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Thursday, January 31, 2013

Print success by orientation

The story is I'm printing a replacement key that someone who had never done home 3D printing designed. Without thinking I just threw the STL he sent me into the printer instead of looking it over first.
Never a good idea. The problem was the peg in the middle was actually raised off the build platform. So when it finally got to printing that peg it was already printing in thin air, attached to nothing. So I went back and forth with the designer a few times while I coached him on how to fix the object to make it more printable. Things like lowering the peg so it touches the bottom and adding support for the LED hole on the face so it won't mess up the bridging on the top of the key. Eventually he asked the question that should have been asked at the start:

"...does it make sense to print from the top down instead of the bottom up?"

In other words if I printed the model upside down of how it's going to be used with the face of the key on the print platform wouldn't that solve the peg problem? The answer of course is, well, yes it would, but I had already done all this work on making it printable the other way around. So I printed it both ways.
Face down means that one was printed with the face of the key on the build platform and is practically unchanged from the original mesh. Face up is printed in the same orientation it'll be used and has been modified to be more printable; thickening up the peg and adding supports to the hole on the key face. The one on the left may look messed up on the face, but that's because I needed to level my build platform. My mistake. Notice the bridge layer on the right is still a little messed up, but the one on the left is pretty. That's because on the left it's not a bridge, it's the floor. If I had gotten the build plate properly leveled I'm pretty sure the one on the left would have looked as good on the outside as the one on the right.

The point of this is you can save yourself some headache if you remember that you don't need to print things out in the same orientation they're going to be used.


  1. I wonder if this would also work well for arcade buttons that have larger surface areas but are cylindrical.

  2. Absolutly. But if you want the rounded top you're going to have to deal with bridging which may or may not work depending on how "dialed in" your machine is. For me, I don't make perfect bridges, but the top will look fine.

    Care to send me a 3D model and I'll print it out for you?

  3. I think I'll have to make one based on measurements taken of some actual ones I have on hand. There's also a groove around the outer diameter so you can screw it into a board. And...I just noticed the button mechanism has a spring on the inside that controls depressing the feet down, which throws the switch.

  4. G'day Joe

    This seems to be kind of the right place to ask you this question.

    I read your blog a lot, it's very informative and you've pretty much become my impartial expert in 3D desktop printing as your posts are very balanced and unbiased and no nonsense.

    Right, now I've got the flattery out of the way... ;)

    On the subject of print success, I was hoping I might ask your advice on my first design for print.

    Following your post about the Makerbot Customizer Challenge, I furiously got to work learning OpenSCAD and have entered a model.

    Now I don't have a Replicator 2X yet (I'm saving up my bikkies in case I don't win the comp) so I am unable to run some test prints of my design.

    I was hoping you could use your expert eye and possibly give me your view of how well/easy the parts might print.

    I'm pretty sure I've got most of them structured to print fairly easy, but I'm sure you could tell better than me.

    I'm not asking you to print them out, just a look would be very much appreciated.

    Thanks Joe, I hope I'm not asking too much and am not being rude posting this here!



  5. How can I not print this? Awesome.

    So here's the skinny. Aside from being exactly upside down most of the parts should print okay. 2mm thick walls, good stuff.

    With the exception of the third, which I'm guessing is no surprise to you. That huge overhang on top. Yes you supported it so it has bridging but the bridging is irregular. Bridging is tricky. The printer doesn't know it's printing a bridge so it will still try to do the outline before doing the fill. The only reason a bridge works is if the bridge is straight across. Anything that interrupts that, like the notches for the fans, won't print.

    Also the letters are sticking out just a little too much. They should only be about 1mm off the face.

    There may still be hope. Maybe if the front, the face that says "LOLCopter" now, is placed face down. Of course the letters will have to be remove or made relief. There'll still be some overhang issues to overcome, but they should be manageable.

  6. Hey, thanks for the feedback :)

    OK, I see I need to structure the script so the STLs are exported the right way up for printing.
    I figured that people would do that in Makerware or something similar. My bad.

    Bridging is definitely something I know little about.
    I figured the front could be layed face down, without any text showing if necessary.
    I'll have to figure out how to make it two pieces and still provide structural stability, not knowing how to account for printing overhangs etc makes it a challenge.

    Again, thank you very much for the feedback Joe, it's very much appreciated.


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