Hello,
Our Anatomy department has been using an AirWolf 3D HD to print complex shapes in ABS plastic. Our current focus has been a model of a brain. Multiple images of the surface file rendered in MatterControl are shown below.
BrainSide.jpgBrainUnderside.jpgBrainModel.jpg



After a number of attempts, we have encountered consistent problems with the print. The top and sides of the object look great, capturing a lot of the details we want. An image of a partial print is shown below. Rectilnear supports with 3 mm spacing have been removed. The card next to the object is ~2 inches.
DSCN9458.jpg

Here are the basic stats from the gcode file.

; layer_height = 0.2
; perimeters = 2
; top_solid_layers = 3
; bottom_solid_layers = 3
; fill_density = 0.3
; perimeter_speed = 5
; infill_speed = 10
; travel_speed = 50
; nozzle_diameter = 0.5
; filament_diameter = 2.9
; extrusion_multiplier = 1
; perimeters extrusion width = 0.85mm
; infill extrusion width = 1.02mm
; solid infill extrusion width = 0.85mm
; top infill extrusion width = 0.85mm
; support material extrusion width = 0.85mm
; first layer extrusion width = 0.84mm

The current problem is that the undersurface of the object looks ugly as sin.
DSCN9462.jpg

There is a lot of drooping of the plastic, such that this portion of the model looks like it is made of spaghetti. The loops of filament lack the densely “stacked” look of the rest of the model. Varying the density of the support materials has little to no effect on the quality of the underside.

A lot of the structures we want to print are complex, such that we really can’t print them without prominent undersurfaces. Is there a way to deal with these really rough surfaces using variable speeds? Some other methods? Any assistance would be much appreciated.