Why does my Lead 1010 keep doing this? Every time I try and make a pocket using a upcut end mill the machine chatters and vibrates bad when cutting along the Y axis on the right side wall and bottom of the pocket. The bit is traveling away from the front of the machine. Doesn't matter if it's a new bit or not.
What size of endmill? Is the work piece securely fastened? The only times I have had chatter was when I didn't get the piece securely fastened down.
What are your speeds, feeds and depth of cut? Have you tried conventional rather than climb milling? If so did you still get chatter? Alex.
17,000RPM 120 feed rate Depth 0.125" step over 0.05" climb milling Why is happening in only one direction?
There could be many reasons (mainly that wood isn't a uniform material - grain lines, variations in hardness, etc.) but in this case, it could be lack of rigidity in one direction - check that there isn't any play in the X or Z axis carriages and that your bearing wheels are all snugged up.
Try reducing feedrate, and definitely try conventional instead of climb. These tests will give us clues about what might be causing this. Ideally diagnosing problems would have us standing next to the machine, but I'm thousands of miles away from you. See @Misterg's post above - starting at the bit wiggle things with reasonable force and the steppers powered on. You can often feel things moving that shouldn't be better than you can see them. Alex.
So here is my setup. 17,000RPM 120 feed rate Depth 0.25" step over 0.05" I used conventional cutting like you asked me to and it worked perfectly. No chatter and no vibrating. If you still want me to change the feed rate I can do that but do you have a suggested number? There always seems to be a tiny amount of play or movement along the X. I've taken that apart so many times and fixed it and it keeps coming back. There is no slop in the Y direction. But before you say "That's your problem!" would it not chatter on both sides while cutting a pocket?
Probably not. The overhung weight of the Z axis will force the X axis wheels against one side of the V grooves. If the force from the cutter acts in the same direction, then there is no possibility of movement. If the cutting force is in the opposite direction, then at some point it will be strong enough to overcome the weight of the Z axis and the Z axis will move to take up the play, causing chatter.
Ok so why didn't it happen when I just did a pocket using conventional cutting and not climb cutting?
update 17,000RPM Depth 0.25" step over 0.05" conventional cutting 120 feed rate = Zero problems 100 feed rate = Zero problems 90 feed rate = Zero problems 17,000RPM Depth 0.25" step over 0.05" Climb cutting 120 feed rate = chatter 100 feed rate = A lot less chatter 90 feed rate = about the same as using a feed rate of 100
The cutting forces in conventional milling tend to push the machine back against the direction of travel. Any backlash or play tends to get taken out at the start of the cut. The forces in climb milling tend to pull the machine into the cut. If there is any play, once the cutting loads are high enough, the cutter will pull itself forward, taking up the play and 'grab' a much bigger cut than it should, sending a shock through the machine. Since the machine has only moved forward at the programmed feed rate, at the next revolution there is no material to cut, so the machine can fall back to the other limit of the play. This may or may not be your problem, but from the very coarse appearance of the machined face in your first photos and the way that it disappears when conventional milling, I'd say that there's a very good chance that it is.
See Problem with tool chatter only on one side along the Y. The first thing I would check is the eccentrics on the X and Z axes, but could also be play in the router/spindle mount. You should just be able to turn a wheel with your finger (have the steppers powered on to stop the gantry moving). Alex.
I did some more pockets and it does in fact chatter on all sides. So I grabbed the bottom of the router and tried to move it and it has slop along the X axis. I even had some one else do that and they noticed it to.You can hear metal tapping on metal like it is slightly loose or something. None of the other Y and Z axis have that movement. Question Should I start thinking about replacing the Nut Blocks, Flexible Coupling and the 2 Lock Collars for the x axis gantry system "You should just be able to turn a wheel with your finger " Yeah I'm not a fan of that method. I might move them and think "that's still too loose" and you might move them and think it's perfectly fine. What I do is keep tightening them until there is no movement or play between the V slots and the Wheels. But even then there is always 1 or 2 wheels that are too loose or too tight. I've messed with those **** things so many times it's not funny. I have never been able to get the wheels on my machine all the same.
Check that your leadscrew bearings are OK and that they and the lock collars are properly seated. Alex.
Well Im on my 3rd trip of taking this x axis gantry, c beam, etc. apart and here are the problem I keep running into, I have to tighten the eccentric nuts all the way and even then not all the wheels are touching the C beam. IMO The holes on your gantry plates are too far apart. You shouldn't even have to turn the eccentric nuts that much to get a proper fit of the wheels in the V slots. No matter how many times I redo the Lock Collars there is still back and forth movement, and when I look at the Flexible Coupling it is acting like a spring. I'm not sure how one would stop that. You guys have machines there that don't have the problems I am having so what's the deal here? I follow your assembly videos to a tee. I don't get it.
If your flexible coupling is springing back and forth, then the lock collars cannot be adjusted properly on the X axis. The lock collar adjacent to the flexible coupling should be tightened when the flex coupling is "relaxed". Then, loosen the lock collar at the other end, turn the collar grub screw down gently until it just enters the "groove" of the acme thread. Then, turn the collar like a "nut" until it pushes firmly against the Y end plate bearing to take up the backlash in the acme shaft. For the Z axis, check that the weight of the extrusion is not hanging on the flex coupling, (adjust the bottom lock collar until the flexible coupling is in a relaxed state) then take up the slop with the top lock collar.
Wheels worn out? Time for replacement? (Med term consumable) Too close would result in people Overtightening them - this wears a groove into the wheels in a matter of hours. That spacing has been tweaked over a decade to find the perfect balance. If its not adjusting as shown in the Eccentric Adjustment video, something else is wrong. Wheel wear on a machine thats been in use would be a good candidate. Make sure to push it all the way tight and keep it there while fastening the setscrew. Its a pretty simple system, but does rely on you pushing it tight up against the bearings on both end before setting the setscrew to lock it down. If you do the bearing at the top first, then the bottom, the springiness shouldn't come into effect, unless you forgot one of the lock collars? You do have both installed, one on each end of the screw? The bearings+collars constrain the screw. The shaft coupler just transfers rotational force. As said above, you can always loosen it, but it sounds more like you are trying to rely on the coupler instead of a collar?
IDK maybe the wheels do need replacing? Do you guys have a picture of a worn wheel to show us what that looks like? Sounds like I am not getting the Locking Collars in place properly. Because when I grab onto the gantry plates and push back and forth the lead screw is moving back and forth.
Extreme example, perhaps pics of yours for review would be better Yip not set correctly. Watch video below (short form, actuator are just what makes up the machine, so transferrable and much shorter to watch) - around 12min onward shows install of lock collars. Note the tip about spinning it around a little so the grubscrew seats best and making sure collar is tight up against bearings, leadscrew must have 0 axial play.
