Quote Originally Posted by Juranovich View Post
Also- I AM THE LAW!!!
No No No I'm most definitely more THE OUT LAW.!!

Quote Originally Posted by Juranovich View Post
Just to get my head around this- if 1m/min and 750rpm are good values for general wood working, what would be the sweet spot for detailed work (eg 3D engravings in wood) or the occasional aluminium job?
Well not sure where your getting 1m/min from but giving specifics for sweet spots for things like 3D work isn't really possible because it's material and cutter dependant, plus 3D work requires a slightly different machine setup to get the best from it.
3D work tends to be lots of really short fast moves with very light depths of cut, so you tune the machine differently and biased more towards acceleration than speed if doing lots of 3D work.
Velocity is not so important for 3D because the moves are very short so even if you had a High feed rate set you'll never actually reach that feed before your at the end of the move and onto the next. So to increase the feed rate it's actually better to lower velocity and increase acceleration. So now the machine can accelerate faster and reach a higher feed rate before the next move comes around.
Because of the nature of 3D jobs being made up of lots of short moves a properly setup machine can shave hours off a job. The simple rule is that you can't have both high acceleration and high velocity, setup is always a trade-off between the two.

Aluminum on the other hand just requires correct feeds and speeds based on the tool and material type and machine setup don't really play much part because the feed rates are so low compared to wood or soft materials there is plenty of torque available with a machine set up for a balance of speed and acceleration.

For instance, I have 2 different profiles one for general work with a balanced setup of speed and acceleration, the other set biased towards acceleration just for 3D work. When doing 3D work I just load the different profile and I'm set up for 3D work.

Now if you want me to make this simple for you then here's what I would use in the machines I build for general woodworking/aluminum use.

16mm Dia x 10mm Pitch screws for machines under 1000mm length with 1:1 ratio using belts to connect to motors. 20mmDia x 20mm Pitch with 1.5:1 Ratio for machine up to 1600mm.

NEMA 23 4Nm for 16mm and 20mm with twin/screws motors. For 20mm with single screw then 6Nm Nema34. Both with coils wired in parallel.
Look for motors in the 2- 4Mh inductance range when wired parallel.

50Vac or 80Vdc Digital Drives with 68Vdc PSU for Nema 23. NEMA 34 with 80Vac or 100Vdc drives. Both using Toroidal Transformer based PSU.

These are proven specs used on machines I build which are used for cutting materials ranging from cardboard to Aluminium and Brass on a daily basis working 12hr plus days 7 days a week in some cases.