sansthelight

3D printing frustration

In 3D Printing, Crafts, software on November 22, 2013 at 11:36 pm

I am in the middle of trying to design and print a steam punk styled chess set for my little sister.  I ran my printer for 12 hours yesterday and did not get a single usable print. My problems were myriad.  The prints where breaking loose from the platform.  The print was not adhering to itself when the print was angling over empty space as it went up,  The edges of the print were curling so that they were unusable for my purposes.  The modeling software I was using stopped generating the .stl file i needed for one of my models.  I was getting weird artifacts in the prints that I couldn’t explain.  One 4 hour print came out squished down a bit.  By the end of the day I was ready to throw the printer in the garbage and forget I ever bought it.

Luckily I woke up today with some of my patience restored and settled down to try and break down the problems into manageable chunks.  Part of the problem was my print platform.  It was not level.  There are little springs set at three of the corners so that you can level the platform but the two on the left were fully compacted and that side was still too high.  I realized that I could raise that side of the x-axis assembly separately from the platform and the right side of the assembly.  I spent two hours fiddling with the adjustments until I was happy with the leveling calibration.

The next part of the problem with models not adhering was software and design.  I had designed the models standing up and then sliced them vertically in half and laid the halves down for printing purposes.  The didn’t end up exactly flat.  This is partly due to not getting it rotated down exactly when I did it initially and partly because I have made adjustments after the split.  These adjustments occasionally extended below the plane of the model or didn’t quite make it all the way down to that plane.  This was causing the slicing program to not anchor the print down where it should and occasionally it tried printing too far above the platform for anything to stick.  I didn’t have support materials turned on because none should have been needed.  Except that because it wasn’t even there was an large portion of the model hanging out over open space.  It wasn’t a lot of space but it was enough.  So I had to go back into the modeling software and make sure that each individual point was at the level it should be at.

The third part of the problem was the slicing program itself.  I had already given up on Slic3r and was using Cura.  Cura was much better than Slic3r but they both have the same Achilles heal.  They don’t show you what problems there are in model.  They attempt to fix things themselves without actually telling you what needed fixing.  Slic3r is much more aggressive about this and can completely alter a model in it’s attempts to fix the problem.  I was using Cura because it wasn’t screwing up as much.  But the same underlying problem remained.  There were problems with my model that I wasn’t being told about.  So now I’m using my third slicing program: Kisslicer.  I’ve had problems getting this one working at all since I first heard about it.  I tried Kisslicer initially because a friend told me that it had won a number of comparisons he had seen online.  I couldn’t get it to work at all when I first tried it.  The way it was laid out was fairly different from the other programs and it used language I didn’t understand.  I might know what I needed to set up but not know what it was called in Kisslicer.  I finally got it to a mostly usable point but was running into problems with it slamming into the print stops over and over again.  I still haven’t figured out why it did that or how to stop it,  I have figured out how to minimize the problem though I think.  I start by making sure the print head is back at it’s “home” point before every print.  I also make sure that the model I will be printing is safely in the middle of the platform.  So far that seems to be working.  The thing that I do like about Kisslicer is that it tells you what the problems with your model are.  What I don’t like is that it doesn’t explain withing the program (either through a help menu, a manual, or tool tips) what those problems mean or what causes them.  What is a “degenerate tri?”  What does it mean if the windings are reversed and how do you fix it?  I did not know.  I started searching online but the first problem I ran into is that this type of thing is apparently common knowledge amongst people who do 3d modeling and so while they might mention it they almost never explain it.  Eventually I found my answers and was able to start fixing my models.  i would import the .stl file into Kisslicer and see where it threw up problems.  Then I would open up Blender (the modeling software I am using) and try to fix each problem.  I needed to watch some tutorials to discover how to fix all of the problems I was having but I’ve gotten to the point where I can generate an error free .stl file for the slicer.

While trying to fix the problems with the models that were generating working .stl files I discovered the problem with my models that were not generating them.  Despite being in edit mode on the object I wanted to print the software somehow had lost focus of that model and was generating an .stl file of nothing.  By backing out of edit mode into object mode I could reselect that object and get a working .stl file again.  Having to start over on some models got me thinking about other ways to take them and now I have a few extra ideas on what might work.  I’ve decided that the models I had already finished will stay finished.  I might use some of the new ideas on models I am still working on though.  After all of this I have a better understanding of what will work and what won’t.  The new ideas are predicated on this new understand so I think it is worth pursuing them with some of the unfinished models.

I managed to get one usefull print done this afternoon (a base for the one of the pieces) and have a second model printing right now.  It looks good so far.  The big issue now is that I probably have 100 hours worth of printing to do.  The design stuff is on schedule.  I have the King and Queen completed.  The models for the bases and for the board itself are also completed.  I have two ideas I am working on for the rook and two I am exploring for the knight.  The bishop I built once already and somehow managed to delete it.  It is the easiest of the pieces on the back row to build and it shouldn’t take more than an hour or so to rebuild.  The pawns will be very basic and shouldn’t take me more than 45 minutes to build.  I already have 70+ hours of printing with the models that are already completed (the board is taking the majority of that) so I shouldn’t have any problems completing the models for my other pieces in time.  Of course it could all go wrong again at any minute but for the moment I have overcome all of the obstacles that have been thrown my way.  If I can find some extra time, I want to experiment with all three slicing programs using models that I have fixed.  I am interested in seeing what the quality of the prints is once the program is no longer trying to fix the model on it’s own.  There may be a final slicer comparison blog in the near future.

-h

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