- [Instructor] So, what makes designing parts
in sheet metal inside of SolidWorks
different from other parts designed in SolidWorks?
Number one is sheet metal is always
gonna be a constant thickness,
we can't have various thicknesses throughout the part.
We're gonna then take that sheet material
and we're gonna cut it using either a laser cutter,
a punch press, a shear, or some other method
for cutting out a flat blank.
Then we're gonna take that and bend it
using standard tooling, or standard bend radiuses,
for the tooling that your shop happens to have.
Once you have that, then you can do additional bends
in the material to create your final part.
So, let's go over a couple of the standard bend radiuses
and some of the different terms
that are used inside of sheet metal.
The first one up here is thickness.
Notice the thickness is very important.
Now, thickness varies not only by the type of material
but also by the region you're in.
If you're in Asia for instance, you're probably gonna be
only using millimeter size materials.
So, gonna be 1 millimeter or half millimeter material
or five millimeter material.
But basically, metric sizes.
In the U.S., those are gonna be different gauge sizes.
And the gauge sizes vary whether you're using steel,
stainless steel, aluminum, or a different alloy.
And the next thing I wanna point out here
is the bend radius, which is right here.
And those standard bend radiuses are right over here,
in America at least, which is an .030, an .060, .090,
a .125, a quarter inch, three eighths of an inch,
or half inch, and you can get beyond that.
Now, those are your standard bend radiuses.
Now, of course, you can create your own custom bend radius,
but that is a lot of work
and you have to probably buy customized tooling.
So, it's best to stay with your standard bend radiuses.
Now, let's go over a couple
other things here like the K-factor.
That is where the material actually is gonna be bent,
the center line of where that bend is gonna be happening,
and we can adjust that K-factor inside of SolidWorks
to match what's actually gonna happen in the real world
with a factor, a K-factor.
And we'll be typing that in,
we'll be looking at that a little closer.
Same thing with the bend allowance over here.
That bend allowance will vary based upon
where that K-factor is inside of the material
and the length it'll be when it flattens out.
That's of course affected by the bend angle,
which is right over here.
That's how much you're gonna be bending it.
So, in this case here we have a 90 degree bend,
but that could be a 45 degree bend, or so on.
And then finally the flange length.
Now, the flange length generally as a rule of thumb
wants to be about four times the bend radius of the material
or the thickness of the material.
Now, the thickness of your material
wants to generally be a one-to-one ratio
with the bend radius or larger.
So, if your material happens to be quarter inch,
your minimum bend radius would probably be quarter inch,
but of course you can go bigger than that.
A half inch or a one inch bend radius would be just fine,
but you generally don't wanna go below
the thickness of the material.
And same thing with flange length,
you wanna shoot for at least four times
the thickness for your flange length.
So, for instance, if you had
a quarter inch sheet of material,
your flange length would generally wanna be
one inch or greater.
Alright, on this page here you can see
I provided you a few different gauge tables.
These are PDF documents in the Exercise Files.
And you can see we have gauge thicknesses
for both aluminum and steel.
So, I go down here, if you look at the 12 gauge
at the very bottom down here, so 12 gauge material.
And notice the thickness of the aluminum is .0808.
But if you go over to the steel table,
that same 12 gauge material over here is .1046.
So, notice even though they're the same gauge,
the thickness is actually different between steel,
stainless steel, and aluminum.
So, just wanna point that out.
So, make sure when you're designing in sheet metal
you don't just pick some random thickness.
Pick exactly the thickness that is supplied
by the material supplier in either steel,
stainless steel, or aluminum,
and look up these values before you start
on your sheet metal part cause that can have
a dramatic effect on your final design.
Over here I just wanna give you
some basic information about how forming is actually done.
So, notice you have a lower die
and then you have your material sitting on top of that.
And you have a back gauge which defines
how long that bend flange is gonna be.
Then you have the bend radius which is actually the end
or the tip of that tool which is gonna engage
the material which is on the upper die.
