Parts I replaced / modified:
Six end stop switches:
The original end stop switch didn’t have strong power, created many headaches.
Print bed holders:
The original parts were kind of jokes to me, unreliable and insecure. The glass bed often was moving around.
It’s a must-have device for printing decent PLA object. Virtuall all Mini Kossel kits have only one hotend fan.
I think I’ve replaced four or five plastic effectors: one from the kit I bought made out of ABS, at least four effectors I designed. After all I settled down to this laser cut aluminium effector I made.
Hotend: E3D V6 Hotend
The printing quality is excellent. I can’t compalin about it.
The thermistor got broken one day so I had to buy ten thermistors from a domestic electric shop, calibrated new thermistor with my multimeter’s K-type thermocouple.
Yesterday I pasted fiber and plaster on the heater block to stabilize temperature of hotend. It does work pretty well. The temperature stays within 1 Celsius degree compared to five to ten low and high oscillation. I’ll replace plaster insulaton with ceramic tape to maximize thermal control.
To have quality printing, the temperature has to be within 5 Celsius degrees at target value. For instance it the temperature of PLA sets at 190 C, 195 C will develop alternative layers that are easy to see.
Carbon fiber diagonal arms
The rod end bearings made out of Traxxis metal balls and rod ends. Proably after two month’s operation of Bulbul Junior, the plastic rod end developed exccesive wears. It rendered precision printing out of touch. I learned that to have longer operation hours, hot and cold method is recommended.
I invested many hours on improvised steel ball joint and spring loaded diagonal arms as you see. I bought 12 steel ball stud from a RepRap 3D Printer user in U.S.
Steel tubes instead aluminium or carbon fiber rods
Guide string – will replace steel wire.
12 rod ends, 3 carriges are PLA parts I designed.
In-place printing was successful!
Improvement in retraction
Bulbul Junior vs RepRapPro Fisher