BaronWilliams wrote:I do both prototypes for structural parts and objects designed just for art/beauty. Sometimes with prototypes, beauty is more important than structural strength.
Actually, with prototypes, I have banned anything but "perfect" looking models from being viewed by outsiders. It is amazing how many people lack the imagination to overlook an ugly print, even when you show them a computer model.
Unfortunately, when showing a print, an ugly 3D print can sometimes cast doubts in peoples' eyes about your abilities despite the model actually being very well designed. If they understand 3D printing, and it's limitations, this is not likely, but for those who don't understand, an ugly print can poorly reflect your abilities. If you are having to explain why the print is ugly, things are not going so well. That's the last thing you want to talk about. That's why I try to give myself some buffer time before a model needs to been shown. I want to at least print a few test runs before showing a model. If the print is not good despite several attempts, then it's time to do some post processing (sanding, polishing, painting, etc.).
Back on topic, the structural properties of the soap bubble and the honeycomb structure don't completely apply to 3D prints. For example, a real soap bubble has it's molecules all equally adhering to each other. If we printed a bubble on a FFF 3D printer, each horizontal slice is a ring made of 1 line of plastic, with a start and end point. Between the start and end point, the line is 1 solid well fused line, but at the end points, it is a weak bond. So it's not a complete ring. It's a ring with a weak point at one end. It will also be impossible to print all the rings from bottom to top using a single wall for each layer without adding support material.
Likewise, the typical "honeycomb" infill most slicers offer doesn't give the strength advantage of a real honeycomb. It's a simulated honeycomb, not a real honeycomb. A true honeycomb structure is not really possible on an FFF 3D printer, because you can't even make a hexagon without having a weak bond somewhere in it, and you certainly can't link these hexagons together without several weak bonds between them.
The "honeycomb" infill that I have seen in many slicers isn't even a bunch of hexagons, but rather a bunch of zigzag lines that sort of look like a honeycomb when combined together. This simply does NOT give the same structural advantages a real honeycomb offers. You could get something similar by drawing hexagons between these zigzag lines, which will give you strength close to a real honeycomb, but this also requires more filament, so it's a trade off. But either way, the infill is pretty strong.
For FFF 3D printers, I think we're still in the early stages of development when it comes to optimal infill. More experimentation needs to be done.
Having infill that becomes less dense horizontally and vertically as it gets closer to the center would help speed things up. The ability to go from 70% infill at the outer regions to 10% at the center would be nice.