At low layer heights (0.1mm) doing fine detail prints, the individual segments are extremely small extrusion volume. Since volume is a distance of a KNOWN filament diameter being pushed in, extremely fine AKA super short sub mm precision distances of filament being pushed is required.

Just like riding a in a vehicle with large knobby tires you can feel additional vibration and variations in that the tire wants to move to flat spots in the tread, a larger tooth gear (in this case) has detents that cause micro variations in the actual filament delivered VS the commanded distance. A fine tooth gear more uniformly bites into the filament, the teeth are smaller and sharper and provide better bite.

The PROOF is in the print. I ran into minor skips in extrusion in an extremely fine detail test print with lots of retraction using the stock gear. I had not seen any errors before this and largely, the print still shows the amazing precision of the printer.

Now, in no way do I claim that is a good print. I’m in early tuning stages but the amazingly small tiny sharp points, on the spikes is just amazing to do that with a sub $400 printer. But, there are fairly obvious variations in extrusion throughout the print- and when it got into the fine retractions at the top when moving between the sections of the print, there was some obvious skippage, but it did recover.

Here is the exact same file. I did not reslice. I didn’t change a single settings. I just changed the drive gear on the extruder, and used the EXACT same filament, same file, same temps, same speed, same settings and reprinted. There is the issue this is 0.1mm layer height and I forgot to add more roof and floor layers so this is only 3 roofs and floors at 0.1 which isn’t enough. But the improvement from simply changing the drive gear is obvious.

Check out this side by side below. Left is the stock i3 brass 26T gear, right is fine pitch D4 series steel drive gear.

It’s so hard to show in a picture the scale of how small this really is

I’m not pulling any bait and switch here, this is all printed on the i3. I simply printed as stock with the brass gear from microSD, then reprinted the same file after swapping the drive gear. Some might claim over or under extrusion differences but that doesn’t account for the skipped extrusions in the fine detail retraction near the top. It’s rather obvious, the previous D4 steel fine pitch drive gear is worth every penny.

From left to right.

  •  A genuine D4 Wanhao drive gear (Source: Uncle Chuck, U3DPS)
  • A Flashforge drive gear (just a tiny bit shorter) (Source: Flashforge )
  • The original brass drive gear.

10.65 outer diameter by not more than 12mm long, but not shorter than 11mm long, 5mm bore. Again, you want those super razor sharp steel fine teeth. There are only a few sources for this gear to do it right.  Instructions to change the gear.