Wavy surface problem.

Hiroaki

Hello.
My printer is work with linear guides and belt Core xy.
So everything moves smoothly.
But when I make a cube, XZ surface become very beautiful but other surfaces become wavy.
Is this because of working with belt or are there any other reason ?
I have two printers, one is small and one is bigger, but the both printers make the same result.
Regards

mrehorstdmd

@hiroaki Photos would help to diagnose the problem(s)...

Hiroaki

This post is deleted!

Hiroaki

@mrehorstdmd Hello
The best surface is like this.

And the other surface including reverse side of the best one look like this.

mrehorstdmd

@hiroaki That looks like ringing- it's caused by the moving mass combined with flexibility of the mechanism and the springiness of the motors. Generally fixed by reducing acceleration and/or jerk and/or speed, but belt tension and motor current can also affect it.

The corner look a bit blobby, too- that's usually fixed by using pressure advance.

Hiroaki

@mrehorstdmd said in Wavy surface problem.:

That looks like ringing- it's caused by the moving mass combined with flexibility of the mechanism and the springiness of the motors. Generally fixed by reducing acceleration and/or jerk and/or speed, but belt tension and motor current can also affect it.
The corner look a bit blobby, too- that's usually fixed by using pressure advance.

Thank you so much.
Can you please explain me in the different way for the last sentence.: that's usually fixed by using pressure advance. Sorry my English is not good enough...

mrehorstdmd

@hiroaki Pressure advance anticipates the XY motion slow-down at the corners and backs off the extrusion a bit so that you don't get over-extrusion in the corners, among other effects.

tpra

@hiroaki even on the first picture you can see the waves on the opposite side.
It doesn't look like ringing to me.
Ringing has a decreasing amplitude, it's not regular along the whole straight line.

I'd be happy to know what it is though, because i have the same kind of problems on my last printer and it's driving me crazy.
What's weird is that i have never seen this before on any of my other duet printers

Have a look at this thread :
https://forum.duet3d.com/topic/4246/vertical-banding/37

Can i ask the reference of your motors ?

ZipZap

I don't think its ringing either.
Can you measure the pitch of the waves? If it matches the pitch of your belt, then this is a possible cause.
I had a similar issue, until i switched to genuine GATES-belts. Chinese belts seem to always be a little off regarding the profile of the teeth.

/Julien

tpra

@zipzap i'm running genuine gates belts and idlers, and i paid a lot of attention to how they are mounted.
I mean : they are so straight and aligned that the belts don't even touch the pulleys and idler flanges through the whole movement, on X and Y.
Honestly, i'm not a professional, but i'm what you would call a maniac, my machine and mechanics are really clean. I have built more than 20 different printers, entirely designed a toolchanger (funX4), i have other machines perfectly running without this problem.
I know everyone makes mistakes, but i spent so much time on this...
Pitch of the waves is variable, i'll take pictures

Clearly, switching the XY from E3D pancake motors to some other slightly bigger 0.9 steppers that i had (from OMC) made a difference.

I also run the e3d pancake on extruder, so i just told myself why not... and i installed a very old super slim 1.8° pancake i have on shelf... quality is much, much better, but still not perfect.

Playing with microsteps also seems to have some effect, but very small.

At this point i'm a bit lost i think i'll just order the motors pointed in the post i linked above, and see.

#edit : forgot to mention : one very noticeable thing when switching motors is the sound. it's just the right sound now. before it was all vibrating. Current was set to 80% of steppers nominal current, double and triple checked and maybe more, i tried less, a lot less, doesn't change anything.

Hiroaki

@mrehorstdmd Hello. Thank you! I will check how I can set it.

Hiroaki

@zipzap Hello The pitch of the wave is 2 to 2.1mm.
So It seems a problem of the belt. I see...
Thank you.

Hiroaki

@tpra The bigger printer has 1.8Degree/step and the smaller one has 0.9degree/step. But both are not perfect.
As somebody said, it seems
1.Belt
2.Current is still too high.
....
I will try fixing it and come back with the answer!
Thank you

Hiroaki

@tpra Hello.
From your experience which is better
1.Core XY (By belts)
2.Lead screw or Ball screw.

I have never made one moving by lead screws, so I just wondered,

If you have a experience of making one (or some) screw version, please give me your idea.

Hiroaki

@mrehorstdmd
Thank you so much!

mrehorstdmd

@hiroaki Small diameter smooth pulleys can cause bumps in prints if the belt teeth are contacting the pulley surface. If that is the problem here, it can be fixed by using toothed pulleys, or by replacing the small smooth pulleys with larger smooth pulleys, or by twisting the belts so that the smooth back sides of the belts contact the smooth pulleys.

If you change the pulleys sizes, you may also have to change their positions in order to keep the belts parallel to the guide rails.

Hiroaki

@mrehorstdmd Hello Yes, both my machines have toothed pulleys for the location belt teeth touches and toothed idler for the location belt teeth touch and smooth idler for the location back side of belt touches. So they seem it's ok. I wondewr if the pulleys located with motors are may be too small. ...

Hiroaki

@mrehorstdmd Hello I think you were right.
I have changed the motors to better one and now getting better, still not perfect. But I will change the belt to genuine lately and check.

tpra

@hiroaki said in Wavy surface problem.:

@tpra Hello.
From your experience which is better
1.Core XY (By belts)
2.Lead screw or Ball screw.

I have never made one moving by lead screws, so I just wondered,

If you have a experience of making one (or some) screw version, please give me your idea.

I couldn't tell if belted coreXY is better than leadscrew i never tried an XY on screws!
I've had the idea to build a machine with Igus high speed lead screws, but budget's not here atm

I'm still struggling with those vertical bands artifacts. It's really driving me crazy. I changed pulleys, rails, belts, tried another PSU, 3 different sets of steppers (from the pancake to the big boys), every possible microstepping combination. Nothing to do.

Now i really have absolutly no idea where the problem comes from.
The only difference i see is all the machines i have that run correctly run rrf2. This particular one runs rrf3. I don't see why it would make any difference though

o_lampe

@hiroaki said in Wavy surface problem.:

@tpra Hello.
From your experience which is better
1.Core XY (By belts)
2.Lead screw or Ball screw.

User @mendelevium has a leadscrew driven CoreXY, he might be able to tell the pros and cons?

@tpra said in Wavy surface problem.:

The only difference i see is all the machines i have that run correctly run rrf2. This particular one runs rrf3.

We all cross our fingers, that there's no backdraw using RRF3, but may I ask you a favor and print one of those with a printer running RRF2.x ?