Extruder pattern

New hotend is producing striations in a regular pattern.

The below shows two calibration cubes. The top one is printed at 0.1mm layer on my old hotend and has nice lines. The bottom cube is printed at 0.2mm layer height on a different hot end and has a pattern on all four sides.



Any ideas what could be causing it?

Check Josef Prusa's calculator for the optimal layer height for your Z axis. If 0.2mm does not work out to be a number of full steps for your printer, that's where the error may be being introduced.

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Seems to be fine. I'm doing 0.2 which is exactly 50 steps according to the calculator. I just popped back to say the problem might actually be the nozzle on the hotend. I extruded some material into the air and then measured it with a micrometer. It was coming in at over 0.5mm wide. I'd expect it to be much closer to 0.4mm for a 0.4mm nozzle. So I've switched in a new nozzle and it seems better.

Being a genius of course I changed a bunch of things and the machine is not printing right now, but I'll know more later

I should probably ask... Actually I'll do that on a new thread.

I experience that myself a few times, it's a result of your extruder stepper motor being overpowered. The problematic nozzle may have increased friction. Each raised point is the point of whole step in the motor, the friction/resistance keeps the off-whole steps from being accurate in their lower torque.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

At least, that's what caused it for me each time.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Could well be a contributing factor actually. I had a lot of issues early on with my extruder and it runs at quite a high voltage compared to the other steppers. I'll turn it down and see if that has an effect

The doctor was on to something, although it wasn't over powered, the stepper driver was actually faulty. For anyone else;

It was driving the stepper around in sharp steps rather than smooth motion. Last night it stopped extruding altogether, it would if I pushed on the filament, so I thought it was clogged. Checked the voltage, was just about to strip out the hot end when I thought I'd try a new driver module. Bing, all working.