Got the build all done, and fired it up. Z would only buzz. I was a bit worried about this as when I was building it, I couldn't turn the Acme thread by hand easily at all. It took some work unlike in Mark's build video. I took it all apart, (GREAT feature of the MK3 build) and even out of the machine the Acme thread in the anti-backlash nut it was kinda tough to turn. How free should this be?
Anyway I re-assembled not really finding anything to free up. Still hummed. I then switched the pulleys around (Small on motor) It now works just fine, all-be-it a bit slower.

On to the X. without foam in the PP3 it works just fine. As soon as I put foam in it, it hummed. As I pulled up on the handle to take pressure off the foam, it would skip steps, and once almost all the pressure was off of it, then the X axis worked normally... all-be-it, it wasn't moving foam. Without foam I can put a fair amount of pressure on the rollers before they skips steps. I also took off the pressure rollers and buffed up the ends where they go into the oilite sleeves. They spun free before, but now they are VERY free.
Could my belt be too tight?

Also I left all my voltages for the driver card set from my old MK1.5 as I had the the upgraded steppers from Mark/Trish and I thought they included the same ones with the PP3. I did notice in the video, Crash mentions cranking the pots to full. Is this OK? Back in the early MK1 days I burned up a stepper for having too much voltage.


Another question... I have the old PS that puts out 30V under load, and the fan states 24 Volts. Will the fan take the extra 6V / is it OK to plug in? Does the PS that come with the boards now put out 24V? If so could also explain why in the build video the pots are cranked to full.

THANKS in advance for helping me get this beauty going.
Dave

 

I had the board set exactly the same way as I did on the MK1.5 and I was using the steppers Mark and Trish were selling at the time. As I'm using all the same electronics except for the steppers I left the settings for stepper current ( measured voltage) the same. I guess my question is are the steppers that came with the PP3 the same as the ones they were selling before? If so I'm sticking with my settings (current) as that is what they were set at before according to the specs on the steppers.

Yea, that's what I'm thinking about the fan too. It will turn for sure... but how long. Curios what others are doing if using the old PS that we got from our original driver board.

 

Do you know what they are? I loaded the settings XML file that came with the PP3 so I am assuming those are OK
THANKS

 

That was my guess too, hence my confusion... But I am using the old power supply which is 30 volts. Not sure what the new one is. If it was lower then that may allow for the fully cranked pots. (and using the 24v fan)
FWIW When I calibrated the Y axis it was spot on just using the included setup file. Can't get one on the X axis, and since I swapped pulleys around on the Z, the included settings were off, but I got it calibrated at 30IPM

 

OK, X-axis issue solved. I was thinking about the issue on the way to work yesterday, and if someone posted here about this issue, the first thing I would reccomend would be to check the voltages...but my setup was working just fine in the old MKI.5 Then it dawned on me; I had an old original stepper on the X axis on my old PP.
It wasn't until later last night I was able to get down to the shop, but when I put a volt meter on the X, it was 1.8 volts. Being the Vexta stepers are 1.4amps per coil, (voltage would be 2 x current) I bumped up the voltage to 2.6 (went a little conservitive on this) and now the X-Axis spins just fine with material loaded.
I double checked the Z axis, and it was set properly, so I still think the issue with this Axis lies in the anti-backlash nut or Acme rod as when I had just the rod and nut out of the gantry and in my hand; the nut was rather hard to turn by hand. I'm OK with the set up though ( small pully on stepper) as I was actually thinking about this before I got the PP3 and saw the big pully on the stepper. With the small pully on the stepper, I would get more torque, and less speed; but less speed on the Z is fine as the travel is so small.

With the new settings, I air cut a large file, and the steppers (X and Z as I couldn't get to the Y) were only VERY slightly warm as were the heat sinks on the driver board.

Still waiting on the official word on the Fan.

 

Glad to hear you have this worked out and you are up and running!
We are looking into the tight acme rod
As for the fan, you may just want to get a 24v wallwart and plug that in to your power strip so that it comes on when you turn your board on. Having said that It may work just fine using the 30v ps at a max rating but may not last as long as it should. We always have more in house if you do try this and need a new one.
Mark and Trish

 

Yea this is what I was expecting. When i had my MK1.25 Kyyu made me a bearing out some sort of UHMW plastic for an Acme rod I had for the Y axis (pre-belt drive ). I was able to spin the bearing the length of the rod with a half-hearted flick. And the Y axis rod was rather long.

With the one for the PP3, it won't go a 1/4 turn with a healthy flick. I'm kinda hoping that running it the way it is now ( small pulley on the stepper) it will free it up some after time.

Hay Mark/Trish.... THANKS for looking into this.

 

Hey guys we tried all the parts tonight acme rod into the bearings with turning the acme nut on with out any problems? We thought maybe they had sent us a wrong size part but they all seem fine. The acme nut was snug but not tight. I am going to try and build another gantry system to be sure.
Thanks again
Mark and Trish

 

I just pulled my parts out to test also.
The rod slides easily into the bearings without a problem but the anti backlash nut seems way too snug for my liking. I took the spring off and ran the rod through the nut and freed it up a bit. Without the spring it moved very free, but as soon as I put the spring on it went back to being tighter than I think it should be. I will probably put a lighter spring on it or modify the existing spring so it doesn't push so much force on it.

I personally don't see why such a heavy spring is used.

 

FWIW, I ran a file last night with a LOT of tabs so the Z axis was working quite a bit. Even using the small pulley on the stepper, it was still plenty fast as the travel was so little. So for now I'm happy with the way it is working, even if it is not as designed.... That and as Yoram mentioned the motor is working less due to the mechanical advantage of the pulley setup.