## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### Stress and deformation of an injection molding tool

• Odin
Subscriber
```Hello everyone,

For a private project I have to model an injection molding tool using Ansys Workbench and examine it for deformation and stress.

I simplified the shape of the tool. Here I kept the resulting volume and projected area the same, but changed the shape itself. From a slightly more complex shape, I created a rectangle shape.

I kept the length of the original and adjusted the area across the width. The height then ensured the right volume.

Using symmetry, the tools have been further simplified (only 1/4 of the geometry is examined).

I took the acting load as the maximum injection/holding pressure that could be produced by the machine.

My question is the mounting surface of the print. As in reality, the negative mold of the piece is complete in one of the two mold halves. The nozzle-side mold half has only one opening for the sprue and is otherwise completely flat.

What is the best way to apply the pressure in Ansys? Do I create an extremely small indentation (0.001mm) to have a surface to apply the print to? Or do I apply the pressure to the entire surface, including the parts that are not touched by the melted material?

Both options sound rather less optimal and I hope you can help me here.

Unfortunately I can't post any pictures, but I hope I've explained everything well enough.
```

• peteroznewman
Subscriber
Reposting so that it is easier to read.
Hello everyone For a private project I have to model an injection molding tool using Ansys Workbench and examine it for deformation and stress.
I simplified the shape of the tool. Here I kept the resulting volume and projected area the same, but changed the shape itself. From a slightly more complex shape, I created a rectangle shape.
I kept the length of the original and adjusted the area across the width. The height then ensured the right volume.
Using symmetry, the tools have been further simplified (only 1/4 of the geometry is examined).
I took the acting load as the maximum injection/holding pressure that could be produced by the machine.
My question is the mounting surface of the print. As in reality, the negative mold of the piece is complete in one of the two mold halves. The nozzle-side mold half has only one opening for the sprue and is otherwise completely flat.
What is the best way to apply the pressure in Ansys? Do I create an extremely small indentation (0.001mm) to have a surface to apply the print to? Or do I apply the pressure to the entire surface, including the parts that are not touched by the melted material?
Both options sound rather less optimal and I hope you can help me here.
Unfortunately I can't post any pictures, but I hope I've explained everything well enough.
• Odin
Subscriber
Thank you, i don`t know why it changed the format.
• peteroznewman
Subscriber
I don't know what you mean by "the mounting surface of the print". Please explain.
To analyze the stress in the mold tool, simply apply the pressure to all faces in the cavity. Do this for the top half and the bottom half of the mold. Apply the pressure only to faces that molten material touches.
• Odin
Subscriber
The mounting surface of the print is a bad translation. I had written this text in a different language, thus resulting in a small error once i translated it in order to save time. Seems like i forgot you correct it before posting. But it means exactly what you assumed. I want to only apply the pressure to faces that are touched by molten material.

But how can i do so without creating an extra indentation of roughly 0,001 mm? I have used that way and it allowed me to apply pressure to only a specific part of the face, but the resulting pictures show a very clear cut and that somehow doesnt seem plausible to me.
• peteroznewman
Subscriber
Oh, you mean the lower half of the mold is a flat face where some portion of that face touches the molten plastic and the outside frame touches the upper half of the mold.
Simply open that part in SpaceClaim and draw on that face the shape that touches the molten plastic. That will split the face into an inner face and an outer face. There is no need to indent anything by 0.001 mm. You will imprint on the face the outline of the part. Both faces will be in the same plane.
• Odin
Subscriber
Yes, i tried that, but it doesnt work somehow. It doesnt split the face, it just created a new one on top of the old geomtry.
• peteroznewman
Subscriber
Use the Project button on the Design Tab. That will split the face.
• Odin
Subscriber
Thank you, i was able to split it.