- [Instructor] A hem is basically another name
for bending over the edge of the sheet metal.
This can make a nice smooth finish
and it also improves the strength
of the edge of the sheet metal.
So to get started, let's go ahead
and choose hem, right up here.
And choose the edges, so I'm gonna go ahead
and choose this very first edge here.
And you can see we've got this nice, big, open hem.
And I can also change that over to a closed type hem
which is very common.
It can also switch over here to something like this
which is gonna be more of a teardrop style.
Or, you can do a rolled hem,
so if you use a rolled style, that's more like
what you do for a piano hinge, something like that,
whereas, just the regular closed hem
is just gonna basically roll over that material
so you have a nice smooth edge
and it does improve the strength of that edge.
Now I can define the size of that hem,
I'm gonna type in .375
and I can also choose other edges at the same time.
Let's go ahead and choose this edge here
and this one over here and you can see that it can do
all three of those, or even more edges,
all at the same time.
We also have the option for the mitered gap.
So down here, you can see, I can type in like .04
and that's gonna adjust this little gap right over here.
And then I can also define what the K-factor is,
if I want to use a custom bend allowance,
which is probably advisable for hems
because it's not a standard bend
cause you're folding the material over entirely.
It's a 180 degree bend, it's not a 90 degree bend
so you don't generally wanna use the same K-factor
or bend deduction values we'd use
for standard 90 degree bends in your part.
So maybe talk with your material supplier
for the correct bend deduction values for the hem style
that you're trying to create.
Alright, once you have the hem looking the way you want,
go ahead and click on OK.
You can see, there is our hem.
Now if you wanna modify that,
go back to that existing hem here, click on edit feature,
and we can also switch the material inside
or material outside condition right over here.
Again, we can also switch to these other styles of hems
at the same time, but right now, let's just go ahead
and change that to the material on the outside.
Click OK and we just made that quick modification.
Now on the other side of the part,
let's go ahead and create a rolled hem
which we can use for a piano hinge style of connection.
So right over here, let's go over here to hem,
I've already chosen that edge
and it creates this big old huge one
which is way too big, obviously.
But let's go ahead and switch over here to the rolled hem
and let's zoom in here and see what's happening.
So my inside radius,
so if I wanted to use maybe
like an 1/8 of an inch pin, which is a .125,
half of that is .0625 and let's go ahead
and make that just slightly bigger
so the pin will slide through.
So instead of .0625, let's actually make it .065.
And as far as our degree, let's kinda use these arrows
so we're making this come almost all the way around
so we can capture that pin.
Once you have that, everything looks pretty good,
just go ahead and click on OK.
And now we've got that nice rolled hem.
Now, to make these type of hems,
we do need specialized tooling so you do have to talk
with the material supplier or the sheet metal house
you're working with and make sure they have
that style of tooling, otherwise,
you're probably gonna be buying a custom dye
to form that style of hem.
But if you do go that route, a rolled piano hinge style
of connection is actually a very cost effective way
to create a connection, as long as you have the tooling,
it's a great way to connect your parts
and it does eliminate the need to buy an exterior hinge
that you'd have to either spot weld, rivet,
or screw on to your sheet metal assembly.