Layer does not fully fill out, doesn't reach the outline

[marcrouffaer 0]

Over the last few weeks my Ultimaker does this strange thing: as you can see on the image it first draws the outline, then starts filling out the whole layer leaving a small space between the layer and the outline. It does this in multiple directions. This I believe impacts the overall strenght of the printed object. I have no clue how to solve this. Anyone?

[gr5 2,225]

This is very common on UMO and is caused by backlash which basically means the nozzle isn't moving all the way to where the stepper told it to go.

Paradoxically it is most often caused by belts too tight or too loose. If the long belts are too tight the resistance can be very high to moving the head. If the long or short belts are too loose then the head isn't moving all the way to position either.

Usually it's the short belts are too loose - loosen the 4 screws holding the motors, push down hard on the stepper and re-tighten. It's possible you need to lengthen the wood slots in the wall of the UMO but not likely.

The long belts don't need to be very tight but if you pluck them they should emit a pitch discernible by the human ear (e.g. like the lowest note on piano). As opposed to slower than 10 times per second (not audible).

[marcrouffaer 0]

Thanks so much, problem solved!

[gr5 2,225]

So what was it?