Jul 31, 2016 at 9:17 pm #11443
I’ve been having great results printing PLA with 70 deg bed temperature and 215/210 nozzle temperatures. The layers are clean and sharp and stick well to the glass. When I allow the plate to cool, the model is waiting to be carried away, as it has already been released by the temperature change.
I recently attempted a complex model with overhangs. The use of PLA as support material results in a mediocre surface and on some parts of the model, impossible to remove artifacts. I have some carefully sealed PVA in 3mm and attempted to use it. There is no popping noise or indication of moisture from the material, which is how it should be, as this first test was performed immediately after opening the filament bag.
The PVA does not bond to the bed surface, but is dragged along by the nozzle until a portion of the model is contacted. If part of the model contains the PLA, the PVA will partly bond but is also easily knocked by the nozzle on the second or subsequent passes.
My research indicates that I should be using temperatures in the range I’ve noted, but I’ve also seen that slower printing is suggested. Currently, the printing speed is at the default of 3000 mm / minute (50 mm / second) for PLA. How much slower should I be printing with the PVA extruder? Are there any other settings I should adjust after slowing the PVA side? I’m using Simplify3D for my slicer.
fredAug 1, 2016 at 10:22 pm #11472vladParticipant
We tried printing with PVA (Esun) support a little bit.
We used Cura and BCN profile for PLA_PVA, can’t remember the temperature for PVA (200-210). Bed temperature was 60. Printing speeds are by default.
We also use 3Dlac – the spray supplied by BCN, I think you need it for everything except for PLA (but it’s still better with spray).
Our problem with supports is that wipe tower usually breaks down somewhere in the middle. The other problem with PVA is that it’s oozing and gets between PLA layers which weakens the part.Aug 1, 2016 at 11:02 pm #11474
Thanks for the insight. It doesn’t sound as promising as I had hoped. In contrast, I have a now-orphaned Cube 3rd gen printer which has dual extruders and the results have been consistently good. Slow print speed, as the head assembly sits idle while the non-printing head cools and the soon-to-be-printing head heats, which makes the Cube a less than ideal comparison. Print time for the Cube with dual extruders operating is four times or greater than the same model with single extruder. The Sigma wins hands-down over the Cube in that respect.
I suppose adding bed glue would be the first place for me to start. I did examine the settings for Cura, but the configuration is a good bit different from S3D other than the obvious stuff. Knowing the speeds are “normal” or “typical” is indeed helpful. I think I’ll build some simple test models, rather than to print a production item.Aug 3, 2016 at 4:14 pm #11520vladParticipant
I was wondering whether S3D gives more control over support structure, because Cura doesn’t have many options available.Aug 3, 2016 at 6:58 pm #11528
There may be other options in S3D, but I’ve been using the defaults thus far. Doing so has resulted in too-firmly attached supports in areas difficult to access. In severe cases, I’ll use MeshMixer to generate spindly supports and those print far better.
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