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Rectangular Coaxial Constraints

Discussion in 'Using Alibre Design' started by GIOV, May 23, 2020.

  1. GIOV

    GIOV Senior Member

    Hi,
    How do I apply rectangular coaxial constraints on an assembly?
    Any help will be welcome.
     
  2. HaroldL

    HaroldL Alibre Super User

    :confused::confused:

    Do you mean to constrain two rectangular parts together? Turn on their Reference Geometry and apply Coincident constraints between them. You can also select the Reference Axes.
     
  3. simonb65

    simonb65 Alibre Super User

    Do you have an example of what you are trying to achieve? Rectangular and coaxial dont fit in the same sentence to me.
     
  4. GIOV

    GIOV Senior Member

    Yes a particular case.
    Well fits if they have the same center like cup and inner race of a bearing or shaft and cutlass bearing or a piston and cylinder but in this case all component are rectangular section. I know solutions but I do like apply a existing constrains (two click) to achieve coaxiality & concentricity. I am attaching an example.
    Thanks very much HaroldL & simonb65.
    GIOV
     

    Attached Files:

  5. wazzu83

    wazzu83 Member

    All non-circular cross-sections will require 2 constraints to maintain alignment. The first is your so called co-axial. The second is a planar or face alignment to prevent rotation.
     
  6. Lew_Merrick

    Lew_Merrick Alibre Super User

    Hi Giov -- I assume that your intent to to "coaxially align" two "Rectangular Features" that have the same relative ratio. In that case so long as the Parts were made Symmetric about (say ) "XY-Plane" and "YZ-Plane: then using Reference Geometry ON" is a simple way -- else you will need to Add "Symmetry Planes" to them to make it work correctly. Other conditions require other approached. Forethought is advantageous. -- Lew
     
  7. idslk

    idslk Alibre Super User

    Hello Giov,
    in mind what you wanna get, i would have designed it like this (only one of a lot of ways)...
    Regards
    Stefan
     

    Attached Files:

  8. GIOV

    GIOV Senior Member

    9 constraints is so much but thanks anyway,
    Ideal 2 constraints..
    GIOV
     
  9. idslk

    idslk Alibre Super User

    Hello Giov,

    for your "coaxial" there are only 2 constraints! (one for bar_new<1>.z-axis and one for bar_new<2>.z-axis with the base_new<1>.z-axis)
    To constraint the complete assembly (what makes sense in real world) you need some constraints more...or your boat will be a sinking one...

    Best Regards
    Stefan
     
  10. GIOV

    GIOV Senior Member

    Hello Stefan,
    Thanks very much for your comment.
    Here is another not perfect solution but I figure out a more simple one.

    Thanks all for your approx.
    GIOV
    upload_2020-5-23_13-34-21.png
     

    Attached Files:

  11. idslk

    idslk Alibre Super User

    where in your solution is an coaxial constraint?
    And simpler? It has 3 contraints less because you've used an achored part, which is equal to 9 over all.
    For example: If you use the winkel(2) constraint in "my" package, you can easily type in 90° to move one bar into an other coaxial position and so on...
    The use of such contraints with values will help to tweak them with an external data table like a spread sheet...
    upload_2020-5-23_22-46-52.png
    That is simple.
    Regards
    Stefan
     
  12. HaroldL

    HaroldL Alibre Super User

    Giov,
    Here is my solution - I added an axis the the center of the cutout after I fully constrained its sketch (need to watch out for sketches that aren't fully constrained). I used that axis to center the square tube in the opening and the horizontal plane to hold it from rotating. An offset was use to position it relative the the plate,

    Cursor over the constraint list and you'll see the constrained items highlight in the workspace.
     

    Attached Files:

  13. GIOV

    GIOV Senior Member

    Thanks very much Harold.
    The ideal is a Constrains for two rectangular section parts like cylinder faces coaxial constrains.
    Here is an other solution.
    Take care,
    GIOV
     

    Attached Files:

  14. HaroldL

    HaroldL Alibre Super User

    What's needed for assemblies is a Symmetric mate similar to the one for sketches.

    Symmetric Constraint For Assemblies.png

    OR a mate similar the the Width Mate in SW.

    These are possible in AD now but it takes some setting up of reference planes at the part level. And if you don't "own" the parts it can be a challenge.
     
    GIOV likes this.
  15. GIOV

    GIOV Senior Member

    Yes, Symmetric Constrains for two or 4 faces. Will be important feature.
    Thanks very much Harold.
    GIOV
     

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