Ironing/Neosanding (coined from the inventor, Neotko) is a means of running an under extrusion pass over an extruded surface layer. By extruding at a low multiplier (between 15-20% flow), via a hot and fast tool pass (typically I use 100mm/s) and not changing the z-height, the second, under extruded pass fills gaps between the original tool path of the top surface, creating a VERY smooth, even top layer.
Example image, from Neotko:
This may not be desirable for all prints, but for prints that have minimal Z height, or large flat areas in the XY plane, it can massively increase the quality of a print for the minimal extra time taken.
Why is this useful?
Achieve injection moulded like smooth surfaces on flat model surfaces parallel to the buildplate, greatly increasing the model aesthetics.
May also improve model’s real-world watertightness, by sealing holes between paths.
- Do other slicers do this?:
Cura has implemented ironing as an experimental feature which is a good proof of concept. It has several flawed aspects sadly. From reporting several bugs/feature requests with it directly to the Cura devs, there is (what appears to me to be) a general unwillingness to improve it without community code contributions or external plugins to post process the gcode.
You can implement ironing in Simplify3D via custom processes.