Have you ever designed a fixture or part
that needed to have threaded components?
Or maybe your design has size constraints,
and you actually need to break it into multiple, smaller pieces for assembly?
There are many ways you can tackle this challenge,
but today we'll review one of the easiest and strongest.
I'm Austin, and this is Reinforced.
So what are heat set inserts anyway?
They're small, cylindrical objects,
typically made of brass,
which have a knurled pattern on the outside surface
and threading that runs through the inside.
Heat set inserts are designed to be melted into place.
This results in a secure bond between the metal insert and the plastic part,
capable of resisting higher pull-out or torque-out forces
than other insert styles or printed threads.
By utilizing heat set inserts,
you can make your parts stronger, more durable,
and easier to assemble, all at the same time.
I'll walk you through an example using this gripper,
and show how to design for heat set inserts.
Then we'll print the part and go over installing them
with a cheap soldering iron.
As I mentioned,
you’ll need a few things before you can get started bringing parts to life
using heat set inserts.
First, you're definitely going to need your threaded inserts.
Make sure that they match the threading of the machine screws
that you plan to use with your part.
You'll also need a soldering iron.
Practically any soldering iron will work,
and they can be had as cheap as about $8-10 dollars on Amazon.
Optionally, for some soldering irons,
you may even be able to find specialized tips
that are purpose-designed for installing heat set inserts.
If not, a regular conical tip will work just fine too.
Lastly, you'll need your 3D printed part
with the proper cavities designed in.
Let's jump into Fusion 360 and take a look at an example.
Okay, so here we are with our part open in Fusion 360.
And you can see with these two holes
that I've already got them designed to fit the M-4 machine screws
that we want to use to assemble the jaw to this gripper.
One thing to note is that with this part,
we chose to design for the heat set inserts to come in from the back side.
This provides higher resistance to pull out force,
and will ultimately make our part stronger.
So we're going to start by creating a sketch
that will transfer over the profile of those bolt holes.
Using the Center Diameter Circle tool,
I'll draw two circles.
And I'm going to match them to a diameter
that's specified on the datasheet for the heat set inserts.
In this case, it's 5.74 millimeters.
If this is your first time designing for heat set inserts,
make sure that you pay close attention to the datasheet.
It will call out the maximum hole diameter
and the length of the insert,
which are the two parameters that you want to make use of
when designing for the holes.
I'll do the same thing for the bottom hole, also setting it to 5.74 mm.
And then we're finished with our sketch.
Using the Extrude command,
we’ll select the two profiles that we just made.
And I'm going to cut them into the part
to a distance that matches the length of the heat set inserts.
Again, you'll want to get this from the datasheet.
In my case, it's 4.7 millimeters.
I'll press enter.
And just like that,
we're ready to export our part to an STL,
print it, and get our inserts installed.
If you'd like to know more about how to export STLs for 3D printing,
check out our video on that topic.
Okay, so here we have our 3D printed part,
and we're going to start by plugging in our soldering iron
and letting it get warm.
A good starting point for its operating temperature
is about 50 to 100 degrees Celsius hotter
than the temperature that you print your plastic at.
For Onyx, we found that about 390 Celsius seems to work well.
We'll start by taking one of our inserts
and putting it on top of our 3D printed part
aligned with the cavity that we've designed.
Most have a small taper that allows you
to actually press-fit the insert
a small portion of the way into the part.
We'll take our soldering iron, which is heated up now
and apply some gentle pressure right to the top of the insert.
Make sure you're pushing in a direction
perpendicular to the surface that you want your insert to go into.
As we do this, it's going to heat the insert up
and allow the insert to start melting its way into the part.
Do your best to be patient with this process.
The slower that you allow the insert to melt its way into the part,
the stronger the bond is going to be
between the metal and the plastic.
Once the top of the insert is flush with the part,
simply pull the iron back out.
We're going to let it cool down, and then we're ready to test it.
Pretty easy, right?
So that's it.
Let's recap.
Heat set inserts are a fantastic way
to add strong threaded features to your 3D printed parts
without much cost or effort.
Start by selecting and acquiring screws and inserts of your choosing.
Then design cavities into your CAD model
using datasheets from the inserts,
minding the insert length and the maximum hole diameter.
Melt the inserts into place using a soldering iron
that’s set about 50 to 100 degrees Celsius
above the nozzle temperature used for your parts,
and keep the iron aligned with the direction of the insert
as you melt it into place.
Be patient,
and make sure you only stop
once the top of the insert is flush with the part.
And just like that, we're ready to put your parts to work.
We hope you found this video helpful.
Do you have a question?
Do you want to see us cover a topic that you've been dying to learn more about?
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Thanks for watching, and happy printing!