Tag Archives: raft

Working on my automated build platform

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I had some technical trouble with my automated build platform today.  (Yesterday?  Last night?  It all blurs.  :) )

I’ve fixed some problems and found others.

Right now I think there may be a slight kink in my filament spindle box.  The extruder motor kept running but no plastic came out in one build job.  I can successfully print using the ABP as a heated build platform – but it is only really successful with single print tasks.  More than that and it screws up the raft.

I’m tempted to lightly sand the automated build platform belt to see if that helps.  If not, a friend suggested using blue painter’s tape on the platform.  I’ll try the tape first tomorrow.

Skeinforge settings changes

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I figured, why not treat this blog as my lab book, right?  It’s a good way to document changes in settings, as well as my rationale for doing so.  Thusly, and without further ceremony, delay, pomp, or ado, I present for your kind consideration and review my latest Skeinforge changes:

  1. Skeinforge->Raft->Activate Raft: checked->unchecked
    • Now that I’m printing in PLA, I won’t need the raft.  As you can probably tell from the pictures below I’ve covered my acrylic build base in blue painter’s tape.  I think I’ll probably just take one of my spare foamcore build surfaces and cover that with blue tape and give that a shot.  I’ve noticed that as soon as my extruder heats up the PLA starts to ooze out.  This isn’t a problem as far as I can tell.  However, it does let some PLA drip – but when I start to run the extruder again it doesn’t extrude at all.  My guess is that the oozing PLA is dripping out of the nozzle, which then has to be filled back up to extrude.  ANYhow, my point is that if I heat up the extruder and don’t immediately start to print it will take a while to fill the nozzle, which means the raft gives the extruder sufficient time to get going before the part is being printed.  Rather than print a raft, waste the plastic, and then have to chip it off later it makes more sense to make sure I advance the extruder a little before I start printing.
  2. Skeinforge->Fill->Infill Solidity (ratio): 0.4->0.3
    • I’ve printed with as little as a 20% fill with no noticeable problems.  I suppose it would really depend on your model.  If the top of the model begins to taper up to a point, then you could probably print with 0% fill.  However, if the top of your build is flat, the topmost layers won’t have much to rest on and will sag just a little.  This doesn’t appear to be a structural problem, but more of an aesthetic one.
  3. Skeinforge->Fill->Infill Begin Rotation (degrees): 45.0->90.0
    • I tried reprinting Zaggo’s whistle in PLA and it didn’t come out – just like it didn’t come out in ABS.  I’m not sure how or why, but my infill rotation got set to 45.  I figure I might have a more solid fill/wall if I had this rotate to 90 degrees.  We’ll find out!
  4. Skeinforge->Fill->Solid Surface Thickness (layers): 3->4
    • This was just a slight tweak to see if I could make solid layers slightly more solid and waterproof/airtight.

MakerBot Raft Settings

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I was having some trouble getting my rafts to stick to the build platform until I did the following:

  1. Switched to the acrylic build base (which I promptly pock-marked with a hot extruder)
  2. Changed the Skeinforge raft settings to those suggested on the Thingiverse blog

If you’re having raft trouble, do both of the above and don’t look back.

First and second test prints

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Well, I’m trying the traditional mini-mug!

Mini-Mug test!

Mini-Mug test!

Something tells me they’re not watertight.  The first one (left) snapped off the foam-core raft part way through the build.  The second one (right) got all gloppy and then snapped off the foam core raft part way through the build.

Except for the fact they’re not even close to done, the adhesion between the layers seems pretty good.  The raft on the second one was a little gloppy which caused me to be a little apprehensive throughout the build.  After a few layers the gloppiness evened out.  However, it cropped up again, accumulated, got super gloppy, and ruined the build.

Suggestions?