Saturday, Jan 20 2018
I was printing some lithophanes when I noticed that the housing that holds the filament detector (checks for end of filament) was flopping around. The housing slides over the bracket that holds the extruder and stepper motor. There is nothing to keep it in place. That needs to be fixed. I thought of drilling some holes through the housing and metal bracket and using cable ties but didn’t like that solution.
Printing extruder/filament detector housing
Print done
Instead I went to thingiverse and found this. That’s pretty much what I was looking for. I printed mine at 0.2 mm with 4 shells and top/bottom layers using 40% infill and a fast honeycomb pattern. I think that will be strong enough for the job it does.
Original parts
Extruder disassembled
Stepper damper
Once the print was done I remove the filament I was using and disassembled the extruder. The bowden tube fitting and spring tensioned lever are used with the new housing. The printed housing does not have threads for the bowden tube fitting. I carefully aligned the brass part with the housing and screwed it in, cutting new threads.
Since the extruder stepper motor was removed I added the spare vibration damper I had on hand. There is a down side to that… the extruder drive gear had to be raised which means there is no room for the extruder hand wheel I’d earlier added. I’ll miss it.
New housing installed
I moved the filament detector to the new housing and marked the location of the mounting holes with a center punch then drilled some 2.5mm holes in the plastic. I used some 3 mm screws to hold the detector in place. I may design/print a matching cover, later.
The screw through the tension arm is one of the two that mount to the stepper damper, holding the stepper in place. It can not be too tight or the arm wont move. I’m going to watch this screw. I might need a drop of loctite to keep it in place.
I made a quick test print to verify all is OK. All is OK. The filament detector can’t flop around and the filament is held just far engough from the Z-axis lead screw that the filament won’t touch.
While looking for the housing I found some more items on thingiverse for the printer. I see more printer changes in my future.