Discussion in 'Using Alibre Design' started by GIOV, May 23, 2020.
How do I apply rectangular coaxial constraints on an assembly?
Any help will be welcome.
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.
Do you have an example of what you are trying to achieve? Rectangular and coaxial dont fit in the same sentence to me.
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.
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.
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
in mind what you wanna get, i would have designed it like this (only one of a lot of ways)...
9 constraints is so much but thanks anyway,
Ideal 2 constraints..
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...
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.
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...
That is simple.
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.
Thanks very much Harold.
The ideal is a Constrains for two rectangular section parts like cylinder faces coaxial constrains.
Here is an other solution.
What's needed for assemblies is a Symmetric mate similar to the one for sketches.
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.
Yes, Symmetric Constrains for two or 4 faces. Will be important feature.
Thanks very much Harold.
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