Hi guys,

I am having a problem regarding the cutting accuracy of the piece from wood (linden).
At the begininning of my tests, I had a lot of tool deflection and the resulted piece was 1mm smaller from what I had in my design (Vectric Aspire). The stickout was 30mm, quite a big one. Then, I decided to reduce the stickout and the quality improved, but not as much as I wanted.

After that, I used the following settings, but the resulted item is 0.5mm smaller than this in the design:

3.175mm spiral carbide end mill 2 flutes,
Stickout:24mm
Cut pass depth:3mm
Feed Rate 1900 mm/min
RPM: 24000

Please take a look at the 1st attached photo in the red rectangle area. This area is 8.5mm width in the design but the resulted piece is ~8.0mm.
The tool I used is from China and is carbide end mill. The material is soft wood (european linden) and it is 18mm thick.

Except from the fact that the resulted item deviates almost 0.5mm from the design in Aspire, in 2nd and 3rd attached images you can see that the cutter leaves a line per pass along the whole toolpath (6 passes of 3mm depth of cut). Even if I decrease my feed rate to 1000mm/min, I keep getting this line. Even more, if I replace the spiral router bit with a straight one, the problem is minimized but it is still there. These lines are like steps and I can feel this "stepping" with my finger.

Could you please advise to where I need to pay attention for these two problems? Could this be caused by material's vibration? I have to tell that I mount my material with screws in my mdf table and also apply hot glue. Also, I measured my machine's accuracy and it is OK (~0.03mm repeatability).

Thanks in advance,
Kostas.