Hi all,

I own a desktop 6040 CNC router that is made in China. I have managed to make some good test boards I designed for evaluating the capabilities of my setup. However, I noticed that the tool I use (Stepcraft's V-Router 45°) has gone bad too early. The milling quality was OK for three really small test boards and one larger 40x50mm board (please see the attached pictures). Also, I am unable to use the classic cheap V-bits (30°/0.2mm) because I get rough edges from the first run. I was pretty sure that my cheap spindle was the main problem and I was going to buy a more powerful spindle (2.2kW 24k rpm 4 pole spindle) since I would like to try cutting aluminum in the future. But, other users state in some posts that it is possible to mill PCBs even with spindle speeds as low as 7k rpm if the feeding speed is kept really slow (I use 20mm/min).

So what you think is the problem here? The spindle and/ or something else? If the spindle is the main problem which cheap alternative would you recommend if you took into account that I would also like to mill soft metals in the future? Is the 2.2kW/24k rpm Chinese spindle OK for this purpose? Should I buy a separate 60k rpm spindle only for PCB milling?

I would appreciate any advice! Here is the current setup:

Machine:
CNC 6040 with SFU1605 ball screws.
TB6560 motor drivers
Backlash must be small as shown in the results (when the tool is new and sharp). I am waiting for a digital dial indicator to verify.

Spindle:
Cheap FitSain-ER11 Collet chuck CNC Spindle 24V 8000RPM (12-36V). Tried feeding it from 20 V up to 36V but I got the same results. In the attached pictures I use 30V (noticed less vibrations). Actual RPM has not be verified yet.

Tools used: Genuine Stepcraft's V-Router 45° (success but premature tool wear) and classic cheap V-bits 30°/0.2mm (can't mill at all).

Software and settings:
Flatcam & GRBL.
Feeding 20mm/min.
Rapid travel speed 100mm/min.
No auto leveling used until now. I manually verify the board's level before starting the milling process.
Milling depth 35 ?m.
4 passes and 40% overlap.

If you need further information/ pictures please don't hesitate to ask.