- If you're designing a part for
any type of a molding process like
plastic injection molding or dye casting,
you're probably going to need to add some draft.
Now draft is just some angles to the outside surfaces
so when the part or the mold separates,
that the part comes out very easily.
So to do that, we have a great tool inside of
SolidWork with believe it or not, it's called draft.
(chuckles) All right.
So click on this one, right up here, draft.
And the first question is, what angle do we want to draft at?
So most of the time for plastic injection molded parts
we want to have about three degrees of draft.
Now you can go below that,
but depending on the texture of your part,
you might have some issues.
So three degrees is generally a nice size draft.
And of course you can have anything above that is fine.
But right now, I'm going to leave nine degrees
so you can see it a little easier.
Now right over here is going to be the neutral plane.
So that's where do you want to start that draft from.
So I can choose something like the top face here,
and then over here is going to be
what are the faces that I want to draft.
So I can go in here and click in this box
and then choose these individual faces here
that we can draft.
So we can do a bunch of faces all at the same time.
And when you're done, just click on the green check mark,
and there you go.
So looking straight down on this,
so I'm going to click "normal" to it,
you can see that now these surfaces in here,
highlighted, those have some draft, right?
There's a little bit of an angle,
a little bit of taper to those faces.
All right?
So if we go back here and we modify this feature here,
edit the feature, we can also change that direction
so I can switch the direction there.
So it's going the other way. And if you look there...
let's look at the top there.
You can see that the draft's actually going the other way.
So that's generally what you don't want to do, right?
Because now it's drafting out
as you go down and
you'd never be able to get that out of the mold.
So make sure you are drafting things the correct direction.
I also want to point out while we're here,
If you click over here in under the draft,
we can come down and we can also choose a parting line
or a step draft which,
a couple of other ways you can do it as well,
so if you have a parting line already defining your part
which you'd probably need to add ahead of time,
that's under the mold tools,
then you can actually split your part from
the parting line.
But in general, most time you, uh, neutral plane drafts,
is going to be what you're going to be probably using.
If you have multiple faces,
we can also use face propagation that's along
the tangent or faces.
In this case here, I don't have anything tangent
because I have no fillets around the edges.
But if I did, I could come back.
So let's go ahead and try that out one time.
Go over here, let's add a fillet.
There's my fillet. Oh, not that one right there.
Let's go back to this style here.
Here's my fillet,
and 0.5.
All right.
So there you can see, we have a fillet.
Now, if I come back over here and
I add some draft...
Right, here's my draft.
And I'm going to choose the neutral plane...
and my face.
I'm going to choose right here
and use the manual version of this.
So over here I faced propagation along tangent.
I'm going to choose this one here.
Oh, hold on. First, you got to choose this one up here
at the top and then face it to draft that one.
And then along the tangency,
choose that one there,
and notice that automatically propagates that
around the edge.
So a couple ways we can do that there.
We also can switch over here to this draft expert
which we saw slightly here.
So draft analysis can be turned on.
So you can see something, that, an how much draft it has.
So this will give you kind of a heads up display
of what's going on with your part.
So you're seeing:
Hey, everything's yellow has zero draft, right?
Everything that's orange has some negative draft
and everything that's blue has positive draft,
and that will allow you, or give you a guide at least,
on how to add draft to your part.
Running that draft analysis tool is also
another feature you can just run
and you can see which of the faces hasn't had
any draft added to them yet.
And when you're working on like,
an injection molded part,
you want to make sure that all those faces
coming from the parting line of your part
wherever you're going to be separating it out,
do have draft so they'll easily separate from the mold.
So anyways, that is how you add draft to your part.
It's a pretty powerful tool
and there's a lot going on there.
One piece of advice though is
if you're going to be adding fillets,
like this fillet over here,
do all the drafting first
and then add all the fillets second.
That will definitely make your part look
a little bit nicer when you get finished up.