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PostPosted: Mon Nov 27, 2017 9:43 am 
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Joined: Wed Aug 31, 2011 5:52 am
Posts: 36
Hello all,

I was wondering if anyone could give me advice on anything I should look out for when designing Photo Etch Angles.

I intend making 1/48 scale 100 x 100 mm angles in 1/48 scale using .2mm brass.

From my understanding each side will be 2.08mm, so when designed flat I get a width of 4.16mm wide. The fold line for .2mm brass is .24mm half etch.

When folded along this axis will this give me a 1/48 100mm Angle? Is there some accounting for the stretch/bend of the "corner"?

Thanks for your help!

Dennis


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PostPosted: Mon Nov 27, 2017 10:04 am 
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Joined: Wed Jan 21, 2009 1:51 pm
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If you have a 100mm part with a fold at 1:48, then the total width is 2.0833mm. I usually apply 1 plate thickness as the fold line thickness. Note that after folding 90 degrees the entire width of the part is what you had plus the fold line thickness, so you need to correct

So I'd go with: 2.0833-0.2 = 1.8833mm for the first width, then a 0.2mm fold line and then another 1.8833mm line.

But, what are you trying to make? Perhaps styrene is easier to use for your application?


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PostPosted: Mon Nov 27, 2017 3:02 pm 
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Joined: Wed Aug 31, 2011 5:52 am
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Thanks EJFoeth but I decided against Plastic as it was not scale thick and I wanted to Emboss Rivets in the Brass.

The 2.08mm was each side of the 90 degree angle.

What I envisioned designing was a flat 4.16mm wide brass strip with a .24mm wide half-etch (.12 either side of the 4.16 centreline) and if bent correctly this should allow me have a 1/48 scale 100 x 100 mm Angle Section (2.08mm each side in scale).

But is there to be some consideration for the cornet or stretching?

Thanks again

Dennis


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PostPosted: Tue Nov 28, 2017 3:41 am 
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Joined: Wed Sep 28, 2011 12:04 pm
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Location: Paris
When you fold sheet metal, the material on the outside of the bend is stretched, while the material from the inside of the corner is displaced into the corner (metal being non-compressible). In order to account for this material displacement, this material is taken away by a line half-etched through, as EJFoeth already said. A width of the thickness of the sheet should be sufficient.

The folded angle then should measure on the outside the width as drawn plus the thickness of the sheet, e.g. 1.8 mm + 0.2 mm. Unfolded, the strip would be 4.0 mm wide with a 0.2 mm half-etched line in the middle.

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