[skray775]

Mike,
I have been following your conversion. Great job!!!

I have been talking with Mr. Li at DMM and he also agrees that the 400 watt system will work on all 3 axis.

I like the versatility of the belt drive and would rather spend the extra time building it then being locked into the direct drive. The numbers shake out the same anyway.

I plan on ordering them soon.

To give you an idea of the minimum required to make the MD001 move, I used (and still am using) the 50oz-in continuous rated Nema 23 servos (350oz-in peak) on the X and Y axis with 4:1 reduction (ie 200 oz-in at the screw neglecting friction loss) and 5mm lead ballscrews form linearmotionbearing2000 on ebay. For the Z axis I started out with the same nema 23 servo and a 5:1 reduction (ie 250 oz-in at the screw). I was able to run it this way for a while but I had to have the acceleration dialed back on the Z, mostly due to tight spots at the top and bottom of the travel. I've since changed to a 119 oz-in (600oz-in peak) and I gained a little bit of acceleration.

Personally the 400w servos are what I'd choose, unless going with direct drive and larger servos can save enough money to pay for themselves (1 belt and 2 pulleys per axis plus additional brackets versus a coupler for direct drive). Looks like the encoder is suitable for direct drive (12 bit accuracy ~ 4000 counts/rev @ .2" rev = 0.00005" )
Checking out the pricing it looks like it can - the high torque servo & drives are only $48 more than the 400w servos & drives.

Mike