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rotary dough cutter

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41 comments

  • Jacant

    It would depend on the size of the circle and cylinder. What are the sizes?

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  • Nenad Blagojevic

    Cylinder diameter is 60 mm, high 350mm and circle is 188,4 mm in diameter. Yet I managed to wrap a circle around the cylinder. Using the parametric equation :

    x=[r]*Cos([t])

    y=[R]*Sin([r]*Sin([t])/[R])

    z=[R]*Cos([r]*Sin([t])/[R])

    and parameters is

    r=188,4 or pi*R

    R=60

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  • tab...

    Hello Nenad Blagojevic,

    That's interesting...

    If possible, could you expand on your method - many users would appreciate it i'm sure.

    Thanks.

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  • Nenad Blagojevic

    Nothing special, just select equation in the sketch tab (the expression must be entered exactly as in the post, which means that the trigonometric functions start with a capital letter and are in parentheses). In my case the x axis is the axis of the cylinder. The parameter r is the diameter of the circle you want to wrap, and R is the diameter of the cylinder. At that point, the 3D curve of the function you entered will appear. Be sure to copy the line of the function you received, and continue to work as with any line in the DSM.

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  • Nenad Blagojevic

    Just not to forget the credit for the mathematical expression goes to Christian Blatter (StackExchange, Mathematics). Thanks bye !

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  • Me Here

    Nenad,

    I cut and paste your equation and entered your parameter values and got:

    The cylinder is 60mm diameter and 350mm high.

    Not quite right?

     

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  • Me Here

    Here is the image that this crappy forum simply refused to let me post above:

    I had to set the scale to 0.5 to make the curve (pink) fit the cylinder:

     

     

     

     

     

     

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  • tab...

    Hello Nenad Blagojevic,

    Thanks very much...this will i hope help others develop true geometry.

    I have typed in as written by yourself but exchanged the parameters r and R to help my understanding with a example. The true arc length measurement confirms the equation result.

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  • Nenad Blagojevic

    I'm glad to hear that. However, I don't have a solution for what I need that curve around the cylinder. In fact, now I need a surface that is perpendicular to the cylinder, height of about 10 mm, which of course follows the curve. Maybe someone has a solution for that?

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  • tab...

    Nenad,

    something like this...all done with normal DSM techniques but i have a small error as shown.

    Just confirm that's what you want and i'll describe the process.

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  • Jacant

    https://we.tl/t-MUGTzFuehn 

    I tried to add an image of 15kb, only to be told that I can not exceed 2MB.

     

     

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  • tab...

    Nenad,

    good geometry but r 94.15 only having to do it the 'work around way'.

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  • Nenad Blagojevic

    Yes, that's what I need, or rather I just need a vertical edge. Now all I have to do is unfold the surface, of course in some external program, and cut it on a laser or waterjet. Thanks to Tom and everyone else!

    Nenad

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  • Nenad Blagojevic

    Of course, it would be useful to describe the whole way to complete the whole process of obtaining such a complex shape.

     

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  • Jacant

    ...Now all I have to do is unfold the surface...

    If you only want to 'Develop' the surface for laser cutting, then draw an 'Ellipse' to the size required.

     

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  • Me Here

    "Draw an ellipse" -- Nice!

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  • Nenad Blagojevic

    And finally after all, this is what 2 quarters look like. The complete form cannot be cut because the paths intersect. Because of that, I had to divide the form in half, but then I had to divide the halves into quarters for economic reasons (saving materials).

    Pretty long way from this:

    To this:

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  • Nenad Blagojevic

      Tim sorry for my typo mistake. So once again thank you all and regards !

     

    Nenad.

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  • tab...

    Jacant

    So simple ...i must have known this somewhere in the dim distant past but sadly forgotten.

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  • tab...

    Nenad Blagojevic

    No problem - maybe post up an image when it's done. I'd like to see how it turns out.

    Cheers.

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  • Nenad Blagojevic

    Tim you are promised to explain the process step by step, of course, if you've got time for that !?

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  • Nenad Blagojevic

        Of course, first there is the transfer to the material, then the cutting (I think I will try the test on a softer metal sheet, which I can cut by hand) and then welding. I think it will take me 1 or 2 days for all this, if everything is fine then go to laser cut on a stainless steel sheet.

    Nenad.

     
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  • tab...

    Nenad Blagojevic

    yes, i will - but it's just basic dsm. It's a little 'long winded' , and the only way i could figure doing it.

    confession... i suspect Jacant has a more efficient way !

    I'll come back later tonight. Busy right now.

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  • Jacant

    The completed file is still here https://we.tl/t-MUGTzFuehn 

    The easiest way to do it is ask a friend who has Spaceclaim and Designspark. They will use a tool called 'Wrap'. Basically it is the same as 'Project' with the option 'Wrap around target' that was available in V1 of DSM

    So the part you want is the 10mm upstand?

    Open the file I created. Copy the '10mm upstand' Paste in a new drawing. Save as STL.

    Import the STL in Meshmixer.  https://www.meshmixer.com 

    Analysis - Inspector - Done.

    Edit - Unwrap - Accept.

    Delete Imported file.

    Select Unwrap1- File - Export - STL

    Open new STL in DSM - Convert to solid.

    Place 'Planes' @ World Origin - Combine /Cut Surface using planes.

     

     

     

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  • Jacant

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  • Nenad Blagojevic

      All right Jacant, thanks for the effort. Unfortunately I do not have access to Spaceclaim. I had a trial version but it expired. Only one thing is not clear to me, namely we used the same unfold software, but my result is significantly different from yours. Take a look at:

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  • Jacant

    Was the STL file you imported in one continuous shape or split? 

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  • Nenad Blagojevic

       The file I was processing is the one from the post where are the  images of two quarters. Since I always double check before cutting the material (especially stainless steel) I made a paper form and glued it to a 60mm Al tube. To me, that looks just fine. Take a look at :

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  • Jacant

    Looks good.

    Don't forget to use the 'Ellipse' to position the upstand correctly.

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  • Jacant

    Tim you are promised to explain the process step by step, of course, if you've got time for that !?

    I am also curious on how you achieved this.

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