Saturday, 12 May 2012

Update 10.. Valves are so rich and warm :)

My last post was a mess was downloading all the photos from my iphone so i jammed pics in later and they only sorta suit the words.. Meh...

I had to take apart my Extruder as i had a problem with the plastic building up above the nozzle and coming out the sides (must have been a lot of force up top there). to fix this i added tube to the top of the nozzles, these poke up through the carriage plate. while i had it in bits i thought why not see about my valves? see if they can work, i was going to just try them out separately while i was printing but the blobs up top forced my hand, thanks to my mate at work Dave, i got my paws onto some spring steel that was 10mm wide and i dunno how thin 0.5 at a guess, and bent them in to a Z shape that hugged the ends of my heater blocks..

 here you can see the valve made from spring steel bent. you can also see the brass tube on the top of the nozzle on the up turned carriage. it slides up inside the peek and goes thru the plate.
 see it fits :)
 here i have installed all three heater blocks, with resistors, these are held in place by a split brass tube. the nozzles are free to move up and down about 5mm, as they do they push the spring steel down and the taper on the nozzles push it to the side.
as the tips push the valves to the side the valves ride and spring up above the height of the print layer.and don't clip the print job.

here you can just see the tips of the nozzle poking down past the vlaves just enough to clear the print job.

these Nozzles will have to be leveled, i plan to do this by slapping down some emery paper or wet and dry sand paper on the bed and gcode it to go back and forth and hope they all end up at the same level. you can see that each of the nozzles have a different profile to their tips this was a bit of machinist error and when i saw it i thought hey i can claim its a test, wanted to see the best shape to get the valves out of the way, i need to model (somehow) how they move so i can get it perfect.

Between you, me and the lamppost my third channel may not work too well, i have something out of alignment and this can only be fixed by a complete rebuild, one of my mates who has helped with the build is now really excited about the printer, before he wasnt totally commited now he has volunteered to build the next prototype, once i have finished poking at this one. so far i need to shrink the camshaft motor (nema17 is beyond "Steven Segal styles" overkill), from playing with this unit the camshaft rolls so nice (even without rolled edges) in the bearings i can use a PM-20 stepper and some gears. i have these sitting here from old ticket printers. i might need to increase the spring tension or the the ratio of the tension arms so i get more grip on the plastic and try out a hyena style drive bolt but i need my CNC mill and the dividing head to be finished for that.. if my brass tube upgrade works i will be set :) then i have firmware and gcode scripts to sort out.. time to buff up on my python.

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