Sheet metal cone fails to create flat pattern

[gloyer37PWF]

I created a truncated cone in sheet metal using this YouTube video (https://www.youtube.com/watch?v=lLDvtLzXwJ4). I confirmed that it is a sheet metal component (the icon on the body of the component).  When I choose to Create/Create Flat Pattern, I choose the edge that the YouTube creator chooses and it creates a "Flat Pattern" with no errors, except that it isn't flat! The flat pattern view shows the cone in 3D perspective in a different orientation.

Here is the public link to the design: https://a360.co/3DSsh3W

I've tried lots of variations to get the flat pattern to be, well, flat, but no luck. Appreciate any help you can offer.

George

[jhackney1972]

You method will fail due to the Sheet Metal Flange operation giving you a mismatched surface.  In the screen capture I have noted this location, at the bottom of the cone, with a red arrow.  I have attached a cone development, using your same, odd, dimensions which uses a different method.  After taking a look at the timeline, if you need further explanation of how it was done please let me know.

[gloyer37PWF]

Thanks, John, I followed the timeline and I want to reproduce what you've done. If I understand the timeline correctly, you started with two sketches. One has a circle at the origin at the z=0 plane and the other a circle at the z=15 plane. Each sketch has three construction lines that start at the center of the circles and extends past the radius and that are separated by 1 degree. Then the circles are trimmed to create a cap where the construction lines intersect.  The next step is to create a loft in the Solid mode between the two broken circles. I can't get that to work. When I start the Loft operation, I'm unable to select either of the circles in the two sketches.  Can you see what I'm doing wrong?

Thanks for your help.

[jhackney1972 · Accepted solution]

You had some wild sketches so I had to clean them up in the beginning of my Screencast.  The construction lines are used to maintain the gap in the sheet metal cone.  You can make these parameters if you like and connect them together.  The main problem you were having is the fact your were trying to use a SOLID Loft instead of a SURFACE Loft.  I have attached the model I used in my Screencast for you to follow if you desire.

[gloyer37PWF]

@jhackney1972 , the video made all the difference in the world - creating the flat pattern with this shape went so fast when you demonstrated it, I had to slow it down to 0.5x to see what was going on.

What I learned:

• I have been leaving a lot of junk lines and other objects in my sketch as I blunder my way through creating the elements I want - it needs to be clean, clean, clean
• Use the Surface tools to get the initial geometry of the surface built
• Switch to Solid tools to thicken (thickening in Surface tools doesn't work, not quite sure why)
• Switch to SheetMetal tools to Extrude (that was a surprise, too, I would have guessed Solid tools)

Watching a pro like yourself was very instructive all in itself. Thanks, I've got my own version working now and confident I can take it from here.