Dial in your FDM tools using Simplify3D with the following settings:
- Extrusion multiplier - typically down to 0.85 for rigid materials, and up to 1.25 for very flexible. Normally a value between 0.9 and 1.1 is appropriate. This is also adjustable on-the-fly in the controller.
- Extrusion width - reduce below the S3D default. Select something 5-10% above the nozzle diameter. If walls are not solid (traces not in contact), then reduce further. If you have a lot of voids, increase it.
- Retraction - higher retraction (6mm) for flexible filaments, lower (2.0) for rigid
- Layer height - no higher than 50% of nozzle diameter
- Number of layers - flexible filament will require more ceiling layers to make a solid top layer
- Infill - rectilinear is faster, more infill is tougher. Higher extrusion width helps bridge gaps.
- Print speed - slower will yield higher-quality (down to 30mm for very flexible filament)
- Minimum travel for retraction - turn off for cleaner prints, turn on for faster prints
The following guide also details the best practices for adjusting print settings: