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sweep not properly supported in sheetmetal?

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bp
Regular Member

sweep not properly supported in sheetmetal?

Im trying to create an assembly with lasercut tubes.

For each tube I use my skeleton model (external merge), switch to sheetmetal and add a sweep. To get the ends to fit to other tubes, I try to add sweeps that remove material. The problem is that the removed material is never normal to the surface. When I use extrude instead of sweep I DO have that option.

Why is this? Any options other than using AFX or surface modelling?

 

 

sweep:

Clipboard02.jpg

 

extrude:

Clipboard04.jpg

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5 REPLIES 5

Re: sweep not properly supported in sheetmetal?

In sheetmetal, you can make sheetmetal cuts and solid cuts, at least with an extrude. It's an option on the feature dashboard. Check in your sweep if that option exists. A sheetmetal cut produces the perpendicular edges, a solid cut will not.

I wouldn't use a sweep if an extrude can produce the same geometry unless there was a good possibility that it'd be curved (and therefore need to be swept) later. I always choose the simplest feature that will accomplish my design intent.

--
Doug Schaefer | Engineering Manager
Crow Works

Re: sweep not properly supported in sheetmetal?

Normal to surface cut is not an option in the sheetmetal dashboard for sweep, at least in my Creo version (2, M90). You can see this in the screenshots Ive added.

My question is: does anyone know if theres a simple way around this? Right now, Ive solved this by starting with surface models and adding wall thickness after cutting the ends, I hope theres an easier way..

Re: sweep not properly supported in sheetmetal?

Tubes are not a sheetmetal application. Sheetmetal tried to maintain normal edges in an unfold state so I tries to show the deformation when it is folded. In reality, sheetmetal does a surface offset and you have to deal with the way it projects the master surface.

Re: sweep not properly supported in sheetmetal?

A tube may not be sheet metal, but this is a moderately clever abuse.

Since the target use for the information is a laser tube cutter and a laser can't make decent tapered cuts in what is essentially rolled metal sheet tubes, the sheet metal module is a decent tool for this application.

That said, it is pretty far from what usually counts as sheet metal fabrication, so the lack of ability to deal with things besides simple cuts and extrusions is not a total surprise.

I'm curious as to the difference it makes. When it is time to program the cuts can't the software be told which edge to follow? Right now it looks like the primary surface is the OD of the tube. If the curve on outside is followed, the tubes can't butt together without grinding, which will leave a knife-edge. Following the ID curve will allow them to fit and provide a decent edge to weld to.

Re: sweep not properly supported in sheetmetal?

Now I see what you meant in the original post. Yep, no option for "normal" in the sweep feature.

Easy fix is to use the inside edge to create a second sweep:

normal_trim.PNG