There is a very weird world inside cura's infill settings that I want to show you today, and
that is the infill type known as Cross....infill.
I'm gonna explain what it's for.. and I'm gonna explain what it's definitely NOT for,
but first I'm going to thank PCBWay for sponsoring this video. More...on that...in a minute.
So, credit for telling me about this setting goes to PJ from discord,
and the setting I'm talking about is here, cross infill density image.
If you choose cross infill or cross 3d infill from the infill section in the settings,
and then scroll down, you can see the box - on recent versions it seems to
always be visible regardless of infill settings.
Putting a path to an image here causes cura to use that image when it slices and you get..
....well, this.
So lets wind back a bit and try and figure out how this became a thing.
Firstly what's cross infill and why does it exist. To get an answer to this we need to take
the radical step of reading the documentation and if you haven't got settings guide installed
already in cura then I made a video about it a while back and it's worth using because, well,
watch the video, if we have a look at what it says about cross infill then...
...it appears to have been designed with flexible materials in mind.
Evenly squishy in all horizontal directions, that's interesting.
The argument about stronger is a sort of moot one with flexible filament too because
it squishes rather than cracking so, I guess yeah, it's for making more squishy things.
I think it also has some value for transparency because it behaves a bit like concentric which
allows light to pass through better, because there's no horizontal bits or whatever.
So why, then, do we have this functionality in cross infill to let us use an image
as the basis for infill density? Again, let's look at the manual.
You can customise the infill...on
flexible filaments, yep....to achieve very specific softness or hardness constraints.
So it's meant for...essentially, controlling where things squish or bend.
As a quick demonstration I can create two gradients which are the inverse of each
other in monochrome, so one is dark in the middle, the other one light in the middle,
when we slice them with those respective images as the density map we get exactly what we expect,
and if we print that out .... we get two identical looking pieces,
but one is squishy in the middle - and the other is hard in the middle and squishy at the edges.
The way the image works is by using the brightness value of the pixels
to determine the density between "nearly zero" and
And if I just randomly create a map like this,
then print that out, when I bend it, it should bend where I tell it to.
This is actually really cool, I can think of a lot of uses for this in compliant
mechanisms or if you're a drone person then you should be interested in this as
you can use it to intentionally determine where parts fail.
So it's not just useful for hiding weird surprises in the infill after all, it turns out,
but if you do want to use it for that then you absolutely can,
you could use it to put your logo as infill if you wanted, and speaking of logos...
here's the logo of the video's sponsor, PCBWay! PCBWay won't mess around with infill...unless you
ask them to...but they will 3d print your model properly including materials that you
maybe can't use like nylon resin or multi jet fusion which you absolutely can't do
at home unless you happen to own an actual lab, those machines are huge and expensive.
But what PCBWay have asked me to tell you on this sponsored segment is that their 4 and 6 layer PCBs
are now cheaper, so if you're making pcbs with that many layers then it now costs less, so start
designing your PCBs with lots of layers and some fancy artwork on the top layer, I just realised
thats how that's done isn't it. Aesthetics and colour are a thing now with PCBs. Getting them
made by PCBWay is super easy, you just upload and choose the options or leave them as default
and submit the order and they will do the rest. As well as PCBs they can also make CNC or vacuum
molded parts and 3d prints as I already mentioned, so check out the link in the description.
Thank you for PCBWay for sponsoring this video and back to infill.
One final thing about cross infill, well two actually, if you read the documentation it
specifies that this only works for cross (3D) but that's clearly a porky because
I've been using it on 2D cross, but yes there is a 3D cross mode which is kind of
crosses that change as you go up vertically obviously, I printed one out, here it is,
it does seem to have more rigidity, reminds me of a mattress somehow.
Second of the one final things is that you can use this for support too! If you choose cross
as the support pattern you can as the manual also says vary the density of the support and I
think it would be also a really good choice for a support type too if you aren't using tree supports
because it's weak horizontally. If you spent time getting the image map right you could supply it
to people with the STL too, I don't think anyone has done that yet, but that could be a thing.
There you go, we are done, I want to also say that the FLSUN v400 and the creality
sprite have both been absolutely amazing at printing the TPU examples for this video,
I haven't reviewed the latter yet - it's the Ender 3 S1 Plus, and funny story,
it arrived with the bed wheels having fallen off in transit, who knew that could happen, except
me of course because I made a video about exactly that, 100% vindicated, am I right? But if you want
to see how the v400 is good at TPU then go look at the review, it's the last video before this one.
Will you use this? I think I might actually, both as infill and support,
now that I know how it works, I think it could be one of those game changing secret
settings. And with that, thank you for watching.