To ring in the new year, I thought I’d post a couple of things that might be of interest to people.
The first is my build of the Papilio Lite Extruder that @Sineos mentioned in this thread:
I’ve designed it into a toolhead with a Dragon V6 Hotend.
Here is the CAD drawing with the front cooling shroud hidden:
Here it is in operation:
I’ve run about 1/4 kg of PLA and 1/2 kg of PETg through the toolhead with good results - no better than another toolhead with a Micro Swiss extruder and a Dragon V6 Hotend. I see no evidence to support the claim that you get a better quality print because there are no notches cut in the filament by the extruder by using belts.
The design is fairly attractive but not without its faults. I used all the parts recommended by kevinakasam and found that the stepper binds unless you place some washers between the stepper motor body and the “BaseLower” print. Along with that, you can easily over tighten the bolts and cause the gears inside to bind. It is somewhat tricky to assemble - I would have liked some tool designs to make installing the belt as well as positioning the belt and pulleys assemblies into the frame easier.
In terms of operation, I was surprised that there was quite a bit of filament slippage at the start but this went away after a couple of hours of printing. I guess there’s some kind of coating on the belts that needed to wear off.
I must point out that in kevinakasam’s web page there is the notice that the design is open source with the CAD files available - this is not the case. In fact, I tried to contact kevinakasam directly asking for a completed unit .stl along with dimensional drawings on his Discord channel, never got a reply and was told that he wasn’t willing to publish this information because he was afraid people would steal it.
In terms of operation, the extruder works well. The thumbwheel requires too much force to move when its installed in a printer but it will easily “Extrude” and “Retract” with the stepper for filament changes. It seems to be able to execute quite quickly and once broken in (see above) I haven’t had any evidence of filament slippage.
For the second piece, I found this tool for calibrating retraction lengths to be very useful:
http://retractioncalibration.com/
It provides gcode for a tower that allows you to fairly quickly determine what is the optimal retraction distance for your hotend.
I look for the value with the cleanest “nub” as well as the printing on either side. It works quite well and is easier to work with than the one in Ellis’ tuning guide.
What I found interesting is how the results can vary from toolhead design to toolhead design. I got very consistent results for my two printers with basic Micro Swiss NG hotend/extruders (the image above is from one of them, starting with a 0mm retraction) but how much it varied for a Micro Swiss NG hotend/extruder with a REVO heater/nozzle combination as well as for the Papilio Lite/Dragon combination presented above along with a basic Micro Swiss Extruder/Dragon tooldhead.
Hopefully this will be of use to somebody.
All the best for 2024!