This is what I had to offer to another user that is having the same problem.
Dave
What do you mean tool stick out? I have my bit almost bottomed out (but not completely buried).
Tool stick out is the distance from the bottom of the collet to the bottom of the end mill. the shorter you can keep it the better. Especially with how far the collet is from the bottom bearing on the stock spindle.
Dave
Try decreasing the depth per pass to 0.020" and increasing the IPM to 80. @TaitLeswing ran it at 110 IPM and it had way less chatter.
Does the Y-Axis move smoothly when you move it by hand with the power off? Or does it give you a lot of resistance.
I had a lot of mysterious problems like this that I tracked down to an intermittent connection between the two Y axis steppers. It does look like you are seeing the issue on the Y axis, but the X axis is smooth.
I’ve had very similar chatter with a 1/4" bit too - especially cutting across the grain as is indicated in your picture.
I’ve given up using a 1/4" bit for milling ATM and I am using primarily 1/8" end mills for profile cuts until I get a more powerful spindle.
Try the same cut with a 1/8" bit - Feed rate @ 10" / Min and 0.2" Depth of pass, I think you will get MUCH nicer results.
Increasing the feed rate helps with chatter. Also, I was using thick double sided tape to clamp my 2" thick material down. A better solution is to screw the material down or use clamps. This stabilizes it more and helps reduce chatter. Hope this helps others!
@DrunkenWoodworker i was getting a very annoying amount of chatter with my Inventables purchased 1/4 bit trying to do some basic oak rough cuts at .032 per pass. I lopped of 1/2" of the bits back side and now the end mill only sticks out roughly 1 1/4 inch from the spindle and I am now plowing thought my oak with no chatter at all.
Thanks for the update! I think my issue was a bit different probably closer to what @WillardChivers said. I’m pretty sure its a bit run-out issue (I think that’s the technical term for it). Unfortunately for my both of my 1/4" bits are mostly cutting length, so cutting them short doesn’t really work! I’ll have to find some short 1/4" bits, but for now the 1/8" ones seems to be working great!
I would ask 2 main questions
First is this with both the X and Y axes? your seeing the chattering? The picture looks like it is only the 1 axsis…
-If the above is true: (I would assume it is the axsis with 2 motors on it giving you the issue?)
-If the above is still true I would make sure both of these rails are square for the entire length of the maching
(I did this by the flollowing steps: when the machine is powered on but not cutting I loosened 1 rail on 1 side only. I then moved the machine close to the loose side. While doing this I noticed the rail moved in. I retightend the screw and then repeated this process with the other side of the same rail on my machine. This helped me a lot. I was having a binding issue
2nd question with power on and moving over long distances can you see the machine shake? or can you see it shake when doing a heavy cut?
-If you only witness the machine shaking during LONG moves or a HEAVY cut it may be not enough power going to the motors (there other forums showing how to adjust that)
3rd thought (bonus?) Are you sure the milling bit is not flexing?
ONLY with Safety Glasses on (seriously) when it is miling i would stick my head down to the level the cutter and peek to see if you can see the cutter’s shaft flex. If the shaft of the milling bit is flexing your going two fast cutting to deep ect!!! (you do not have to be extremely close to witness this eater just at the same levil) noticing shaft flex will be most noticeable when your X Carve starts / stops cutting to see the flexing happen.
Not sure if this may be causing your issue, but I had my X-carve suddenly leaving the path and doing unwanted moves in the middle of projects. However when doing an air run with the spindle off, it always worked fine. Whenever the spindle was on, it hardly completed any project correctly. I am using the lowcost spindle by the way. Increasing the drive current of the stepper motors did not solve the issue.
Upon coming across a few comments mentioning spindle noise interfering with the stepper drivers, I hooked a 5µH LISN into the supply line of the spindle to check conducted noise with a spectrum analyzer. The conducted noise level that I measured was extremely high. Far beyond the limits to pass any EMC standard.
Next I built a simple filter consisting of a common mode choke with 330nF capacitors at each side. The common mode choke is a salvaged part, a 30mm diameter ferrite toroid core with 2x 15 windings. This filter, in series with the spindle supply, inserted close to the spindle, significantly reduced the noise, except in the range somewhere below 100kHz.
After inserting the filter, the issue with my X-Carve disappeared.
I am about to order a few common mode chokes from Digikey to further reduce the noise in the low frequency range. I will then post the schematic/BOM in this forum
Appendix:
Here a picture of a typical failure
And here the measurement setup
here the initial filter
and here the current status, still not final, but it solved the issue
@MichaelMayerhofer I am fairly sure I am having the same issue. I was hoping to find this exact post. Would you mind posting a picture of the bottom side of the board you soldered? Also the digikey link when you select a part would also be welcome. Thanks for the thoughtful posts everyone!
Cheers,
Gregg
Here a sketch of the filter:
The capacitors that I used are 100nF in parallel to 220nF, 250V
Here a link to the common mode choke that I am about to order:
http://www.digikey.com/product-detail/en/8120-RC/M8915-ND/775454