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  1. #1
    Join Date
    Jun 2005
    Posts
    55

    Geometry from NC

    I am working on a HUGE relief cut into a sphere (30 ft in diameter - in parts of course!). My custom written software generates stl files from images. I wanted to use BobCad, but I needed to machine a spiral toolpath in 3d whose center start could be off the geometry. I wound up purchasing Desktproto to generate the toolpath with a chosen tool. I took the NC file into BobCad and created geometry from it so that I could delete the vertical plunge walls that were in the file due to the part being only a pie slice of the circle in plan. Also, to get rid of the rapid moves across the "pie" to start the next spiral segment, sort of like a typewriter return of days past. Anyway my question has to do with the integrity of the geometry from the STL file. After converting to geometry in BobCad and defining my 3/16" ball nose cutter on the NC-side of things again in BobCad, I then re-generate the g-code from within BobCad. Now, being that the spiral segments were created as line segments, BobCad is simply following them with no offsets and is placing the chosen tool on the line and running. Can I expect the same results as the original NC file brought in minus the vertical plunge walls and rapids criss-crossing the part? I will attach pics once I get permission to do so. It is the hardest and largest CNC project I have worked on to date considering it is aesthetics and not measurements, and the huge file sizes. I'd rather be making parts for the Space Station!

    Thanks,

    Rob

  2. #2
    Join Date
    Jan 2006
    Posts
    4396
    Post your Text G-Code so you don't need permission. Then Post a picture of a simple example of what you want.

    This will be much faster than waiting for an Ok from someone else.

    :cheers:
    Toby D.
    "Imagination and Memory are but one thing, but for divers considerations have divers names"
    Schwarzwald

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

    www.refractotech.com

  3. #3
    Join Date
    Jul 2003
    Posts
    1220
    rherman
    If I understand what you are say correctly, I reckon you have the same NC data as you had less the lines deleted.
    I don't believe BCC altered the path because you entered 3/16" ball nose.
    I would think that BCC will only take into consideration the 3/16 cutter when you have a solid model and not just a tool path. Correct me somebody if I'm wrong.
    You maybe able to check by re-generating the g-code again from within BCC with a cutter of zero diameter if thats possible.

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