Tapering off a helical sweep?

Forum|Forum|2 years ago
September 19, 2023
2 replies
2915 views

I am using Creo Parametric 6.0.4.0 How do I go about having this helical sweep taper off at the ends?

Flexible Modeling

Best answer by tbraxton

The easiest way is to add a feature (cut or add on) at the proximal and distal ends of the helical sweep that create the taper to "zero" or the shape you require. There are more sophisticated ways using graph driven features and the trajpar parameter in the helical sweep sketch but IME it is not worth it. Using separate features to create the terminus geometry of the sweep is easier to manage changes to the model and is often more robust when another user interacts with the model.

If the example below is not suitable for the geometry required on your model, post additional details on what you need.

This shows an example of a swept cut at the end of the helical sweep thread profile. This is for an injection molded thread geometry.

Helical sweep thread profile

Taper thread start

tbraxton

Answer

22-Sapphire II

The easiest way is to add a feature (cut or add on) at the proximal and distal ends of the helical sweep that create the taper to "zero" or the shape you require. There are more sophisticated ways using graph driven features and the trajpar parameter in the helical sweep sketch but IME it is not worth it. Using separate features to create the terminus geometry of the sweep is easier to manage changes to the model and is often more robust when another user interacts with the model.

If the example below is not suitable for the geometry required on your model, post additional details on what you need.

This shows an example of a swept cut at the end of the helical sweep thread profile. This is for an injection molded thread geometry.

Helical sweep thread profile

Taper thread start

P

ptc-4710498

Author

1-Visitor

I ended up doing something similar. How does this look?

tbraxton

22-Sapphire II

It looks fine. If it captures your design intent, then you should be good. If there are DFM considerations or functional requirements for the geometry make sure you captured them.

Here is another example of a molded thread where the ends are driven by mold design considerations to be able to unwind the core to eject the part. It uses a helical sweep to get the geometry as needed. The main helical sweep is to capture the thread spec requirements and the second is to reduce to practice a molded version of the specified thread.