should C axis deliver a hexagon with 'rounded' sides ?


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Thread: should C axis deliver a hexagon with 'rounded' sides ?

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    Default should C axis deliver a hexagon with 'rounded' sides ?

    hy, recently i used the C axis to get a hexagon, and it come out a bit round; pls check atached; is it normal ?

    so far i did not noticed this, and a while ago i was told by the dealer that C axis is not delivering 'true' lines

    code is ok, it uses G101, endmill o12 for sw27 / kindly

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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    It is my understanding that even on a lathe with polygon turning functions, producing perfectly parallel sides using polygon turning on a lathe without a Y axis is not possible. What you got is likely the best you're going to get.

    Dave



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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    Is your tool parallel to the Z or X axis?


    Last edited by Technical Ted; 11-09-2019 at 03:33 PM.


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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    If it is using G101 and not getting straight lines, your tool comp is either over or undersized. It will definitely make straight lines. Polygon turning will be close but never flat.

    Experience is what you get just after you needed it.


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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    hy mr wizard, hy guys

    It will definitely make straight lines
    yes, of course ... usually i generate the toolpath on tool center and use Xoffset-40, but now i tried to take a shortcut, by having the toolpath = part, and measuring the tool towards x-; as a result, the sides ended up a little rounded, but i didn't foreseen it, i only realized this a few seconds ago also, before milling it, i turned the od in such a manner, that the edges of the hexagon would be rounded, not sharp; in the end, the hexagon is more tangent at each corner, and looks nice, smooth ...

    If it is using G101 and not getting straight lines, your tool comp is either over or undersized
    if i may, if tool comp is not correct, when milling a hexagon, then maybe the final shape would be proportional, scaled

    It is my understanding that even on a lathe with polygon turning functions, producing perfectly parallel sides using polygon turning on a lathe without a Y axis is not possible
    hy giant is all about tolerances, and when it comes to polygon turning, loci shape is the one that can predict deviation ( attached ) : for example, for a sw27, for tool diameter range o20 to o100, deviations range will be 0.351 to 0.032

    a tool o50 will deliver a deviation of 0.1, and this deviation can be reduced by 13%, only by chamfering the corners (0.6chamfer) of the hexagon, in order to remove the sharp edges; the chamfering operation can be done by turning the od of the material at o30.6 before polygon-turning, and repeating the od turning after that, in order to remove the burrs

    also, there is no need to have this function installed, as long as the operation is done in one-shot, without restarting / kindly

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    Last edited by deadlykitten; 11-11-2019 at 04:15 AM.
    ... chip happens


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    Cool Re: should C axis deliver a hexagon with 'rounded' sides ?

    Quote Originally Posted by deadlykitten View Post


    if i may, if tool comp is not correct, when milling a hexagon, then maybe the final shape would be proportional, scaled
    Most people make that assumption, but it is not correct. If the tool comp is wrong you either get a convex or concave flat. You need to remember that the control is using a round tool and a rotating axis to generate the flat by essentially cutting an arc. If the tool diameter is not correct, the arc used to make the flat calculation is not correct and the flat becomes slightly curved. If you are using the Y-axis rather than c-axis contouring, you will have the shape scaled.

    You can prove this by making your tool comp drastically wrong and watching what happens. C-X makes arced flats and X-Y makes scaled flats.

    Try not to melt your igloo while thinking about this...

    Best regards,

    Experience is what you get just after you needed it.


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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    hy mr wizard, so far i don't have an optimized code for milling hexagons, so i use a toolpath that is on tool center, Xoffset=-40, no compensation, and code looks like this :

    hex ( rough. ) vtwox or vzshx = 1.2
    hex ( rough. ) vtwox or vzshx = 0.6
    hex ( finish ) vtwox or vzshx = 0


    if final size is not ok, i edit x_offset ...

    if i need to deliver a hexagon with a different size, i edit 2-3 values inside a soubroutine, because the hexagon is being cut by running same soubroutine 6 times, shifting C-origin by 360/6

    if i need to deliver only 2 flats, i will call the soubroutine only 2 times, shifting C-origin by 360/2

    it is a way to deliver flats ( rough & finish ), that messes with offsets ( or spindle center, when vtwox>10 ) instead of using comp

    Try not to melt your igloo while thinking about this...
    i will look into it, and let you know how the temperature goes

    Last edited by deadlykitten; 11-11-2019 at 12:55 PM.
    ... chip happens


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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    i will look into it, and let you know how the temperature goes [/QUOTE]

    Wait you have Igloos on the south pole and here I thought it was a Greenland thing?



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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    the only green thing in here is you

    ... chip happens


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    Default Re: should C axis deliver a hexagon with 'rounded' sides ?

    Quote Originally Posted by deadlykitten View Post
    the only green thing in here is you
    You watch it Kitty, you wont like me when im angry LOL



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should C axis deliver a hexagon with 'rounded' sides ?

should C axis deliver a hexagon with 'rounded' sides ?

should C axis deliver a hexagon with 'rounded' sides ?