[ADDED] Honeycomb infill

[AndersE]

But he did not invent the rock, he invented the pet (rock)

[CT4]

I would also like the developers of this great software to add Honeycomb infill. At the moment I am having to use 50% infill in S3D whereas I can use 20% Honeycomb infill in Makerware or Slic3r and get a stronger print! PLEASE PLEASE add Honeycomb as an option.

[joesoap583]

HoneyComb infill. It is slower to print but helps to strengthen the part.

Is there any scientific evidence that this does strengthen the part? I would have thought that maximum strength came from a lattice of straight lines which alternate 90 degrees from each other. With honeycomb the lines continually change direction, and I wonder if each of those line joints might introduce a weak point?

Just asking like.

[BaronWilliams]

Good point joesoap583. A honeycomb structure is one of the strongest simple structures there is for certain materials. But for FFF printers, bends of any kind introduce weak points if they rely on adjacent bonds for their strength. With the honeycomb all the print lines are like zigzag almost, with each bend point relying on an adjacent bond from another line for their strength. This is not a true honeycomb, but rather a series of zigzag like lines making something that looks like a honeycomb. The bonds that make up the honeycomb from the different line are weak bonds. I highly doubt an FFF created honeycomb infill is going to give you the strength advantage people are assuming because it's not a true honeycomb structure because the bonds making the honeycomb are not full bonds.

We need some actual scientific proof.

[joesoap583]

That's what I thought. If it doesn't increase strength then the justification for honeycomb infill would come down to cosmetic reasoning. Sure, the honeycomb looks nice and its "busyness" might suggest extra strength, but in reality it might actually detract from its stated purpose.

I'm happy to be persuaded otherwise, I'm just not convinced.

[CT4]

I have printed a number of objects that are used on a daily bases in a company I work for. All of the ones with Honeycomb infill have yet to break, the ones printed with S3D liner infill fail in a few weeks. Out of intrest I have printed a few cubes with different types of infill and placed these in a load press, in every case the honeycomb withstood up to 2 twice the load before failing. While i acknowledge this is not a scientific proof of the difference in the 2 infills it is an observation under actual usage conditions. I know that we must all believe in the science and principals of engineering after all they proudly tell us a Bee can not fly!!! fortunately no one told the Bee.

[jimc]

ct4, you may have done this already but do you have "random infill placement" turned off?

[BaronWilliams]

CT4, I don't doubt your test results. I also don't think the infill options in Simplify3D are that great. I think they are the software's weak point because of how the lines are laid down. There is no option to even have a square or triangle, just lines.

My argument is that the honeycomb that slicers make is not a true honeycomb and so the assumed benefit is less than predicted. There are many different ways to slice a honeycomb. Some are expected to be stronger than others. The "zigzag" method is quick but probably the weakest. Drawing each hexagon using full single strokes is slow but better, etc. Plus most slicers are only making 2 dimensional honeycombs which is weaker than a 3 dimensional honeycomb, if it's a true honeycomb. But again, a true honeycomb is not possible on an FFF printer.

On a 3D FFF printer, a single wire frame 3D cube is STRONGER than a single wire frame 3D honeycomb, because the diagonal lines made of many horizontal layers are super weak. A 3D printer can make a line rising straight up easily, but a diagonal line rising up is vary hard to print. Hence, why a cube is much stronger in the Z direction. That's why slicers don't offer honeycomb infill that's a rising Z ordered honeycomb; they are always flat honeycombs (X/Y).

I'd like to see a comparison of all the different infill patterns that exist.

[coberdas]

I would have to agree about the honeycomb pattern in adding strength to a part. I would sure be nice if it was added to this software because we did pay for it and should be able to get the request of honeycomb added so we can then test it using S3D software instead of saying it works great in makerware. Let's add it and then we can say if it's better or not. I hope my request and the $140 dollars i spent will validate the reason for honeycomb to be added. Anyone else agree with me? Cory

[joesoap583]

I accept the findings of the tests that have been made, and apologise for having raised a non-issue with my concern about the strength of the hexagonal infill.

With regard to hexagonal copyright which MakerBot might hold, would it not be possible to consider octagonal (8 sided rather than 6 sided)? That would give a uniform pattern.

Alternatively, provide some sort of editor capability within S3D so that the user can define their own infill design. Maybe some sort of point-and-drag a line across an an editor area comprising of pixel boxes, so that the S3D infill can follow the line as it does the infill. I'm sure there must be lots of scope there for a developer to be inventive