printing tips please, my print is all bubbly on one side mostly...

Months ago, I ran tens of test pieces with different layer heights and widths, following the calibration guide here [github.com] at the time slic3r was defaulting to around 0.78 for width, I overrode that and set it to 0.5 for my tests, it worked, requiring an extrusion multiplier of 0.9. I use 0.5 mm because I want 1mm walls on my prints, many of my prints are designed for other parts to press or snap fit into (such as rectangular sockets for photomultplier modules measuring 50.2 by 22.2 by 5mm deep the first two dimensions are taken from the module, which stands 22.2 tall also - the modules snap in and out of the sockets perfectly) - maybe you're overlooking something?

Perhaps it's because you seem to think that adjusting extrusion multiplier is somehow wrong? The rheology of the molten plastic makes for a pretty complicated set of factors affecting what happens on the print. The viscosity and elasticity of the plastic are important, and also temperature sensitive, and it's impressive that slicers (in general) can compute so well - the extrusion multiplier is pretty much a fudge factor that you can use to make sure that the calculations it's doing come up with the right answer at least if you keep the printing conditions the same as those you used on the test piece.

Ray

Inspired by your answer, I run some more tests, now with different extrusion multipliers and even nozzle width settings. Rather than high-jacking this thread, I've started a new one here.
If you want 1mm walls I suggest you set the perimeter width in Slic3r to 1mm, rather than changing the extrusion multiplier. If you try that now, with your current extrusion multiplier, I think you will see that it does not extrude enough material to reach 1mm.

Edited 1 time(s). Last edit at 03/09/2014 12:19PM by Flyskyhy.

The only thing is that having a perimeter width as big as 0.75mm will surely make sharp corners on such things as gear teeth etc. worse than a thinner wall thickness. The sharpest corner would have a 0.325mm radius. My prints seem to turn out OK after I set an extrusion multiplier of 0.833 to get the perimeter width correct at 0.5mm

Dave
(#106)

Sorry late replying,
Didnt get much of a chance to print over the weekend. I havn't yet had a chance to try the cube wall thickness test as i was having some trouble with teh Zprobe and zaxis gears.
however, last night I tried to print IamBurny's herringbone zgears as i'm getting worried mine are making a fair bit of noise at the moment (out of curiosity i set the extrusion multiplier to 0.9) The result was much better.
I then set the bed calibration manully (as suggested on another thread) and lowered the extrusion multiplier to 0.85, and the result was SPOT ON, Unfortunatly i didn't get to finish the prit as it was getting late but it looks like the extrusion multiplier was the issue. I will print the cube next to get a more accurate reading of what the extrusion multiplier should be set at.
Will try again tomorrow, thank you all for you input

Edited 2 time(s). Last edit at 03/11/2014 06:21AM by 88Zombies.