trouble printing propellers

Hey guys ,

I have been having trouble trying to print propellers, they always seem to mess up at each end. It almost looks like there is a line separating the good print from where it gets crappy, and holey. I am printing them upright with support material, forced for the first 40 layers (the crappiness happens where the support is and when there is no support). Any help is appreciated.

I have a prusa mega, using 1.75mm PLA, I run realllly slow speed settings otherwise it jumps, printing at 187oC. It mostly prints ok, but for some reason these propellers are always terrible.

Thanks guys

You did the basic troubleshooting? Like, print at 200 and see what happens. Print with multiplier of 1.1 or 0.9. Etc. And then see if one of those prints is better.

Ive no clear answer for this messy print.

Is your drawing watertight? After you slice can you see any weirdness in that spot?

is your gcode good? I sometimes not that happy how thin sections are sliced.

What did you slice it with? It looks like you have a continuous gap, maybe caused when the layer changes. Can you randomize layer changes so it doesn't change in the same spot?

Also, try adjusting the retraction.

Do you have active cooling on the PLA part? That will help.

Hey guys,

sorry for the delayed update. I pretty sure my issue has been poor quality filament, it was not very accurately 1.75mm, and not even round in some places.

When I tested the extrusion it was not accurate (so I told the extruder to extrude 100mm and it only extruded 86mm, and because I am using the prusa mega from 3d stuffmaker I cannot update the firmware). So basically I have been waiting for better quality filament, which arrived today. I did the same extrusion test and it extruded 95mm of filament so I have changed the multiplier to 1.05 (does that sound right?). Also I have increased the temperature, the manufacturer suggested between 200 and 220oC.

I am using pronterface to print and Sic3r to slice, does setting the seam position to random what you mean DonaldJ? I'll give it a try..

There is no weirdness in that particular spot on the drawing, I downloaded it from thingiverse, looks solid in solidworks.

I have a fan cooling the PLA as it comes out of the extruder, set to enable autocooling in slic3r with the first 2 layers turned off (not a heated bed).

Thanks for your help guys, I will give the propellers another try shortly and let you know how it goes..