Friday, 6 May 2016

Step up the reactor power three more triangles!

Took apart the hotend after failing to do an atomic while it was put together. Saw some black stuff on the second pull. These pulls are more difficult than I'm used to, I guess the tolerances are smaller.

Several pulls later. It still takes a lot of pressure to get filament through, even at 200 C. At 210, it goes smoothly (and slightly smokingly at first!), but soon becomes tougher and eventually it becomes almost impossible to press anything through. The pulls come out clean, though.

Could I be feeding filament too fast? I would rather not turn down the speed, but it could be a start, then up the speed to as much as it can handle.

Could there be a gap between the nozzle and the heat break? Then filament would squeeze in there once it softens enough and gets under enough pressure, and that would create extra drag.

I also need to fix the gears before they eat each other. Dremeled the hole some more, and rotated the nut, now it

Weird. I set up to do a 5cm test extrusion at 25% speed. When I first hit extrude, it ran crazy fast for a few seconds (while actually extruding), second try was indeed at very low speed.

Doing a second test, I notice the filament comes out at an angle before falling down nicely. I seem to remember that being a sign of clogging.

Second test @25% speed, 200C (properly measured) was spot on in length, good.

Third test, same settings, the filament doesn't fall in the same nice circle, but more randomly. Length is 4 mm short.

Pro tip: After doing test extrusion, check for random pieces of filament around the moving parts.

Fourth test @25% speed fell 2mm short. Chalking this up to random variation or poor measurement.

First test @50% speed (50mm/min). Extrusion is now straight and the filament falls in a nigh-perfect circle. 4 mm too short.

Second @50%, accidentally 10cm. Fell 9.5 mm short.

Added a piece of soft foam at the filament intake to get dust off.

Third test @50%, fell 4mm short. I'm starting to see a pattern here.

At 75%, fell 4mm short. Good.

There's definitely drooling going on at 200C.

At 100% speed, fell first 8 then 10 mm short. Not so good.

Back at 75% speed, first 6 mm short, then 5mm, then 6, then 5.

Some posts indicate that the e3d is not the best for PLA, because it has a relatively small heating area, so you need to raise the temperature or lower the speed. That matches what I have seen. I guess I will print at 200 or 210.

Recalibrates ro 204.5. Look, I gained half a millimeter of printing height due to much engineering effort on the e3d team's part.

Putting the new fan duct on. For reference: Red goes on the left of the two bent fan pins,  right goes on the loose wire from the ribbon cable. Gcode to start/stop fan is M106 S127/M107.

The current assembly (not cabled to avoid touching the bed yet). If you look carefully, you'll see the hotend mounting screws sitting at an angle and not all the way in.

Aaand... it's totally misaligned. There is no way this fan will work, it goes over a centimeter below the nozzle. A better design would lay the fan flat like the original, but just have a wider opening for the hotend.

Update: Looks like this design might work:

No comments:

Post a Comment