Yet another case of under extrusion? but this one I don't understand

[nssorensen 2]

Lately I've printed a lot of Gridfinity bin's and generally without any problems.

 

A few days ago I printed a Custom 2x4 Gridfinity bin and two 2x2 Gridfinity bin's in one go. The 2x2 bins were identical and with a label tab.

The custom bin were located towards the back and the two 2x2 in front of that - side by side.

 

They came out fine with one exception. One of the 2x2 - the one placed on the right side on the build plate when looking into the printer had sign of under extrusion on the "back" wall between the base and where the label tab started (in 'z'). Sign meaning rough layers, pour layer adhesion and just not a very "strong" wall. Just touch the walls and the groves makes them crumble. The rest of the bin were fine - just like the other 2x2 and the custom bin. And just to clarify - the other 3 wall's of this bin were perfectly fine - even on the same layer that were bad on the back of the bin.

 

Anyone has any idea what can have caused this ?

 

I'm using PLA and typical PLA settings and my printer is an Ultimaker 2+. For slicing I use Cura 5.6

 

 

 

 

 

[Slashee_the_Cow 271]

It always helps if you can provide a Cura project file (.3mf, in Cura get it ready to print and go to File > Save Project).

 

I can't really think of any good hardware reason it would do that just on one side, just on one of the bins. I doubt you'd have a spool of filament which is so accurately inaccurate that it would only have a problem exactly that often for that exact distance. I also can't think of a reason Cura would slice just that bit wrong.

 

In your case I'd try slicing just that bin in the centre of the plate and printing it again. 3D printers can be sort of like 2D printers - if something weird happens once, you accept it and move on; if something weird keeps happening for no known reason you throw it out the window because you're sick of the outrageous price for ink anyway.

 

Err... if it has the same problem when you print it again, or you have the same problem on other prints, you should probably look through the knowledge base on UltiMaker's support site and if you can't find an answer, then contact support through there.

[nssorensen 2]

Unfortunately I don't have the exact .3mf file for that project.

I did look at the g-code in Cura but nothing stood out.

I have tried printing the bin many times (also afterwards) but as a single bin but also several with bins in the similar position without any issues

Anyway - thanks for your feedback and willingness to share you advice.

 

 

[nssorensen 2]

So a small update ....

I did do another print with a different filament and it started out well but 5-10 layers into the print layer adhesion started to  get bad - especially in one corner of the printer (and actually a different place than where I had problems with the bin's)

I decided to change the filament and when I did I noticed that the tension on the filament feeder was a bit "loose". Now - the filament still had marks from the feeder/grinder but at places it was not as much as I usually see.

I still went ahead and changed filament but also tighten the feeder and the print came out just fine.

Not sure what to make of this and whether this could be what caused my original bin problems? Wondering whether the angle of the bowden tube and filament coming out of the feed could be such that their just was inadequate grib at very specific angels (as a function of where my print head was in x, y and z.

Maybe too crazy of a theory but thought I would share my thinking

 

[Slashee_the_Cow 271]

9 hours ago, nssorensen said:

Maybe too crazy of a theory but thought I would share my thinking

No theory too crazy. Unless you're saying your print failed because you're on the wrong side of the flat earth.

 

It's also worth noting with a Bowden extruder the filament flow can be affected by the print head having different tension on the Bowden tube depending on its position.

And because I love taking macro photos and will show them off at any excuse, here's some filament that's been chewed up by the extruder:

[gr5 2,176]

I think you want tensions somewhere between these two - more like the one on the right.

 

 

By the way, that's from an ultimaker feeder on 2.85mm pla.  I don't remember which printer.  Probably UMO or UM2 classic.  This diamond pattern is typical of UM printers.  UM claims that the diamond shape knurl is less likely to clog the feeder gear with plastic and that the diamond knurl allows powder and small chunks to fall out (self clean).  I'm skeptical.  Non ultimaker printers are more likely to have a horizontal lined pattern.

[nssorensen 2]

The pattern I saw did at various distances resemble your picture and the filament on the left.

 

"It's also worth noting with a Bowden extruder the filament flow can be affected by the print head having different tension on the Bowden tube depending on its position."

 

This is interesting as well. Right now I do have a small area on by bed where less material is extruded. 

Do you have any suggestion on addressing this?

[Slashee_the_Cow 271]

15 hours ago, nssorensen said:

"It's also worth noting with a Bowden extruder the filament flow can be affected by the print head having different tension on the Bowden tube depending on its position."

 

This is interesting as well. Right now I do have a small area on by bed where less material is extruded. 

Do you have any suggestion on addressing this?

Other make sure the tube between the extruder and the hot end is the correct length - not too short that it strains when it's far from the extruder, not too short that it kinks up when it's near the extruder - and that it's fitted properly at both ends... sorry, not really.