2:1 Nylon Gear Reduction, Maintaining Belt Path
Description
As the 2BEIGH3 Printer is a large unit, there are times when I want to take advantage of very small nozzle sizes. To do so, I designed a 2:1 gear reduction system that uses the standard mounting holes.
A second requirement was to maintain the belt path. To accomplish this, two idlers are used.
The Belt System for the 2BEIGH3 is the XL 3/8" .200" style.
Operation is best demonstrated in a video:
youtube.com/watch?v=pD0TGcQcKG0&feature=plcp
A second requirement was to maintain the belt path. To accomplish this, two idlers are used.
The Belt System for the 2BEIGH3 is the XL 3/8" .200" style.
Operation is best demonstrated in a video:
youtube.com/watch?v=pD0TGcQcKG0&feature=plcp
Instructions
These are printed in 618 nylon, therefore they need no bearings. Instead, stainless steel "Partially Threaded metric bolts" are used. While nylon is pliable in thin parts, after about 5-6 solid layers, it becomes very strong. The pliability is used to maintain a friction fit of the drive gear, while the slippery properties are used in the main belt drive and idlers. The gears are ever so slightly oversized to maintain a constant mechanical mesh to eliminate any backlash.
The belt drive 8 T XL comes from thingiverse.com/thing:16627
The XL drives are a bit long, so you can cut to a needed length.
Print:
2-3 perimeters depending on your current nozzle size.
3 solid surfaces
60%-90% fill
For holes, we use "inch" sizes just over or just under the required metric size. This gives a tight friction fit of the drive gear, as well as just enough clearance on the idlers.
The lengths of bolts required depend on your stepper mounting flange thickness.
You'll need to update your steps/mm in software or the part will be 50% of design DIM.
The belt drive 8 T XL comes from thingiverse.com/thing:16627
The XL drives are a bit long, so you can cut to a needed length.
Print:
2-3 perimeters depending on your current nozzle size.
3 solid surfaces
60%-90% fill
For holes, we use "inch" sizes just over or just under the required metric size. This gives a tight friction fit of the drive gear, as well as just enough clearance on the idlers.
The lengths of bolts required depend on your stepper mounting flange thickness.
You'll need to update your steps/mm in software or the part will be 50% of design DIM.
License
2:1 Nylon Gear Reduction, Maintaining Belt Path by Taulman is licensed under the Attribution - Share Alike - Creative Commons license.

Yes, I noticed the belt after I took the video, but you can see it's simply clamped to a table and I just used a large plastic tube on the other end of the belt, so it's not tight. I really wanted to show that the center idler rotates opposite of the drive gear. Any 3mm hotend will do. I've had testers use all kinds from J-Heads to Budas..etc to stock. These printed at bout 238c or so.