BEND RELIEF ON INTERNAL CUTOUT BEND 4

[aero101]

I am designing sheet metal part, it has an internal cutout with .25 edge flange all around it. Is it ok to create my custom bend relief - picture attached - or should I stick to SW custom relief type in edge flange feature? Those look rather strange for this application and I like that my own custom relief allows me to avoid edge interference without chamfering the flange.
Hope this makes sense. Thank you!

 

[CorBlimeyLimey]

You should use whatever works for the part, but should check with the sheet metal shop whether it can easily produce your design.

 

[MadMango]

I agree with CBL. Remember that premium charges may develop if your vendor is not tooled for it, but might not matter if they water or laser cut your parts.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[MDGroup]

I agree with the others, as long as they are lasering it (not punching) you can make it any style you would like, within reason.

Also, Double Check the flanges you have extending upward. It is hard to tell from the picture, but when you unfold those to the middle they look like they will overlap. You will need to chamfer those edges.

 

[dgowans]

Agreed on checking with your fab shop. Even if the blank will be punched you have some latitude with your relief cuts, provided the cutouts can be made by nibbling the profile with a standard punch. In your example, this is not the case because of the sharp corners that are internal to the bend relief. Adding a radius to these corners might allow your fabricator of choice to make the part without water jet / laser cutting.

 

[applejack2]

aero,

I understand your question but I don't understand the picture. can you post a screen shot from another angle, or unfold it and post the flat?

for the most part I agree with what was already said. custom bend relief is fine but may cost more.

 

[aero101]

thank you all for your input, the shop has laser cutting abilities and wants to keep the relief as small as possible.
I attached another pdf, I changed the approach a bit. I would like to have only a tear type relief approximately as shown with red lines but only am able to achieve whats on the pdf. Here is the problem - 1/ if edge flange is just one feature for both edges (I am mirroring the other 2) - I am unable to change sketch of the second edge. 2/ if edge flange of the second edge is a new edge flange in design tree, it is not created from the corner but offseted by .075 as you see on the attached pdf
is there any way, I can achieve simple tear for the model as shown with red lines?
thank you again

 

[CorBlimeyLimey]

Have you tried using the Mitre Flange?

 

[MDGroup]

If you already know what you want the reliefs to look like, you can start by sketching the entire flat pattern with those reliefs. Then fold up each of the flanges.
This method allows you to design the reliefs and then the material flows however it wants when the flanges are bent.
Currently, you are doing the opposite, creating the flanges straight and getting the 'default' reliefs; which you aren't satisfied with.

See attached images.

 

[aero101]

MDGroup - thanks for the idea! What are the proper steps to do it right? I edited the sketch in base flange but I have a feeling it's not way to do it.

CorBlimeyLimey - - I have tried that, but it wont let me unfold the miter flange.

Thank you again

 

[CorBlimeyLimey]

"I have tried that, but it wont let me unfold the miter flange."

That's strange. When you say "unfold" do you mean Flatten ... there is a big difference where SW is concerned.

Can you post the part (or a similar test part) where the Mitre Flange will not flatten?

 

[applejack2]

maybe I'm not seeing it correctly, but it looks to me like it will interfere when you try to flatten it.

see my attached example.

 

[CorBlimeyLimey]

applejack2 ... the images posted by aero are showing the flattened/unfolded state.

 

[applejack2]

CBL, I see it now.

Aero, I would run the bend relief cutout past the material that is going to be formed.

 

[DiegoLGraves]

For a specific shape of relief, add your flanges, hems, miter flanges, or whatever with one of the standard relief options. Then add a sheetmetal unfold feature, start a new sketch and cut the reliefs the way you want them. You can often use convert entities for part of the sketch. Then add a fold feature. Check how it appears in the flat pattern configuration and in the dxf export for your laser machines. Sometimes the export to dxf contains extra junk that needs to get cleaned up before nesting.

Hope this helps. Diego

 

[MDGroup]

Aero,
Attached is the SW file I used. It isn't the most straight-forward approach, but gets the results you are looking for.
Instead of 'Edge Flanges' it uses the 'Sketch Bend' Command.

You can also consider what Diego mentioned. After the reliefs are made, you can alway go back in and do an extrude to 'fill in' the parts of the extrude that you don't want.

Good Luck.

 

[aero101]

thanks again everybody for your very valuable input, this was a great lesson for me
CorBlimeyLimey -
for reference i am attaching my unsuccesful miter flange attempt