Adapt sketch when material is folded

Anonymous · ‎02-23-2017

Hi,

Can anyone tell me if it is possible to adapt the sketch whet your part is already folded? For example is it possible to adapt the width between the two folds directly up to 30 mm? Whether to unfold again, adapt the sketch and see if it is OK (trial and error)?

Thanks!

WHolzwarth · ‎02-23-2017

You can add the difference between 30mm and your measurement manually to the bottom face.

But better way is using a contour flange. Change happens in a hurry.

Walter

Walter Holzwarth

TheCADWhisperer · ‎02-23-2017

Can you attach your *.ipt file here so that someone can demonstrate the correct technique?

Anonymous · ‎02-23-2017

Sure,

Here it is.

The intention is not to go to the base sketch, but adapting the distance in the fold situation.. this is a simple example, but there are some more complex examples i.e. when starting from an imported complex DXF.

Regards,

Bart

TheCADWhisperer · ‎02-23-2017

@Anonymous wrote:

..... this is a simple example, but there are some more complex examples i.e. when starting from an imported complex DXF..

Can you attach one of these "complicated" dxf files here?

I suspect that you are going about sheet metal design all wrong. None of the dimensions on the part that you attached (2010 version) make logical sense.

In modern MCAD programs you model the sheet metal in finished form (that is what the customer pays for).

Are you familiar with terms bend allowance, bend deduction, k-factor?

Anonymous · ‎02-24-2017

Hi, thanks for your answers.

I'm indeed not an expert in sheetmetal drawing.

I received a DXF file from an unfolded piece (see picture and DXF in attachment).

In the DXF you can also see the view from above in the folded situation: these dimensions needs to be achieved. However, when I make a 3d file from the flattened piece, the dimensions of this view from above are not corresponding to the ones on the DXF due to bending rules. Therefor, I will need to make some adaptations on the flattened DXF. I was wondering what is the best way to do this in order not to mess up the DXF (place of holes and cuts), and not to calculate manually the dimensions needed for the flattened DXF. Also, the small 'flaps' also need to be bend.. but I have also problems because there is no small cut foreseen in the corners (see also picture). So I will aslo need to adapt this on the DXF..

I hope this is a bit clear as my English is also not perfect.

Thanks in advance for the help!

Thomas_Savage · ‎02-24-2017

Hello,

Can you ask the person who sent you the DXF what K-Factor, Bend allowance and Bend radius they used? Then you can apply them to the sheet metal defaults. And then bend it in inventor. And should achieve the sizes.

Thanks,

Thomas

Thomas Savage

Design Engineer

Anonymous · ‎02-24-2017

Ok thank you a lot for the help,

I will try some values as I'm not in direct contact with them at the moment. How about the small flaps? Do I have to make some small cuts in the DXF in order to achieve the 3 bends in the corner?

thanks again

Thomas_Savage · ‎02-24-2017

Hello,

Do you mean these 3 flaps? Attached as a screenshot.

Thomas

Thomas Savage

Design Engineer

WHolzwarth · ‎02-24-2017

This DXF looks strange to me.

Most dimensions with many digits, and I wouldn't trust in drawn sheet metal thickness

Walter Holzwarth

Thomas_Savage · ‎02-24-2017

Hello,

Yeah I thought the sizes were weird as well. The thickness is 2.9633. Which doesn't make sense. Who ever draw it up has obviously done it wrong.

Thomas

Thomas Savage

Design Engineer

Anonymous · ‎02-24-2017

Yes, I mean those 3 flaps 🙂

Thickness should be 3mm

Anonymous · ‎02-24-2017

In attachment a DWG and another DXF, maybe these are better?

Thomas_Savage · ‎02-24-2017

Hello,

Yeah put a bigger cut in, else it will not bend properly. It will clash when bending the rest of it.

Because it doesn't go past the radius. I will show you a close up.

Thomas

Thomas Savage

Design Engineer

Thomas_Savage · ‎02-24-2017

Hello,

I am on a computer with an older version of AutoCAD so can't open that other DXF at the moment. But when I get home I will have a look.

Thomas

Thomas Savage

Design Engineer

Thomas_Savage · ‎02-24-2017

Hello,

If you put a cut in it, go past the radius like in the screenshot attached.

Else it will not bend properly.

Thomas

Thomas Savage

Design Engineer

WHolzwarth · ‎02-24-2017

Second DXF was empty, DWG had contents.

But DWG showed, that flat pattern only used the length values of the outer faces.

You can get this result in Inventor with k-factor and bend radius equal zero. But it's not realistic.

Walter Holzwarth

Anonymous · ‎02-24-2017

Thanks for the help guys!

In attachment maybe better files? I deeded them to copy from a huge DXF file (205Mb)...

Anonymous · ‎02-24-2017

Yes WH,

I also thought that I can not adapt the K-factor and bend radius to achieve this... thus is there a solution?

Thomas_Savage · ‎02-24-2017

Hello,

Like WH said. The flat pattern has the same dimensions as the model. There is no thickness to the flat pattern basically. You need to add 3mm to the outer bends, and 6 mm to the inner. In order to get the right size. And add thickness to the flat pattern. If I was you I would ask whoever gave you the drawings to provide a better drawing.

Thomas

Thomas Savage

Design Engineer