This post is kind of long, so if your lazy and still want to help there is a TLDR at the bottom.
My plan is to CNC a X3 from Grizzly while still keeping the stock ACME leadscrews. I will probably update this later with ballscrews but for now my plan is just using most of the stock components from the X3 and retaining manual use. (side note, would the opto-isolation on the Step/Dir pins of the G203V drivers make it so spinning the motors by hand and thereby producing a voltage would not damage the drivers or circuitry?)
First off is the PSU. I have three options here: converting either a 70V @ 17A or a 48V @ 12A transformer. Or I could purchase a 48Vdc 8.3A transformer PSU. The kelinginc power supplies (the cheap ones) do not have enough amperage for the motors I would like to get, but based on those motors the 70V power supply is too much voltage, although I could just add in some resistors to lower it and still have a great PSU for future use.
Next up is the BOB. I have seen the most common two recommendations, in order, are the PMDX-132, the C11G. It seems to me the PMDX board is better overall and I love the fact that I can use 110VAC for power. Its downfall is that it costs at least another $33 for a c6 board for spindle control and its already the most expensive. The C11G seems very up to the task and already has spindle control built it which is a big plus at a cheaper price. I am leaning towards the C11G but I would like any input on a recommendation for a BOB.
I have pretty much decided on the Gecko 203V drivers. After looking over the specs and comparing it with others it is by far the most capable driver and maximizes stepper output. Its downfall is the cost, but I have no problem spending that on a quality driver and supporting new innovation of that sort. Although it might be much more cost effective to use a G540 if I can find a proper Z-axis stepper...
I have picked out a few motors from Keling inc (who seem to have the best selection for the price and I am happy with previous purchases from them). For the Z-axis I have chosen the Nema34 KL34H280-45-8B which has 640oz/in or torque at 2.2mH of inductance, and for the X/Y-axises the KL23H284-35-4 which has 387oz/in torque at 2.8mH of inductance. Depending when they are available (hopefully soon) I would much rather have the KL23H2100-50 on the X and Y axises. The website says its in development and boasts 570oz/in of torque at 2.5mH of inductance all in a Nema23 frame!
To control the machine I am leaning towards using timing pulleys on all 3 axises. This will free me up to use the manual side of the mill without needing the high precision of the direct drive (and not needing to buy pre-made mounts). I will keep it at a 1:1 ratio because the steppers I chose will hopefully be able to push it well enough on the stock leadscrews (I know people have used them for ballscrews, not sure on ACME). The main advantage here is keeping the motors out of the way.
TLDR:
CNC'ing an X3 with planned:
48V@12A or 70V@17A (resisted to less than 50V)
PMDX-132 or C11G (prefer 110VAC of PMDX but want the spindle control of the C11G)
Gecko 203V or G504 (pending the finding of a 3.5A ~600oz/in stepper)
pulleys on all 3 axises with a 1:1 ratio
:TLDR
Please post any recommendations/preferences you guys might have on any of my choices, thanks!
List so far (in USD):
1x PSU_____________= 71 or 110 (depending on how powerful I go)
1x C11G/PMDX-132___= 109/183 respectively
3x 203v____________= 417 (289 for a G540)
1x 640 stepper______= 89 (what to do with this if using a G540?)
2x 387 steppers_____= 98
pullys/belts______~ 50? (no idea yet really)
===================================
__________________ = 834-947
P.S. Does anybody have any experience with homeshopcnc? They have $73/76 single/dual shaft Nema23 motors with 570oz/in of torque at 2.3mH with 203V's at $129. That looks like a better buy and they have the 570 steppers developed already.