just wanted to update on my progress on the big printer with dual pellet extruder.
The progress has been slow since I ordered various pieces at different times and it slowed the process.
Also did some mistakes !
Anyway, got all the pieces and changes a bit some.
The blocks are now aluminum instead of stainless steel for 2 reasons, first needed a bigger block to heat up the tube with pellet and drill bit and second steel sucks at heat conductivity.
I am doing some tests to fine tune the marlin firmware, here is a picture of the extruder
So right now I am having some issues to heat the aluminum block which is 50mm height and it cannot go above 210C !
My resistance 3.8 ohm cartridge heater is 12v 40watt 50mm height, got it from Alibaba.
I performed PID Autotune and got the following with a M303 E0 S200 C8 command: Kp: 57.84 Ki: 1.31 Kd: 640.15
Edited 1 time(s). Last edit at 07/04/2016 05:34AM by biskero.
Looks nice! You might need a second heater cartridge or a larger first one, that's a big block to heat with a 40w cartridge. Maybe insulate the block with glassfibre wool, or something, you must be losing a lot of heat from the large surface area.
just wanted to share an update on the pellet extruders which changed a bit from the pics above.
I can extrude HIPS pellets but I am having issues with carbon fiber pellets which are half the size of the HIPS and my guess is that they float instead of been pushed down.
I will post some pics as soon as possible but if anyone has any suggestions please let me know.
Loving these. Bringing some future uses to pellets and recycled plastics.
What I really want to find is a cheaper shredder for plastics to make the pellets. At the moment they are industrial and very expensive designs to have made and cut. For say the home user wanting to shred a small water bottle they only need a small shredder to do that, not an expensive industrial shredder.
I know this is an old topic, but was wondering if anyone had a reasonable amount of success or experience with pellet extrusion? I sell large printers and would like to consider pellet printing, if it is in fact upto a reasonable quality standard...
I don't care about no retraction as much...I'm mostly interested if the pellet extruders spurt or spew air often? I can fix ooze a different way. I see several designs out there for pellet extruders, and it seems none really needs a heatsink fan...I guess as long as the pellets come in solid and leave liquid eh?
Thanks in advance for any advice anyone is willing to share!
Quick idea without much thought afterwards because I need to go to bed... to remedy the "can't retract" problem, what if you hook up a small vacuum to the nozzle somehow to "pull" the material up a bit, or at the very least have it just strong enough to keep any from seeping out. Thoughts? This is an interesting topic, and despite the nay-sayers, ill stay optimistic in that I think that while it may never get quite as good as filament, we engineers, tinkerers, and makers can get one working to make acceptable, if not halfway - decent and worthy, prints.
just wanted to share an update on the pellet extruder.
I redesign the hotend aluminum block since the previous one had some issues.
Now is thinner 20mm and has clamp style lock for the stainless steel tube that goes into the block.
Also reduced the nozzle M6/M7 screw height from 13mm (vulcano style) to 7mm standard nozzle screw.
In addition I ordered some new stainless steel nozzle M6/M7 with 3mm enter hole which I will enlarge.
one question is about the extruder block is aluminum and I imagine you have a drill bit, is that part steel?
I am asking because in my project I will be using Carbon Fiber so the drill bit, the tube and the nozzle are all steel, the extruder block is only used to heat these parts