making a pipe wrap template for cutting compound miters on tubes

[anthonyws]

I  am having trouble creating properly dimensioned drawings of compound miter cuts on HSS square tubes. The annotations are difficult for the shop to interpret. ( see picture attached) So the next best thing is a pipe wrap template that the shop can use to mark the tube for cutting.

I've had some luck:

1. converting to sheet metal and then making a flat pattern drawing and exporting to DXF for laser cutting a marking template and also

2. some luck creating a surface wrap and unfoldng that as well.

Neither one is ideal however, and both were found by accident and not easily repeatable. Furthermore the "convert to sheet metal" method was irreversible so it requires making copies of all the tubes in the model which is a royal pain when there are more than a few parts.  

[kdirth]

Here is a little inspiration on how I would detail a compound miter:

[StephenW]

Ooooh...lets talk descriptive geometry using vellum and led!!! One of the most infurating classes I took that made no sense at the time...then I got a real job and discovered, "HEY, that is used!!!"

[anthonyws]

This is basically how I have been doing it. The difficulty is when the tube orientation relative to the cuts is not on a surface but at an angle and there are more than one compound miter per end and there are other miters on the other end. Keeping track of XY, XZ, YZ etc planes is a challenge and bogs down the productivity. Sadly we have no standard, several engineers using several different CAD systems as we are all freelance designers working autonomously on a common project with multiple builds going on so fitting my job into the shop flow is best done with clear and obvious prints. The closest thing to consistency is sending the flat patterns DXF's to our laser guy to cut wrap templates. How we get to that point is a up to each persons preference and system capabilities. I think avoiding such joints may be a worthwhile effort. 

[StephenW · Accepted solution]

Unwrapping via a surface is really the way to go for this specific application. It is much like a piece of paper on the outside of the tube. Surfaces can also be left with the model/layered off and layered on the drawing. There would likely be some tweaking you would need to work out but other than that, it should good. I've done it for saddle cuts on a round pipe.

Sheetmetal, while applicable would be problematic based on the thickness you use and the y or k factor you have in your setup. It would change the length based on the calculated stretch of the material (see machinery's handbook if you are interested).

[anthonyws]

Thanks for the confirmation. I'll have to practice and write down the workflow steps to recreate it reliably. 

[anthonyws]

I cannot for the life of me get this to work. I realize I have done it with round pipe using offsets and flatten quilt. Kinda clunky and does not work with square tube profiles from AFX. Maybe its the AFX tube that causes the problem. but if you know a step by step on how to create a surface from a sq tube HSS and flatten it I would be grateful. 

I have tried sheetmetal convert-rip-flatten but it ruins the original part and is unnecessarily tedious. 

Thanks in advance!

[StephenW]

@anthonyws 

I selected the external surfaces.

Copy/paste to get a surface feature I could work with.

Then I used the trim command to "trim", See the second image for the tangent line I picked.

Then went to surfaces - flatten and picked an origin (I used a vertex)

people with more surfacing experience may have a much better process! I'm a hack, get the job done and move on!

[anthonyws]

That's right. copy/paste. ok, that works to create the surface and I can flatten. now I have to make a dxf of this "flattened" surface. I can't figure out how to hide the tube part or copy paste the flat surface to a drawing for export to DXF. 

Thanks for getting me on the right path!

[StephenW]

To show just the flat surface, make a layer, add the tube as "solid geometry" using query select to get that to show up, I honestly have no idea how to get there except using query select (pick from list on RMB)

To show the tube in the design, make a layer for the surfaces and add the surface features to the layer and blank it.

On the drawing, you'll have to manage layers by view.

You likely could do this with part simplified reps too, may or may not be less/more complicated ?!?!?

Or family tables...

Whichever way, it's not a single click thing. It's more about your tolerance for the steps.

[tbraxton]

Does your organization have a standard for how to document compound miter cuts? If so, are you not able to document this in Creo? If not, you should establish one now and get agreement with the fabricators. How are they making the cut on the shop floor? Is it with a miter saw?

With only two angles (bevel & miter) one can define the cut orientation relative to the workpiece and then specify a location on the tube to make the cut.

[anthonyws]

tbraxton, Thanks for the reply.

Sadly we have no standard ( see reply above) and there is a shortage of talented guys to interpret complicated prints. It's doable on one end with one compound cut. The second cut on the same end is hard to document and then adding another at the opposite end and oh boy... gets hard to document and harder to decipher.