topic Re: Sheet metal problem, bend lines going too far in Fusion Design, Validate & Document Forum

Sheet metal problem, bend lines going too far

Anonymous — Mon, 17 Jun 2019 13:18:21 GMT

Afternoon

I am doing some sheet metal work and i am working from a sketch, after turning my sketch into a body (Flange command) and drawing lines so i can use the bend command i get the problem shown in the picture bellow. My bend line is only to the corner but the bend carry's on past that and starts to bend the section next to it.

How would you suggest how to fix it? i have also gone down the route of making flanges and not using the bend command but for this job using a whole sketch and bending it seems to work better for my angles (This is a chute and will be at a angle, fusion is treating it as a flat so when it's angled in its normal angle the sides will be at the wrong angle)

Even if i take the corner out with a circle on the sketch it still bends the next piece to it past the bend line.

Any advice would be appreciated, thanks.

Re: Sheet metal problem, bend lines going too far

TheCADWhisperer — Mon, 17 Jun 2019 13:40:41 GMT

@Anonymous wrote:
Any advice would be appreciated, thanks.

File>Export and then Attach your best attempt *.f3d here (you can wack and hack using standard tools if necessary just to get it as close as possible to the true Design Intent). Once I understand the Intent - I can present possible solutions.

In general - I am only interested in Finished Form dimensions, so it is very unlikely that my "solution" would make use of any Bend features.

Re: Sheet metal problem, bend lines going too far

Anonymous — Mon, 17 Jun 2019 14:02:08 GMT

Hi, thanks for getting back to me.

I would like the triangle sides bent at 90 degrees and the smaller rear tab to be bent at 80 degrees across the lines but the corners keep conflicting.

Hopefully you can help and i can learn something, Cheers.

Re: Sheet metal problem, bend lines going too far

TheCADWhisperer — Mon, 17 Jun 2019 14:46:51 GMT

Your Sketch 1 is not fully defined?

No solid geometry?

Can you hand sketch your design intent?

What are the dimensions when placed in the assembly?

I have little interest in flat pattern dimensions as those are all a fudge due to Bend Allowance.

(Material stretches on the outside of a bend and compresses on the inside of a bend.)

Attached is my wild guess.

Re: Sheet metal problem, bend lines going too far

Anonymous — Mon, 17 Jun 2019 14:55:37 GMT

No i understand i haven't made it very easy for you in the first sketch.

With this one i have folded the sides with a "Bend line position" of "start" to give me my desired external dimension of 210mm at the end but as you can see i can not bend the small section at the back as the corners conflict.

I've attached a screen shot of the bend i would like to do to finish but the error rightly says they would self-intersect.

Re: Sheet metal problem, bend lines going too far

Anonymous — Mon, 17 Jun 2019 15:04:06 GMT

That is exactly what i wanted, thank you. I will go over the timeline and see how its done.

Edit - Looking at the timeline i was way off the mark

Re: Sheet metal problem, bend lines going too far

chrisplyler — Mon, 17 Jun 2019 15:07:35 GMT

@TheCADWhisperer wrote:

I have little interest in flat pattern dimensions as those are all a fudge due to Bend Allowance.

More accurately/specifically, Bend Deduction. If you subtract the Bend Deduction out from the desired dimension, and place your bend lines appropriately, the finished, bent body will come out as desired.

PS - When are you coming to Texas? Hope I'm still alive to get my doughnuts.

Re: Sheet metal problem, bend lines going too far

TheCADWhisperer — Mon, 17 Jun 2019 15:28:27 GMT

@chrisplyler wrote:
PS - When are you coming to Texas? Hope I'm still alive to get my doughnuts.

No plans in near future for me to head that way.

Re: Sheet metal problem, bend lines going too far

TheCADWhisperer — Mon, 17 Jun 2019 15:30:19 GMT

@Anonymous wrote:
Edit - Looking at the timeline i was way off the mark

You will note that I started with finished form and worked backwards to Flat Pattern.