For a while now I’ve been exclusively using Slic3r for converting .stl files to .gcode files, so I can print things on my home-built 3D printer. The current version of Slic3r is 0.7.0, and it does what I expect it to most of the time. I’ve been successfully experimenting with different settings for things like ‘Lift’ and ‘Retract Speed’ lately so I’ve updated the file I’ve posted as the Slic3r config page on this blog.
These settings work fine for me, except for a touch of stringing now and then. Rumour has it that one cause of this stringing has already been fixed in Slic3r’s github build. I’m not set up to build the executable from the source code, so I’ll have to wait for the next general release before confirming this.
I’ve turned on 0.1mm of ‘Lift’, so that when hopping between regions the printhead doesn’t catch on the slightly raised plastic of the current layer. The nozzle lifts by 0.1mm before the start of the hop, and lowers again by the same amount where it needs to start extruding the next segment.
My understanding is that there is a very slight degree of ‘swell’ as the plastic is extruded out of the nozzle. This means that the newly laid plastic is slightly too tall for the nozzle to pass over it again without contact. As the nozzle moves from one area to another over already printed plastic the nozzle rubs on the raised surface. Sometimes you can hear it. It is even worse if you are over-extruding plastic through having your extruder poorly calibrated.
Now that I’ve got my retraction speed set correctly – so no more blobs at the beginning of line sections – the addition of 0.1mm of ‘Lift’ has dramatically reduced the incidence of layer offsets caused by the nozzle dragging, especially on complicated build plates with lots of parts and serious fan cooling.
I’m printing on my MakerGear Mendel Prusa kit, with 0.35mm Bruthead extruder and 1.75mm silver PLA filament, and using Pronterface and Marlin non-gen6 version 0.9.10L software and RAMPS 1.4 hardware. You’ll obviously have to set the temperature and sizes to suit your filament, but otherwise these values should work ok.