Problem with ripples

Hello,

I just got my robo a couple of days ago and have been following a lot of advice on the forums. I managed to get a .3, .2, and a .1 layer height print completed, but all of them have a weird rippling effect on them. Regardless of the layer height the ripples are always the same size. I've attached an image of the .1mm print to show what I mean.

Note: I have also tried 0.2046mm and 0.1058mm layer heights, looks the same.

Any help at this point is greatly appreciated.

General settings:

1.75mm PLA
180 nozel temp
print speeds have been tested varying between 20 - 60 had no effect.
varying infills from 0 - 0.4 and using linear and honeycomb had no effect.

 

Not the first time wee things like this here.
Are the belts thight so they don't jump over teeths?
Are the pulley fixed good enough on the motor axis?
these are the 2 things than come into my mind at the moment.

 

Belts jumping over teeth would not cause this consistent and symmetrical a ripple right? Is the ripple symmetrical all the way around?

What is the approximate diameter of that print? Do you know what firmware you are using? Repetier should output this when you connect to the printer or you can manually give it M115. Mine which is the latest Robo supplied firmware gives:
09:42:41.625 : FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:http://www.robo3d.com PROTOCOL_VERSION:1.0 MACHINE_TYPE:RoBo 3D EXTRUDER_COUNT:1

 

M15 is a Gcode command that you can type in on the manual tab. The firmware version will be output in the status are at the bottom.

 

Yes but some said that this was caused by a loose belt, there was a huge discussion about this, and the non metrical rods, and so on, some say it's the belt or wahtever (they solved the issue with fixing that) some say they solved it by switching layer height.

 

Hi Polylac, Thanks for mentioning that thread. The loose belts really don't convince me here although he definitely should check them. The photo really looks too symmetrical and repeated. The X and Y belts would have to skip repeatedly in weird synchronization to cause this.

If that print is an inch or so in diameter and height then that is really a huge amount or ripple. So I don't think the non-metric rod Z heights that he tried would help.

 

The ripples go all the way around the model.

The wavelength is about 1.33mm and consistent the whole way up the model. I'll double check the belts when I get home, I checked them earlier and they seemed tight. I'm unsure of the firmware, I'll check that as well, it likely needs an update.

I figured it's a software problem simply because of just how consistent it is. But I'm new to all this.

Thanks very much for the suggestions I'll post back as soon as I've tried these changes.

 

I printed something using Repetier 0.90d looked good. Then I upgraded to Repetier 0.90f and my prints were ugly. The higher it printed the layers were getting higher and higher. Stringy stuff all over the model. I thought it was my bed and nozzle level issue.

Then I decided to not change the level bit the version of Repetier back to 0.90d and it's printing smoothly.

What version are you using?

Try 0.90d and go thru the Robo3dprinter youtube setup of that software.


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Updated firmware, problem is still there.

I feel like it's probably mechanical, something to do with the Z rods. The ripples have almost (as accurately as I can measure) the exact same frequency as the threads on the Z rods.

 

Is anything loose?

 

Is the z-threaded-rod good mounted on the motor axis?
actually it should not affect the print, because the threaded rods are only fixed below and can move freely on top (otherwise they would push around the build platform)

 

This problem has plagued me since I got my printer, even though my belts felt tight I tightened them a little more and this helped a lot but aslight ripple is still there. I have checked everything and the only thing I can find is that if I hold the carriage assembly I get no movement backwards or forwards but if I gently twist it there is a considerable amount of play between the bearings and rods bot sure if anyone else has this but at some point my intention is to replace the rods and bearings to see if that eliminates the problem comletely

 

Mike, nothing feels particularly loose, I think I could probably tighten the y axis belt a little, but not by much. There's no real play in the bed when I push on it.

Ziggy, I'll check the mounts tonight, that sound like it may be plausible.

Deadwood, I'll look at the bearings as well as tightening the y axis belt.

Thanks for the advice guys, I'll post back tonight.

 

What about your smooth rods? Do they have any play in them. The supports break a lot

 

I had this problem. And on my unit the vertical smooth rod supports were loose on one side. The screws used to secure the supports area bit short and the lock nut treads don't engage with the screw allowing the support to work loose on long jobs. More noticeable on taller objects. Using a touch of blue locktite helps.

 

What software and version are you using. I recently discovered that Repetier version0.90d makes smooth prints while v0.90f is a total mess. Same settings. Go figure. Try the d version and set it up as the online youtube video. See if that works for you.


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Version v0.90f may affect the quality too, but this was defiantly an assembly problem as there was half an inch of play when lightly pushing on the top of the rod. I am actually, surprised that there is no upper support for the vertical rods.
I was able to tighten 3 of the 4 screws holding the vertical smooth rod support, and as I noted the locking part of of the locking nuts were not engaging the screw, so without some locking agent this will creep loose again. Proper screw length would have prevented this.

However, there is still a little ripple on large radius, maybe I will try the "d" version and see if that works better. Thanks for input.

 

@CaptKim, did you find the root cause of your rippling? I have similar problems.

 

Someone shared this link that goes through most root causes to Z-axis artifact problems.
I think the most likely reasons on the Robo3D would be:

• Z-ribbing due to imperial z-threaded rods
• No proper filament guide, resulting in the head being lifted when tugging the filament down.
• temperature fluctuations in the bed, making it rise and sink periodically
• Z-axis wobbling could be a problem if the z-smooth rod supports are broken.

I have the new heated glassbed, otherwise stock setup.

Regards, Daniel