Small features suddenly not being printed

I have a design that I have printed successfully probably 100 times or more.  Suddenly, it has stopped printing the small circles at the very top of the print.  It isn't obvious from the picture, but there are multiple standoffs, so there is travel between each layer of the standoff being printed.  Any tips on what to try to fix this are appreciated.

 

Monoprice Maker Select v2

Hatchbox PLA

Cleaned, then replaced the nozzle.  New PTFE tube is on the way, but current one looks fine.

Tried extruder temps from 190 - 200, 200 is what worked originally

Tried 3.5 mm retraction, then 2.5 mm.  3.5 mm worked originally.

 

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Kind of looks like it is under extruding.  Is this a Bowden setup or direct drive on the extruder?

 

What slicer?  Did it needs supports or something?

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I believe you're right about it under extruding.  It is direct drive.  I disassembled to take a look at the feed gear last night, and noticed the v-groove bearing had fallen apart.  The bearings are still in place, but the cap fell off one side.  Spinning it by hand, I imagine it binds a little bit, maybe.  I have new ones on order.

 

I used Cura 2.4 to slice.  No supports.  As mentioned, though, I've printed it successfully ~100 times, so I'm thinking it is probably a mechanical issue causing it to fail.

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I was going to say that the retraction seems really excessive for a direct drive.  You might try about 1.2mm and see how it is.

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I tried with a 1.2mm retraction, and while I got lots of stringing between the standoffs, it made a bit more of an attempt at the small rings on the top layers.  It's still missing some, though.

 

I then tried with no retractions, and obviously it was a mess of strings.  The top part did print, though.  There seems to be something causing retractions, or more specifically, the prime afterwards, to not be working correctly.

 

As a learning experience, I decided to modify G-code to chop the design into pieces and force it to print each standoff separately, in sequence.  Something like the image below.  That way there would be no travel between them, and no retractions would be needed.  The result was a perfect print.

 

Obviously, I need to get my printer working properly, but I'm curious about options.  Is there a slicer that can do this without resorting to editing G-code like I did?  I know with Simplify3D, you can do things like different infill at various heights, but could you have it (or another slicer) treat those standoffs as separate objects and print them in one-at-a-time mode?  I realize this is a question probably best left to a separate thread.

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I see what you did, good idea.  IN S3D you could do this fairly easily as long as the standoffs are far enough apart so the extruder doesn't hit them.
What was the material and temp and speed?

 

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Hatchbox PLA

190 C

Wall Speed 40 mm/s (wall would be what's used for those features)

Retraction Speed 35 mm/s

Travel Speed 130 mm/s

 

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Finally, I wanted to follow up after replacing the PTFE tube.  I printed the original design after replacing the PTFE tube, and that appears to have fixed the problem.  There is still a very small amount of stringing, but I have had that on and off before.  The small rings printed correctly.  Thanks for all the help.

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