Re: Comments on this new CNC

> Hi, all.
>
> I have recently received the following picture from a friend in China of a new
> Milling Machine about to be introduce in the market 2nd half of this year:
>
> http://i152.photobucket.com/albums/s172/CNCQuest/KX3-NU-Forum-2.jpg
>
> This is supposed to be a milling machine installed with 3-axis stepper motors,
> ball screws, variable speed spindle motor, limit/home switches, oil lubrication
> line/pump, and J7325/ISO50 milling chuck ready to be converted to a CNC milling
> machine with end-user provided CNC control system.
>
> The end-user will just have to install stepper drivers and hardware/software
> controller to turn this milling machine into a CNC milling machine.
>
> Can I have your comments whether this will be a good choice to turn it into a
> CNC milling machine?
>
> TIA!
>
> Regards,
>
> WT

Looks like a genericmachine that's produced over there but two things I'm concerened about given I have seen some of the various machine siliar to this and parts.
One is the ball screws, so far unless we are talking new suppiers their cheap ballscrews leasve a lot to be desired.
I have seen some with more play than a decent acme screw, this may be latering but it's hard to judge from a picture.

Secondly and more important is the motor / drive combination.
In an effort to cut costs this is single belt driven from a 1,000W motor with a variable speed board, the earlier ones were DC, later ones 3 phase AC and cheap invertor or VFD.
They give a speed range of 100 to 3,000 and it's not possible to get WORKING speeds over this range.
What happens is you get no torque down the range where you need the torque for large slow running cutters.
Sorry just a fact of life.
Only way to hget tourque at lower revs is to gear down by gears or belts to increase torque or do like the big boys do fit 30 HP motors because they know when throttled back they will have a
useable 10 HP for the cutter.

The Super X3 has this same drive on it and it's crap. It can't drive a large cutter at the speeds the cutter requires so you either have to go faster and burn the cutter out or take tiny cuts so as not to stall.

Unfortunatly this is were marketing and costing takes over from practical experiance.

John S.