topic Re: Variable width living hinge pattern in sketch? in Fusion Support Forum

Variable width living hinge pattern in sketch?

martin_s_andersen — Fri, 17 Feb 2023 23:46:41 GMT

Hi All,

I'm currently experimenting with living hinges in various laser cutting designs. I would like to make a living hinge pattern that expands or varies in width depending on the sketch elements. It seems like it should be relatively simple to do in a sort of parametric pattern, but I'm struggling with how to do it in Fusion360. I've made a simple example for this post. I would like to make a simple living hinge pattern where the width of the individual lines in the sketch expands/varies depending on the contour of the part. I've attached photos. I would like to make so the horizontal cuts of the living hinge are equal length (per row), but each row width can vary. I know I can 'brute force' it by manually constraining each row, but I figured there could be a smarter way?

Hope you're able to help or point me in some direction, thank you!

Re: Variable width living hinge pattern in sketch?

johnsonshiue — Sat, 18 Feb 2023 03:03:17 GMT

Hi! I believe you are talking about Fill Pattern. Essentially, the selected geometry will be populated within a selected boundary. At the moment, Fusion does not have the ability to do that. I have heard some internal discussion about it.

Many thanks!

Re: Variable width living hinge pattern in sketch?

martin_s_andersen — Sat, 18 Feb 2023 11:42:02 GMT

I see, thanks for the answer. Fill pattern seems as something that would be useful in this case. Is there a way to get around it? Pattern individual lines with constraints or something similar?

Re: Variable width living hinge pattern in sketch?

TheCADWhisperer — Sat, 18 Feb 2023 11:56:02 GMT

@martin_s_andersen wrote:
It seems like it should be relatively simple to do in a sort of parametric pattern,…

I know I can 'brute force' it by manually constraining each row, but I figured there could be a smarter way?

It appears to me that you are attempting to use a sketch pattern where a feature pattern would be more appropriate.

@martin_s_andersen
Can you Attach two simple “brute force” examples to illustrate your true Design Intent.

I suspect this is a typical use of Sketch/Feature Parameters in any parametric MCAD software.

Re: Variable width living hinge pattern in sketch?

martin_s_andersen — Sat, 18 Feb 2023 13:05:13 GMT

Yes. I'll try to explain from this example. So I'm attempting to make a straight line based living hinge on a not square part. I would like to have all lines in the same row to be of equal length, but as the part expands in width each row will be of different width, and therefore the lines width on each row will be different (but equal to each other within the same row). Essentially I would like a pattern like this to repeat downwards where the lines width automatically adjust compared to the width of the part in the specific row.

You can see my brute force way of constraining it here. I would like to keep the gap between the lines constant and also the distance between rows (these are controlled by user parameters):

And ideally I would like the pattern to repeat over the entire part here so it acts like a living hinge:

Does this clarify my design intent? It is for laser cutting, so I really only need the lines, which is why I have been using the sketch mode. Should I make it a thin extrude instead, and pattern the feature? How would that work?

Re: Variable width living hinge pattern in sketch?

martin_s_andersen — Sat, 18 Feb 2023 16:54:38 GMT

I spent the last few hours filling it out the 'manual way' but with an angled pattern instead of horizontal. Ideally I would like to be able to create this pattern from a few variables:

Angle, Gap between lines horizontal, Gap between lines vertical, number of rows, cutting overlap (at ends).

I would look at it like a parametric programming problem essentially and I am searching for a way to do it smartly in fusion360. I can do it manually, sure, which works fine if I only have to do it once. But for every following iteration this would be a pain to update with all the constraints and dimensions you can see here.

Re: Variable width living hinge pattern in sketch?

TheCADWhisperer — Sat, 18 Feb 2023 16:57:21 GMT

@martin_s_andersen

Can you File>Export your *.f3d files to your local drive and then Attach it here to a Reply?

Re: Variable width living hinge pattern in sketch?

martin_s_andersen — Sat, 18 Feb 2023 17:09:16 GMT

@TheCADWhisperer Sure, it is attached here. It is sketch 5 I have shown in this post.

Re: Variable width living hinge pattern in sketch?

TheCADWhisperer — Tue, 21 Feb 2023 13:05:07 GMT

@martin_s_andersen

Bump.

I have been busy and forgot about this one.

Hopefully someone will jump in here.

I am confident there is an easier technique.

For one thing - I would not likely have any repeated dimensions if it were my design.

It sounds like you need ONLY lines for the laser, not 3D geometry - in which case I have to wonder if Fusion 360 is the appropriate tool for the job.

Re: Variable width living hinge pattern in sketch?

martin_s_andersen — Thu, 23 Feb 2023 11:26:44 GMT

Thanks for bumping. I hope some has an answer.

For this specific example no, 3D design is not needed. But this is part of a bigger 3D piece, where this pattern forms a swirl structure, and I therefore need this to follow the same dimensions as the swirl in Fusion. But maybe another program is better, as long as I then remember to transfer the correct dimensions of the part from Fusion.

We'll see what others come with. Thanks for your answers so far @TheCADWhisperer

Re: Variable width living hinge pattern in sketch?

TrippyLighting — Thu, 23 Feb 2023 14:04:28 GMT

I can do this fairly simply with some minor compromises without resorting to excessive sketching.

However, looking through the file I can see several different geometries. What is your final desired shape ?

Re: Variable width living hinge pattern in sketch?

TrippyLighting — Thu, 23 Feb 2023 15:34:03 GMT

Here is one approach that requires a lot less sketching and updates quickly and properly to parameter changes.