Adhesion problems with larger nozzle size.

I recently changed my nozzle from size 0.4 to 0.8, to be able to print larger objects in reasonable time. Now I'm having some difficulties to get the layers to stick to the layer below it seems. The gaps as you can see are created when the nozzle leaves the edge and going in or out while printing the thin walls. I'm using a prusa i3, slic3r, 0.4 layer height. Does anyone have any suggestions how to solve this issue? Thanks, Frans.

That's an interesting object. What materiel are you printing with? In the second photo it looks like filament has pulled away from the complete width of the the 3 perimeter inner cylinder. Is it possible that the thin walled radials are cooling more quickly than the thicker inner and outer walls, shrinking and pulling away? If so, you might need a heated chamber to control the cooling more evenly, or to make the radials thicker so that they cool at a similar rate to the cylinders.

PLA. It seems like on the first 2-3mm after starting to print after a retraction/jump the filament doesn't stick and is dragged a few millimeters. It's hard to explain, but it is only at points where the extruder has retracted and starts to print again i get gaps.

Edited 1 time(s). Last edit at 05/03/2015 01:21PM by Frans_Printa.

Being a much bigger nozzle maybe your extruder cant quite keep up all the time pumping through the filament?
So its retracted but then needs to very quickly extrude again to fill the melt chamber ready to print but not getting quite enough in time?

Gordon

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Gordon
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Cut in half your retraction and increase your temp 5 to 10 degrees. If you want to keep your retraction settings then increase your extruder acceleration.

Thanks for the suggestions. I tried to disable retraction and increase extruder temperature, but there is no improvement.

Instead of using 0 in extrusion width for automatic calibration, change it to same size as nozzle or even 0.02 smaller and do a few layers test.