Chatter issue Chinese CNC6040

Hello,

So I get some wicked chatter issues on my 6040 mill. Now, it's a Chinese machine, so I know it's not going to be as steady and wonderful as maybe a better engineered machine. However I have noticed some particulars that make me think it might be solvable and an issue that I caused in my ignorance that might even be the issue.

I will describe what I did (the mistake) and when the excessive chatter happens and see what you guys think...

My mistake: This is my first mill. When I was setting up the machine for the first time, and for the life of me I can't remember why, but I "unscrewed" the Z-axis ball screw enough that the ball nut came off and the "what the hell are those little ball bearings" came out. "oops... uummm... okay..." I googled what the heck this thing even is and eventually "learned" how to put it back together, but I know for sure I didn't get all the balls back in. Some of my balls fell through the cracks. my balls were lost. I couldn't find my balls. I thought, "I have enough balls...I think..."

So, I put it back together and 178 hours later I was the very proud papa of a new CNC mill. That was two years ago and I am more in love today than the first. Hooked indeed - BUT!

Let's say I'm cutting out some 6061 .125 plate in the shape of a heart, not that the shape really matters, but just to let you guys know I am a man who can make hearts, powder coat'um red and give them to my land lady so she can never again have to use finger nail polish to spiff up her Tin-man decorations.

The heart is big enough to where I feel like I would like to have some holding tabs... THIS is where I sure seem to always run into "chatter" issues.

my .125 2 flute, coated for aluminum bit, seems to run fine until it has to start "lifting" and "reseating" for the holding tabs on the bottom of the outside profile cut...

Meaning- while the z pressure is constant, through the first .09-ish (my tabs are .04 x .04) everything seems fine. The random chatters start sometime after the Z starts going up and down, you know- to go up and over the holding tabs.

SO MY THOUGHT is... could this be some kind of backlash or ball bearing- missing- loading issue inside the nut?

I know the flimsier design is more prone, but way nut at the surface? Why Always after the Z load shifts? etc?

Without seeing the machine or the build style there is to many variables. And if you have a ballnut missing balls then that needs to be corrected. Since your fixturing sounds a little sketchy swap to a 3 flute endmill. Equal flute numbers tend to give you "KickOff" when not in a rigid setup. What's happening is the opposing flutes are pushing from side to side basically leaving small gouges everytime they come in contact with the work. 3,5, etc gives you some clearance so the opposing side doesn't "dig in" effectively giving what you think is chatter from the machine.

g-coder05 said:

Without seeing the machine or the build style there is to many variables. And if you have a ballnut missing balls then that needs to be corrected. Since your fixturing sounds a little sketchy swap to a 3 flute endmill. Equal flute numbers tend to give you "KickOff" when not in a rigid setup. What's happening is the opposing flutes are pushing from side to side basically leaving small gouges everytime they come in contact with the work. 3,5, etc gives you some clearance so the opposing side doesn't "dig in" effectively giving what you think is chatter from the machine.

Click to expand...

"CNC6040" as per title suggests (I did a google search) a shitty stepper driven aluminium extrusion built router, not a 60x40 VMC that happens to be built in china.

Some missing bearings in the ball nut is the least of it's worries.

Yeah, "China 6040 mill" is not a mill at all.

I'm kinda shocked it has ballscrews

This is trolling.

"CNC6040" as per title suggests (I did a google search) a shitty stepper driven aluminium extrusion built router, not a 60x40 VMC that happens to be built in china.

Some missing bearings in the ball nut is the least of it's worries.

Click to expand...

I guess I assumed when it said 6040 it was at least a real 60" machine. Them Chinese are so good at misleading.

g-coder05 said:

I guess I assumed when it said 6040 it was at least a real 60" machine. Them Chinese are so good at misleading.

Click to expand...

Ain’t they!

“We’ve got the virus under control”

Oh god, I googled it too!!!
My freaking eyes are bleeding.

It gave me COVID-19 through my phone!





If it’s either one of these, throw that crap in the trash

Close due to home shop type machine discussion