Cura or firmware issue?

[solonari 0]

Running a UM2 with 14.07 f/w (I know, I know, but waiting for 14.10+ with fixes for the 14.09 travel issues and whatnot). I apologize if it's fixed in 14.09, but I did not see it in the release notes, so figured I'd post it here for review.

Being relatively new to printing, I'm not sure if the following is something that Cura is placing in the gCode, or if it's something the firmware is responsible for.

Was doing fine with Initial Layer Thickness at 0.15 and my Layer Height at 0.1 ... Printer would warm up, extrude a small pile, then pan the head and raise the plate.

Then I wanted to do a couple quick and crude prints, so I set the Layer Height to 0.25 (on the Basic tab, didn't look at the Advanced tab at the time). Suddenly the printer would warm up, extrude a small pile, raise the plate to sink the nozzle into the pile, and then pan the head to drag that mess into the print area.

Setting the Initial Layer Height to 0 causes the print to behave normally again.

Didn't do the obvious additional tests (was pulling molten and congealed plastic off the bottom of my extruder), but thought it was worth mentioning in case someone working on the code happened to notice something along the lines of if (initialLayerThickness < layerHeight) { dragThePile(); } ...

 

[pm_dude 27]

I run with 14.06.3 f/w and its behaving the same regardless if initial layer is < layer height or not. Model was sliced in Cura 14.07.

 

[Dim3nsioneer 557]

@Solonari: Do you have the RetractWhileCombing plugin activated for the first layer?