Originally Posted by
reg.miller
I have a pretty similar combination. Running on domestic single phase 220V supply.
Where does that 6000 rpm come from, experience or spec ? I got a fairly complete manual with the VFD but NOTHING with spindle.
With hindsight I realise I did not research this properly. I did some chip load calculations to get HP and 2.2kW seemed good. I bought a spindle / VFD bundle so assumed the supplier had matched them correctly.
I can cut ali at quite good rates: 2mm cut , 3mm deep at 3mm/s , that is limited by machine rigidity more than anything else. Some times tools bog up if I don't baby sit the machine , prevent chip build up and squirt it once in a while.
However, when I'm drilling at slower rmp the spindle often stalls. I'm OK at 4mm or 5mm but above that when rpm comes down it stalls at the slightest snag. That usually gets messy unless I get to the E-button quickly. ( Which is a pain to reset work afterwards ).
From what I've been reading here on CNCZone, it seems it is the spindle which is weak, not the VFD.
There's a metric ton of parameters on these VFDs, so maybe I'm not set up optimally to get best torque at low speeds. I have not changed defaults for PD11,73 but it seems this is a kind of override to prevent the control voltage setting some speed known not to work. I need to determine the best set up before doing that.
At the moment the best I can do is use the CNC to to drill accurately placed pilot holes, then pull the work of and drill larger diameters by hand drill or pillar drill. This is crazy because I probably only have 800W motors on those drills but get loads more torque for drilling.
I chose a 24000 rpm spindle which I don't really need that often since I don't do much wood or really small diameter work. I guess on the odd occasion, it becomes essential so probably was not a stupid mistake.
Is this asking too much from one spindle or can this be set up better ?
TIA.