Danger of reaching end of spool when filament is attached
The spool is almost empty and the filament is attached to the inside of the spool.
The MK4 has so much force, it will break the filament guide and bend/move the filament spool holder.
The first time I was away and came back to a mess. Had to print another filament guide.
The second time I was listening to weird noises and walked over to cut the filament and release the tension.
Might be nice to detect when a crazy force is on the extruder motor and pause the print. That parts won't get overloaded and break.
RE: Danger of reaching end of spool when filament is attached
If using a filament that locks the end, i try to see I am getting close and use side-cutters to snip the end of the filament.
Some brands like "Overture" (my favorite) do not lock the end of the filament and don't even bend it sharply. Good engineering to their production folks!
This way, the end is simply sensed and my MK4 (or MK3) politely waits for a refill.
RE: Danger of reaching end of spool when filament is attached
I suppose one way to detect this problem and fix it would be to use an accelerometer (the port is empty currently).
When the filament is super-tight, the extruder doesn't move on the x-axis.