This page tracks development of the shell, or first layer plastic case around the device. This page mainly covers making a shell with a 3d printer but if you are good with a dremel tool there is nothing stopping you from modifying an existing project box. If you would like a shell printed or modifications to a shell please create an issue.

Model 48 Shell:
https://github.com/bobbybudnick/SFS-Mobile-Internet-Device/blob/master/Shell-15-1.stl

Model 44 Shell:
https://github.com/bobbybudnick/SFS-Mobile-Internet-Device/blob/master/Shell-14-4.stl

General

New shell and printer
Instone 3D Inventor Pro

Slic3r settings to start with
currently using 10% fill
rectilinear supports for easier removal
10mm exterior brim to keep print flat to bed
rotate prints 90 degrees for device shells

Slic3r crash
slic3r crashes when setting custom temperature and closing filament window
just keep the filament window open before exporting

Finishing tips
carefully slide the device into the shell
colored tape can be used to match the filament color and fill in gaps
for better cellular performance/cooling the bottom can be left untaped

Cutting a hole with Tinkercad
this does not function because a hole can not be cut
the failure mode is the cutting piece does not disappear after grouping
the hole must be turned to solid then grouped with cutter then turned to hole

Troubleshooting

Stringy prints/sometimes bad layer adhesion/extruder clunking
spool naturally becomes more difficult to unspool when low on filament
change to 205c for second layer - no effect
adjust speed - 35% fixes problem - make speed proportional to spool remaining
change nozzle - not tried
z-axis calibration - should only be for first layer problems
some clunking may be acceptable for higher speeds
if spool pulls from bottom it will tend to move toward user
if spool pulls from top it will tend to move away from user
making sure the holder is spooling the filament correctly is important

Prints balling up at print head
clean nozzle and bed with alcohol - did not work
try brim - worked well
try raft - not tried
try 25% speed - improved but not enough
height calibration - improved but not enough
adhesive on bed - not ideal
new filament due to water contamination - expensive

Weak or no manual extrusion
replace nozzle

Weak or no automatic extrusion
check position of extruder gear on motor shaft and tighten tiny allen lock key
check cleanliness of extruder gear and roller and bottom and top pathways

Poor bed sticktion
clean with alcohol
replace kapton tape if needed

Erratic touchscreen
check connection of ribbon cable to display board

Continued print failures with new filament
the new filament is advertised to be tougher than regular pla
this filament seems to clunk the extruder more
was some dirt in extruder but expected with all the clunking
a melted ball of material was preventing extraction this time
may not be a nozzle clog it seems to be more of a problem with tough filament
heat and speed seem interrelated
lower speed and higher heat should lead to higher reliability
it is best to target no clunking at all
previously the idea was to keep 70% speed and increase temperature until reliable
to realize higher temperature prints the temperature needs to go past set point
for example for a 230c print do the following
set to 245 to prime then 231 to start print then 240 to keep around 230 actual
temperature safe minimum in gcode - 230 - around 220 actual
if set to 240 in gcode then it needs 240 to start and could be dangerous
0 degrees on each layer can be specified in slicer to allow manual heat control
nano can edit gcode directly and remove temperature lines just fine
also found that after a very long time temperature reaches set point
indicates a printer firmware problem perhaps with pid feedback control
this filament is going to need to be backed out and refed each cooling cycle
essentially the filament is not melting enough before being ejected
currently the idea is to keep 220c temperature and back down on the speed
70% - fail/60% - fail/50% - fail/40% - fail/30% - fail/20% - fail
try 210c and 20% speed - fail
ultimately the diameter or hardness of the material is the problem
the original filament is much easier to push manually through the print head
the strength of the extruder may have something to do with the problem
a huge problem was spool holder which was modifed to spool with less resistance
holder modifications - bottom lubricated/outside cut away/teflon pad on outside

Various problems
remember when in doubt slow it down!

Model 16 Changelog

original
/////
add notches
/////
move button access hole towards tail 15mm
add sleep switch access hole

Model 22 Changelog

original
/////
expand width by 5mm
equalize wing widths
move cellular hole down 10mm
expand sd/reset hole down 10mm
add charging hole
/////
add screen power button hole
add cooling holes
expand charging hole

Model 20 Changelog

original
/////
increase width by 8mm
decrease wing width by 20mm
/////
increase width by 5mm
increase length by 5mm

Model 21 and 23 Changelog

original
/////
reduce wing widths by 6mm
reduce top hole height by 10mm and increase width by 10mm
increase overall width by 5mm
reduce side hole length by 20mm and reduce height by 5mm
/////
increase side hole length by 19mm
increase top hole height by 10mm

Model 48 Changelog

based on shell 12
a few mm less wide to fit in bag better - 105.42 to 102
a few mm taller to better accomodate mid - 39.28 to 42
hole for usb-c connector - 15 x 15 and 15mm high on right slant inside
hole for power switch

Model 48 Changelog 2

based on 14-1
add ventilation grid on both sides of shell
increase size of usb-c hole
trim left side top so screen is visible

Model 48 Changelog 3

based on 14-2
series 15
increased size of usb-c hole further

Model 44 Changelog

based on 14 series
width increased from 104.5 to 110mm
usb-c hole size increased

Model 44 Changelog 2

based on 14 series
width increased from 110 to 115mm
increased size of usb-c hole further