On my xmas new 3018, I had a wicked vibration. Showed up when I was doing a spoilboard using James Dean Designs youtube as a guide. If you haven’t watched them, I strongly suggest them. Learned much from about an hours worth of time. Anyways, turns out my particular problem was due to the surfacing bit I was using. Ordered from Amazon. Was a solid, heavy two blade bit. Had to be off balance and just too much for the machine. Was sniping, chattering, and causing mass vibration.
This one. CNC Spoilboard Surfacing Router Bit, 1/4" Shank 1" Cutting Diameter, Carbide Insert Slab Flattening Router Bits Planing Bit Wood Planer Bit Woodworking Tools by BINSTAK https://smile.amazon.com/dp/B08SKYYN7P/ref=cm_sw_r_cp_api_glt_i_1ZV3BKN6J6EYWQWE3AZT?_encoding=UTF8&psc=1
I tried a different, 3 blade and runs smooth as butter, quiet and perfect.
This.
And it's also a great way to make sure your machine is trammed properly. I use a 1 inch wide flattening bit (like this one https://www.amazon.com/gp/product/B08SKYYN7P/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&psc=1).
They are out there they just don't say they can cut aluminum for some reason. As long as they use carbide inserts and you go slow. The only thing is that a 1/4" collet will experience more torque and the cutter shank could slip. Get one with a 1" cutting diameter to reduce the overall torque.
This might be good https://www.amazon.com/Spoilboard-Surfacing-Flattening-Woodworking-BINSTAK/dp/B08SKYYN7P/
This one has carbide edges and a 1/2" cutting diameter so would be much less likely to have torque problems but I think carbide inserts would be better but you could probably get away with this one: https://www.amazon.com/Magnate-Surface-Planing-Bottom-Cleaning/dp/B0093C1ZNC/