Oh that is not the seal, the seal is further down and actually inside the heater block, while the part shown is mechanical to help adjust the length of the pin during manufacturing i supposed. The seal is not shown on the animation. There are several existing patents making the use of this sort of pin technology in various other industries so you are correct; you will need to investigate their spby aimdy - General
this is the machine i was referring to. you can see here a basic cartoon of what happens in the heater block this shows the needle valves (pin) as well from outside the heater block in the dual material head they offer a single material head, with 2 nozzles for .3mm and .8mm and a dual material head with .4mm nozzles. The main issue is as I mentioned in my initial post. The machine's proprby aimdy - General
hello LoboCNC, i am not sure how far along you are but please check the following patents before investing a lot of money in this project. the design you mention is already in use in a fairly popular machine, the only difference is that the filament in yours feeds parallel to the valve pin. as you guessed the o-ring seal is the weakest point as it generally last only about 500hrs in this harsh enby aimdy - General