Learn how to create inside geometry with the core method.
- [Instructor] The method that I want to use going forward for our injection molding is what we call core cavity. So in the process of designing your injection-molded part, you also basically designed the tool that's going to be used to create the part. Again, for smaller plastic parts, maybe household items, some smaller automotive bits and pieces, aerospace parts, the core cavity design works exceptionally well for us.
So based off of your need, you want to make sure you use the right method. Now the way the core cavity design works is the outer shell here that I have in the PartBody is the, basically, cavity shape. Next, I need to define the core shape. And the way that I do that, pretty straightforward, is to insert a new Body, not a Geometrical Set, but an actual solid volume. I'm just going to take this CloseSurface, right-mouse-click, copy and paste it into Body.2.
And what happens is you can see it creates a new CloseSurface in Body.2. Here's my PartBody. I'm just going to go ahead and hide this for a moment. Right-mouse-click, hide that. Next thing I'm going to do is, there's a tool here, it's called Thickness Definition, and I'm going to pick the faces that I want to create a thickness on. Once I pick that first face, you'll see it picks all tangent faces. And to get the proper direction and thickness, I'm going to go into my entry field, right-mouse-click, and say Edit formula.
Go to Renamed parameters, and for this, I'm just going to simply say minus because with the thickness I have to specify a negative value to go into the solid to remove material. Select Thickness, and we double-click on that. Put it into the field and select OK. You'll notice I have created the link, so I have a negative 2.5 millimeter value. I've specified my face. I select OK, and it offsets inward.
Next thing I need to do is go back to the PartBody. I'm going to right-mouse-click on it and say Define In Work Object. As soon as I do the Define In Work Object, you'll notice that it shows the body. It was hidden, but now it's shown. And it is the In Work Object. You'll see here the Body.2 is offset inward, and it creates that space for that gap that I need for the part thickness. Now, I'm just going to right-mouse-click on Body.2.
Go to Body.2 object, and go all the way over to Remove. As soon as I select Remove, you'll see it creates the void space or the core to the part. And, again, this lends itself well to your smaller plastic parts, power tools, maybe some bottles, things that you have floating around in the house, anything related to your computer, your mouse. This is a really good method to use because now when I go and attach additional features, those features are going to be attached to the actual core volume that's going to be used to create the actual core part of the injection mold.
- Inputting styling data (the A side)
- Defining the parting surface
- Creating the B side
- Adjusting part thickness
- Creating bosses and ribs
- Draft analysis
- Adjusting wall thickness
- Final fillets to represent the real-world shape