3D printers can be pretty persnickety; failing to complete prints for reasons that are not immediately obvious. After some weeks of prints that failed to finish printing with a particular plastic type (PLA), it became apparent that the problem was not in the software, designs or printer hardware - but the filament rolls.
It turns out that PLA when printing is particularly sensitive to drops in feed pressure. So if the roll of feed filament "hits a snag" and fails to spool smoothly, the feed stops... The printer keeps going - but no plastic is being laid down.
The solution is a simple holder for the filament spool.
This shows the yellow bracket with blue ball bearing wheels to make the spool turn with almost no resistance. Perfect! 20 minutes to design and an hour to print. The bearing come from roller blade spares I had on hand.
The output snaps together and onto the 3D printer in 30 seconds.
Problem solved! Those interested in finding out more can look here.