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.
Hi, I can’t comment on the Extruder steps setting page for some reason so am adding the comment here. The Gcode specified in the extruder calibration page ( G1 E100 F150) will not give true calibration. The F150 value is too fast and the extruder will skip. I recommend F50, so G1 E100 F50.
Thanks. I will change it. It works for some depending on the extruder they use but it will always work if you go slow so it won’t be a problem.
any idea where you can get one of these in Australia?
I am not sure about a direct reseller in Australia. You may check with the resellers of the I3 and see if they can carry them.
Aargh! I wasted my money buying a new gear. My Wanhao Duplicator i3 v2.1 came with a stock steel fine tooth gear. I didn’t notice until I had it opened up ready to replace. The v2.1 gear still has the same smooth section like the older brass gear, but the teeth count look like the “genuine D4 Wanhao” drive gear and has the same steel color. I guess Wanhao read this wiki.
Can you email me a photo of it and I will modify the wiki. Wanhao does update the printer over time based on feedback.
The “new” gear that Wanhao is supplying is not as good as the recommended gears so you didn’t really waste your money. They are really just using a gear designed for driving belts and the teeth have a flatter profile and still don’t bite as good into the filament. There is a whole discussion on this on the google groups.