Z artifact that's time/speed related

Phaedrux

If you send M307 H0 in the console, what does it reply back with?

screwyluie

@Phaedrux said in Z artifact that's time/speed related:

If you send M307 H0 in the console, what does it reply back with?

M307 H0
Heater 0 model: gain 90.0, time constant 700.0, dead time 10.0, max PWM 1.00, calibration voltage 0.0, mode bang-bang, inverted no, frequency default

I have tried so many things and so far nothing has had any effect on this... I've gone over and replaced basically all the hardware that could affect it except the duet... I'm wondering if I should get a different board and swap it out to see if that fixes it

Phaedrux

As I suspected you're using bang Bang mode for the bed. I suggest changing to PID mode and do an auto tune of the bed heater. This can help eliminate changes in the bed shape due to the heater which can cause issues as you're describing. Worth a try.

https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control

screwyluie

@Phaedrux said in Z artifact that's time/speed related:

As I suspected you're using bang Bang mode for the bed. I suggest changing to PID mode and do an auto tune of the bed heater. This can help eliminate changes in the bed shape due to the heater which can cause issues as you're describing. Worth a try.

https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control

so as a quick test of the theory I just disabled the bed heater and put down some glue instead and what do ya know.. it worked. Now read that link you sent and figure out how to setup PID and hope it doesn't do the same thing. I can't thank you guys enough for the patience and help provided.

Phaedrux

@screwyluie said in Z artifact that's time/speed related:

Now read that link you sent and figure out how to setup PID

This may help: https://duet3d.dozuki.com/Guide/Ender+3+Pro+and+Duet+Maestro+Guide+Part+4:+Calibration/40#s161

jmshep

Now you have established that the fault is connected with the bed heater and it is in bang bang mode it may be that it is a power supply issue?
It could be that when bed heater switches on, the voltage dips and causes the problem. The solution would be a new more powerful power supply.
To test this you would need to connect a volt meter to the 12v (or 24v) output of the power supply and watch the readings. (I doubt the Duet voltage reading will respond fast enough).
PID tuning may mask the problem because the heater is not being switched from 0 to full power all the time as is the case with bang bang.

droftarts

@jmshep said in Z artifact that's time/speed related:

PID tuning may mask the problem because the heater is not being switched from 0 to full power all the time as is the case with bang bang.

Actually, it IS being turned on full power, and off again, just very quickly, with a MOSFET. It’s not able to vary the voltage.

@screwyluie But yes, I’d suspect an under-performing PSU, or an underpowered one, that’s causing voltage drop issues, such that the hot end can’t maintain temperature. Do you notice a variation in hot end temperature? Have you tuned the hot end with M303?

But could also be the bed warping while heating. Check bed thermistor is making good contact, as if it’s not, the actual bed temperature will swing more than the thermistor is reporting.

Ian

screwyluie

@droftarts said in Z artifact that's time/speed related:

I’d suspect an under-performing PSU

I will test the psu to see if that's the issue, but i think on paper it should be fine:

24V 16.7A 400W LED Driver Switching Power Supply （SMPS）110/220VAC-DC24V Transformer CCTV Monitoring power supply Industrial Power from MEISHILE

is what I have on hand. I don't have a screen or anything extra on the machine just the duet, e3d v6, bed, and motors.