Makerbot 2: Why is my print skipping a few layers? Pictures

[sapient24]

I printed out these hands with my Makerbot 2, and it seemed that the print skipped layers and added support instead. This doesn't seem like an extruder problem. It's happened to my last 4 prints.

I'll put these photographs so it can explain itself. You can see in the side picture, that the curve on the hand is fine, and that its leaving the layers empty with support.
http://www.mediafire.com/view/l3pzbh...i/IMG_0912.JPG

http://www.mediafire.com/view/j3hv5h...5/IMG_0913.JPG

I'm wasn't sure where I should post this, I found this site.

[American 3D Printing]

Try a different slice. Looks like Makerware had some kind of issue. I have seen that happen to me too.

[sapient24]

Try a different slice. Looks like Makerware had some kind of issue. I have seen that happen to me too.

You mean I should re export it?

The other hand on the other side of the model had the same thing happen on the exact same level? I wonder if it has something to do with the stl.

I got home today, and ran into the last 2% of the feet's print. It was printing in mid air with nothing coming out of the extruder. Leaving the feet with no toes. This is weird. I really don't understand. Seems like it could be two different problems. Why would the extruder stop extruding? It didn't seem to stop on the hands, just seemed to make support structures or infill instead.

I'm trying out Microsoft's netfabb repair service to see if it changes anything.

[sapient24]

Used Microsoft's model repair service here https://netfabb.azurewebsites.net/ , all my prints didn't have layers skipped so far. but printing the feet still skip the toes?

Any Idea why this could be? Could this also be the STL?

Picture: http://www.mediafire.com/view/3ba5kz...j/IMG_0917.JPG

I had this happen to the face I printed as well. Skipped the back of the skull, and nose big time. I still need to test that newly repaired file.

[wpilgrim]

I can’t fully tell from your picture if that in between line is actually support or if it is just a layer or two that is near air printing (extreme under extruding). If it is the later then I have had this issue before and it basically comes down to a couple different things.

1. Your model could have errors thereby causing the slicer to behave strangely. – You say you ran it through netfab so it is probably fine.
2. Your slicer could have just sliced it oddly. As was mentioned above, try a different slicer, not just reslicing but a different slicer all together.
3. You are experiencing a clog mid print but it minor enough that your print is recovering and doesn’t go into all out clogged air print mode for the rest of the print.

Diagnosing the last of these can be a bear, and without going too far into it, let me just say that I spent a great deal of time on this problem, upgrading, replacing parts, etc, but what finally got me past the hurdle of having the issues of a crappy extruded layer was by lightly oiling about 10 cm of filament with canola oil prior to putting it in the extruder.

I know it sounds crazy but it works. The theory behind it is twofold, it prevents the wet/melted filament from adhering to the barrier tube. It also helps by allowing the filament to more evenly dissipate heat to the barrier tube, thus preventing heat creep up into the extruder. Plus sides are, the oil has a high enough smoke point when using with PLA that you don’t actually ever burn the oil, and it is less dense than the molten plastic so it rides above it anyhow. I don’t oil before every print, in fact others have said only once every few months is fine.

I recommend giving it a shot and seeing how it turns out.

[sapient24]

Thanks you very much wpilgrim.

Looks like the problems were 2 and 3 for me.

Played around with a few slicers and ended up buying simplify3d. Loving it.

Iv'e only had a problem with one print where the girls back of the model im building, was built slanted on top, finishing the build, along the Y axis.
I recently tightened my belts, but not my pulleys...When I printed the feet afterwards, they weren't slanted. I thought it might be because I didn't use rafts on the gilrs back...?

Some more trial and error for me.

Thanks again!

[wpilgrim]

I would need to see pictures to fully see what you are saying here, but if you are having a slanting build up (depending on the slant) it sounds as if your motor is skipping steps, ie shifting the print, but again without pictures I can't confirm.

[sapient24]

I would need to see pictures to fully see what you are saying here, but if you are having a slanting build up (depending on the slant) it sounds as if your motor is skipping steps, ie shifting the print, but again without pictures I can't confirm.

I got it to work just by adding rafts it seems.

Here is what I printed without rafts.
http://www.mediafire.com/view/1uq3l2...4/IMG_0918.JPG

With rafts.
http://www.mediafire.com/view/ust225...h/IMG_0919.JPG

I didn't change anything else.