The mechanics were bolted, glued and zip-tied together, the headers of Rostock-Marlin somewhat configured for the dimensions of my RoStrap, pronterface was able to issue some commands (move to X/Y/Z, extrude) and read the temperature back…
…time to try a first print!
OK, trying to print PLA on Kapton tape, that has not even been glued wet, was not a good idea. And the metal plate seemed to be flat enough, but it’s quite cold – so let’s do something else.
As I did not have adjustable end-stops, I tried to tilt the „platform“ (cork table mat, „base plate“ see below). But next the PLA jammed.
Filament grinding is always an issue with these direct drive bowden extruders – even with 1.75 mm filament. Additionally I had ordered my hot end too cheap – http://airtripper.com/1236/j-head-mk-iv-hot-end-clone-design-quick-review/ sums up, what can go wrong, when you just buy any hot end on eBay.
Furthermore: IMHO the PTFE liner tube thing is a design flaw. Period.
Moreover: in my installation the filament was not guided properly. http://www.themgames.net/j-head-conversion-to-1-75-mm/ gave me some hints, so I tried to improve this point wit a „sharpened“ tube running through the whole PEEK insulator.
Afterwards I was actually able to have the PLA squeezed out of the nozzle in a controlled manner!
Somewhere I read that Lexan or Makrolon was a suitable substrate…
…but although the speed was still slow there was a considerable amunt of force needed to feed the material. The feeder motor got hot enough to just fold the (softened) filament.
Having overclocked plenty of PCs in the past I coose to keep a high current running through the motor windings an getting rid of the heat afterwards:
„Baking“ as well as lubricating the PLA were on the agenda afterwards. To no avail. I had to da something about the nozzle. Back then I had not heard about the atomic / cold pull method (http://support.3dverkstan.se/article/10-the)…