I use OpenSCAD to view the design and fine tune it. I type "openscad tube.scad" to run OpenSCAD. Once I like how it looks, I type F6 to render the design, and then "File -- Export -- Export as STL" (F7 is a shortcut for this) to export the design as an STL file. I work entirely in mm. Here is the file:
I want to select more infill. There is a display on the upper right that shows the settings, but is also a menu, just click on this and drag the blue ball to 100 percent. Easy, but I need to remember to reset it for next time. A little "x" dismisses this dialog.
A button on the lower right says "Slice", so I click it.
The button changes, now predicting a 7 minute print time and offering a button to save to disk. I click this button. I get a file save dialog and save to "tube.gcode".
cp tube.gcode /run/media/tom/6331-3331/Which does the job on my linux system. I take the card back to the Ender 3 Pro. It plugs in upside down. The Ender doesn't know there is a TF card, so apparently the thing to do is cycle power -- and that does it. I select print from TF card, select tube.gcode and away it goes.
It heats the bed to 60, the extruder to 200, then I discover the filament is broken. See "printer hell" below. Once I get filament set up, it indeed heats first the bed, then the extruder, then starts printing.
First it prints a line along the far left (to get crud out of the extruder presumably). Then it prints a circle around where my washer will be. Then it gets busy printing my washer.
While it is printing, I start up Cura again and put the infill setting back to 20 percent, which I guess is the default.
They say PLA shrinks about 2 percent, which for a 30 mm object would be 0.6, hence giving a 29.4 diameter as we see. Oddly the outside diameter did not shrink this much. It looks like good old trial and error is the only thing here. Note also that OpenSCAD approximates circles by a polygon (which I specified to have 60 points). This will change dimensions somewhat.
Don't expect to be able to move the filament feed motor until you get the print head heated up. So heat up the head for PLA, then move the extruder axis until you see a worm of filament coming out of the extruder.
Adventures in Computing / [email protected]