Having a reliable extruder is key to quality printing.
I’ve run into four extruders that gave nasty operational problems on Steel Fisher.
B’Struder: Universal Bowden 1.75mm Extruder
http://www.thingiverse.com/thing:711401
I call it B-struder beta for Steel Fisher.
Stepper motor plate
– B-struder_1515_plate.stl
– Layer height: 0.25 mm
– Kysan Nema 17 5.18:1 geared stepper motor
– M3x12 x3
– M3 washer x4
Steppr motor plate
Idler arm
– B-struder_arm_M5.stl
– 623 bearing x3
– Pushfit Fitting x1
– M3x12 x1
– M3x25 x1
– M3 nut x2
– M3 washer x3
B-struder
Fisher mount bracket
– steel-fisher-mount.stl
– M3x12 x2
– M3x15 x2
– M3 washer x4
– M3 nylon locknut x4
B-struder
How it performs?
It could push through grooved filament like the photo.
B-struder
1st trial
the position of B-extruder was too low. It prevented the effector moving to Y tower.
Wrong position
2nd trial
I designed the mount bracket using OpenSCAD.
B-struder
The design error of the bracket created slight bending of Bowden tube. Heavy retraction during a print, B-struder failed to extruder filament.
The bending of Bowden tube creates retraction problem.
3rd trial
I thought the compression spring would provide enough force against the idler arm. But it turned out lack of tension again created retraction problem during a print.
4th trial
I was lucky to find a spring that was almost identical to the description on B’struder document at a spring shop.
Specification:
Length: 30.00 mm
Outer diameter: 10.00 mm
Wire thickness: 1.30 mm
B-struder
The plate showed layer sepration, eventually fell apart middle of printing. The idler arm was moving back and force during retraction which caused no extrusion.
Filament is eSun 1.75 mm. Half of printed parts out of this filament cracked or broken. This is by far worst PLA filament I’ve encountered. I hope this is just a misfortune of picking a bad spool.
I decided to use eSun which is 20% more expensive than other PLA brands in South Korea after using a eSun filament came with Fisher Beta kit. eSun PLA was more flexible, showed consistent property over temperature variation.
