Sweeping along a Helix
Sweeping along a Helix
(OP)
I am working in NX5 and I am trying to make a tap. The tip of the tap starts at a small diameter and finishes at a larger diameter. In creating the Helix I have chosen the "use law" option followed by the "linear increase". I get the helix that is desired but, when I sweep along it the cut twists and I end up with something other than what I am after.
How do you keep from having your section twist along an increasing diameter helix?
How do you keep from having your section twist along an increasing diameter helix?
Paragon Medical
www.paragonmedical.com





RE: Sweeping along a Helix
When you sweep along a helix using a surface of orientation curve as a spine usually helps control the amount of twist. However even if you build your section as sketch on a plane that is positioned on on end of the helix you use for your guide curve then there is still a problem it either the pitch or diameter of the helix are variable. You can change the pitch when building helices from law curves and the curve function for a helix supports variable diameters. However when either if these changes are invoked the angle of incline relative to the base plane if the helix, or the section you are sweeping more importantly, will vary. This introduces a small error in the the calculation of the swept geometry. an axis as a spine curve provides some control but it may be imperfect.
I have encountered similar cases in the past and found it may be simpler to construct the section by other means often sweeping sections as a construction technique and thickening them to maintain the correct sectional volume.
Cheers
Hudson
RE: Sweeping along a Helix
RE: Sweeping along a Helix
On the Swept dialog set the orientation method to "Forced Direction" and select a vector that is normal to the axis of the Helix. This will keep the section from twisting.
John Joyce
Tata Technologies iKS
1675 Larimer St.
Denver, CO
www.myigetit.com
RE: Sweeping along a Helix
ht
A client has submitted this to us in a pdf and I will have to remodel and make other design changes.
When I try to use the "swept" feature it just creates a solid. It will not allow me the option to cut away the material. I tried to use subtraction after making the solid but what I have left behind isn't correct.
Stated in my first post is the result I get when I "sweep along a guide".
I have not found where I can specify the axis to keep things from rotating about the guide as it sweeps.
Paragon Medical
www.paragonmedical.com
RE: Sweeping along a Helix
I make threads on occasion. Picture threads on a plastic bottle. I've never made any on a conical type surface, but these settings have helped fix weird results, particularly Face Normals. Select the face that the threads are winding around. In your case it would likely be the conical face.
Mike
RE: Sweeping along a Helix
Ron
Design Analyst
RE: Sweeping along a Helix
Cheers
Hudson
RE: Sweeping along a Helix