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Topic: Pre-grinding pellets for diameter consistency

I read a post by Tim where he said that one cause for filament diameter variation is the inconsistent size of the pellets and the random way they fall into the auger flights. I was wondering if grinding the pellets into smaller pieces (like with a coffee grinder) would facilitate a more even packing inside the barrel and thus give a more consistent diameter. Has anyone tried this?

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Re: Pre-grinding pellets for diameter consistency

That variation doesn't really matter with the way a Filastruder is typically set up, it only matters on direct pull setups that try to pull the filament at a constant velocity. Extruding onto the floor, the floor doesn't care about output speed changes. The Filawinder has the laser sensor to adjust for output speed changes as well.

Folks get +/-0.01mm variation with normal pellets and a Filawinder. Hard to beat that!

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Re: Pre-grinding pellets for diameter consistency

Just to note, I tried to grind colorant in a coffee grinder and it did not work. It basically just halted the grinder and wouldn't turn. I used a hand-grinder with the burr grinder style. I even tried ABS pellets and, basically, it would have taken me days of grinding to grind even a pound of the stuff.

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Re: Pre-grinding pellets for diameter consistency

I've been able to grind masterbatch with a bur grinder, but it had to be something like a teaspoon at a time, running in short bursts.  It came out pretty fine, but it was difficult to handle because static would cause half of it to stick to everything.

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Re: Pre-grinding pellets for diameter consistency

I just bought one of these to reduce the pieces that come out of my harbor freight wood chipper.  Trial run seems promising, but just got it and haven't had time to do too much with it yet.

http://www.ebay.com/itm/291347863958

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Re: Pre-grinding pellets for diameter consistency

garbage disposal maybe? only dry with drain tilted down like 45 degrees used like cement mixer. just a thought.

Solidoodle 2 with Deluxe kit cover & glass bed with heater. and 2nd board SD2 used not 3rd and alum platform not installed yet still wood. also need cooling fan installed to board. use Repetier Host couple vers. Slic3r also have all free ware STL programs

7 (edited by magstang1775 2016-04-18 19:02:36)

Re: Pre-grinding pellets for diameter consistency

I have ground bulk material (not pellets) in an industrial blender, and a coffee grinder (the kind with a blade). This only works well for harder polymers like polycarbonate (PC) or high-density polystyrene (HDPS). It may be that ABS is just too soft.

Possibly freezing it in ice or dry ice would help. Be very very careful with dry ice! Someone in my office burned themselves on dry ice just this weekend. It hurts!

Edit: as Tim said earlier, this may not help depending on your setup. Just figured I'd provide info for what's worked for me.

8 (edited by jlauzon 2016-04-18 23:45:32)

Re: Pre-grinding pellets for diameter consistency

I'm grinding abs quite nicely....  Cut it to a couple inches with the band saw, put it through the HF chipper and the the Chinese pulverized (that I modified) and I'm good to recycle.