Problems with contour flange

[RwSkinner]

I've been fighting contour flanges for awhile now. Sometimes I can get them to work but other times I continue to get the error they are not valid sketches.
It says it's under defined but I have dimensions every possible place, I think.
Can anyone tell me what I got going on with this sketch please?

Thanks,
Richard

 

[DavidJ]

Arc is not tangent to straight line.

 

[RwSkinner]

And how do I fix that? I set a reference line, set a tangent constaint, then referenced the ref line to the axis which provides a tangent constraint but it complained about that as well.

Arc is not tangent to straight line.

 

[RwSkinner]

Insert a plane then do a tangental constraint? Would that work?

 

[DavidJ]

Difficult to say without knowing what you are trying to obtain. The arc in your sketch is not tangent to the line it joins, Geomagic Design reports that when you close the sketch.

Planes have no meaning within sketch, so not sure what you are suggesting ...

 

[RwSkinner]

The trick to make it work, which is insane, is to add a very small fillet/radius to where the top arc meets the the left vertical line, which provides a tangent constraint and allow the contour to work.
Problem solved but seems pretty crazy.

 

[DavidJ]

Seems exactly in line with what the error description said...

If making it in real life there would be a bend radius.

GD is smart enough to recognise right a sharp angle between straight lines of a contour flange sketch (and automatically insert bend radius), it can't work out by itself a sharp angle between straight line and an arc - you have to give it some help.

 

[RwSkinner]

True, but it is smart enough in most cases to automatically add the radius according to the Sheet metal dimensions provided in parameters. It does this when creating tabs and flanges, and contour is a flange.
In real life, yes, the brake leaves a bend radius. The solution is easy enough, if you know what they are trying to say. Honestly, a tangental constraint to a reference line should be valid if the reference line is constrained?

 

[RwSkinner]

Ah, I just read your response again so the sharp line to arc is what confused it. I understand.

True, but it is smart enough in most cases to automatically add the radius according to the Sheet metal dimensions provided in parameters. It does this when creating tabs and flanges, and contour is a flange.
In real life, yes, the brake leaves a bend radius. The solution is easy enough, if you know what they are trying to say. Honestly, a tangental constraint to a reference line should be valid if the reference line is constrained?

 

[HaroldL]

If you check the Status of the feature it will usually tell you what is wrong (except when there is some cryptic coding message). In this case it gave an indication of how to fix the sketch.

Once I added a Fillet between the vertical line and the arc it still would not complete. I then noticed a short arc segment that didn't make any sense to me. After I deleted the short segment and extended the main arc to replace the deleted segment it resolved just fine.

 

[RwSkinner]

Yes, I had to fix that segment and I had done that actually before I tried the radius which between the two fixed the issue earlier today.
I see segments like that on arcs I create all the time using the arc tool. Why does that happen, and is there not a way to Join or Weld the two together and get rid of the point without having to trim and extend?

Richard

 

[HaroldL]

. . . I see segments like that on arcs I create all the time using the arc tool. Why does that happen, and is there not a way to Join or Weld the two together and get rid of the point without having to trim and extend?

Richard

Nope . . . the only option is to Delete the unwanted segment and Extend the remaining one.

If you are seeing this a lot, it may be related to how fast you (need to) click the mouse. I've had to turn down my mouse click speed (in Windows control panel) so I could have better control on my double-clicks as sometimes I ended up with super-short line segments, I talking so short you couldn't see them, even zoomed way in to the max.

 

[lamar]

When using the contour flange you must always have a short strait line before a 90 deg bend. it can be a couple thousands of an inch but it must be there and constrained to work. I us contour flanges a lot and have run into this behavior before.

I have uploaded the change file.
I done like this it has always worked for me.

 

[RwSkinner]

Thanks for all the pointers!

Richard