Seeking some advice. These were printed on type A machine. One at 25mm/s and the other at 60mm/s I thought the ringing was because I ran it at 60 but reducing to 25 didn’t solve the issue either…
The ringing only happens on the x axis so both front and back of the circle had ringing but not the y walls… Could it be that my x belt is too tight?
Ringing can be reduced or made more prominent due to accel and jerk settings. You can print at 50 or 500mm/s but once you approach sharp changes the printer will decelerate and move and accelerate according to its settings. That’s why slicers don’t usually get print times perfectly right. Could be the belt too tight but if you have access to the printer’s firmware I would mess with the settings. Typically Cartesian printers are almost impossible if not impossible to get rid of all the ringing.
That’s not ringing. At least, most of it isn’t. Most of what you’re seeing there is the x/y resolition of the machine. It could be skipping microsteps due to a bad driver current setting, or maybe it just doesn’t have enough steps per mm (hard to tell exact scale).
Could also be the resolution of the STL, or an artifact of buffering or too many segments. Firmware will drop segments that are too close, most slicers will too.
In a circular part like that ringing will be virtually nonexistent. Check your gcode with a visual analyzer for artifacts.
@Stephanie_A That’s what made me concerned about it. I never get ringing on round parts aside from a little where it moves up a layer or to another shell.
It looks like aliasing to me, a possible artifact of steps being too coarse. But if it doesn’t show on Y, maybe try adjusting tension.
Do you have the stepper driver and motor specs or part number? I’m thinking stepper ripple due to missing microsteps. Really common with 8825s, can happen with 4988s too sometimes. I just don’t know what your machine has in it.
I can confirmed that it’s not the STL. when I did the second time I actually rotate the model 90deg so the side that showed ripple on the first one actually came out really smooth on the second one.
@Ryan_Carlyle it’s the original A4988
Not sure if you use marlin as firmware. The new version supports the advance mechanism aka jnk feature. Would u be able to test that and see if it reduces the ripples. For those who don’t know jnk, it is adjusting the extruder flow when accelerating or braking the x y movements.
It’s definitely to do with current on the stepper motors … there is a fix for this that’s electronic by adding little stepper motor current stabilizers that will remove the harmonic noise through the motors. I need to do it on my printer too. You can google it.
I’m betting that you have a different pulley ratio or microstep settings between your X and Y axis. That definitely looks like your X axis doesnt have the same resolution as your Y axis and the firmware is rounding coordinates to the nearest step it can accommodate. The bullseye pattern being circular across all the layers on the curve is a dead giveaway. Electrical noise or loose belts would be less likely to produce a pattern so consistent layer after layer.
My printer has twice the resolution on the x axis due to the manufacturers mainboard design. I havent gotten around to taking the soldering iron to the board to make the axis identical so i am very familiar with the appearance of this pattern on some of my prints.
If it’s a microstepping current problem, which I am 75% confident of at this point, you can confirm by plugging the motor specs into my stepper driver simulator: https://github.com/rcarlyle/StepperSim
Lots of nice printers have ripples like this at low speeds because of driver/voltage/motor mismatch. Ultimakers and Airwolfs for example.
The fact that it’s happening on X but not Y could mean the X stepper current is set wrong, or it’s a different motor that has inappropriate specs for the 4988 and PSU voltage. One common solution is to switch the 4988s to “low current microstepping mode” with a small bit of soldering. They have MUCH better current control in that mode, but all the StepStick/Pololu type drivers have it in the worse mode by default.
@Paul_de_Groot you mean JKN Advance. That won’t do anything for this problem, it only really affects corners and the start/end of extrusion at travel moves and layer changes. Doesnt affect gentle curves.
@Ryan_Carlyle Have you or anyone else posted what it takes to correct the UM2? I repaired one recently and I’m seeing more aliasing than I’d like.
@Jeff_DeMaagd For Pololu 4988s and StepSticks you need to solder-blob across resistor R4, which is the only one marked “01C”. I don’t know whether the UM2 drivers are different from that or not.
@Ryan_Carlyle OK. It looks like UM2’s drivers are integrated, so I’ll have to trace out the configuration pins. What driver mode is supposed to be best?
@Jeff_DeMaagd Pull ROSC to ground to use low-current microstepping mode. Recommended for 16-24v printers. The default 4988 mode is usually fine for 12v but it really depends on the motor inductance/resistance.
Oh, that’s easy, now that I’ve found the schematics and know this tidbit. Thank you.
Contacted the type a machine support and they recommend setting the stepper driver current from 0.03v to 0.44v. we’ll see if this fix it.
Ok so I checked with multimeter at the x was 0.31v per type A machine support it should be 0.44v to be optimal. So I did that and problem still persist…
Has anyone tried mix matching stepper driver? I wonder what happen if I swap the x driver with DRV 8825 and leaving the rest as A4988…
