Help with 3 mm stainless steel sculpture — thickness

[ARES1 (ARES)]

Hi everyone,

I’m modelling a horse sculpture in Rhino that will be fabricated from 3 mm stainless steel sheets, cut, curved and welded together. Each surface represents a separate sheet.

At the moment, my surfaces have no thickness. The fabricator has asked me to account for the 3 mm thickness so the flat patterns have the correct dimensions after forming, especially because some pieces are strongly curved.

I’ve tried using OffsetSrf to add the thickness, but when I use UnrollSrf, I get the result shown in the attached screenshot, with separate faces and narrow strips rather than a single usable cutting pattern.

What is the correct workflow to account for the sheet thickness when developing these surfaces? Should I model the thickness, unroll a middle/neutral surface, or use another method?

I also have another issue: on most pieces, UnrollSrf reports that the area has increased by an amount ranging from 0.01% to 1.2%, depending on the surface. How should I interpret these differences? Could they cause significant problems with the cutting dimensions and fit between neighbouring pieces? What should I check to decide whether a development is usable?

I’m fairly new to this process, so a simple, step-by-step explanation would really help. This is urgent for us, and I would greatly appreciate any advice.

Thank you!

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Título: Ayuda con escultura en inoxidable de 3 mm — espesor y diferencias de área con UnrollSrf

Hola a todos:

Estoy modelando en Rhino una escultura de un caballo que se fabricará con chapas de acero inoxidable de 3 mm, cortadas, curvadas y soldadas. Cada superficie representa una chapa independiente.

Actualmente, mis superficies no tienen espesor. El fabricante me ha pedido que tenga en cuenta los 3 mm para que los desarrollos tengan las medidas correctas después del curvado, especialmente porque algunas piezas tienen bastante curvatura.

He intentado añadir el espesor con OffsetSrf, pero al utilizar UnrollSrf obtengo el resultado de la captura adjunta: caras separadas y tiras estrechas, en lugar de un único desarrollo útil para el corte.

¿Cuál es el procedimiento correcto para tener en cuenta el espesor al desarrollar estas superficies? ¿Debo modelar el espesor, desplegar una superficie intermedia/neutra o utilizar otro método?

También tengo otro problema: en la mayoría de las piezas, UnrollSrf indica que el área ha aumentado en un porcentaje que va desde el 0,01 % hasta el 1,2 %, dependiendo de la superficie. ¿Cómo debo interpretar estas diferencias? ¿Pueden provocar problemas importantes en las medidas de corte y en el encaje entre piezas contiguas? ¿Qué debería comprobar para saber si el desarrollo sirve?

Tengo poca experiencia con este proceso, así que agradecería mucho una explicación sencilla, paso a paso. Nos urge resolverlo y cualquier ayuda sería muy bienvenida.

¡Muchas gracias!

[Tom_P]

check google for: "k-factor" sheet metal bending.

there is also some other topics in this forum about sheet metal bending.

you may also want to learn about developable surfaces.
for example this topic

there was a similar topic

how will the detail at the edge look before the welding is applied ?

[theoutside (Kyle Houchens)]

I have worked with Zach Oxman for almost 30 years now

Zachary Oxman

I’ve done quite a bit of this type of work.

the thing to remember is how this is going to be fabricated. and that is a detailed conversation you need to have with the person who is going to take these sheets and weld them together.

simply put if you are building a cube for example you need to think of it not at a cube but an assembly.

it’s going to have full face pieces, and smaller, inset pieces…or it will have identical pieces and the corners will be made up of weld.

Or it will be chamfer cut so it fits together perfectly. (expensive in my experience)

see image below-

in this case the faces have to be shrunk so that the inside corners fit together so that the exterior dimensions = 10x10x10 to compensate for the overlap-

then weld and finishing will make up the corners.

this is the simplest way to do it and leaves zero room for error as the parts are identical.

you can do it like this but have to label the parts and take care to assemble them properly.

ultimately you will be sending 2d patterns of only the exterior faces that they can feed to their waterjet or laser. you just have to size them correctly to account for overlap and fabrication method.

hope that helps
-K