1 Topic by wahada (edited by wahada 2014-04-10 05:18:26)

  • wahada
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Topic: Low Extrusion Rate

Hello,

My recently built Filastruder seems to be making good consistant ABS filament, 1.70 mm +/- 0.01 mm. The extrusion rate however seems to be on the low side
( 5.75 to 3.75 inches per minute) compared to reading posts of people getting 10 to 12 inches per minute for 1.75 mm. I recently replaced the original screw motor with the newer one with the square drive. I am using Ian’s newly designed  vertical hopper and seems to be feeding the pellets just fine. I am using the fan to cool the filament at the nozzle. I am extruding at 180 degrees and the nozzle temperature is dead on varying only +/- 0.1 degrees. At each run I cleaned out the melt filter completely and saw no debris at all on the screen. Nozzle completely clear. The extruder screw is turning at 4 rpm which is the same as the replaced screw motor. I wrapped the entire barrel with carbonized felt insulation Here is a description of  two recent runs:

Run # 1 - Extruded 0.93 lbs of OSP MG94 ABS resin colored with 4% brass masterbatch colorant  for 25 hours. Filament measured 1.71 mm +/- 0.01. The extusion rate measured at 5.75 inches per minute.

Run #2 ( still running as I am writing this ) – Extruding red Makerbot ABS 3mm filament that I pelletized. The filament is measuring 1.70 mm +/- 0.01. The filament is extruding at 3.75 inches per minute.

I have attached photos of my setup to this post. I read in one post that the drill bit that is supplied with the Filastruder has changed somewhat from time to time. Is the pitch of the screw exactly the same in all these variations? I don’t understand how some are getting rates 2 to 3 times what I am getting. What am I doing wrong?

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2 Reply by insta

  • insta
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Re: Low Extrusion Rate

I had a similar problem with low extrusion rates, but I also was experimenting between different plastics (and still do).  In my case I had plastic building up on the extruder screw because the inside of my barrel was becoming lubricated by polypropylene.  I had to disassemble everything and cleanse it with fire.  Lots and lots of fire (yay black iron pipe).

I hope yours is a simpler solution... it likely is.

3 Reply by elmoret

  • elmoret
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Re: Low Extrusion Rate

A few thoughts:

1.) The flavor of ABS matters - the Makerbot stuff is probably PA-7x7, while the OSP stuff fix MG94. (http://www.soliforum.com/topic/3935/pol … -tutorial/)
2.) Masterbatch can sometime reduce output rate, as it lowers effective MFI.
3.) 180C is on the lower side. As you're getting nice tolerances (congrats!), try bumping up the temperature to 185C or 190C. The controller may be reading a few degrees higher than actual.
4.) If running vertically, pellet feed is sometimes problematic and will lead to reduced output rate. I have not personally used that hopper design, so I can't comment.

The auger has changed - not intentionally, but due to supplier issues. The first one (v1.0) seemed to have the fastest output rate, but I've since matched that (18"/min+ on MG94 1.75mm) using the current (v1.4/1.5) auger by fully insulating and running a little hotter.

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