Spindle Air Leakage

[ThatguyDave]

There seems to be alot of air leaking out from the bottom of the spindle on my 4020. Is this common? Should I try to correct this by removing and resealing the plate on the bottom of the spindle? What exactly is this plate doing anyway? Does anyone have any kind of cutaway picture or literature which describes the insides or dimensions of Fadal spindles? At the very least I'm curious. Thanks. Dave

[denmar]

Newer spindles have sealed grease packed bearings, needs the air to cool down,,fittings
are on top an botton!!
SOME OTHERS SPINDLES SHUT AIR INTO THE DRAW BAR ASSY.

[little bubba]

Originally Posted by ThatguyDave There seems to be alot of air leaking out from the bottom of the spindle on my 4020. Is this common? Should I try to correct this by removing and resealing the plate on the bottom of the spindle? What exactly is this plate doing anyway? Does anyone have any kind of cutaway picture or literature which describes the insides or dimensions of Fadal spindles? At the very least I'm curious. Thanks. Dave

First thing, is what year is your machine. The OLD machines used an oil mist on the bearings, then they went to a grease pack and then somewhere in the late 90's they used air to lightly pressurize the spindle to keep coolant out of the bearings.

I've only dealt with '93-'97 these were all grease packs, and before they were pressurized. However they all have an air blast on the toolchange. One machine I had, had the airblast to the inside of the spindle going on with the spindle orient arm, which turns off on the actual spitting of the tool, when you actually need or could use air to help blow the tool out and hopefully clean any crap off of the tapers. Another has the air to the spindle going with the drawbar. The third had air on all the time, except for when the spindle orient arm was on, some dipwad attached the air line to the wrong side of the wrong valve, its now fixed.

Anyways, talked with Fadal to figure out if I should be pressurized or not, he said I shouldn't, it was only the newer machines and they used a very slight regulated pressure. Too much air, and it can blow the grease out of your bearings.

Lets start with the year of the machine and when you do and don't have air coming through the spindle.

[CRS1]

I have a 3016 with a new spindle that was using ridiculous amounts of air.

You maybe talking about the air curtain to stop coolant getting into the bearings?

I have just fitted an inline variable restrictor and turned the flow down a bit.

There is a line going to the top which i have also turned down.

Let us know how you go.

[ThatguyDave]

Thanks guys. My machine is a 96 with a 10K grease pack spindle. And yes the air remains on the entire time the machine is functioning in auto mode. This doesn't seen to be at all related to any effort to clean the tool tapers during a tool change so the air curtain CRS1 is describing sounds like a more likely culprit.

If I pull the bottom plate off the spindle what happens? Is it simply holding a grease seal? Thanks again for the advice.

[little bubba]

As far as I know, a '96 shouldn't have a pressurized spindle. Possible somebody decided it would be a good idea and bypassed the valve for the spindle air blast? Where you are showing your spindle leaking is where mine that was hooked up wrong was blowing out buttloads of air.

[CRS1]

My machine was blowing air as soon as you start the spindle.

Are you sure the air is leaking from the plate and not from inbeween the rotaing spindle and the housing? That is where the air curtain is(see pic)

Can you start the spindle without a tool installed and carefully feel where it is coming from?

Machine dealer says the air line going to the top is the basicaly the same deal - keeps coolant out of the bearings in case the through spindle coolant leaks.

[quickturngreg]

My '96 3016 emits just a small amount of air out of the bottom of the spindle when the spindle is turning.

As said, this is an air curtain to keep contamination out of the bearings. The air is very slight, you can hear it better than feeling it. So if air is really gushing out, you've got a bad valve or something.

Virtually all high quality vmc's use this air curtain system to protect the spindle. The air also offers a bit of spindle cooling as well.

[ThatguyDave]

Yea, it looks like my machine is just emmiting the std air curtain it was designed to in order to protect the bearing from coolant infiltration. I might still add some kind of restrictor to tone it down a bit though.

[DareBee]

You can get the 10K spindles with or without the "air curtain"
I was always told that the air spindle was only recommended for cutting graphite and other non coolant dusty applications. I went with non air on my last spindle.
When I had the air spindle I always used an M19 in my program footer to turn it off and not run my 10hp compressor needlessly.

[machinehop5]

Sounds like your "Tool Out" Valve is stuck on or open.

Good Luck on Mission,
DJ

[ThatguyDave]

Thanks again for the input guys and gals. Its defintely not the tool in/out blowdown because that's significantly more air than my spindle is emitting. I'm pretty confidant now that its just the air curtain thats supposed to be there. Evenually I will restrict it a bit to minimize compressor usage.