retraction issue at layer change Cura 2.7.0 Mac

[alexrosen 0]

Hi everybody,

I am trying to print thin wall (O.4) to make a model from 3D lab print.

I managed to solve most of the retraction issue except when there is a layer change.

"retract at layer change" is selected however it does retract right before starting the new layer and not at the end of the previous layer. I have then some lost filaments between the end of the layer and the next one.

Is there a way to fix that?

(I have tried different version of Cura)

[gr5 2,266]

I'm confused. You want to *uncheck* retract at layer change.

In general you can improve underextrusion and stringing issues by cooling the temperature by 10C and set ALL printing speeds (especially infill speeds) to 30mm/sec.

[alexrosen 0]

Thanks for your advises.

I already have a speed of 30 mm/sec and the temperature is 200 degrees. I am quiet happy with the result exept for that stringing between the end and the beginning of a layer.

The extruder should retract at the end of a layer and not at the beginning otherwise the retraction is useless.

Is there another box to check?

I could fix that issue by having the same point for the start/end of a layer. In that case no more stringing.

Any idea how to do that?

[gr5 2,266]

I guess I need more information.

When cura slices a single layer it loops up all the line segments into loops or "islands". Typically a layer only has one island but very very often there are many islands on a given layer. Normally there is a retraction when leaving one island to go to another island.

Now that we have the word "island" defined...

Are you saying it finishes an island, moves the z axis, then retracts, then moves to a new island? or something else.

I think there is some limited control over what order things are done - shell first or shell last for example. This might affect this stringing you are talking about. Maybe a picture would help.