0.2mm nozzle: worth the wait?  

Re: 0.2mm nozzle: worth the wait?

Especially for the functional parts you will get less robust result. Smaller gears will break faster.
Beside of that 0.2 nozzle generates more back pressure and requires more or less perfect calibration if you want to print small parts.

Plastic shrinkage is independent of nozzle size. It's material(plastic) property.

Re: 0.2mm nozzle: worth the wait?

I have printed a few gears with my MK3 using the default 0.4mm nozzle. The first item was a mechanical hummingbird downloaded from Instructables. The gear teeth in that design are extremely small, somewhere around 36 dot pitch. This would make a 36 tooth gear around 1 inch in diameter. It is functional, but slightly pushing the capabilities of the standard nozzle.

My next gear project was a pendulum clock with 20 DP gears. I started with an experiment to find out the best size. I tried 16, 20, 24, and 30 DP sizes in addition to the 36 DP from the hummingbird. 20 DP appeared to be a great size and that is what I used in my clock. They are easy to print and appear to be fairly strong. I made the large gears 0.2" thick and the pinions 0.35". As a reference, I make 10 DP gears on a CNC router with a 1/8" router bit. The 20 DP gears in my clock are half the diameter of the gears in a wooden clock.

A 0.2mm nozzle should be capable of printing smaller gears. My biggest fear would be nozzle clogging with such a tiny hole size. Use the highest quality filament that you can find.

Steve

Re: 0.2mm nozzle: worth the wait?

I have tried using a 0.20mm with no luck, but have since gained a lot of experience working with a 0.25mm nozzle. A smaller nozzle makes sense if you need to print details on your XY plane smaller than your existing nozzle. For example, I printed 1:100 miniatures with bolts on the top surface. Using a 0.40mm nozzle, there was just a smear at that location. Using a 0.25mm nozzle, the bolts were clearly printed. However, the bolts also printed nicely with a 0.30mm nozzle, and more quickly. Printing that part with a 0.20mm or 0.15mm nozzle would take longer and not gain more detail in this case. Also keep in mind that details on vertical walls will depend more on layer height.

FWIW: I believe the smallest supported noze from E3D is 0.25mm. They do produce a 0.15mm but it's sold as experimental. Cheaper nozzles may not be as accurate and might have other quality issues. My 0.20mm was a generic brass. My 0.25mm is an E3d plated copper. The 0.30mm generic brass seems fine. I've got an E3D 0.35mm plated copper on order.

Re: 0.2mm nozzle: worth the wait?

For gears specifically I'm indeed looking at higher detail in the XY plane, where the plane of the teeth normally is.
I never had limitations in the resolution of Z.

@bobstro: I'd be curious if you have some pictures of the same gear printed with different nozzle sizes.

My guess is that at these nozzle diameters, anything but PLA doesn't make sense, but I'd be happy to be proven wrong. Any success in using PETG?

Re: 0.2mm nozzle: worth the wait?

[...] @bobstro: I'd be curious if you have some pictures of the same gear printed with different nozzle sizes.

My guess is that at these nozzle diameters, anything but PLA doesn't make sense, but I'd be happy to be proven wrong. Any success in using PETG?
I have tested PLA using the "Shermie" 1:100 miniature print that I use in place of Benchy:

The 0.25mm nozzle print is on the left, 0.40mm nozzle print on the right. Both are printed at 0.10mm layer height. The treads are printed horizontally with the round surfaces facing up. You can see the difference in detail on the bogey frames and the bolts on the large idler wheel.

I'd be happy to do similar prints with your gear model if you provide a link to the STL. I mostly use PLA for detail prints, but will give it a go with PETG, NGEN or XT if you like. I don't have nylon available.