From large to small

Having had a lot of fun with the 0.8mm nozzle, I decided it's time to try out some other nozzle sizes - small one! I got both a 0.25mm and an experimental 0.15mm (!) nozzle. I'm starting with the 0.25mm one, as that has a preset in PrusaSlicer. Swapping was not a problem (when done right and not trying to unscrew the nozzle without holding on to the heater block like I did on my old printer), and the calibration strip came out fine, best at a Z offset of -0.8mm. A test block with insane overhangs came out like this - almost all the overhangs just feel off:

According to the Prusa page on different nozzle sizes, the advantage of a smaller nozzle lies mainly in flat details, like printing your own business cards. They have an example of printing miniatures with 0.4mm and 0.25mm nozzles, and they show little difference in detail. However, they both use the same layer height, and a 0.25mm nozzle should be able to achieve even thinner layers. As a virtual test, here are some snapshots of the slicing at different nozzle sizes and layer heights, using this skeleton warrior that has plenty of detail.

Unsliced version, look at that chainmail detail! Also notice the width of the sword

Similar to the example on the nozzle size page, 0.25mm nozzle with 0.10mm layer

The same with a 0.4mm nozzle - roughly same detail in the chainmail, but the sword is thinner!?!

The finest preset for 0.4mm is 0.05mm - some more detail in the chainmail

The same with the 0.25mm nozzle - I would say the chainmail is better here

If the 0.4mm nozzle can do 0.05mm layers, surely the 0.25 nozzle can do 0.025mm layers?

Thought experiment: 0.015mm layers

Here some shots of actual prints:

0.10mm:

0.05mm:

0.025mm:

I can't say there's a huge difference in quality. 

Having a small nozzle again also lets me print another couple of things for the printer itself that need to be a bit finer than the 0.8mm nozzle can do:

A filament filter, to prevent dust from entering the nozzle. This is particularly important with small nozzles, so it's high time. Having it integrated with the extruder assembly is a very nice approach.

Just for the cuteness, an extruder motor movement indicator. There are many such available, I opted for a gear. It's theoretically possible to have a full gearing that would give a purely mechanical usage gauge, but since the connection to the motor is only with a tiny magnet, that would probably take more torque than can be provided.

And finally, a nifty little bolt-o-meter:

Numbers hand-painted with a sharpie

Note: This post is backdated to the 22nd because all the prints except the smallest head was from then, and there\s a certain sequence to the posts.