Video of the Vavle nozzle bench test.

Last night and yesterday i was rather industrious and made some good headway with my extruder, i tore it down after using it for a little bit for some preliminary testing, i would get close but then decide to add or change something so i would have to start again. This morning i have done a first test on the first nozzle, it also the first time i have tested a 0.25mm nozzle, there is nothing like changing only 1 thing at a time :D.

in this video you can see the valve work as the filament is pushed by the extruder the nozzle moves down and the valve slides out of the way ready for printing, there is one little problem with this profile of nozzle the step in the tip has two problem, A) the valve gets caught on the edge, this can be solved by forming the edge of the valve more, this may require a thicker but narrower valve. And B) the valve (if watch carefully) is pushing the nozzle back up into the extruder, this may or may not be a problem. Either way i am very happy with the way this works for a first try this is Awesome..

each time you hear the stepper feed its going slowly at a rate of 100mm/min and feeding 5mm of stock each time, tests will prove how well this actually works out, these valves are very crude, if i had better tools i would have made them 8mm wide and possibly attempted to put a V grove in the end to see if that helps with the riding up on the nozzle, i can see this riding action causing a problem down the path when the nozzle becomes worn from repeated opening and closing, but for a first attempt i am happier than a pig in mud..