Again a big thanks to everyone for the feedback on my previous threads.

Here are my first few tests of the steppers motors in action --> YouTube - CNC X, Y, and Z Steppers working.

The steppers motors are powerful at 72v & 2.8A drivers I'm not able to slow them or stop them even at 750IPM (Machs highest limit.) Though I didn't check how many steps were lost, and I probably only applied about 50ish pounds of force when testing.

What rapids to most people set? any recommendations on how to figure out my highest IPM I should use?

I itch for an bigger table now, should have gone for the X3! Now I understand why everyone says CNC is addicting!

Setup
Keling KL-8056 Drivers max 80v, 5.6A.
Keling KL23H286-20-8B Stepper motor 425 oz-in, X & Y in Bipolar(P) and Z in Bipolar(S).
Keling KL- 7212 powersupply 860W, 72VDC/12A.

Looks good! Just curious though: Why do you have the Z motor wired Bipolar series? It should work even better wired Bipolar parallel.

CR.

Looks good! Just curious though: Why do you have the Z motor wired Bipolar series? It should work even better wired Bipolar parallel.

CR.

I too thought the same also, then came across this http://www.kelinginc.net/KL-11078.pdf

Series Connections
A series motor configuration would typically be used in applications where a higher torque at lower speeds is required. Because this configuration has the most inductance, the performance will start to degrade at higher speeds.

Parallel Connections
An 8 lead motor in a parallel configuration offers a more stable, but lower torque at lower speeds. But because of the lower inductance, there will be higher torque at higher speeds.

At the time I then decided I wanted more torque on the mill head since I don't have any counter weight for it, as I removed the head counter spring, and figured I could live with less torque on the X, and Y but faster rapids.

But now seeing how powerful the current X and Y are, I'm sure having Z in Parallel also would easily have enough torque for the head and still have good rapids speeds (I'll have to try this configuration out soon.)

Spaceballs, I have pretty much the same setup but only with 269oz steppers and a 24v power supply. I was able to get to 240ipm and 170ipm reliably in testing stages. I now cut around 10-20ipm and rapid at 20ipm. For now this is good for me because it gives me time to hit the O**** button when I mess something up. Im not winning a race right now, but Im having fun learning without destroying to many tools or projects.

Were you moving the table @750ipm in the video. I know when I moved mine at 240 it was crazy. Touched the arrow key and the table was already at the other end. You might want to check the velocity under the coordinates, you might be able to set it for 750ipm but the computer figures if you move 8 inches your max speed might only be 80ipm so that it can come back down to 0 at the end.

With my current setup as well I have no problems at all with the z axis binding or loosing steps so I dont think you have to worry to much about torque.

And lastly I just did this yesterday but the screw that was holding on z axis coarse feed handles. If you drill it out to the same size as your allen key. You can tighten the z axis gibs just by removing the 3 screws. Keeping pressure on the large screw lower the z axis by the stepper motor and the connection point will slide down. Tighten the gibs, raise the zaxis and tighten put the 3 screws back in and your done. No need to take off the head just to tighten the z axis gib.

Good luck and have fun.

Spaceballs, I have pretty much the same setup but only with 269oz steppers and a 24v power supply. I was able to get to 240ipm and 170ipm reliably in testing stages. I now cut around 10-20ipm and rapid at 20ipm. For now this is good for me because it gives me time to hit the O**** button when I mess something up. Im not winning a race right now, but Im having fun learning without destroying to many tools or projects.

Were you moving the table @750ipm in the video. I know when I moved mine at 240 it was crazy. Touched the arrow key and the table was already at the other end. You might want to check the velocity under the coordinates, you might be able to set it for 750ipm but the computer figures if you move 8 inches your max speed might only be 80ipm so that it can come back down to 0 at the end.

With my current setup as well I have no problems at all with the z axis binding or loosing steps so I dont think you have to worry to much about torque.

And lastly I just did this yesterday but the screw that was holding on z axis coarse feed handles. If you drill it out to the same size as your allen key. You can tighten the z axis gibs just by removing the 3 screws. Keeping pressure on the large screw lower the z axis by the stepper motor and the connection point will slide down. Tighten the gibs, raise the zaxis and tighten put the 3 screws back in and your done. No need to take off the head just to tighten the z axis gib.

Good luck and have fun.

That video was when I had it tuned down, but I think your right, I'm no where close to getting 750 ipm speeds.. oh now that I think of it, I got 1/8 micro stepping on the drivers... so do I divide by 8 to get IPM? How do I configure mach to let it know I'm using mico stepping..

Hey that is a great idea to get access to the z axis gib, I'll plan on doing that!

Turns out I had my Steps per Inch (SPI) wrong in Mach, I left them at the default 2000.
Once I changed it to 8000 (5tpi screw * 200 motor steps * 8 microstep), Mach max IPM is 337.5 which works fine for X,Y, but Z will stop, after some testing it works fine at 150 IPM. This is also with the motor drivers at its lowest current 2.8A setting.

Is that the fastest Mach can move when set to 8000 SPI? Is it a parallel port limitation?

That's about right for Z if still wired Bipolar series. You just don't get much RPM out of series. You COULD come down on your Z micro steps to make it faster as-is. Even if you went all the way down to FULL step, the Z resolution would still be only .oo1 inch movement per step. Half step would be .0005 movement etc. Each added stage of microstepping steals speed.

Max Mach pulses depend on processor speed. How fast is your computer?

CR.

Yeah 8000 Steps per Inch is likely unnecessary, I'll prob change the microstepping down and see what it does on speed. Also I'll rewire the Z from series to Parallel.

Processor is Athalon 1.8ghz, EPP\ECP Printer Port, Clean XP with 1gb ram.

Here's some rapid speeds illustrated. This is a Sieg KX3 with Nema 34 566 oz on X and Y and 850 oz on Z:


http://www.youtube.com/watch?v=-RaEThG0I0A&NR=1

http://www.youtube.com/watch?v=OjAS2t9fXxs&NR=1

That will sure gitter done!

CR.

Here's some rapid speeds illustrated. This is a Sieg KX3 with Nema 34 566 oz on X and Y and 850 oz on Z:


http://www.youtube.com/watch?v=-RaEThG0I0A&NR=1

http://www.youtube.com/watch?v=OjAS2t9fXxs&NR=1

That will sure gitter done!

CR.

Thats impressive! This will give me something to aim for! once I get my Z bearings replaced (just picked up an set today.)

What power supply does that setup use?

I don't know. The motors are 6 amp. Most stepper motors fall into the 36-50 volt range though. I would guess that it's 48 volts and 15-20 amps. The specs claim a resolution of .0004, so they aren't micro stepping much--maybe only 1/2.

Oh, and those ballscrews are only 4mm per revolution, so about 6 TPI. Those big hairy N34 motors must really be honking to drive those screws so fast.

CR.