The design of the first extruder was improved by using the principle of captive parts. By inserting the metal parts and mechanisms directly during additive fabrication, less parts remains to assemble. The design is cleaner and easier to handle.
For example of captive parts, the springs and the compressor now reside inside the clamp. The mechanism is entirely closed and invisible. Also the two nuts that used to be inserted on each side of the pivot cylinder are now inserted during the fabrication of the pivot. A border was also added on the edge of the clamp for better grip.
For more information on the captives parts.
There are several models of ball bearings easily accessible and affordable can be used. I got my hands on a box bearing 625ZZ (5x16x5mm). However, the inner diameter is reduced, it is best to keep it with a metal rod for more resistance.
The list of materials required for the production remains the same, but the end user assembly instructions are a little more simple.
See the complete description of the latest version here.
The bowden extruder is also available for sale.
B- 1x Clamp
C- 1x Pivot cylinder
D- 1x Base
E- 1x Bearing shaft
F- 1x Idler
G- 1x Drive Gear(MK7 or MK8)
I- 1x Ball Bearing (skateboard) 5x16x5mm 625ZZ
J- 2x Pneumatic 4mm Tube Push In M5 Fitting
K- 3x Machine Screw M3x30mm
M- 2x Machine Screw M3x50mm
N- 1x Tube PTFE (Teflon) outside dia: 4mm, inside dia: 2mm, length: as needed
O- 1x Stepper Motor NEMA 17 (not shown)
P- Bolt and nuts diameter M6 or 1/4″ as long as necessary to attach the extruder on the printer (not shown)
1- Insert the M3x50 screws (M) in the clamp (B). The screw head should fit inside the bigger holes of the clamp.
2- Insert the pivot cylinder (C) in the main body (D)
3- Screw the M3x50 screws (K) with the clamp (B) and the pivot cylinder (C) through the grooves of the main body (D)
4- Screw fittings (J) on the main body (D).
5- Insert the metal rod (E) in the bearing (I) and insert it in the idler (F), squeeze a bit if necessary.
6- Place the drive gear (G) on the motor shaft (O), taking care to orient the set screw on the flat side. Lightly tighten the screw with an Allen key to hold the gear in position facing up.
7- Use three M3x30 screws (L) to screw the base (D) on the stepper motor (O) without forgetting to put the idler (F).
8- Open the extruder and insert a filament to align the drive gear (G) on it. Fix the gear in position with the set screw (Allen key required).
9- Install the extruder on the 3D printer by using the brackets and M6 or 1/4″ bolts.
10- Insert PTFE guiding tubes in the fitting(s) to the hot end and/or the spool.