Hello,

We currently purchased an 04 VF 4 and practically from day one there seem to be a problem with an extremly rough tool changing.
After any end mill or milling head work (side milling / face milling) during the tool changin process (umbrella type) the tool is being "ripped" from the spindle making a loud popping sound. The local HAAS service claims that they are aware of the issue and will monitor, but im affraid that with my luck the thing will brake as soon as the warranty is up.

Has anybody experience similar problem? Are there any solutions (other then service recommended light lube on the tool taper surface that makes no difference)

Thanks

Peter

We have several Haas machines that sometimes behave this way; it seems the tool is being pulled out of the spindle by the tool changer as the spindle lifts. This occurs most often using tools that are taking heavy cuts (around 100 to 120% spindle load) for a long time. It occurs most with regular helix mills but not as much with high helix mills and I think it is just the taper snugging in really tight under prolonged load and high helix cutters prevent this because they generate a strong down pull. We keep spindle and tools clean and lubricated to minimize it but for some programs we have had to put in a dummy tool change to reset the taper in the spindle. On one machine we put a reserve air tank downstream from the pressure regulator on the machine. The normal operating pressure for the tool changer is 85 psi but during a tool change the pressure can drop around 20 psi below this because the regulator itself constricts the flow. With a ten gallon reserve tank the pressure drop is less than 5 psi and tool jams in this machine rarely occur now.

How do the tool shanks look after many changes? Are there any outstanding blemished spots that might indicate some kind of defect in the spindle taper?

If you have a defect in the taper, its been my experience that the tool actualy comes out easier. Although this is a poor solution do to the increased TIR of the tool because of what amounts to poor taper seating.

We Have done something similart to geof and increased the air line size going to the regulator and replacing the regulators on the problem machines with a better (higher flow) regulator.

Thanks !!!

I will put an air tank (actually have a spare one) next to the machine and try to increse air pressure too.

seeing all these replays - are we saying that HAAS actually refuses to acknowledge that there is a problem with the tool change?


peter

I think it is not really a problem with the Tool Changer but more a problem with the air powered tool release cylinder. I think if they put a high flow solenoid valve at the cylinder, enlarged the air line going from the regulator up to the solenoid valve and had either a high flow regulator or reserve tank on the 85 psi line the problem would be solved. Except maybe for the times you let a hot spindle cool down overnight with the tool still in place from the last cycle. Then you have real fun.

I agree... solution seems very simple and inexpensive - one would think that HAAS would address it promply.
Does the problem also exist with that high speed arm tool changer?

luckly we are being very particular with the overnight shut down - always leave it toolless ..

regards

Peter

Send a suggestion to Haas. They have address and email info at
http://www.haascnc.com/custserv_SUGGESTIONS.asp?formtype=a&sourcecode=websug&redir=http://www.haascnc.com/custserv_sent.asp#custserv

Do any of you guys run an air dryer on your air lines? I'm thinking that maoisure could be the cause of this - I have noticed it on my vf2ss been told it was a non-issue... it's out of warranty in a week so we'll soon see...

I have an air dryer in my shop, and now that you mention it since we've gottin it there has been less tool sticking, but, it hasn't been eliminated completely. So, the problem probably is contaminantes in the taper if, having a dryer reduces the symptoms.

Air dryer? Yes, definitely. We installed a refrigerated dryer a few years ago and that solved a lot of problems we had with both lathes and VMCs. We did have moisture traps but they just weren't good enough. Dry air solved all our problems except when we were doing heavy cuts as I mentioned earlier. I also checked with my guys; it is probably close to a year since the VF machine had a tool jam i.e since we put on the reserve tank.

We also experience this problem with our VF3 on heavy cuts. Lube and cleaning the taper helps, but I suspect the problem is the female taper expands and traps the tool under heavy load.

We also experience this problem with our VF3 on heavy cuts. Lube and cleaning the taper helps, but I suspect the problem is the female taper expands and traps the tool under heavy load. Not sure what to do about that though, proberly should have a heavier machine spindle (BT50). Will look at Geofs sugguestion re air tank and valve flow/pressure drops.
Best Regards Burgs

I've been been runnung my two Haas machines for eight years in everything from Titanium to Aluminum. The problem is HEAT in the spindle causing the taper to tighten up when it cools a little. If you machine parts without coolant, it really helps to run a line from the spigot back to the tank to help cool the head, since that is one thing that gets almost no mention is the flood coolant acting as an additonal cooler.
Second, coat the inside of the spindle taper with a FINE coat of axle greese to serve as a release agent and the problem is gone for about 48 hours of run time.

A hot spindle cooling is certainly one of the reasons tools jam; don't ever shut a machine down with a tool in the spindle after 10 hours almost non stop at full speed.

I did discover a different fix a few days ago when our VF0 jammed a tool for the first time in over a year; use a cheaper tool holder that does not fit the taper as accurately! Not really a solution if you have a high speed spindle.

I have run VF0's,VF2's,VF3's,VF4's and a VF6 with both high speed and carousel type tool changers. It seems to me that that its a crap shoot with sticking tools. We had purchased 2 VF4's at my last shop with carousel type tool changers. Both machines where bought at the same time. One had this problem constantly and the other never. At my present shop we have a VF2SS and a VF6 with the high speed tool changer. Again the VF6 gives us some problems and the VF2 never. I've found that keeping the taper clean and lightly oiled helps to reduce the the frequency.

I would put rough tool changes into a couple differnet classes. Those that are caused by the tool change mechanisms, and those by tools binding or sticking in the spindle. The first ones are usually easy enough to fix, if you adjust and time your tool change mechanism. The second type. . . Mostly teaching the help not to airblast into the tool changer and making sure that everybody knows how the shop deals with the issue.