If you didn’t adjust the voltage on the mini rambo that stepper should be smoking hot as is.
Well it running cold. I didnt adjust anything but the steps. I havent run it very long. Maybe 10 layers at the longest.
Looks like your steps are off a bit.
Snagged from E3d’s site, highlights are mine;
Firmware Calibration
Because Titan uses a known gearing ratio and a consistently machined drive gear, we can offer a fairly accurate steps / mm set-point.
Steps per Unit (Extruder) = Motor Steps * Micro-stepping * Gear Ratio / (Hobb Diameter * Pi)
Standard motor steps / rev = 400 for the new style motor or [highlight]200 for the old style motor[/highlight] (Refer to assembly steps if unsure which motor you have).
Standard micro-stepping = 16x
Gear Ratio = 3
Hobb Diameter (Effective) = 7.3
[highlight]200 * 16 * 3 / (7.3 * 3.142) = 418.5[/highlight]
400 * 16 * 3 / (7.3 * 3.142) = 837
To test your value, mark the filament 120mm from the extruder then extrude 100mm slowly. If you do not measure 20mm after extrusion has finished, you may need to tweak this value.
Yeah i just check my calculator and i had 418 on it and some change. But after talking with ryan i decied to run the test again and its only putting out about 50.
Now this was right after trying a cube and letting it run for a few layers. So its either slipping which it dosnt seem to be, its got a firm grip on the filiament, or something isnt working well with the motor. Maybe the voltage isnt right. But the motor dosent seem to get hot
An error in the z could also cause problems, because it would be trying to fill a space that’s twice as big.
Well it’s something that’s happening after the motor has been running for a little bit. I ran the test again cold. Passed, Ran it again. Passed. Started printing a block. Let it run maybe 10 layers. Stopped ran the test again, failed, under extruded by more than 50mm.
Try this I think it is still too high but it is half the power to that tiny little z stepper. It should at least print longer until the heat kicks in.
MP3DP511_MRambo_halfZ.zip (763 KB)
Thanks, Seems to be working now. I was looking at the section of the firmware and couldn’t figure out which one was the extruder and then I wan’t sure what to set it too.
Is it just my machine? But I had to change the steps for everything and e and z are backwards.
- Default Axis Steps Per Unit (steps/mm)
- Override with M92
-
X, Y, Z, E0 [, E1[, E2[, E3[, E4]]]]
*/
#define DEFAULT_AXIS_STEPS_PER_UNIT { 100, 100, 200, 418 } //MPCNC
this is what I changed it to.
That looks right, you made those changes to the firmware one post above? (Sorry I forgot to change the steps, I was more worried about you smoking that stepper.
Yeah, My cube came out 10mm to small. Opps. Look like that z needs to be 400…
Edit.
I’m guessing the only reason it worked last time was because the z was moving half as much as it should have.
So with the z fixed i’m having the same issue I had before. I’m guessing i’m going to have to throw this stepper in the bin, and figure some thing else out.
Any chance that the thermostat is reading wrong?
Fedex is due with my shipment in the next 2 hours. I will build a test one ASAP, with a rambo and let you know shortly.
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It is a different thermistor, it is not the #11 I use on the MK8 I believe it is a #5.
The firmware is set for the extruders I sell, all the setting have to be changed. E steps, thermistor, driver values. I saw a post that showed your firmware didn’t stick but now it is gone, with the rambo you need usb, and power to flash it properly.
Yes, i changes it to 5 and have power when i flash it.
If the thermostat is wrong, that would certainly cause underextrusion. I have been wanting to measure the temp of the hot end for a while, but I don’t have a good way to do it.
I have the tools at work to do it, but i dont know how they would feel about me taking them home.
Well, they are here. But now I have to wait on a spacer to print…you would think that they give you extra screws they would include the necessary spacer…
Do you have any way to print one? 
My bad, ig i was thinking i would have told you about that. Its a short print anyway.