When switching spools on the printer it's very important to always secure the loose end of the filament in the holes on the sides of the spools.
Never let go of this loose end or let it hang unsecured, as you run the risk of the filament crossing underneath itself.
It's completely possible to print for hours with a tangled spool once it has been allowed to coil freely, usually the tangled bit travels backwards on the spool while the spool is unwinding until tension is built up.
However at some point the tangled filament will get stuck and pull itself into a knot, leaving your feeder unable to pull the filament through and thus start grinding.
Luckily a tangled spool can be untangled without much effort.
The trick is to pull the knot over the side of the spool, in order to do this you'll need to push back the filament so the actual windings that form the knot increase in size.
Then you'll be able to pull the filament which is knotted over the side of the spool which makes it easier to untie the knot.
Make sure that the knot does not simply slide along the spool but is actually lifted off of the spool.
From a production point of view it's impossible for us to create tangles / knots in the filament.
When starting a new spool the start of the filament is secured in the core of the spool.
The winding process starts and the filament is kept under constant tension throughout the process and each step it goes through.
It is a continuous process, so the end of the filament is still coming out of the extruder on our production line when the spool is full.
This means so there is no loose end to create a knot or tangle during the winding of the spool. It's physically impossible.
Only when the end is cut and fastened on to the spool can our operators make a mistake and let go of the filament.
But there are features in place to prevent this and if it did happen the knot will be present on the very first winding of the spool and will give issues immediately when loading the material in to the printer.
Please also check our company video here which shows the process of making our filaments.
So please take care to properly fix the free filament in to the side holes of the spool.