As I am trying to become a 3D printing Noob, I am practicing both 3D design in Autodesk Fusion 360 and 3D printing my designs. I made a fairly simple Heart-shaped box for my wife.
The design of this box is quite simple. It was done by drawing two circles and two lines in Fusion 360 and then extruding that shape, then adding fillets to make the edges softer.
The box measures 135 x 117.5 x 50 mm when closed. The lid has a height of 20 mm and the box a height of 40 mm.
I made this very late night/early morning so I mistakenly sliced it in 0.4mm layer height but saved the file with a name defining it as 0.2 mm layer height, which was the layer height I had intended to print it in.So when I started printing it the next day, I realised it was 0.4 mm layer height when the print was a fair bit in. So in order not to waste that print, I let it continue.
As the first print of the box was 0.4 mm the print only took about 3 hours, but several things failed.
One of the problems is how the elephant raised in the bottom looked (see photo). I am not quite sure why this happened, but when printing it with a 0.2 mm layer height at a slower speed (version 2) it looks a lot better.
The other challenge is one I generally have with non vertical or non horisontal surfaces (see photo). I am not sure what causes these and I have no idea how to remove them other than through post processing (sanding). It does seem that slowing down the print lessens it a bit though.
Third problem is another general problem I have: First Layer. It seems that the plastic "bubbles" during first layer. Other layers (including second layer) looks a lot better. It may be because the nozzle it too close to the build plate - I will have to experiment with that in the slicer as this printer has an auto level probe on the Z axis. Changing the print speed helps with this, but it is not completely gone.
Forth flaw was how the elephant looked in the lid. First time I printed this, it was top down to the build plate. That way it would need no supports. But unfortunately that left the inset elephant looking a bit unfinished (see photo)
Fifth fail was a design error I did not realise until I had printed the lid. The box and lid were both designed with an overlapping lip so that the lid grips the box and thus do not fall off when being inverted. When designing the box in Fusing 360 I did not leave any tolerance between the two, so the grip was a bit too tight.
The main reason for version two was to make the lid and box fit better. I accomplished this by going back in to Fusion 360 and redesigned the box (bottom) part so that there is a space of 0.4 mm between the box and the lid parts. That was done by changing the inner lip to having a width of just 0.8 mm - equal to that of the lid. As the wall of the box is 2 mm that leaves the 0.4 mm gap between the parts. Unfortunately that left a gap where the two curves meet. This will be changed in version 3.
The lid remains unchanged in version 2. I did however slice it differently. First I turned it upright, that is where the top of the lid was printed on the bed on the first print, the top of the lid was facing up when I printed it the second time. The result I was hoping was that the Elephant would print better - which it did.
But as the slicer did not put in supports under the lid, except for the lip, the printer had to bridge the span of the box, which resulted in a lot of stringing. When I have corrected the gap in the box (bottom part) I will reprint the (unchanged) lid with its top on the bed itself. This seems to produce the best result overall.
Parts were printed in a generic "silver" PLA.
You can find this design on Thingiverse no 30489143048914 (opens up a new window).