Issue creating a wrap

[IbrahimTayyab]

I want to create a quilt and then wrap a sketch around said quilt. 

To do this, I create a circle with diameter 360/pi and then extrude the sketch to 250. I create a sketch of a rectangle with height matching the extrusion and width 72. If I set the width to be 80 the wrap is successful but if I put the width to be 72 it fails. I have no idea why and would appreciate all help.

I am using Creo parametric 9.0 Student version.

[IbrahimTayyab]

The sketch.

The wrap error.

Same wrap working when I set the width to be 80 instead.

[kdirth · Accepted solution]

I would guess the issue is related to part of your sketch being on the very edge of the surface you are projecting onto.  As @MartinHanak indicated the entire sketch must lie within the surface.  The model has a level of accuracy that can cause an issue when you are defining the sketch to extend to the edge of the surface.  the copy of surfaces may also be contributing to the error.

On another note, I know you are a student, but this is a two feature curve created with 9 features.  Extrude the cylinder as a surface with an internal sketch and wrap an internal sketch from the front datum plane.  No need to copy surfaces and remove solids.

Creo 7 file attached.

[IbrahimTayyab]

Oh i never realised there was an option to extrude as a surface, that is so helpful. I just  burst out laughing when I realised this, thank you very much.

[IbrahimTayyab]

This solution worked first try, it seems the copy of the surfaces led to stacking accuracy errors. I am really thankful that I am able to recieve help like this, thank you.

[kdirth]

We are glad to help.  We all learn a little bit each day by posting questions and trying to answer others. 

[IbrahimTayyab]

When I started the process in a new part it behaved as expected. I am not sure what caused this behaviour, I will try to recreate it in a new part.

[IbrahimTayyab]

I have recorded a video of me creating the wrap in real time. I used the following relations:

Perimeter=360
radius=perimeter/2/pi
diameter=2*radius
extrude=300
width=72

Kindly let me know what I am doing wrong.

[MartinHanak]

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@IbrahimTayyab wrote:

I have recorded a video of me creating the wrap in real time. I used the following relations:

Perimeter=360
radius=perimeter/2/pi
diameter=2*radius
extrude=300
width=72

Kindly let me know what I am doing wrong.

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Hi,

wrapped curve must lie inside surface.

[IbrahimTayyab]

I am not sure I follow in the first sketch the height was constrained by the end references while in the second sketch the wrap failed when the sketch height was 300 same as the extrude

[MartinHanak]

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@IbrahimTayyab wrote:

I am not sure I follow in the first sketch the height was constrained by the end references while in the second sketch the wrap failed when the sketch height was 300 same as the extrude

---

Hi,

I apologize ... unfortunately I can't test all your attempts. I give up.

[IbrahimTayyab]

Thanks for all your help, I think it will be resolved when I implement kidrth and stephenw's solution of extruding as a surface and checking the accuracy.

[StephenW]

This may be an accuracy issue. Go to file prepare model properties, then change the accuracy to the smallest number it will let you.

You should be set to absolute accuracy also.

[StephenW]

No matter my construction method of the geometry, I could not make it fail like it did on your geometry, unless I went over 300 on the height, which makes sense.

[kdirth]

I was able to get a failure only when using copied surfaces and some widths worked and some didn't.  If I extruded a cylindrical surface and wrapped it, it worked for all widths.

Creo 7.0.11.0, absolute 0.001,  mmKs

[IbrahimTayyab]

I used kdirths correct method of creating the surface and it worked first time with no errors. 

I also recreated my original method of creating the surface and tried changing the accuracies.

The wrap still failed with abs 0.0001 inlbs.

The wrap was not successful with abs 0.0001 mmKs either.

It seems the roundabout way of creating the surfaces add some accuracy errors or something of the short as kdirth pointed out.
Thanks a lot for your answer I didn't think imagine it was due to the accuracy from my method but that does seem like the most plausible answer.