Flatten a contoured surface

[DaSalo]

Using NX 7.5:

We have a need to take a surface that is contoured and flatten it out to create a flat blank. The solid looks like a bannana with a half twist along the length. So we want to split the solid in half lengthwise (we've already done that) and then project the resulting half outside surface onto a plane to create the outline of the flat bar blank we would need to create this part. Is there a tool, perhaps in the sheetmetal module, that is designed to do this? We don't have a sheet metal license but could look into getting it, or some other module, if there is a tool that will easily accomplish this.

Perhaps this could also be done accurately by projecting edge curves. I'm asking this question on behalf of another Engineer here so haven't looked into this in any depth myself yet.

Thanks for any help.

 

[Arkance/PhoeNX]

Depending on your license, you could try Global Shaping ( not in sheet metal), Metaform (Advanced Sheetmetal) or One Step Formability (not sure on license needed). Not an expert in using them, but I've seen our demo jock use each of those to do what you want. Global Shaping is probably the only one you could try without having a sheetmetal license but I don't think the result is accurate enough for a flat pattern.

Anthony Galante
Senior Support Engineer

NX4.0.4MP10, NX5.0.0->5.0.6, NX6.0.0->NX6.0.5, NX7.0.0->NX7.0.1 & NX7.5.0.32-> NX7.5.4.4, Beta NX8.0.0.23

 

[JohnRBaker]

What you're looking for is something called 'Meta-Form' which is part of the NX Advanced Sheet Metal module (BTW, you should already have access to NX Sheet Metal, but Advanced Sheet Metal is an extra-cost add-on).

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.com/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[DaSalo]

OK, I'll read up on Meta-form and see if we can get a demonstration from our reseller.

Thanks for the help.

 

[DaSalo]

I read through the help document and am curious which of the constraint types would best apply to my situation: taking a contoured surface and flattening it. I assume either point-to-point or curve-to-curve. Not sure what the difference would be.

 

[DaSalo]

Global shaping did not completely flatten the surface. There is one corner that sticks up ~.200 and then the rest of the shape gradually lays down flat from there. It is not exact but for our application, which is to create a blank for milling, it is probably close enough. I can now project the edges of the new shape down flat and I'll be within .025 or so.

I suppose I could do another global shaping operation on the new surface and that might lay it down the rest of the way.

Never used that function before. There are several options and I believe I used "Variable Offset" instead of "Stretch" or "Overcrown". This took a LONG time to calculate so I'm not inclined to play around with it too much on this machine. Can anyone give a rough description of how these different options effect the output?

Thanks for that suggestion. Never would have thought of that.

 

[JohnRBaker]

This software was originally developed in an attempt to provide a way to model in what's known as 'spring-back' which happens when you're stamping sheet metal for something like the hood of a car or the roof panel. The idea was to create the as-desired final model and then try to modify it's shape so that it now looked like what it would be before any post stamping 'spring-back' had taken place. In that way, this new surface would represent what it is that you needed to machine to have the proper die-face shape. This used a technique which was basically a computerized version of what people used to do by hand in estimating what the spring-back might be and then try to translate how this would effect the shape of a surface. It basically tried to reshape the surface by moving the control points using some sort of averaged and proportional scheme based on years of practical experience designing dies from math data.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.com/museum/

To an Engineer, the glass is twice as big as it needs to be.