Strange Moire like texture on prints [SOLVED]

3DPMicro

trying to think how you can isolate the problem. Raise the nozzle 100mm or so and extrude filament in to air at different speeds and see what that looks like, if its smooth and consistent. I would switch to a single wall cube or cylinder and continue making changes. I think this will make it easier to see the effect (or no effect) of a change

rbjam83

@doctrucker I'm printing PLA, with a 0.4mm nozzle, 0.45mm track width, 190ºC temp, 0.2 layer height.
I have tried temperatures between 170ºC and 200ºC with no difference.

Also, I got pretty excited about disabling mesh bed compensation, but it did nothing...

rbjam83

@3dpmicro I've tried under extruding till I saw holes on top layers (at 0.89 extrusion) and again, no difference on the perimeters.

rbjam83

@benkay Yes, I did that. Swapped my 0.9 deg for a 1.8 and still the same. Also disabled interpolation on the stepper drivers, no difference.

rbjam83

@3dpmicro I printed a vase in spiral mode and I don't see much improvement to be honest, here are some pics:

3DPMicro

Did you try extruding into air to see if what is coming out of the nozzle is smooth and consistent. I might even try tripping the z home switch with the nozzle 100+ mm above the bead then running a program and just see what the material looks like coming out. If its smooth amd consistent then we can be fairly confident it's in the x or y. If that looks good print a cube in vase mode (no top) to see if it's x, y or both. Need process of elimination

DocTrucker

Watching this thread with interest.

Have you tried emailing E3D direct to see if they are aware of any possible causes?

rbjam83

@3dpmicro Just did the extrusion test, and is was super smooth. So I guess I can check the extruder off the list then.

I just tried a different set of pulleys, both 20 and 16 tooth on X and Y, and again no difference.
I already did a print in vase mode, it's showing equally in x and y. So equally in fact that I'm thinking the stepper drivers just don't "like" my axis motors for some reason.
This is my first time on TMC drivers. Is there any thing else to configure in them besides microstepping and interpolation? I've got a feeling I'm missing something...

rbjam83

@doctrucker I'm starting to think this is some combination of stepper motor/driver setting issue.
The Titan seems to be fine.

timothyz

@rbjam83 Here's something to try because I have a hunch, try setting your microstepping on the extruder to 8 instead of 16.

My intuition says that that would isolate it to either the extruder, motion axis, or firmware.

-Tim

Phaedrux

How recently did you get the Titan Aero? Older batches had issues with bearings failing and causing all sorts of intermittent problems. Do you see any rust like residue around the bearings? Does it ever make any clicking or squeaking sounds?

E3D will send you replacement bearings free of charge if you request them. Made a world of difference for me.

I would also try increasing your motor currents for X and Y to 85% of their rated max.

rbjam83

@timothyz Just printed two more cubes, in one X and Y were set to x8 microstepping without interpolation, and on the other, I did the same with the extruder motor. Nothing. No change.
But I'm reading other threads about more in depth settings of the stepper drivers. I'll try some of those later.

rbjam83

@phaedrux I bought the Titan just three weeks ago from Filastruder. I'ts already from the new batch and the bearings are fine.

timothyz

@rbjam83 Have you tried upping the current to 1.4 or even 1.7 as rated? If you don't drive with enough current, I think steppers tend to cog more, you really need current to microstep well. (Anyone correct me if I'm wrong)

Phaedrux

@timothyz said in Strange Moire like texture on prints:

@rbjam83 Have you tried upping the current to 1.4 or even 1.7 as rated? If you don't drive with enough current, I think steppers tend to cog more, you really need current to microstep well. (Anyone correct me if I'm wrong)

I would agree. I get smoothest motion when driving ~85% of rated current as recommended by the setup guide.

rbjam83

@phaedrux FINALLY!!
It was the motor current that was too low.
I never would have guessed it, since I was operating on the "but I print slow" mind set.

Thanks everybody! It really was quite the learning experience for me.

Now I can go on with the rest of the tweaks...

3DPMicro

@rbjam83 that was the my first question
Looks good now go have fun

dc42

I'm glad you solved it. Microstepping is not accurate at low motor currents, because of the interaction between the detent torque and the torque resulting from current.

Can you tell us the rated current of the motors, the current you were using originally, and the current that resolved the problem?

rbjam83

@3dpmicro I know. And I did increase the current from 800mA to 1000mA and got no improvement. As I said, I had the wrong mind set about this. I was doing incremental changes when I should have gone bigger.

rbjam83

@dc42 The full spec of the motors are as follows:
Steps / mm: 200
Rated Voltage: 3.4 V
Rated Current: 1700 mA
Phase Resistance: 2 ohms
Inductance: 3 mH
Holding Torque: 40 N

Initially I was using 800mA when the issue fist presented. I then increased it to 1000mA to no effect. It was only when I went to 1400mA that the texture disappeared.