on 15-5 stainless and my holder is turning black in one day. this is why I always separate my heavy roughing with fadals. I have to have someone push the tool out button for me so I can give the holder a good hit on the side. I use scotch brite pads to clean out the taper but it will be black again tomorrow.

[scadvice]

try this it works alot of the time: Because the spindle and tool both warmup during the cut and during heavy cuts the tool flexes in and out of the taper slightly it draws the tool tighter into the spindle taper(are you sure its not fretting your seeing on the tool taper?). I do two things.....(1) when I first start the run and a couple of times during the day I clean the tools and the taper then apply and wipe all but a little film of way oil on them. If you still have problems, you may have to load (a pain) the offending tools by hand and when not in use keep them wrapped in a heating pad in between use. Don't store a tool in the spindle at night.
The last suggestion I have is that you may check for water/oil in your air supply to make sure the gunk is not getting in during the tool change air flush.
A 1/2 EM should not stick. Other thoughts... worn retension knob or some problem with the retension system. Spindle cooling system (if you have one) not working correctly.

[VTEC]

get your bellevue washers replaced the two fadals at my shop started doing that and we replaced the bellevue washers. for some reason fadals dont hold up to heavy roughing without the washers needing replaced

[recordist]

Yup - our Fadals often had problems with tools sticking.

It became the "morning thing" to go around the entire carousel, and wipe off every tool taper and put a very light coat of molybdenum grease on, and to use a clean rag and wipe out the spindle. Yes, every morning. Five minutes and it ran like a dream all day.

The real problematic times often ended up being the washer/springs in the head which had broken/worn out. Worth having a repair guy in once to do it, watch him/ ask him questions, and then buy the kit and do it yourself all the other times. Our Fadals needed it done about every 4 years.

Also try a good squirt of oil directly into the air line to the spindle, also helps to release any sticking in the mechanism.

[milldoe]

thanks for all the feedback