Skeinforge Quicktip: The Raft, Part II

For the last Skeinforge tip, I’m going to run over the temperature and support settings, which are part of the raft dialog.  (Presumably this made sense when the software was being written.)

Support material settings:

The inexpensive 3D printers with which Skeinforge is commonly used do not have a secondary support material.  However, using the very plastic to be printed *as* a support material can be marginally successful.  The raft option “support minimum angle” defines how steep an overhang can get before skeinforge automatically adds threads of support plastic.  By entering different temperatures for “temperature of support layers” and “temperature of supported layers”, you can have the two kinds of extrusion happen at different temperatures.  Plastic extruded at a relatively low temperature tends to turn out more brittle, so making the temperature of support layers close to the minimum working temp (this can vary from machine to machine) can result in some fairly easy to remove support structures.  Setting up temperature change times between these two (time before support, time before supported) can seriously slow down a build, though.

Temperature settings:

I’m currently working under the logic that the raft should be extruded pretty hot so that it will adhere reliably to the base, but I defer to Nophead beyond that.  Skeinforge offers temperature options both for the main object (the “supported layers” and “next shape layers”) and the raft, but also has separate temperatures for the first layer outline, and the first layer infill.  Although the properties of ABS are fixed, it’s hard to get a dead-on calibration of the thermistor, so odds are you’re going to have to experiment with temperature settings a bit.

One thing I’ve had happen is that one of my settings in here was too low, and the plastic froze, causing the pinch wheel to strip the filament.  If you have an extruder that stops extruding at the same point in the build twice with a stripped filament, make sure none of the temperatures in this box are low enough to freeze your plastic.