Jitters when routing

[crane550]

Hi,

Not sure what the terminology for this is, but I have some little "jitters" with my router whenever I cut. The little waves in my cuts. You can see it most on the horizontal lines in this picture, but they are present everywhere.

From CNC

No speed control on my router, but it's a decent 1-1/4 horse deWalt. Microstepping at 1/2 ATM, 305oz steppers on a wooden solslya build, that was built with care IMHO. Still using 3/8-10 rod. Feeding at 25ipm.

Didn't put this in my build thread because others might have this problem too. May have already been addressed, but like I said I don't know what to call it. I can retag it with the proper terminology so others can find it, too.

[MrWild]

X axis lead screw whip with a flexible axis rail. It might go away with 2 start 1/2-10 acme lead screw. It might go away if you impose preload to the axis rail assemblies. Somewhere there is slop. I had some of the same problems with a JGRO and loose axis rails.

[Phife]

looks like a problem with rigidity, i suspect your Z axis is flexing and while the router cuts it flexes and causes those "jitters" its called "chatter"

Having an adjustable router speed can help you dial out the chatter if its not too bad, also adjusting the feed rate should help, try slower.

[15mgtar]

where exactly the little waves? I can not see it

[louieatienza]

I've had some issue in the past with "chattering", usually it's when I have the feed or pass depth set too high that it pushes past the "ridgidity" of the machine. The obvious solutions are to either "slow down" the feedrate or use a "shallower" pass depth so the router can remove the material without being "dragged" through, or just do a "once over" on all axes, to make sure you remove as much play as possible without making the bearings too tight.

Another thought: if your pipe rails are too "rough" that may telegraph onto your piece; you may have to sand or file where the bearings track.

And another: only if you have home-made leadnuts; it's possible the backlash in the leadnut is causing the chatter, but if you have AB nuts that shouldn't be too much an issue unless you push the router past the spring-load of the AB nuts. Related to this, double check your bearing mounts (and bearings) that there is no play there, especially the z...

Having had built the 25x37 machine, I have had no issues with chattering when cutting woods and MDF, and maybe a little bit cutting outside profiles in aluminum. I'm only using a palm router, about 1HP. I do believe the 25x25 machine to be a sturdier machine than the original 25x37. Then again I used ipe for the frame which is about four times heavier than pine, and it's possible that the weight helps me with chattering.