# Thread: Sheet Metal Cylinder - "Creating" & "Flatten" Question

1. ## Sheet Metal Cylinder - "Creating" & "Flatten" Question

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I need to create a cylinder that is 30"Ø, 36.00" tall, with a wall thickness of 0.25".
I don't see where to set the wall thickness.

Here is the procedure I followed:
• Start a new part;
• Go to SHEET METAL > BASE FLANGE/TAB;
• Select the Top Plane;
• Select CIRCLE;
• Create a circle that is 30.00"Ø,
• Exit SKETCH;
• For Sheet Metal Parameters, I enter 36.00" to make the cylinder height 36.00";
This is where I get confused.
I do not know what the K-Factor & the Auto Relief are, or what they do.

I do not see where I would specify that the wall thickness should be 0.25".

Am I supposed to specify the wall thickness on this page, or is there another place to place that dimension?

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Once this cylinder is created, I also need to be able to unfold (or flatten) it.

Sheet Metal Cylinder.jpg

Is there a better way to create this cylinder, that will allow me to FLATTEN it?

2. I found a way to create the cylinder, but I don't know if this is the correct way to do it.

I sketched a circle that was 30.00"Ø.

Then, I trimmed out 1/8" out of the circumference of the circle, so that, now the circle was not a complete circle.
I then went to SHEET METAL, and created the 36" tall cylinder, with a 0.25" wall thickness.

Circle Split.jpg

The cylinder will now FLATTEN, and UNFLATTEN.
I just have to remember that when I need to know the length of the cylinder, when it's flattened, I have to ADD the 1/8" that I originally removed from the circle.

Cirle Split - End Results.jpg

This is the end result.

If this is NOT the correct method, someone please let me know.

3. Actually, I was just informed that, when they construct a cylinder, they will roll the steel to where the 2 ends almost meet, leaving the 2 ends 1/8" apart from each other, to allow for welding. So, I guess, until someone shows me a better way to create a cylinder, this way will have to do.

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Hi Vert,
Unfortunately, this is the correct way to do a rolled cylinder in Solidworks (e.g. creating a circle and breaking it at a point.

The exact K-Factor is dependent to your Brake Press tooling and forming methods. It may vary from company to company and machine manufacturer. I'll try and give the layman's terms.

K-Factor is the expression given to the to point in the thickness of the material where there is no-compression. the k-factor itself relates to a percentage of the thickness of the material:
e.g. 44% = 0.44, 50% = 0.50 etc.etc

This percentage is taken from the inside radii when formed.

Generally material under 3mm has a k-factor of 0.44 but then again this depends on the material used (alloy, M/S or St/St)

http://sheetmetal.me/k-factor/

http://designandmotion.net/design-2/...etal-k-factor/

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