[Spinnetti]

To create a pattern... Looked at some vids, but not working - is it because of my cross holes? I'm trying to flatten this part so I can make a cutting pattern.

Tips?

Thanks!

[Mike 1948]

Try suppressing the holes and see if it works.

Mike

[Spinnetti]

Mike, thanks for the response. Tried that, but same result...

[Mike 1948]

Can you post the model?

[keebler303]

I can't look at your model right now but is your cylinder continuous? If so, that is likely the problem. Your cylinder has to have a break somewhere so that it can be flattened. I'd draw a circle with a tiny piece of the arc missing, it should then flatten with that tiny seam being the end of the flat sheet.

[Spinnetti]

I posted the model in the original post... I did put a cut through the model, and my understanding is, you pick that cut edge and "insert bend", then Flatten, and I watched videos of how to do but can't recreate

[cygnus x-1]

I tried to open your file and got an error.

Take a look at this one. I tried to do this with a swept bend but it wouldn't unbend for some reason. Lofted bend seems to work though.

C|

[Spinnetti]

I tried to open your file and got an error.

Take a look at this one. I tried to do this with a swept bend but it wouldn't unbend for some reason. Lofted bend seems to work though.

C|

Lofted bend eh? that sound promising - Thanks for the help... I'll check it out...

[twoartistic]

I have never been able to get sheet metal to give me a flat pattern of a part that has a compound curve. Since you do not have a straight cylinder or cone, I suspect that is the problem. Your part cannot be simply rolled/bent, So the software does not know what to do with the geometry. So here are a couple of options, Step your tapered part as a series of straight edge cones. This ends up as a multi piece part that will have to be welded. Turn your seams to run parallel to the center axis of your cylinder, and make it a multi sided part. Again these will have to be welded. How do you intend to manufacture this part? Think about the pragmatics of that, and design the part that way. Your current part cannot be manufactured in a standard roller, or a break press, you will have to do the flat pattern old school, and have a sheet metal artisan make it, or design a custom manufacturing process, if you want to keep the smooth transition taper.

[Spinnetti]

I have never been able to get sheet metal to give me a flat pattern of a part that has a compound curve. Since you do not have a straight cylinder or cone, I suspect that is the problem. Your part cannot be simply rolled/bent, So the software does not know what to do with the geometry. So here are a couple of options, Step your tapered part as a series of straight edge cones. This ends up as a multi piece part that will have to be welded. Turn your seams to run parallel to the center axis of your cylinder, and make it a multi sided part. Again these will have to be welded. How do you intend to manufacture this part? Think about the pragmatics of that, and design the part that way. Your current part cannot be manufactured in a standard roller, or a break press, you will have to do the flat pattern old school, and have a sheet metal artisan make it, or design a custom manufacturing process, if you want to keep the smooth transition taper.

Thanks for in insights. My thinking was to unroll it, cut it from 18ga sheet steel, roll it up and weld it. Couple options would be to do it two parts and weld together (tube and taper parts). Maybe it should be a regular cone? I'm reproducing an aircraft part from the 1940s. Maybe the pictures I references are deceiving. The real thing was rolled and welded, so has to work somehow. I was originally going to simulate by machining it out of billet aluminum as that shape is easy to do on a lathe... Might have to stick with that if I can't unwrap it. Good points to ponder... Will experiment more on that tomorrow.

[inov8r]

Roll and weld a cone, then build a swage (mandrel) the shape you need it to be. use a hydraulic press to push it in. May have to build an outside mold as well.

[Spinnetti]

Roll and weld a cone, then build a swage (mandrel) the shape you need it to be. use a hydraulic press to push it in. May have to build an outside mold as well.

Yep, that would work, (also need to grind the inner weld face before swaging) but all that is too much effort for a one off (large) scale R/C build though. I think I'll just machine from billet. Heck, I could probably just 3d print it with a couple metal inserts for piece of mind.

[keebler303]

Folks are also using pressure washers for hydroforming things like tuned pipes for dirt bikes.

Build a female mold, weld a pipe fitting to one end of your tube and cap the other, apply pressure with pressure washer, tube expands to fit mold. Some videos on youtube...

[Spinnetti]

Folks are also using pressure washers for hydroforming things like tuned pipes for dirt bikes.

Build a female mold, weld a pipe fitting to one end of your tube and cap the other, apply pressure with pressure washer, tube expands to fit mold. Some videos on youtube...

Yeah, that's pretty cool... who would have thought that would work?