Mk9 / Mk10 Extruder - Precision Feeder, reliable flex filament prints

When trying to print TPU on my maker select v2, the filament would inevitably jam after only a few minutes by wrapping itself around the extruder motor gear, even when printing at only 10mm/s.

To enable reliable TPU printing with the Mk9 extruder, I designed a new frame/housing/feeder with less open space around the extruder gear and guide wheel, below the point where filament is being fed/pushed, so the gap is too small for filament to bunch up into, and the only place for it to go is down and out the nozzle. There's still a slight bevel on the guide entrance to improve ease of filament changes. It just finished a ~1-hour print at 40mm/s and 0.1mm layer height, so I'm calling it a success.

I used support (on build plate only) for the cutout for the circular bump on the motor surrounding the shaft. The support was easily removed using the tool that came with the printer and a few seconds of prying. Here are the Cura 3.2.1 settings I sliced it with. Printed in PLA.

adhesion_type = raft
layer_height = 0.1
layer_height_0 = 0.2
material_bed_temperature = 60
retraction_combing = all
speed_slowdown_layers = 5
support_enable = True
support_type = buildplate

alternate_extra_perimeter = True
default_material_print_temperature = 215
fill_outline_gaps = True
gradual_infill_step_height = 0.8
gradual_infill_steps = 1
infill_pattern = cubic
infill_sparse_density = 40
layer_0_z_overlap = 0.2
line_width = =machine_nozzle_size
material_print_temperature = 215
optimize_wall_printing_order = True
raft_airgap = 0.2
raft_base_speed = 10
raft_base_thickness = 0.2
raft_interface_speed = 20.0
raft_interface_thickness = 0.2
raft_margin = 5
raft_surface_line_spacing = 0.4
raft_surface_speed = 40.0
raft_surface_thickness = 0.2
retraction_amount = 6
retraction_speed = 40
skirt_brim_minimal_length = 400
skirt_gap = 7
speed_infill = 40
speed_layer_0 = 10
speed_print = 40
speed_topbottom = 40
speed_travel = 40
speed_travel_layer_0 = 40.0
speed_wall = 40
speed_wall_x = 40
support_infill_rate = 20
support_line_width = =line_width
support_pattern = grid
support_xy_distance = 1.5
support_xy_distance_overhang = 0.4
support_z_distance = 0.2
top_bottom_thickness = 1.2
wall_thickness = 1.2
xy_offset = 0