HAAS VF 3

[JACKOFTRADES]

I am new to this forum and I am glad to be a part of it and share information as well as recieve. I have read some of the posts on this web site and I can tell that Haas mills are notorious for tools sticking in the spindle. I to have the same problem. When the toolchanger moves over to grip the tool the drawbar releases the tool and z axis moves up. Sometimes when it releases the tool their is a popping sound almost like the drawbar has still got ahold of the tool as z is raising up. If I just walk up and start doing tool changes it makes a slight popping noise when it releases the tool and z raises up. If I am machining a part and it does a tool change the popping is more violent and it has a tendency to drop the bigger tools. I have cleaned all of my tapers as well as the spindle this did not help. I also replaced the springs in the tool grippers this did not help. The device that releases the draw bar is air powered it is set at 90 to 100 psi. I am thinking that the drawbar is releasing enough to make up the switch that tells z to pull up but its not releasing all the way all the time causing tools to drop randomly.

[JROM]

It's an oil lock problem.
Keep your tool holders clean and wipe out the spindle nose every day.
I have my operators clean the tool holders with naptha before they put them in the machine and clean the spindle nose every day. Problem solved! Also if you have thru spindle coolent this will make it worse because it drips down on the tools and make the tapers lock up.

[JACKOFTRADES]

Your suggestion makes sense. I didn't use naptha I used a red brillo and some acetone. It still randomly drops the bigger tools after you have been cutting with them.I have worked on a lot of machine tool changers Makino,Kitamura,Mori Seiki,SNK just to name a few, but this Haas vf 3 has kick my butt. What I don't understand is why does it just drop the bigger tools when it is putting it back up in the tool holder after machining. I am wondering if regrinding the spindle taper would help me at all or if pulling the drawbar out and cleaning it and replacing the spring washers would help or maybe I have poor spindle cooling.

[dvaliket]

I think it is a spindle heat issue. I ran a '99 VF-3 that had that problem. It was the worst if you left a program finish at night without programming in a toolchange to an empty pocket. By morning it wouldn't come out as the spindle cools down with coolant in the taper. We started a different shop and bought a VM-3 new a year ago, it hasn't once tried to stick the toolholder. Last week we got a new VF-2 and although it hasn't stuck to the point where the toolchanger couldn't remove it, it comes close with the loud POP. The big difference is the way the the VM machine keeps the spindle cool. Even after running the warm up program in the morning, the VF spindle is very noticably warmer.

[JACKOFTRADES]

I do know that the spindle oil cooler could stand to be cleaned. The spindle coolant probably needs to be changed. I will try this when we get some down time. I have been working at this facillity for about one month. They have never had a maintenance tech or practiced preventive maintenance. I have 2 Haas mills dropping tools I think they both have the same problem. One is the VF3 and the other is the VF2. We have 3 other Haas mills and thier tool changes just seem all around a lot smoother. We currently have 3 VF3, 1 VF2 and 1 VF6 the rest of our machines are Mori Seiki lathes.

[pup96]

Hi, I used to run one of 2 VF-3 when I worked as a machinist (man I miss those days,) they were both used machines but in great condition. The only thing I hated about them was they tended to leak trap oil from the lubrication systems into the coolant. Anyway, they are very messy machines and you need to keep them clean as possible. When ever we changed tooling we would wipe down the holders and spray some stuff on the end to prevent them from sticking in the spindle. I know it was called dry slide, but I am not sure who made it. I am leaning towards CRC, but not 100%. We also would take time to clean them on long runs and recoat with the dry slide. Usually at least once a week we would clean the spindle out with a special tool, kind of like wht you clean your windows with ( I cant spell it ) it was designed to match the tapper of the spindle. After that we would use a clean rag to get into the tip where it holds the tool, I don't remember what that part is called. After all that we would spray a light coat of the dry slide in there too, usually that was done at the end of the day so it could dry. We only ran one shift, so we would clean the filters once a month, on Fridays when we would clean the machines out real good and spray them down with rust preventative. One machine had a filter on the back of it, and one on top of the spindle, this machine had a two speed spindle. The other only had one filter on the back. Usually we didn't have to many problems with the machine, good up keep took care of it before it happened. The only time I can remember having trouble with it dropping tools was when we used a heavy angle head in it. It was just to heavy for the tool holder, and we only dropped it 3 times, basically that was cause we didn't use it very often and everyone forgot that it was to heavy but me, and they didn't believe me when I told them not to try it.

[thetrillionaire]

It's been my experience with every Haas mill i've ran that it seems the z load forces the toolholder into the spindle. Large plunges with large end mills launch themselves with more force when released.

[JACKOFTRADES]

I think you are right trillionair. I am fed up with this to the point that I am going to have a haas service tech come and try to fix the problem and hold him to it. If they can't fix the problem the haas mills just have thier flaws.We loose money and downtime every time we drop a tool.

[serviceman]

you need to check your tool unclamp switch by first checking the pushout on the drawbar put a block of aluminum on the table and jog an empty end mill holder down on to it until it is snug and you can barely move the block then jog up .090 and hit the tool release button the block should be just as tight and it was when you jogged into it if you can push up on the tool or the block you may have a problem with your drawbar. if the block is tight at .090 then jog down to .060 and look at the diagnostic page and hit the tool release again. i think haas specs out that the db open switch should change at .060 i like to set it a little higher like .065 just to make sure that the tool is unclamped. you can adjust the switch by moving it left and right and keep trying make sure the switch does not trip below .050 or it will be ripping the tool out of the spindle. you can also blue up a new holder with the paste blue not the liquid and check your taper. you should never use abrasives on your taper because you will knock out the concentricity some people say put grease on a pull stud but i see sometimes that the grease actually collects crap and makes it worse. i have also seen on this forum that some people crank on the stud which actually swells the top of the tool causing a bind. maybe you need to service your tool release psiton as well. have the hfo put a clamp force meter on your machine as well to check the drawbar, but the only real way to check it is to pull it out and make sure you do not have broken springs sometimes the broken springs can make the drawbar difficult to move in the spindle. if you have tsc then there is a whole other set of problems that can occur.

[JACKOFTRADES]

Thanks I will give it a try when I get my vf-6 fixed.

[Geof]

We have had this problem on several machines. Nearly always it was a holder that is doing heavy cuts for a long time and I think it is a combination of heat build up and the cutting forces helping to wedge the taper in tighter. Keeping things clean helps and we have tried no oil, light oil, light grease but it still happened with some tools.

We have more or less solved it now with two fixes:

One was to put an air tank down stream of the regulator on the machine and make sure the regulator is set at least at 85psi. What we found was that when the tool changer air cylinder operated the pressure in the system dropped to about 65psi because the flow through the regulator could not supply air quickly enough to the cylinder. With a ten gallon reserve tank the pressure only drops to just below 80psi and it is possible to hear the cylinder operating more powerfully.

The second fix was that we found some tool holders jammed more often than others so now we try to make sure the big cutters doing a lot of work per cycle are in the holders that do not jam as often.