A huge advantage of 3D printing
is the ability to design and print your part as a single unit.
So why would you go through the trouble of splitting up your design
and printing multiple parts and then assembling them later?
The answer is to increase the strength of your parts.
I'm Peter and this is Reinforced.
At Markforged, we're all about strong parts and getting the most out of them.
Today, I'll walk you through a real-world example step by step.
How to design, print, assemble, and even test
multiple parts printed separately in their ideal orientations
and joined together
so they can be put to use in their strongest possible state.
So let's take a look at our example part.
This is a mounting plate that's designed to secure a tent pole to the ground.
The plate is secured to the ground through these four holes,
while the tent pole is secured to this boss.
This is a common case where the direction of the load
is perpendicular to the plane that the part is mounted to.
With Fused Filament Fabrication printing,
or FFF for short,
parts are fabricated layer by layer,
which means the X, left to right,
and Y axes, front to back,
will inherently have more strength than the Z axis, up and down.
This is primarily due to the bonds of thermoplastic materials
being stronger within the layers that are printed than between them.
If we printed this as a single part horizontally,
the bottom plate would be strong,
but the part would fail on the plane with the lowest cross-sectional area
when enough load is applied,
like this part here.
We could turn it on its side and print the part vertically,
which would give much more strength to the center boss.
However, we've made the part weaker in bending
about one of the axes parallel to the printed layers
like this tested part here.
This also adds additional print time and support material usage.
But if we split this into two distinct parts
and print them in their ideal orientations,
we give them the ability to withstand higher loads when assembled together.
Let's hop into CAD and get to work.
So we have our mounting plate open in SolidWorks
and we don't want to modify the overall geometry.
We only want to modify it so that we can print this as two co-parts.
So first, what I want to do here
is create the volume that one of the co-parts will occupy.
So to start that,
I'm just going to make a sketch on this bottom face here
of just a rectangle centered at the origin.
And I'm going to extrude this so that it's offset about two millimeters
just so that we have some material
to resist the co-part pulling through the other co-part.
Before completing this, I'm going to uncheck “Merge Result”
so that these two bodies don't get merged together.
So you can see now I have two bodies,
one of the original part, and that boss we just made.
Next, I’m going to make another sketch on top of this extrusion we just made.
I'm going to make that circle co-radial with that boss.
And that's just going to be another circle here
that’s extruded through the rest of the part.
And I'm going to only merge this with that body that we just created.
So in order to make inserting this co-part easier,
I'm going to use the “Chamfer” tool
and chamfer around these edges at about eight degrees.
So by adding a chamfer,
this will make assembly easier and guide the parts together.
And next, I'll go to “Insert > Features > Intersect,”
and select our two bodies that we have.
And hit the “Intersect” button, and unselect that volume we just made.
And I'm also going to make sure that I uncheck “Merge Result”
so that these two parts don't get combined together.
And just like that,
we have two co-parts that are ready to print.
So if I hide one, you can see what they look like individually.
And for my case, I'm good with these parts as is.
But if you want to use an adhesive
or want them to be more of a loose fit,
you can use the “Move Face” tool on one of the parts
to add more of a clearance between the two.
I'm going to go to “Save As”
and change to save as an STL.
And I'll just call it “Mounting Plate 1,”
and save that,
and make sure I only export the selected body.
And I'm going to do the same thing for the other co-part.
So if you're not a Markforged user,
just be aware of how your slicer is orienting your parts.
If you're a Markforged user using Eiger,
you can just go to “Import STL(s)”
and select your two files, or however many co-parts you have
and import them separately.
And here I'm going to be selecting the optimal orientation
like we discussed before.
And for this part it'll be laying flat like this,
and for this one, it will be laying in this orientation.
Okay, now that we have both of our parts sliced,
we can add them to a build and put them together.
So we have our parts printed.
Let’s remove them from the build plate and separate the supports.
Once we finish with that, we're ready to assemble.
And there's two ways you can assemble the parts together.
You can use an Arbor Press by press-fitting the parts together,
or you could use adhesives.
One thing to note with adhesives, you're going to want to do some research
on which adhesives work best for your materials.
If you're using a Markforged printer with Onyx,
we recommend using Loctite 401,
Scotch-Weld DP 100, or Scotch-Weld DP 420.
For other common 3D printing materials such as PLA, PETG, and ABS,
good candidates include cyanoacrylate adhesives,
epoxies, and silicone glues.
For today's demonstration, I'm going to be using an Arbor Press
because it's the easiest way to assemble co-parts,
and I know that this part will only be loaded in one direction.
So at the Arbor Press, I'm going to loosely assemble the parts together,
and then I’m going to press down in the middle of the part,
joining them together.
And then to ensure that everything is seated,
I'm going to press down on all four corners.
And just like that our part is done and ready to be put to use.
So this small bit of extra effort will be worth it.
Don't believe me? Let's test it.
We tested three different parts,
all printed on a Markforged X7 with Carbon Fiber Reinforcement.
Part number one was printed as a single unit,
horizontally, in Onyx with carbon fiber.
Part number two was printed as a single unit,
vertically, in Onyx with carbon fiber.
And part number three was printed as two parts,
in their ideal orientations, with Onyx and carbon fiber.
And just as expected,
the co-parts reinforced with continuous carbon fiber
performed much better than the single parts.
The co-parts reached a maximum load
of 5,747 Newtons, or about 1,292 pound force.
That's an 87% improvement
over the next best mounting plate
printed as a single part with continuous carbon fiber.
And that's it. You're done.
I hope you found this video helpful. Do you have a question?
Do you want to see us cover a topic you've been dying to learn more about?
Make sure to leave a comment.
If you're interested in seeing some additional example parts
and more in-depth testing, check out the open access paper
we recently published in the Rapid Prototyping Journal,
which is linked in the description of this video.
If you want to see more 3D printing tips and tricks,
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Thanks for watching and happy printing!