Now, when that comes down, it's gonna push on the material.
And again notice we have a V at the bottom on the lower die.
So, that has to span from one side of the die to the other.
That's generally where you see that 4X multiplier
of the thickness is required so that you can have
the material hitting both sides of the lower die.
Then over on the right-hand side
you can see the actual formed part.
Notice it turns up into a V, it comes off the back gauge,
and now it's being completely formed.
And you can see the bend radius
has been implemented into that piece of sheet metal.
Here's another example of what we call a gooseneck die.
So, if you have to do kind of a return flange here,
you can see how the material comes in over
and it gives you a little space to allow
that return flange to bend when the secondary bend is made.
So, it actually allows some space there.
But we do have a couple requirements here.
We have to make sure that we actually leave
some material here or we have enough material here
so the return flange and actually that bending tool
can get inside here.
So, if you make it too small, it's just
not gonna be able to be bent using standard tooling
or you might have to come up with something special.
So, just I wanted to point out these things
so you can see how the tools actually look
when you're building things
inside of the sheet metal package and in real life.
So, here's a few examples of bend radiuses
and what the flat pattern will end up looking like.
So, notice all of these examples all use
a one and a half by a one and a half flange length.
But we're changing the bend radius
from quarter inch to three eighths to half inch.
And notice using the quarter inch,
down here at the bottom of the screen
you can see we've got a 2.44 overall length.
But notice if you change to the next size radius,
which is that three eighths radius,
the flat pattern gets a little bit shorter.
Right, we're making a bigger bend which makes
the material flat pattern a little bit shorter.
And same thing if you go over to the half inch one,
notice that's the shortest piece of material
because we're putting a lot bigger bend radius here
and therefore the flat pattern can be quite a bit smaller.
Alright, here's a couple of other examples
of bend deduction tables.
So, these is how much material
we wanna remove from that flange length
to get to the final length of our flange.
Generally, inside of the sheet metal package
you can type these values in to get the exact bend deduction
so when you flatten out your part
the flange length is the right length.
And notice based upon the gauge
and the material, the values change.
So, steel, stainless steel, and aluminum,
for like, for instance, 12 gauge,
have similar values for steel and stainless steel,
but notice for aluminum it's a different value.
Same thing with most of the other columns.
So, just make sure you're using the right bend deduction
for the type of material that you're using,
because each one has a specific way the material bends
and forms and therefore has a different K-factor
and therefore you have to use a different bend deduction
based upon the type of material as well as
the thickness of material that you're using.
Finally here I'm gonna show you the K-factor values.
So, these are some standard K-factors
for different materials.
And notice as you get thicker and thicker material,
it all kinda gets to about a .5 K-factor.
But below that, you get pretty varying K-factors
depending whether you're doing air bending,
bottoming, or coining on the material.
That means how hard you're pushing on it
or if you're actually completely forming the top dying
to the bottom die or it's actually got
a little bit air gap below that.
Couple different options here,
and you might wanna talk with your sheet metal supplier
about what the correct K-factor
or bend deduction values you should be using.
If you wanna get really accurate flat patterns,
this will definitely help you out.
And the last thing I wanna provide to you here
is the setback Excel spreadsheet.
Now, this is not 100% accurate, but it does do
a calculation depending on the thickness of the material,
the bend radius, and the angle you're gonna be bending.
So, if you're bending some weird angle
and you have a standard size thickness and bend radius,
you can use this setback table and figure out
what the bend deduction should be,
at least it's a close approximation.
And if it's too far off, you might also wanna just
do a test piece, bend it, and then measure it
and see what that setback value actually is
if you're working on something very critical.
But this Excel table here does give you
a pretty good estimation of what that should be.
So, hopefully there's a couple different tools
to help you get started understanding the way
sheet metal is designed, the available gauge thicknesses,
as well as some standard bend radiuses,
and some of the tools that are provided for you
in the tables as well as this Excel spreadsheet.