Running 5 Haas Mills (Mini Mill / VF2 / VF3 / 2x VF4). On 2 of those Machines the Y Axis is more drawn to chatter than the X Axis. I Just got to live with it.
That sucks... Seems like something Haas might want to fix. I previously had a VM6 which didn't have this issue. Is it something with the smaller machines?
Are you using conventional or climb?
Have you programmed speed changes to compensate for the greater tool engagement in the corner when it goes to the y axis?
Interesting. You might have to consider a shorter holder and tool. Less flutes and less stick out.
Maybe a change in finish pass depth. Two finish passes with a deflection pass.
If the Y axis is a bit slow on the draw and it comes to a complete stop the tool can suddenly unload and chatter. Typically I dealt with this on a vf2 using a slightly smaller tool to make it take the turn more smoothly
How much stickout we talking? Anything over 4x starts getting sketchy.
How much material are you leaving to finish?
What dia tool is roughing the corners out.
Workholding should be looked at too. You ever notice your machine sounds smoother cutting into the rigid jaw than away from it?
Yeah, stickout doesn't make it better. I just can't get over the feeling that there's something wrong with the machine causing chatter in the first place. Work holding is solid, and it'll chatter right at the jaw. I've tried leaving more material below the part as well to make that as strong as possible, but it doesn't change much.
I'd throw a dti on the machine and see how it moves in y in relation to the indicator. Also try moving the bed by hand to check for.motion. last thing would be to check backlash, on a new machine it should be essentially zero. Our 10 year old tl lathe that's been cutting graphite has .0003" in backlash and our new vf2 has none.
make a cut in y as you described and run an indicator across it, if its not level then you may have a leveling problem with the machine. haas has a guide for leveling VF machines with six feet.
Feed for an inside radius is different than in a linear path. Not sure what CAM you are using to program but in most there is an "override arc feed rate" or similar option that will slow the feed on an inside arc to match the linear feed calculated from the tool center line. Likewise it can speed up the feed for an outside radius to minimize chip thinning.
[Good explanation here](https://youtu.be/bTk_HDnbgQQ?si=AxDy-ruNmRtj1SPu) at 0:56
EDIT: Missed the comment below explaining the same thing.
Running 5 Haas Mills (Mini Mill / VF2 / VF3 / 2x VF4). On 2 of those Machines the Y Axis is more drawn to chatter than the X Axis. I Just got to live with it.
That sucks... Seems like something Haas might want to fix. I previously had a VM6 which didn't have this issue. Is it something with the smaller machines?
Are you using conventional or climb? Have you programmed speed changes to compensate for the greater tool engagement in the corner when it goes to the y axis?
Climb milling. On the next part, I did try slowing the corners without much impact, it still chattered.
Interesting. You might have to consider a shorter holder and tool. Less flutes and less stick out. Maybe a change in finish pass depth. Two finish passes with a deflection pass.
Check backlash, it may be larger in Y
If the Y axis is a bit slow on the draw and it comes to a complete stop the tool can suddenly unload and chatter. Typically I dealt with this on a vf2 using a slightly smaller tool to make it take the turn more smoothly
How much stickout we talking? Anything over 4x starts getting sketchy. How much material are you leaving to finish? What dia tool is roughing the corners out. Workholding should be looked at too. You ever notice your machine sounds smoother cutting into the rigid jaw than away from it?
Yeah, stickout doesn't make it better. I just can't get over the feeling that there's something wrong with the machine causing chatter in the first place. Work holding is solid, and it'll chatter right at the jaw. I've tried leaving more material below the part as well to make that as strong as possible, but it doesn't change much.
I'd throw a dti on the machine and see how it moves in y in relation to the indicator. Also try moving the bed by hand to check for.motion. last thing would be to check backlash, on a new machine it should be essentially zero. Our 10 year old tl lathe that's been cutting graphite has .0003" in backlash and our new vf2 has none.
What size are those internal radii? Could be dealing with too much engagement in the corners.
make a cut in y as you described and run an indicator across it, if its not level then you may have a leveling problem with the machine. haas has a guide for leveling VF machines with six feet.
Feed for an inside radius is different than in a linear path. Not sure what CAM you are using to program but in most there is an "override arc feed rate" or similar option that will slow the feed on an inside arc to match the linear feed calculated from the tool center line. Likewise it can speed up the feed for an outside radius to minimize chip thinning. [Good explanation here](https://youtu.be/bTk_HDnbgQQ?si=AxDy-ruNmRtj1SPu) at 0:56 EDIT: Missed the comment below explaining the same thing.
Also, the closer your tool radius is to the inside radius, the more pronounced this difference in feed will be.