New i3V owner: A few beginner questions

[clough42]

I'll be interested to see how the tape works out. It doesn't seem like adding insulation to the motor is the way to go. I was told by a mechanical engineer at work that the motor is designed to dump most of its heat through the machined front face. You really need to get rid of heat--not hold it in. The screw will still be conducting heat into the extruder block. I think the hot screw is primarily what causes the extrusion to yield and let it through. Maybe I'm wrong. Let us know.

I have been doing some test prints with the Makerfarm knob. I'll upload some videos when I'm done. I noticed that the design of the knob requires the printer to make a last pass around each layer, filling in a small gap at the tip of each ridge on the knob. This requires an retract/advance cycle as it moves over each gap in the knob perimeter. If your retraction is having any trouble at all, you'll get gobs of plastic built up around the sides of the knob.

[printbus]

...I noticed that the design of the knob requires the printer to make a last pass around each layer, filling in a small gap at the tip of each ridge on the knob. This requires an retract/advance cycle as it moves over each gap in the knob perimeter. If your retraction is having any trouble at all, you'll get gobs of plastic built up around the sides of the knob.

You're likely using a newer version of Slic3r. v0.9.9 just left the gaps. Newer versions fill in those gaps. I don't remember which version it was, but this "fix" is described in the release notes for one of the versions between 0.9.9 and 1.1.6. Something to the effect of improving fill between perimeter and infill. Generate some gcode from Cura for comparison.

EDIT: v1.0.1 and v1.1.1 mention improving gap fill

[clough42]

I managed to replicate the mesh top by printing on glass at 70C with no print cooling fan:

2014-08-03 18.52.23.jpg

Then I re-ran the print on cold painter's tape, with a cooling fan, and the holes in the mesh are gone:

2014-08-03 18.52.38.jpg

With the hot bed and no cooling fan, the first layer of bridging drooped down into the cavities in the knob, so it didn't provide any support to the top layers. Without any support, the top layers didn't squish, and they didn't spread out wide enough to touch, leaving gaps:

2014-08-03 18.54.31.jpg

Otherwise, there doesn't appear to be too much difference between the two prints:

2014-08-03 18.53.01.jpg2014-08-03 18.53.07.jpg

[DanSilov]

Then I re-ran the print on cold painter's tape, with a cooling fan, and the holes in the mesh are gone

This is really interesting. I will try to play with heat bed temperature to see, if my results change. I do feel that the problem with blobbing I have is related to retraction, but need to play with parameters more, to understand, what helps in my case.

[clough42]

If you're interested (and who wouldn't be?) here are videos of the above prints.

First on glass, with a 70C bed, no fan:


And on cold painter's tape, with a print cooling fan: