Solved Strange gaps in printing

Hi, all!

Just got my refurbished Robo-3D R1+ this week, and I'm quite happy with it (as an upgrade from my Printrbot Simple Metal). It worked right out of the box, with the exception of one of the screws on the filament holder on the extruder (the ones with the screws) popping off. I screwed it back on and the printer has worked fine, however...

While I've been dialing in the settings, I've discovered that my prints are all experiencing strange gaps on some levels and I'm not sure what setting to tweak. I've tried varying temperature (starting at 210 and down to 195) and changing some retraction settings, but it hasn't really gone away.

Basically, on some slices, you can see that it has some gaps when extruding. I've seen this behavior in both MatterControl and Simplify3D. The attachepicture should illustrate it.

Any suggestions as to what would cause this sort of behavior? I've tried the filament that came with the printer and some Boots Super Premium with the same result.

 

You may have a mechanical problem with the z rods, I would start there then check the top solid layers. Even though it has auto leveling I had more problem when both the rods are slightly uneven, Just adjust by hand to make sure they are level.

I use this guide all the time:
https://www.simplify3d.com/support/print-quality-troubleshooting/

I also run models thru https://netfabb.azurewebsites.net/ to repair it just in case it is a design flaw.

 

Thanks, Chuck. I use that guide all the time, myself. I know it's not the model, as it's happened with multiple prints, such as the 3D Benchy, which was one of my previous prints before this one. I'll check on the rods, thanks.

My main concern is that, since this is happening with multiple models,multiple slicers and multiple filaments, that it's an indicator that the refurbished unit has an issue. I'm hoping it's just a problem with settings, but I've never seen this particular issue before.

 

Geof, I'll try checking those options. I tried a larger print last night using Colorfabb's Corkfill and it looked better,though the gaps were still there. I believe the fan is running, but when I get home tonight I'll verify. That print was made at 210, so I'll try increasing the temperature and see what the does.

I watched it print last night and I saw it sometimes under-extrude on the middle of large areas, which makes me think it's not a retraction issue. I don't use an oiler.

 

I can confirm that the small fan was running. It's odd because it isn't consistent where the fail happens. I increased the temperature to 215, but that doesn't seem to have significantly altered the print. The first layer goes down mirror-smooth. The prints are succeeding, generally, but I'm seeing lots of little under-extrusions throughout the print. I don't mind making an oiler, but it worries me if it IS micro-clogging that perhaps there are problems with the refurbish job on this printer if it arrived to me in that condition from day one. In a year of solid use on my Printrbot Metal Simple, I'd never seen an issue like this.

In the photos below, you can see how the bottom of the frog print looks perfect (that garbage on the print was a mistake of mine...forgot to turn off supports). The face and 3D Benchy print show the actual errors.

 

have you already gone through the exercise of calibrating your extruder? Also is your filament roll able to move freely and you aren't seeing any ways it might get snagged while feeding the extruder?

 

I have not calibrated my extruder. I didn't think that would be something I should do right out of the gate for a "new" printer. It sounds like seasoning might be the next step and then I guess I could try to calibrate it.

I don't see any issues feeding the filament through. I've mounted both the filament from R3 and some colorfabb on the provide spool holder and they appear to feed fine.

 

You would be amazed at all the calibration you should do on a new printer. They just throw in default settings, but they don't do things like tuning the stepper drivers current, calibrating extrusion, PID tuning and the like. It's all good fun!

 

That's not a problem, but I generally expect that someone calibrate and tunes it before shipment, whether new or refurbished....or at least the 'welcome to your new printer' manual should probably discuss that it's something that will need to be done. I'll hopefully have time to do that tonight.

 

A little Olive Oil and some seasoning and it looks the problem is pretty much fixed! That appears to have been the problem. I did it three times then tried printing the 3D Benchy again and the results were much better, as you can see in the attached pic (blue is before, corkfill is after). It's most visible in the wheelhouse, were you can see the under-extrusion the best. I have to tell you, this community is really helpful.

Thanks, all!