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0.25mm nozzle for miniatures.. just a lot of nope  

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charwoodeng
(@charwoodeng)
New Member
0.25mm nozzle for miniatures.. just a lot of nope

I've been trying to get a 0.25mm nozzle to do anything, but I've had no luck.  I did update to the latest Prusa Slicer and firmware.  I tried the 0.15mm layer height presets for a 0.25mm and added support.  It seems to clog quickly and I get what's in the picture.  I did do a first layer calibration.  I am also pretty n00b, but I've had a lot of success with various 0.4mm nozzle prints  (including a mini which took a lot of damage removing support material... at least displacer beasts have 6 legs).  The 0.25mm is just for detailed minis, BTW.

So, am I missing something?  Is there something that I'm just missing?  I can get the PLA to flow freely from the nozzle, so any clogs are melted and cleared very easily.  (I did mention that this is still the siilver PLA that came with the printer, right?)

 

This topic was modified 6 years ago by charwoodeng
Posted : 23/05/2019 1:03 am
bobstro
(@bobstro)
Illustrious Member
RE: 0.25mm nozzle for miniatures.. just a lot of nope

There's no particular magic to using smaller nozzles, but you do need to re-calibrate your Live-Z setting after switching nozzles. The picture is a bit small, but it looks like your nozzle is too low on the 1st layer, essentially grinding in on the infill at the top-left of the circle until it peels up and makes the mess at the top-right of the circle. At some point, the gap is so small that filament jams up the nozzle. It also looks like your PEI surface could use a cleaning. Even if you're not convinced these are your problem, they're essential steps to getting a solid print. Here's some of momma's original copypasta recipe to take care of the basics...

Adhesion issues are usually caused by 2 main problems:
  • A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. Take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails, and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent to give it a very light buff, but only infrequently.
  • If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. 
And above all else, avoid touching the PEI print surface.
 
Try those 2 steps. If you're uncertain of the Live-Z results, post pics here of the 75x75 print bottom and you'll get quick help. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When it's right, you should be able to gently rub it without it coming loose. Then start lowering (more negative) the level until there are no gaps between layers. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines without dislodging them. 
In the future, a good dunk with Dawn will restore both sides of your to like-new condition and is always a good thing to try when you encounter 1st layer problems. 
 
If you want more detail, I've consolidated my notes on Prusa PEI adhesion, bed cleaning, and Live-Z calibration. I've done a brain dump on nozzle sizes as well.
My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 23/05/2019 4:04 pm
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