spiral sweep

Discussion in 'Pro/Engineer & Creo Elements/Pro' started by Dammerl, Jul 3, 2003.

  1. Dammerl

    Dammerl Guest

    Hi group,

    does anyone know, how to model a spiral groove on a cone? Well, that
    alone is easy enough, but I want that groove to end in the middle and
    leave a shape as you would see, if you have a endmill make that groove
    with ramping out at the end of it. If I use a rectangle (2D projection
    of the tool), the end is wrong (as is the exact shape of the groove
    itself). All I can think of is to create multiple points on the
    trajectory for the groove and cut out holes perpendicular to the cone
    down to those points. Then I wold create surfaces to connect the sides
    and the (somewhat) round bottom of those holes to complete the cut. This
    approach seems to be quite complex and only would give me an approximation.


    Any better ideas on how to create a true 3D-cut?

    Tom
     
    Dammerl, Jul 3, 2003
    #1
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  2. Dammerl

    David Janes Guest

    Sweep your rectangular cross section. Then round the ends as follows: create
    a revolved cut using the flat end of the previous cut as a sketching plane.
    Place a center line in the middle of the plane for an axis of revolution.
    Then made a rectangular sketch aligned to the centerline and the top, bottom
    and side edges of the existing cut. Make the degrees of revolve 180 and it
    will round the ends. Make sure that the height of the cut is above the top
    of the cut. Also, the sketching planes will be no problem, but you may have
    difficulty, especially on elliptical geometry of a cone, of finding
    something to use as a vertical or horizontal reference. You may have to
    create datums, possibly on the fly, for this purpose. You can use the
    sketching plane as a normal reference and thru the bottom edge of the
    existing cut.

    I predict complete success in your nutty endeavor.

    David Janes
     
    David Janes, Jul 3, 2003
    #2
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  3. Dammerl

    Dammerl Guest

    Hi David,

    thanks, and I will be a complete success ... but not to what I need. A
    rectangluar sweep won't give me the correct geometry, since in a spiral
    cut parts of the cutter before or after the recangular crossection of
    the cutter will remove material as well - this is not modeled with your
    approach. Also, I do not want the cut to end at the same depth as the
    groove, but to move out of the material while still feeding. So the edge
    on top of the material will not be a circle but some kind of ellipse.
    Here, mostly the front part of the mill (before the x-section through
    the centerline) will do the material removal.

    But thanks anyway, I probably have to model the mill on several places
    to remove material and then conect those cuts with a surface to finish
    my groove.

    Tom
     
    Dammerl, Jul 4, 2003
    #3
  4. Dammerl

    Ron Roberts Guest

    Tom,

    Maybe a "Variable Section Sweep" would be in order here? With this
    feature, you can specify that the section always remains normal to the
    trajectory and you could achieve the blend-in and blend-out by moving
    the sections onto or off of the trajectory curve. With the section
    specified as normal to the curve I think that you would get the correct
    "as machined" geometry that you are looking for.

    Ron
     
    Ron Roberts, Jul 5, 2003
    #4
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