Sheet metal conversion Query

pshepherdson · ‎May 29, 2015

Hi All,

Ok, so I believe I understand this, but it doesn’t seem to work as expected. Any help or explanation is greatly appreciated!

I have an unusual, but not complicated part. I start with a solid, then "Convert to S/M" and remove the sides I don’t want from the shell process. Great, I have my form. Now, I want to convert it to a proper S/M part, and I hit the "Conversion" button.

This is where I seem to get lost: the part should be relatively simple; 3 bends in the brake, two of which are identical. These two ‘flanges’ should have a split, where they come together on the 3^rd 135° bend (on the back). To me, this should be a simple "rip connect" from the 4 options shown in the "Conversion" tool. I can select the inside 90° corner, and I want the outer corner of the 135° bend to place my rip. But I can’t. I can select all the other corners except this one.

But, if I add bends to the five edges where I want my bends, I can then go back and add the "rip connect" to split this flange. Great! But not so great. I want a gap at this split, and when I click on the "add gap" button, the rip cut is now not do-able. I’d also like a relief hole at this point, but it won’t add that either.

I’ve tried a few other way of making this part work, using the "conversion" tool. And when I add an ‘edge rip’ to the back bend (the 135° bend) it all seems to work out fine. I get my gap on the split on the opposite flange, and I have any relief hole I want. But that makes for an ugly flat pattern, and a bear in the brake! Not to mention an ugly seam where a bend should be.

My fix/ work around has been to Model the solid shape, shell it in the ‘convert to S/M', then add my bends in 'conversion'. Only then to add an extrude feature the size & shape of my split (with gap) and relief hole. But this seems excessive, and superfluous due to the 'conversion' tool.

I feel this should be an easy task for Creo 2.0 to perform; to add a rip cut & relief on a face, between two corners. I believe I’m missing some keystroke or setting to make / select one of the faces to be my main, driving face, which is causing my grief..

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mpeterson · ‎May 29, 2015

I am not a sheet metal expert, but created many sheet metal parts years ago in solids and converted because I was new with Pro/E and didn't like the old sheet metal interface/functionality so I learned the do's and don'ts of solid designs for sheet metal conversions.

What I did was create the profile shape and included the radius at the main bend so I could reference that in my cut feature which is to create the bend relief. That radius should be your metal thickness plus inside bend radius. Next was the bend relief cut per the sketch image attached that is a thin cut symmetrical about the normal to the bend tangent and outside of the bend geometry at the bend. Extrude that cut the planned material thickness plus your planned bend radius which should be equal to the radius in the profile protrusion sketch. Next mirror that cut or create on the opposite side. Then shell all appropriate surfaces. Then convert to sheet metal. See attached image and part file. If you want a more robust bend relief corner you might as well model it in sheet metal. There are probably many other ways, but again I don't know sheet metal module real well.

pshepherdson · ‎Jun 03, 2015

Thanks for the reply Mark. I managed to get what I wanted, but was hoping it would have been simpler, as "they" would have you believe.