NX5 Sheet Metal - Outside Mold Line Display
NX5 Sheet Metal - Outside Mold Line Display
(OP)
I'm working with a group migrating from Ideas to NX5 (5.0.6.3 specifically). I've been presented with the existing work flow and drawings and I'm trying to re-create them in NX. The attached PDF shows a current drawing. Basically showing the flat pattern fully dimensioned with Bend CL's and OML's. These OML's are sketched in the viewport then hidden after dimensions added in Ideas.
My thoughts on this were to have NX show the outer mold lines that could be dimensioned in drafting. This would eliminate the sketching in the views. My issue is that I cannot seem to get the outer mold lines to show. In Pref > Sheetmetal - I have the Outer Mold lines turned on (also in the drafting view). <see attached .prt files>
A note that states how I got my flat pattern with either the K-factor (or Neutral Factor Value) or the calculated bend deduction should be enough for the vendor to build the part accurately based on the flat pattern & formed part.
The other question, of course, is how useful is the flat pattern to the sheet metal vendor? It shows the vendor the thought process and how you got to the end formed part but in the end, all I want is the formed part to be accurate.
Thanks in advance for your input,
Matt
My thoughts on this were to have NX show the outer mold lines that could be dimensioned in drafting. This would eliminate the sketching in the views. My issue is that I cannot seem to get the outer mold lines to show. In Pref > Sheetmetal - I have the Outer Mold lines turned on (also in the drafting view). <see attached .prt files>
A note that states how I got my flat pattern with either the K-factor (or Neutral Factor Value) or the calculated bend deduction should be enough for the vendor to build the part accurately based on the flat pattern & formed part.
The other question, of course, is how useful is the flat pattern to the sheet metal vendor? It shows the vendor the thought process and how you got to the end formed part but in the end, all I want is the formed part to be accurate.
Thanks in advance for your input,
Matt





RE: NX5 Sheet Metal - Outside Mold Line Display
Yes you can make a flat pattern in NX. You need an "NX Sheet metal" license to do so at the very least. There is an advanced sheet metal license at extra cost that contains a capability for much the same thing as a set of curves that may require less preparatory modelling, and which I actually prefer. If all you make are flat patterns then you might want to at least request a demo of it from your local sales guys.
Are flat patterns useful. Yes of course. The manufacturing shop generally needs the profile to cut and where to bend the part. We generally provide them with a DXF for the profile and dimensions to the bend centrelines shown on the drawings. We also dimension inside bend radii on separate views and sections as required. For straight up and down sheet metal that is I think about as much as anyone needs.
If the shape and design involve variable angles blends around curved profiles, (aircraft fuselage and wing sections typically have a lot of those), then you probably will need the advanced sheet metal. At that level of complexity you'll need tooling for the job, require accurate flat patterns and may describe the flange lengths a little differently in more detail on the drawing.
Some of the information that may have been carried on older drawings shouldn't be necessary in today's environment. The calculation of bend allowance neutral axis value etc may have been a cross check for those developing flat patterns manually. These days that information is contained/embedded within the CAD file and the development is 100% as reliable as you can ever make it, (obviously some very complex forming notwithstanding). So you could show less of that on the drawing. Instead I'd keep it simple clear and uncluttered to make it easier to read if anything and avoid OML's if they aren't going to be used in the bending shop.
Best Regards
Hudson
www.jamb.com.au
Nil Desperandum illegitimi non carborundum
RE: NX5 Sheet Metal - Outside Mold Line Display
Looking at your parts, I can't see what the 'problems' are. The drawings look just like I would have expected them to be.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: NX5 Sheet Metal - Outside Mold Line Display
The "problem" per se is that i'd like to see the Outer (or Inner) Mold lines on the flat pattern. I cycle through the flat pattern display to see what NX means and will display for Bend Center, Joggle, Interior, etc. When I have Inner or Outer Mold selected and Bend Tangent off, I don't have any lines displayed where I would expect them. If I wanted to dimension to the mold lines I have no way to see them and therefore I can't dimension to them.
What should I see for Inner (Outer) Mold lines in the flat pattern display?
I agree with Hudson that the flat pattern on the drawing is not needed in todays world. I tend to keep it simple and only dimension the formed part. I'll show a flat pattern as reference only on complicated bends to show what I was thinking when I developed the part.
Matt
RE: NX5 Sheet Metal - Outside Mold Line Display
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: NX5 Sheet Metal - Outside Mold Line Display
I change flat pattern preferenes to bend CL & tangent lines (slide 1) and I see them. When I turn off bend tangent lines and select inner or outer mold lines I see only the bend CL.
The attached shots are from the flat pattern in the model.
Thank you,
Matt
RE: NX5 Sheet Metal - Outside Mold Line Display
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: NX5 Sheet Metal - Outside Mold Line Display
What you're actually displaying is what most people usually display which is the Bend Centre and Bend Tangent lines.
I have created as you should a very simple example of a flat pattern. If you look at the attached PDF then you'll see that I've made a quick and dirty over dimensioned drawing that analyses everything about what is being produced in the flat pattern. The boxed dimensions for the purposes of this exercise are shown as such to indicate dimensions that wouldn't ordinarily appear on the drawing.
I would ordinarily show the left hand (or central) flat pattern view dimensioned pretty much as shown here. You need it because with bend allowance the overall length and 23 dimensions aren't shown elsewhere. So the workshop would otherwise have to make a calculation that they could get wrong.
As I said we'd often supply a DXF to cut the flat pattern profile to but that still need to know where the bends fall and the bend allowance calculation that determines it is something we prefer to take from CAD.
You might also want to change the settings in your customer defaults so that the changes you've made to the flat pattern display are set permanently.
Also
The right hand flat pattern view is the same as the left one except that I suggested a way of showing and changing the standard annotations to something I thing many would find more suitable. What I'm showing is something based on an older Aircraft style standard annotation which you might like to adopt since the system supports it quite nicely.
Best Regards
Hudson
www.jamb.com.au
Nil Desperandum illegitimi non carborundum