Filament Drive Perfection

After producing a large number of my aluminum filament drives, I've been looking at my "reject pile":

when i make one of these things, i do things a little differently, every single one is done by hand on a small American built lathe , the aim is to produce a filament drive with both consistant roundness in the hobbed area and sharp well defined teeth , the actual diameter of the hobbed section can end up anywhere between 10mm and 11mm this is almost irrelavant since you have to go through the extruder steps/per mm calibration procedure anyway


looking at my reject pile, the main reason for rejection is that the hobbing goes too deep or the gear goes out of roundness. if it goes out of roundness they end up in the bin, the rest are generally get given away or used for testing, the irritation is that for every ten good ones i normally get at least 3 rejects
just due to the hobbing going smaller than 10.50mm however they are all still round to less than 0.05mm and realistically make little to no difference on most direct drive extruders anyway

Aluhotends V2 - the next generation

here is the next generation of ALUHOTENDS

from the left -  mk2 clone jhead for sizing  1.75 cartridge version 1.75 resistor version 3mm resistor version 3mm cartridge version experimental deltabot lightweight version

1.75mm and 3mm - i have bowed to pressure to produce both sizes, however certain features in the future for things like the ultra short meltzone might not be as easy to produce as the 1.75mm versions

resistor and heater cartridge versions - some of us prefer heater cartridges some of us prefer wire wound vitrious resistors, both have their place, there is now two different heater block styles to suit them both

cold side is now shorter and lighter - give about the same z height as a jhead

the experimental delta bot version - this is a very experimental hotend currently weighing only 19 grams I'm looking to reduce the weight even further, this one by default with have a pushfit connector in the entry hole and will only be for 1.75mm filament, the meltzone on these i am looking to reduce to less then 7mm and a 2mm diameter space all the way down to the bottom, this should allow near retractionless use which would be perfect for bowden tube setups, currently this one is not up for sale yet

1.75 direct drive extruder,

OK,recently i've had enough of the accessible wades extruder and the whole hobbed bolt and printed gear thing, unless you have a bolt that is hobbed properly, it's a nightmare to get properly setup,  the other main problem is that the wades extruders were really built for 3mm filament, which is fine , but it's hopeless for 1.75mm due the filament packing up under the hobbed bolt

i took some inspiration from several existing designs, the mk7 and an modification done to the up! by DrewPetitclerc (pictured above) and devised my own extruder that mounts on the standard 50mm hole spaced x axis carriage

so far it is only 1 printed part and 1 machined part and a spring from an artline pen 

so far this has actually proven quite reliable,  since the moving parts are kept to a minimum and the rate of flow is at the mercy of a hobbed filament driver, not two printed gears and a hobbed bolt, the kind of quality prints i get off this now are better than what comes off the up! and with slic3r now doing support material which literally falls off the only other problem to solve is my abs parts lifting of the table which i think might be more the crappy abs which i don't think is actually abs this extruder is now available as a printed part complete with spring and filament driver gear on our website www.3dindustriesaustralia.com.au

stl files for it are now on thingiverse,@ http://www.thingiverse.com/thing:34896