STL Thread files

From: lblasch@opw-fc.com
Date: Fri Sep 25 1998 - 08:32:46 EEST


     Dear list,
     
     I have been creating helical threads for use in SLA models for 9+
     years with my CAD modeling program Unigraphics.
     
     Originally, I created them by defining the helix that the thread tooth
     must follow and then sweeping the tooth profile along it.
     
     4+ years ago, with the release of Version 10 of Unigraphics, the true
     threadform capability was added as a parametric feature which meant
     that you only need to define the thread pitch, root diameter and
     thread length when adding threads to a cylinder.
     
     Roughly 1/4 of the 1500 different geometries I prototype each year
     contain threads or helical fastener features so I do this all the
     time. I usually build threads in place on the SLA machine and then
     just clean them up with a tap or die if necessary.
     
     If you need to prototype threaded components and cannot model them
     with your CAD system, You have the wrong system!
     
     For anyone who has never seen or built threaded STL files, I am
     uploading to the Clemson FTP site (fantasia.vr.clemson.edu) several
     PKZIP files:
     
     threads.zip = STL versions of a 3/8"-16 NC nut and bolt
     Parasld.zip = Parasolid V9 of the 3/8"-16 NC nut and bolt
     
     You should be able to import the Parasolid files into Solidworks.
     
     The STL files were exported at medium resolution by my standards. The
     STL surface matchs within .001" to true surface. I usually work at
     .00025" but these are corse threads so this resolution should be more
     than adequate.
     
     Larry Blasch
     System Administrator for Engineering Services
     
     OPW Fueling Components Voice: (513) 870-3356
     P.O. Box 405003 Fax: (513) 870-3338
     Cincinnati, OH 45240-5003 USA
     *********************************************************************
     Disclaimer...The views expressed are personal opinion and not those of
     OPW Fueling Components.
     *********************************************************************
     * "Yeah, I know...Unigraphics is very expensive; but so is RP" *
     *********************************************************************

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