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Authors: MakerBlock
Plastruder base top plate - with ooze!
Yesterday I tried to print in pink plastic (a bath hook for my daughter) only to discover I was unable to back the black ABS out of my MK5 plastruder. I could extrude, but I just couldn’t back it out with the motor or pull it out after loosening the Delrin plug.
By way of background, and in the interests of experimentation, I had recently tried a few things with my Thing-O-Matic that are kinda contra-indicated by the assembly and usage instructions. In no particular order, and at different times I had:
- Kept the plastruder warmed up and let it sit for a while
- Let a filament run all the way into the plastruder and shoved another filament in after it
After trying the above and a few different filaments recently, I noticed a whitish smear along the inside of my plastruder. The smear was between the toothed pulley and where the filament entered the heater barrel. I didn’t think anything of it since I had still been able to extrude and print.
Obviously, being unable to remove filament from my plastruder is not really an option. In order to fix this problem I disassembled my plastruder. I quickly discovered that the white smear wasn’t just along the path of the filament. Apparently I had managed to ooze some plastic up out of the heater barrel, around the top of the heater barrel, around the circular hole in the acrylic base to the plastruder, and around the entrance to the heater barrel all along the inside of the plastruder. This had the effect of “gluing” the acrylic plates of the plastruder together. Fortunately, there wasn’t a lot of plastic and it came apart rather easily.
The only explanation I have for this is that I must have kept my plastruder hot for too long without running the extruder motor. This would allow the heat from the extruder to travel up the barrel and essentially liquify the plastic. Then, once I started up the extruder motor, it must have squished the plastic out of the heater barrel and up into the plastruder. I also suspect that jamming one filament in after another exacerbated this problem by squishing the filament entering the the barrel with the new filament.
With the plastruder disassembled I found white smear could be scraped off. It had a gooey residue-like consistency – like old toothpaste. It was easy enough to scrape it off with a putty knife. Since I already had the plastruder disassembled, I flossed the extruder toothed pulley. I also was able to remove the filament with everything apart. I discovered that the black ABS filament was also covered with the white plastic residue. The extra width created by the residue on the filament probably contributed to my inability remove the filament in the first place. I also noticed a few notches ground into the filament from when I was trying to back it out.
Once done, I reassembled the plastruder, reinstalled it, fired up the Thing-O-Matic, heated the plastruder, and did a test extrusion. All in working order!
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