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Dimensioning curves by arc length?

At my work we bend tubes and prefer to use the full sizes that we keep in stock instead of cutting them. That requires knowing (and sometimes controlling) the center line length of the arcs.
Hi Nate -- But that (finding the Length of the Bend) depends on the Neutral Axis Radius rather than the CL of the Bemd. -- Lew
 

NateLiquidGravity

Alibre Super User
Hi Nate -- But that (finding the Length of the Bend) depends on the Neutral Axis Radius rather than the CL of the Bemd. -- Lew
Irrelevant to the discussion at hand - but yes - I know that and that depends on the materials. Either way makes no difference in Alibre Design if I can't dimension it.
 

sz0k30

Senior Member
Yes Lew, your post #16 is exactly what I am talking about and want to see. When I was working, many of my jobs involved tubes, hoses and wires. Always needed total lengths. And if I remember (its been a long time), hoses and wires were usually splines that needed length dimensions.

And Nate & Lamar I agree 100%.
 

idslk

Alibre Super User
Hello colleagues,
if you are talking about bend lines, i would imagine that they are coming out of an module like sheetmetal...
(or you can calculate them by yourself...including the length ;-) (looks like a little bit more work...)
An dimension on an arc with a known radius an an known start and end angle looks like the first step to it.
This one should be possible by Alibre programmers with not so much effort (the measuring tool is already capable of this calculation;-).
Regards
Stefan
 

Kunstmaan

Alibre Super User
I tried the solotion here but got a strange result.
Having a diam of 140mm and the desired arclenght of 70mm i got a angle of 57,3 degrees.
that sounds not to be correct, so whats wrong ??

Mareike
 
At my work we bend tubes and prefer to use the full sizes that we keep in stock instead of cutting them. That requires knowing (and sometimes controlling) the center line length of the arcs.
Hi Nate -- What you need is not the centerline length but the formed Neutral Axis length. See attached. -- Lew
 

Attachments

  • Non-Rectangular Shape Neutral Axis & K-Factor -- Rev -- .pdf
    272 KB · Views: 10

NateLiquidGravity

Alibre Super User
Hi Nate -- What you need is not the centerline length but the formed Neutral Axis length. See attached. -- Lew
Yeah, we talked about it 8 posts and 15 weeks ago.

I tried the solotion here but got a strange result.
Having a diam of 140mm and the desired arclenght of 70mm i got a angle of 57,3 degrees.
that sounds not to be correct, so whats wrong ??
Looks right to me.
upload_2020-6-19_13-2-36.png
 

sz0k30

Senior Member
We've been asking for it for at least 2 years!!! But it seems that too often Alibre seems to spend more time & resources on cosmetic changes (such as the look of Icons in V26 vs V25) rather than real improvements. And I still keep getting RED dimensions in drawings when I don't touch anything near that particular area.
 
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dwc

Alibre Super User
We've been asking for it for at least 2 years!!! But it seems that too often Alibre seems to spend more time & resources on cosmetic changes (such as the look of Icons in V26 vs V25) rather than real improvements. And I still keep getting RED dimensions in drawings when I don't touch anything near that particular area.
You are very impatient. I've had things in the cue for over 6 years. But in the mean time they have been added. Yeh!
 

DavidJ

Administrator
Staff member
And I still keep getting RED dimensions in drawings when I don't touch anything near that particular area.
Doesn't have to be 'near' to affect the underlying index numbers - any topology change will lead to re-assignment of edge/face/vertex numbers.

V26 does have a 're-attach dimension' function, to reduce work tidying the aftermath.
 

laverne3ca

Senior Member
Sadly, No!
A requirement for exactly this came up for me today, calculating the major axis of an ellipse that had to be laser cut in a tube to produce a round hole on the ID for a round part crossing the tube, perpendicular to the axis of the tube.
 
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