Retraction Lift Z

Some designs from thingiverse I could not get printed correctly. This chain always failed to print and this bangle sometimes failed.

Chain that always failed to print until I found the retraction option 'lift Z'

Also this tree frog failed from time to time, having three instead of four feet. These designs have in common that they do not have a lot of printer bed contact and that they have discontinuous layers. With discontinuous layer I mean that the design contains gaps in one layer. The solution was the retraction Lift Z option of Slic3r. This option makes the printer head jump over the gaps. It moves up on one site of the gap and moves down on the other site of the gap. With this option set to 0.5 mm I was able to print all of the above designs without any problems. You can set this option using the config.ini file or the Slic3r user interface. In the config.ini file this option is  called 'retract_lift'. You can find this option on the Slic3r userinterface on the 'Printer Settings'-tab. If you select 'Extruder 1' on the left, you find the option 'Lift Z' in the group box 'Retraction' on the right.