Unresolved Distance Problem

I've been printing a model I've designed and have been having issues in almost exactly the same spot.

I believe I have narrowed it down to an issue with print distance, not sure what the proper term is. I've attached some pictures so that hopefully someone can help me identify what the problem might be.

The print itself takes about 2 hours. What happens is as it begins to print the final layers, basically the 4 pieces sticking up higher, it skips layers and at some point stops extruding filament all together. The filament is grinding at the extruder gear so it seems like the nozzle may be getting clogged which leads me to believe that because of the distance that the print head travels between these final pieces that the nozzle cools too much and the filament gets stuck or somehow because the filament is retracting, whatever may be left in the nozzle is getting hard so the filament can't continue to feed?

Does anyone have any ideas? Would this be a retraction issue?

 

I'm not sure what is causing your particular issue, but you needn't worry about the extruder cooling off. You lose the most heat when the filament is extruding very quickly, as the cool plastic is being pushed into the extruder rapidly. If anything, the extruder should be able to maintain its heat more efficiently when the plastic is being held in place.

When I'm printing a thin, tall object that takes less than ten seconds to print each layer, I have my machine set to lift the extruder up and away if it is printing too quickly even at the minimum speed, to give the printed piece some time to cool before starting the next layer. I never have any extrusion problems in that mode of operation.

If your hot end fan isn't cooling the hot end well enough, the heat from the heater block may travel up the heat break and soften the plastic too high up inside the hot end. If that starts happening, it can cause the filament to jam inside the hot end. If you're using the stock fan mount (assuming you have a hexagon hot end) it isn't very efficient. You can print a better one that will cool the heat sink much better.