Better Screw Design Using Lofted Boss/Base & lofted Cut Feature

Hello All,

I seem to have a small issue when creating screw and threaded parts using Lofted Boss/Base & Lofted Cut feature.

After first creating a helix feature from a circle I then add two independent sketches of triangular shape to be added as two profiles, then I add the helix as the centerline parameter.

I get the extruded threaded feature perfectly, yet when reversing the helix for the proper mating surface for the screws threads as a Lofted cut I get a middle section which has mis-aligned profile in reference to the helix?

I have tried many options for correcting yet still the same thing happens.

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Permalink Reply by Deepak Gupta on July 5, 2009 at 5:53pm

Christian, any specific reason for using Loft feature. Did you tried Sweep. Also can you upload the problematic file for someone to look at.

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Permalink Reply by Christian Kepler on July 8, 2009 at 11:32am

Hello Deepak,

How are you my friend? I uploaded 3-files showing first a shaft with an external lofted revolve detailing a screws thread pattern. Then 2nd is a connecting part which details an internal lofted revolve of a screws thread pattern(so it's the female).

The 2nd file which is named hand-plunger handle is showing a gap between the two triangular profiles that is not consistent to that of the circular helix feature setup for the loft feature.

After some testing with different parameters within Solidworks I have been able to get the center section to correctly and consistently create a proper loft-revolve of the internal screw pattern between to two triangular profiles; by checking the taper helix within the helix feature.

This seems to help create a better path for the profiles along the helix feature for the lofted revolve with is later completes the operation for the screw thread pattern.

Still, I think that a formula for an ideal triangle is also fital for a proper screw thread pattern.

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Permalink Reply by Deepak Gupta on July 8, 2009 at 12:43pm

Christian, seems you did a lot of homework and that sounds interesting. I will check the file tomorrow my morning and update you the results.

Deepak

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Permalink Reply by Deepak Gupta on July 8, 2009 at 11:18pm

Christian, I not able to understand that why you have used loft cut feature where as these can be achieved easily by simple sweep. We use loft where we have two or more than two different section. When we have a same cross section throughout, it is always recommended to sue sweep. Look at the attached file. Do roll to end after you unzip and open the file.

I will be happy to hear more about this if you are successful with the sweep or not.

Attachments:

Shaft.zip, 42 KB

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Permalink Reply by Christian Kepler on July 9, 2009 at 11:32am

Yes, you diffinetly are correct the sweep feature does make the operation faster and more simple. Hmm, it is always interesting that we can get the Solidworks program to do things for us almost seeming as if by shear will power?

Well, now I have two ways to create a screw profile feature.

Thank You Deepak

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Permalink Reply by Deepak Gupta on July 9, 2009 at 12:20pm

Nice to hear from about this. One more thing I would like to add. The part which you have uploaded mostly contains undefined sketches. As a advice, try to create parts with defined sketches and make it a habbit.

Deepak