Victory is Near... so near i can taste the plastic!!

Had a hard day at work trying to make some soothing sounds from a PIC micro and a mosfet driven speaker, feeding it a square wave at varying frequencies to make a bleep and a bloop sound for good and bad report. I was eager to get to the mill, as soon as i sat down at home i rang my mate to see if he has finished work for the day, and he was, so i scooted out there as fast as traffic would allow. I got there at about 6:30ish and proceeded to setup the mill to enable the Y axis as i am still waiting on the replacement stepper drivers, so i am plugging the A axis into a axis that is not required, this time i needed the Y axis, first time i needed to use it so i had to calibrate the axis and document the backlash.  after about and hour or so and nice hunk of chicken i had the axis' setup and ready to roll.

i whipped up some gcode to make the teeth that i need, forgetting my notebook that i scribbled the formula in last night i had to go off memory and plain forgot how many teeth i wanted and some how ended up only cutting 18 teeth on the first groove so i manually cnc'd the last two teeth.

%
G21
G91
o100 repeat [20]
G1 Y-2.6 F25
G1 Y2.6 F50
G1 A18 F1000
o100 endrepeat
%

this fed the cutter into the groove nice and slowly then retreats to clear the job and rotates 18' and repeats. simple code. i then manually cranked the X axis to line up with the next groove and let it rip and repeated this for the last groove. the teeth are a little off center to the grooves but that shouldn't affect anything as i pre-grooved the job.

so now i need to go to jaycar.com.au and buy me a 10 tooth gear to mesh with the worm drive and mount that. i will venture into hobbyco in the city to latch onto a new set of skateboard bearing ( i know i have four fresh ones here somewhere but meh) then i will be all set to start a print, i seem to have lost one of my nozzles, probably hiding with the bearings so i might order some 0.25mm & 0.35mm drills and make a new set or two, now i have the mill under control they wont take so long to make, well at least i wont have to crank it by hand to peck drill them out, last time it was a PITA, might have a better look in the work room.. once i have the hardware sorted i will have to find out what the best firmware will be to use, i haven't been in #reprap for a while..

here is a vid or two of the bolt being machined on my cnc X2 Sieg mill with Dividing head..

 here you can see the cutter making the teeth for the drive bolt for my 3d printer. its cutting 20 teeth.

 this is the cutter that i made from a piece of 5mm hss tool steel that i bought off the internet for about 1$au each, bought 10 bits in the buy it now sale, so $10 delivered, i have posted about a company that will make/does make, cutters that would have done the job but i am an impatient sort of person and wanted to try and see if i could do it, as it turns out its not that hard i used a 6inch angle grinder with a 1mm cutting disc to form the profile then turned it to an angle of about 30' in the tilting vice to cut the cutting edges/flutes.

 my iphone doesn't seem to like taking photos of things up close but the videos are not that bad..

the cutter seems to have survived enough that i will probably use it to make the new extruder with any improvements that i can think of. i would like to see if i could make this thing printable and post it to thingiverse.com, that reminds me i should update my existing things i have posted to reflect the progress that has been made. 

Triple extruder gets a work out

Ok so i have been sort of using the triple extruder, when i made the hobbed bolt i mis-placed one of the hobbings and it doesn't align with the idle roller :(

but i have been able to use the other two feed paths of the extruder, i had some fun with nozzles and such but thats another post..

so basically the extruder works as far as i have been able to test, i have to make a little mod to actually have the material change to happen, so far i have had no cam shaft installed. i am starting to think my measurements are wrong..

i am learning how to use solid works so i will draw up what i have and animate the movements to double check things..

 i have two fans one to cool the heat that the entire extruder soaks up and the motors.
 then the smaller one with all the broken blades cools the print for the first layer and maybe bridging when it all works better.

 top down where the filaments run, only one in the middle path in place at the moment

you can also see the dove tail join that hold the extruder in place, and leaves it removable for when i need to work on it, its a bit tight and i have been hitting it to free it up... bad me :(

 here you can see where the cam shaft with a 40tooth gear on it would go in the bearing and across the tension arms/blades the cam shaft has 180' sections taken out @ 90' to each other, this leaves one position where they are all free or one is gripped by the hobbed bolt.

 this is the 20:1 reduction worm drivve that turns the hobbed bolt that is hobbed in three places 10mm apart

here you can see the micro switch that will run on the head of the bolt that has been filed to only have a lump where the cam shaft has all three springs compressed, thus all three filaments are free to be hand loaded or withdrawn if you need to change it is very easy.

when i built this extruder i used all the conservative numbers where i could so this unit is probably a little on the large side, i picked the positions of the fulcrum points by eye and what i thought the motors could handle not what they can handle.. stepper motors are very easy to under estimate... i could probably have gotten away with a smaller motor for the cam shaft, i think once i complete the rebuild i will have a better idea, maybe i will be able to make it printable. then others can enjoy this as well.

i lost a little print area when i installed the triple extruder but it was only 40mm in the X..
i need to replace the hobbed bolt some day soon.. i also need to install stronger springs to get better grip on the filament

you cant see it well but there is a hobbed bolt in there, its driven by the stepper on the right via a 20:1 reduction worm drive. the stepper on the right drives the camshaft the is not installed in this pic, you can see the bearing on the left above the 40 tooth gear on the left, i used two of these gears to move the camshaft up and the motor and its weight down.

one problem i had was that because my hobbed bolt is so far away from my heater barrels my filament bowed out and refused to go down the nozzle. this was easily fixed with a little brass tube from the hobby store, this was pressed into the peek block that i have holding my three nozzles, this extruder could easily be extended to accommodate more  materials with only a 10mm increase in over size in the X axis with my current install but that could also be taken from the Y axis.

my nozzles are made from 5/8th brass threaded rod that i machine down the thread off and wrap with kapton and nichrome wire. i use 100k thermistors. started out with 0.5mm and now want 0.25mm holes.. but thats another story.

 here you can see two nozzles installed but only one wired up with nichrome wire and thermistor.

So far this has been giving me good filament up to about 1000mm/min but i need to install harder springs and better hobbing to get better speeds, once i ditch the lead screws i will have lots more  speed in my movements and needs a extruder that can keep up..